Progress 02/10/14 to 03/13/18
Outputs
Progress Report Objectives (from AD-416): The overall goal of this project is to develop sustainable management systems to improve the productivity and sustainability of cacao (Theobroma cacao L) cultivation. To accomplish this goal the following objectives will be addressed Objective 1: Identify cacao genotypes with superior ability for establishment under conditions of environmental stress. [NP 301, C1, PS 1A] Sub-objective 1A: Evaluate and identify cacao genotypes with superior tolerance to soil acidity. Sub-objective 1B: Determine key physiological and growth responses of selected cacao genotypes under different levels of irradiance (shade). Sub-objective 1C: Evaluate and identify selected cacao genotypes with superior drought tolerance. Objective 2: Characterize and manage soil nutritional components essential for optimal cacao yields. [NP 305, C1, PS 1C] Sub-objective 2A: Determine the residual effects of cover crops with and without NPK fertilizers on production potentials and bean quality. Sub-objective 2B: Determine the effectiveness of controlled release fertilizer formulations on improving growth, production, and cocoa bean quality of selected cacao genotypes grown in specific soil types. Sub-objective 2C: Determine optimum concentrations and nutrient use efficiencies of macro and micro-nutrients in selected cacao genotypes. Objective 3: Develop environmentally sustainable cacao management systems that improve soil quality and yield. [NP 305, C1, PS1C] Sub-objective 3A: Integrate improved canopy management, phytosanitation, and other management practices into cacao field experiments to evaluate their combined effect on yield. Sub-objective 3B: Develop an improved cacao rejuvenation system that integrates improved management practices and evaluates its effect on cacao yield. Approach (from AD-416): The major emphasis of this project is to identify cacao genotypes tolerant to abiotic stresses (drought, infertile acidic soils, and high/ low irradiance) and develop sustainable management systems to improve their productivity and bean quality. The residual effects of cover crop cultivation and improved management systems (agroforestry planting, high density planting, fertilization, sanitary and phyto-sanitary practices) on the changes of soil quality parameters (physical, chemical, biological) and bean yield and quality will also be determined. Nutrient use efficiency of macro-micronutrients of elite cacao genotypes and cover crops at various abiotic stresses and management systems will be evaluated. Enhanced nutrient use efficiency and sustainable high productivity of cacao will be achieved through improved management practices. To achieve these objectives we have established collaborative research programs under specific cooperative agreements with government and non-government organizations (NGO) and national and international agricultural universities in cacao growing regions of Peru, Brazil, and Ecuador, and the University of Florida at Fort Pierce as well as the USDA ARS in Puerto Rico to establish controlled studies in greenhouses and large scale field trials. University of Reading (UR), UK will be collaborating on abiotic stress assessment. Cacao genotypes with superior ability for establishment under abiotic stresses will be identified and incorporated in cacao improvement programs. Improved management systems will be developed, based on the results of this research, to enhance cacao yield potentials and bean quality and further improve soil fertility and halt the further soil degradation. This is the final report for Project 8042-21000-278-00D, which was terminated as directed by the January 31, 2018 PDRAM and this project has been replaced by the new NP301 Project 8042-21000-281-00D. Substantial progress was made over the four-year period on all three objectives and their sub objectives. Objective 1 and Subobjectives 1A, B, and C, fall under National Program 301, Plant Genetic Resources, Genomic, and Genetic Improvement Component 1. Crop genetic improvement and Objective 2 and Sub objectives 2A, B and C and Objective 3 and Subobjectives 3A and B, fall under National Program 305 Crop Production, Component 1. Integrated Sustainable Crop Production Systems. Collaborative research was undertaken with scientists from the State University of Santa Cruz (UESC), and Cacao Research Institute (CEPLAC/ CEPEC) Bahia, Brazil in a funded agreement to assess the cacao genotypic response to abiotic stresses (drought, light, elemental toxicities and deficiencies) and to evaluate the effects of the �cabruca� cacao agroforestry management systems on soil quality factors. Significant progress was made in the evaluation of cacao genotypes and their response to toxic levels of cadmium. Growth, physiology and molecular responses, and leaf anthocyanin contents of cacao in response to light was also evaluated, as well as the effect of drought and flooding responses of different cacao genotypes (Objective 1A, B, C). Drought affects the growth and development of roots, and shoots and root volume was identified as the growth variable most influenced by drought (Objective 1C). Drought also reduced biomass accumulations and leaf area. Flooding reduced photo synthesises and macro-micronutrient content and flooding susceptible clones showed lower chlorophyll content and increased activity of peroxidases and polyphenol oxidases. At Beltsville, Maryland, significant progress was made in the evaluation of cacao genotypes and how they respond to deficit and adequate levels of macro-micronutrients (Sub-objective 1A, B and C). Intra specific differences were observed in cacao genotypes for use efficiency of nitrogen, potassium, iron, zinc and copper. Toxic levels of cadmium in the growth medium reduced photosynthesis, and led to irreversible damage to cellular and root ultrastructure and consequently affected the growth and development of cacao (Objective 1A, and 2C). In Bahia, Brazil 15 long-term cacao agroforestry management systems were evaluated for their effects on soil quality parameters. Cacao agroforestry systems accumulated high organic carbon in the soil, suggesting a potential benefit in mitigation of greenhouse gases. In highly weathered soils under agroforestry system, the main mechanisms of carbon stabilization appear to be physical protection within macro aggregates thereby minimizing the impact of converting forest to cacao agroforestry systems. Agroforestry based cacao cropping systems affected the mineral composition of dry cacao beans. Variations in the mineral content of manganese, iron, zinc, copper, cadmium and barium in cacao beans were influenced by the cropping sites and in some sites, cadmium contents were higher than the limit set by the European Union (Objective 2C and Objective 3A). Collaborative research was undertaken with scientists from the Tropical Crop Research Institute (ICT) in Tarapoto, Peru and National University of Agraria La Molina (UNALM) Lima, Peru under a funded agreement to develop sustainable production systems for tropical tree crops and assess cacao germplasm to improve cacao sustainability under various abiotic stresses. At ICT Tarapoto, Peru a clonal garden has been established to evaluate wild cacao accessions collected from the Amazon River basins of Peru and Common Fund for Commodities (CFC) clones from the University of Reading, United Kingdom. Substantial progress was made toward Objectives 1.A, B, and C to assess the performance of cacao varieties or genotypes collected from various Peruvian river basins, along with national and international cacao genotypes to abiotic stresses (drought, and soil acidity). Intraspecific differences in wild and domesticated cacao were observed in response to drought and light quality. Various plant traits such as growth, and physiology were recorded and shoot samples were analyzed for macro-micronutrient content to evaluate nutrient use efficiency of cacao accessions under abiotic stresses. In another study, leaves and beans of cacao were collected from 70 farms in northern and central regions of Peru that had been exposed to a varying range of heavy metal concentrations cadmium, chromium, copper, iron, manganese, nickel, lead and zinc. The results show a large variation in the accumulations of heavy metals. From these observations, it appears that it may be possible to select for low heavy metal accumulating cacao genotypes, which would be useful in crop improvement programs. Furthermore, heavy metal content of soils from northern, central and southern cacao growing regions of Peru were evaluated with soils from the northern region having toxic levels of cadmium and it was observed that in general soils pH, and percent clay and magnesium content had a high degree of correlation to soil heavy metal content. Two long-term cacao management studies were established in ICT Tarapoto, Peru in an area originally inhabited by 30 years old native secondary forest (SF). The two agroforestry systems adapted were: improved natural agroforestry system (INAS) where trees without economic value were selectively removed to provide 50% shade and improved traditional agroforestry system (ITAS) where all native trees were cut and burnt in the location. Yield data were collected to assess the yielding ability of various cacao genotypes grown under these two management systems and in areas previously grown with cover crops (Objective 2A, Objective 3A). The overall improvement of soil organic matter (SOM) and soil nutrient status was much higher in the ITAS than INAS. The levels of physical and chemical properties of soil under cacao genotypes showed a marked difference in both systems. In collaborations with ARS scientists in Beltsville, Maryland, the effects of long-term cacao genotypes management and the influence of cover crops on soil biological quality factors were analyzed. (Objective 2A, Objective 3A) Soil microbial community structure under cacao was affected by soil chemistry, agroforestry management system, and cover cropping. The success of sustainable cacao production systems in the Peruvian Amazon areas is dependent on the proper management of the physical and chemical properties of these soils. Long-term field studies continue to evaluate cacao genotypic performance for growth, diseases, insect intensities, and yield under different agroforestry systems. Improved canopy management and phytosanitory practices have been implemented on these field experiments (Objective 3A). Significant progress was made in collaborative research undertaken with ARS researchers in Mayaguez, Puerto Rico to assess soil acidity complexes on the performance of different cacao genotypes (Objective 1A). Intra specific differences were observed in cacao accessions for tolerance to soil acidity complexes based on plant growth traits and soil acidity tolerance indexes. Efforts are underway to assess these various soil acidity tolerant cacao accessions for drought. Considerable progress was also made through collaborative research undertaken with scientists from the University of Florida Indian River Research and Education Center (IRREC) Fort Pierce, Florida, under a funded agreement to evaluate nutrient use efficiency of cacao genotypes subjected to abiotic stresses (Objective 1A, B, C). Progress has been made in the understanding of changes in the elemental composition of macro (nitrogen, phosphorus, potassium, calcium, magnesium) and micronutrients (boron, copper, manganese, iron, zinc) of different cacao genotypes subjected to abiotic stresses. Accomplishments 01 Heavy metal accumulations in cacao (Theobroma cacao L.) leaves and cacao beans in the main cacao growing regions of Peru. Cacao in South America is grown on soils that may have high levels of cadmium and cacao plants are efficient in transporting soil cadmium to aerial parts and into cacao beans. Peru is the tenth leading exporters of cacao beans in the world and the accumulation of heavy metals in cacao beans significantly reduces bean quality, which reduces the market value of this crop, drastically affecting the economic well-being of resource poor farmers. An ARS researcher in Beltsville, Maryland, and international collaborators measured the range of heavy metals concentrations (Cadmium, Chromium, Copper, Iron, Manganese, Nickel, Lead, Zinc) in leaves and beans of cacao grown on 70 farms in northern and central regions of Peru. High levels of Cadmium were found in bean and leaf samples of cacao grown in the Amazonas, Piura, San Martin, and Tumbes, regions of Peru. Soil chemical properties and the levels of heavy metals accumulated in this crop are being used to identify methods to monitor and reduce the toxic levels of heavy metals in cacao beans. This information will help Peruvian scientists and farmers avoid areas that are high in cadmium and to screen for cacao germplasm with reduced uptake thereby promoting sustainable cacao production and protecting the market value of Peruvian cacao in the international cacao trade. 02 Impact of drought on morphological, physiological and nutrient use efficiency of elite Cacao genotypes from Bahia-Brazil, Tarapoto-Peru and Puerto Rico-U.S. Worldwide, drought is one of the most limiting factors for cacao growth, development, nutrition and production; further, quantity and distribution of rainfall, have been a major cause of variation in cacao productivity and sustainability in many cacao growing regions. Very little is known about cacao's ability to adapt to short or long duration drought and most of the current cacao germplasm maintained in cacao growing regions has not been screened for drought tolerance. An ARS researcher in Beltsville, Maryland, and international collaborators identified morphological, physiological and nutrient use efficiency of cacao genotypes from Bahia-Brazil, Tarapoto-Peru and Puerto Rico in greenhouses and growth chambers that were effective in separation cacao genotypes with various degrees of drought tolerance. Root volume was identified as the growth variable most influenced by drought. Understanding plant growth, morphology, physiology and nutrient use efficiency influenced by drought can be used to identify cacao genotypes tolerant to drought. These findings will lead to the utilization of drought tolerant cacao genotypes to breed superior cacao cultivars that are resistant to drought thereby enhancing the cacao sustainability in drought prone regions of the world.
Impacts
(N/A)
Publications
- Almeida, A.F., Santos, E.A., Ahnert, D., Branco, M.C., Santos, I.C., Valle, R.R., Baligar, V.C. 2018. Drought tolerance in cacao is mediated by root phenotypic plasticity. PLoS One. 13(2):1-16.
- Arevalo-Hernandez, C.O., Conceicao, P.F., Souza, J.O., Queiroz, P.A., Baligar, V.C. 2017. Variability and correlation of physical attributes of soils cultivated with cacao trees in two climate zones in southern Bahia, Brazil. Agroforestry Systems.
- Romaria, A., Pereira, L.S., Pereira, L.S., Mangabeira, P.A., Souza, J.O., Ahnert, D., Baligar, V.C. 2017. Photosynthetic, antioxidative, molecular and ultrastructural responses of young cacao plants to Cd toxicity in the soil. Ecotoxicology and Environmental Safety.
- Arevalo-Gardini, E., Arevalo-Hernandez, C., Baligar, V.C., He, Z. 2017. Heavy metal accumulations in cacao (Theobroma cacao L.) leaves and cocoa beans grown at three main cacao growing regions of Peru. Science of the Total Environment. 17(2):410-428.
- He, S., Yang, X., He, Z., Baligar, V.C. 2017. Morphological and physiological responses of plants to cadmium toxicity: A review. Pedosphere. 27(3):421�438.
- Buyer, J.S., Baligar, V.C., He, Z., Gardini, E.A. 2017. Soil microbial communities under cacao agroforestry and cover crop systems in Peru. Applied Soil Ecology. 120:273-280.
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Progress 10/01/16 to 09/30/17
Outputs
Progress Report Objectives (from AD-416): The overall goal of this project is to develop sustainable management systems to improve the productivity and sustainability of cacao (Theobroma cacao L) cultivation. To accomplish this goal the following objectives will be addressed Objective 1: Identify cacao genotypes with superior ability for establishment under conditions of environmental stress. [NP 301, C1, PS 1A] Sub-objective 1A: Evaluate and identify cacao genotypes with superior tolerance to soil acidity. Sub-objective 1B: Determine key physiological and growth responses of selected cacao genotypes under different levels of irradiance (shade). Sub-objective 1C: Evaluate and identify selected cacao genotypes with superior drought tolerance. Objective 2: Characterize and manage soil nutritional components essential for optimal cacao yields. [NP 305, C1, PS 1C] Sub-objective 2A: Determine the residual effects of cover crops with and without NPK fertilizers on production potentials and bean quality. Sub-objective 2B: Determine the effectiveness of controlled release fertilizer formulations on improving growth, production, and cocoa bean quality of selected cacao genotypes grown in specific soil types. Sub-objective 2C: Determine optimum concentrations and nutrient use efficiencies of macro and micro-nutrients in selected cacao genotypes. Objective 3: Develop environmentally sustainable cacao management systems that improve soil quality and yield. [NP 305, C1, PS1C] Sub-objective 3A: Integrate improved canopy management, phytosanitation, and other management practices into cacao field experiments to evaluate their combined effect on yield. Sub-objective 3B: Develop an improved cacao rejuvenation system that integrates improved management practices and evaluates its effect on cacao yield. Approach (from AD-416): The major emphasis of this project is to identify cacao genotypes tolerant to abiotic stresses (drought, infertile acidic soils, and high/ low irradiance) and develop sustainable management systems to improve their productivity and bean quality. The residual effects of cover crop cultivation and improved management systems (agroforestry planting, high density planting, fertilization, sanitary and phyto-sanitary practices) on the changes of soil quality parameters (physical, chemical, biological) and bean yield and quality will also be determined. Nutrient use efficiency of macro-micronutrients of elite cacao genotypes and cover crops at various abiotic stresses and management systems will be evaluated. Enhanced nutrient use efficiency and sustainable high productivity of cacao will be achieved through improved management practices. To achieve these objectives we have established collaborative research programs under specific cooperative agreements with government and non-government organizations (NGO) and national and international agricultural universities in cacao growing regions of Peru, Brazil, and Ecuador, and the University of Florida at Fort Pierce as well as the USDA ARS in Puerto Rico to establish controlled studies in greenhouses and large scale field trials. University of Reading (UR), UK will be collaborating on abiotic stress assessment. Cacao genotypes with superior ability for establishment under abiotic stresses will be identified and incorporated in cacao improvement programs. Improved management systems will be developed, based on the results of this research, to enhance cacao yield potentials and bean quality and further improve soil fertility and halt the further soil degradation. Collaborative research was undertaken with scientists from the Tropical Crop Research Institute (ICT) in Tarapoto, Peru and National University of Agraria La Molina (UNALM) Lima, Peru under a funded agreement to develop sustainable production systems for tropical tree crops and assess cacao germplasm to improve cacao sustainability under various abiotic stresses. Progress was made toward Objectives 1.A, B, and C to assess the performances of cacao varieties or genotypes collected from various Peruvian river basins, national and international cacao genotypes to abiotic stresses (drought, soil acidity, and light quality) and soil cadmium toxicity. Various morphological, physiological plant traits have been recorded and plant samples have been submitted for macro- micronutrient analysis. This research is focused around the identification of abiotic stress tolerant genotypes. Progress was made (Objective 2A) to evaluate the effects of 10 years of cover crop residue on cacao genotypes performance and the soil samples have been collected and are being analyzed to evaluate soil quality factors. Substantial progress was made to address Objective 3A through long term field studies that have been established to evaluate cacao genotypic responses to different agroforestry management systems. Data was compiled on soil physical and chemical quality factors. Overall soil nutrient status was much higher in the improved traditional agroforestry system than in improved natural agroforestry systems. Therefore success of sustainable cacao production systems in the Peruvian Amazon areas is dependent on the proper management of the physical and chemical properties of these soils. In collaborations with ARS scientists in Beltsville, Maryland, the effects of long term cacao genotypes management and the influence of cover crops on soil biological quality factors were analyzed. In tropical agroforestry systems microbial community structure was significantly affected by management systems and cover cropping (Objective 3A). Long term field studies continue to evaluate cacao genotypic performance for growth, diseases and insect intensities, and yield under different agroforestry systems. Improved canopy management and phytosanitory practices have been implemented on these field experiments. A clonal garden has been established to evaluate wild cacao accessions collected from the Amazon River basins of Peru and Common Fund for Commodities (CFC) clones from the University of Reading, United Kingdom. Seedlings of different clones are being prepared for field evaluation and green house studies. Studies on heavy metal accumulations in leaves and beans of cacao in major cacao growing regions of Peru was completed. The mean values of heavy metals with the exception of cadmium in leaf and bean samples were below the critical limits; however high levels of cadmium in beans were found in some cacao growing regions of Peru. Collaborative research conducted through a funded agreement was undertaken with scientists from the State University of Santa Cruz (UESC), and Cacao Research Institute (CEPLAC/CEPEC) Bahia, Brazil to assess the cacao genotypic response to abiotic stresses (drought, light, elemental toxicities and deficiencies) and to evaluate the effects of the cabruca cacao agroforestry management systems on soil quality factors. Progress was made in the evaluation of cacao genotypes response to (1) flooding under low light intensities, (2) soil potassium levels, (3) drought and (4) toxic levels of cadmium (Objective 1A, B, C). Morphological and physiological plant traits and root plasticity were evaluated. The root volume was the growth variable most influenced by the change in water regime. Cacao quality index and biochemical attributes of cacao beans were evaluated from different agroecosystems. Cacao quality indexes and biochemical attributes of cacao beans were evaluated from different agroecosystems and the cacao system that utilized rubber as the shade tree on Latosol Red-Yellow soil showed the best quality characteristics in dry cacao beans. (Objective 3A). Substantial progress has been made to address Objective 1A in collaborations with ARS researchers in Mayaguez, Puerto Rico to assess soil acidity complexes on the performance of different cacao genotypes. The third year of a field study was completed and data was collected on plant growth traits and soil acidity tolerance indexes to assess the range of tolerance among the tested cacao genotypes. Plant and soil samples have been submitted to determine the chemical composition. Further progress was made studying the response of cacao genotypes from South America and Puerto Rico to abiotic stresses such as drought, low light, and elevated carbon dioxide. A growth chamber study with two cacao genotypes (Hybrid 27-1420, Amelonado) from Puerto Rico differing in acid soil tolerance were evaluated for their response (growth, physiology and biochemical) to adequate and deficit soil moisture levels. Plant samples were prepared for determination of nutrient composition. In collaborations with the Adaptive Cropping System Laboratory at Beltsville, Maryland, metabolites compositions in cacao leaf samples were completed. Water and nutrient use efficiency, drought tolerance indexes, growth and physiological parameters are being determined. To achieve sustainably high yielding cacao production it is essential to understand the nutrient status of plants subjected to abiotic stresses under different management systems. Changes to soil quality factors under different cacao management systems are critical to correct soil fertility limitations and to formulation of fertilizer management practices. Considerable progress was made though collaborative research undertaken with scientists from the University of Florida Indian River Research and Education Center (IRREC) Fort Pierce, Florida, under a funded agreement to evaluate nutrient use efficiency of cacao genotypes subjected to abiotic stresses (Objective 1). Changes in the elemental composition of macro (nitrogen, phosphorus, potassium, calcium, magnesium) and micronutrients (boron, copper, manganese, iron, zinc) of different cacao genotypes are being analyzed as a response to deficit soil moisture levels. Accomplishments 01 Ambient and elevated carbon dioxide and low light on growth, physiological and nutrient uptake parameters of perennial tropical leguminous cover crops. In the tropics, soil degradation is a major cause of poor plantation crop establishment and low productivity. Inclusions of quick growing legume cover crops during the early establishment of tropical plantation crops reduce soil degradation due to erosion and nutrient leaching. Adaptability and optimum growth of cover crops in plantation crops is affected by the inherent nature of the cover crop species and the light intensity at canopy levels. Global concentrations of atmospheric carbon dioxide are increasing and have an implication on crop growth. A better understanding of required light intensity in these changing carbon dioxide levels will help in increasing the success of cover crops utilization in plantation crops. The growth and essential nutrient uptake parameters of five important perennial tropical legume cover crops (Calopo/frisolla, Jack bean, Brazilian Lucerne, Leucaena, and Mucuna) were analyzed and were found to be significantly influenced by light intensity and by the carbon dioxide level. Brazilian Lucerne and Jack bean were more efficient in nutrient use efficiency of nitrogen, potassium, magnesium, copper, iron, and manganese, while Calopo and Leuacena were more efficient in zinc use efficiency and Leucaena was more efficient in potassium use efficiency under elevated carbon dioxide levels. Overall, the total growth parameters measured were significantly influenced by the higher carbon dioxide levels. This information allows farmers, extension specialists and researchers to select the appropriate tropical cover crops to reduce soil degradation and improve soil fertility and crop yields.
Impacts
(N/A)
Publications
- Baligar, V.C., Fageria, N.K. 2017. Nitrogen forms and levels influence on growth and nutrition of cacao. Journal of Plant Nutrition. 40:709-718.
- Baligar, V.C., Elson, M.K., He, Z.L., Li, Y.C., Paiva, A.D., Ahnert, D., Fageria, N.K. 2017. Ambient and elevated carbon dioxide on growth, physiological and nutrient uptake parameters of perennial leguminous cover crops under low light intensities. International Journal of Plant and Soil Science. 15:1-16.
- Nkengafac, N., Baligar, V.C. 2016. Soil physical and chemical properties of cacao farms in the south western region of cameroon. International Journal of Plant and Soil Science. 16:1-10.
- Arevalo-Guardini, E., Cerpa, M., Cernades, L., Baligar, V.C., He, Z. 2016. Heavy metals in soils of cocoa plantation (Theobroma cacao L.). Journal of Applied Ecology. 15:81-89.
- Silva Branco, M.C., Almeida, A.A., Dalmolin, A.C., Ahnert, D., Baligar, V. C. 2017. Influence of low light intensity and soil flooding on cacao physiology. Scientia Horticulturae. 217:243-257.
- Chavez, E., He, Z.L., Stoffella, P., Mylavarapu, R., Li, Y., Baligar, V.C. 2016. Evaluation of soil amendments as a remediation alternative for cadmium contaminated soils under cacao plantations. Environmental Science and Pollution Research. 23:17571-17580.
- Santos, E.A., Almeida, A.A., Ahnert, D., White, M.C., Valle, R.R., Baligar, V.C. 2016. Diallel analysis and growth parameters as selection tools for drought tolerance in young Theobroma cacao plants. PLoS One. doi:10.1371/ journal.pone.0160647.
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Progress 10/01/15 to 09/30/16
Outputs
Progress Report Objectives (from AD-416): The overall goal of this project is to develop sustainable management systems to improve the productivity and sustainability of cacao (Theobroma cacao L) cultivation. To accomplish this goal the following objectives will be addressed Objective 1: Identify cacao genotypes with superior ability for establishment under conditions of environmental stress. [NP 301, C1, PS 1A] Sub-objective 1A: Evaluate and identify cacao genotypes with superior tolerance to soil acidity. Sub-objective 1B: Determine key physiological and growth responses of selected cacao genotypes under different levels of irradiance (shade). Sub-objective 1C: Evaluate and identify selected cacao genotypes with superior drought tolerance. Objective 2: Characterize and manage soil nutritional components essential for optimal cacao yields. [NP 305, C1, PS 1C] Sub-objective 2A: Determine the residual effects of cover crops with and without NPK fertilizers on production potentials and bean quality. Sub-objective 2B: Determine the effectiveness of controlled release fertilizer formulations on improving growth, production, and cocoa bean quality of selected cacao genotypes grown in specific soil types. Sub-objective 2C: Determine optimum concentrations and nutrient use efficiencies of macro and micro-nutrients in selected cacao genotypes. Objective 3: Develop environmentally sustainable cacao management systems that improve soil quality and yield. [NP 305, C1, PS1C] Sub-objective 3A: Integrate improved canopy management, phytosanitation, and other management practices into cacao field experiments to evaluate their combined effect on yield. Sub-objective 3B: Develop an improved cacao rejuvenation system that integrates improved management practices and evaluates its effect on cacao yield. Approach (from AD-416): The major emphasis of this project is to identify cacao genotypes tolerant to abiotic stresses (drought, infertile acidic soils, and high/ low irradiance) and develop sustainable management systems to improve their productivity and bean quality. The residual effects of cover crop cultivation and improved management systems (agroforestry planting, high density planting, fertilization, sanitary and phyto-sanitary practices) on the changes of soil quality parameters (physical, chemical, biological) and bean yield and quality will also be determined. Nutrient use efficiency of macro-micronutrients of elite cacao genotypes and cover crops at various abiotic stresses and management systems will be evaluated. Enhanced nutrient use efficiency and sustainable high productivity of cacao will be achieved through improved management practices. To achieve these objectives we have established collaborative research programs under specific cooperative agreements with government and non-government organizations (NGO) and national and international agricultural universities in cacao growing regions of Peru, Brazil, and Ecuador, and the University of Florida at Fort Pierce as well as the USDA ARS in Puerto Rico to establish controlled studies in greenhouses and large scale field trials. University of Reading (UR), UK will be collaborating on abiotic stress assessment. Cacao genotypes with superior ability for establishment under abiotic stresses will be identified and incorporated in cacao improvement programs. Improved management systems will be developed, based on the results of this research, to enhance cacao yield potentials and bean quality and further improve soil fertility and halt the further soil degradation. In the Andean region of South America increasing abiotic stresses such as drought due to lack of rains, high light due to loss of shade trees and low soil fertility due to soil degradation are severely affecting the sustainable production of cacao and other economically valuable tree crops. Collaborative research was undertaken with scientists from Tropical Crop Research Institute (ICT) in Tarapoto, and National University of Agraria La Molina (UNALM) Lima, Peru under a funded Agreement to develop sustainable production systems for tropical tree crops and assess cacao germplasm to improve cacao sustainability under various abiotic stresses. Progress was made toward Objectives 1.A, B, and C to assess the performances of cacao varieties or genotypes collected from various Peruvian river basins, national and international cacao genotypes to abiotic stresses (drought, soil acidity, and light quality). Various morphological and physiological plant traits have been assessed. Leaf samples have been collected for determination of elemental content. This research will assist in the identification of abiotic stress tolerant genotypes. Progress was made (Objective 2A) to develop a soil fertility study in an area where various cover crops were grown for 10 years and where cover crop residue were incorporated into the soil. Fertilizers have been applied and the soil samples have been collected and are being analyzed for evaluation of soil quality factors. Substantial progress was made to address Objective 2B through a long duration, field experiments to determine the effectiveness of controlled released fertilizer on two systems of cacao production. Experiments were completed and data are being compiled. Substantial progress was made to address Objective 3A through long term field studies that have been established to evaluate cacao genotypic responses to Andean and agroforestry management systems. Soil physical and chemical quality factors of soil samples from the 8th year were completed at the University of Florida, Indian River Research Education Center (IRREC), Fort Pierce, Florida and at the Tropical Crop Research Institute (ICT), Tarapoto, Peru. Surface soil biological components of these soil samples are being assessed at ARS-Sustainable Agricultural Systems Laboratory in Beltsville, Maryland. Diversity of soil fungal communities in this field study was completed. Long range field studies established at ICT, continue to evaluate cacao genotypic performance for growth, diseases and insect intensities, and yield in different agroforestry systems. Improved canopy management and phytosanitory practices have been imposed on these field experiments. In the Atlantic region of Brazil, frequent occurrence of drought, low light quality at the crop canopy level, soil infertility and lack of proper management systems are preventing the development of sustainable high production cacao management systems. Furthermore, a lack of suitable cacao genotypes adapted to various prevailing abiotic stresses is affecting the cacao improvement program for the region. Collaborative research was undertaken with scientists from State University of Santa Cruz (UESC), Brazilian Cacao Research Institute (CEPLAC),and Institute Cabruca, Bahia along with the National Rice and Bean Center of Empresa Brasileira de Pesquisa Agropecu�ria (EMBRAPA), Santo de Antonio, GO, Brazil in a funded Agreement that has been implemented to evaluate the cacao genotypic and cover crop species response to abiotic stresses (drought, light, elemental toxicities and deficiencies) and to evaluate the effects of cacao agroforestry (cabruca) management systems on soil quality factors. Progress was made in the evaluation of leaf pigments on photoinhibition, leaf anthocyanins contents provided no protection against photoinhibition in cacao accessions (Objective 1B). Substantial progress was made (Objective 1C) in using growth parameters (stem diameter and biomass, root biomass and length, total dry biomass) as selection tools for drought tolerance in young cacao plants derived from hybrid crosses of varying drought tolerant cacao accessions. Progress was made (Objective 2C) to evaluate the mineral element composition (essential, non essential, toxic) of dried cacao beans of PH 16 grown under different agroforesty management systems in Bahia Brazil. Influence of soil zinc levels on growth and nutrition of the cacao clone PH 16 in three acidic oxisol soils was completed (Objective 2C). Soil acidity complexes (low pH, deficiency of essential nutrients, toxicities of Mn and Al) are major growth limiting factors for cacao in low fertility soils of the tropics. Substantial progress has been made to address Objective 1A in collaborations with a USDA-ARS scientist from the Tropical Research Station, Mayaguez, Puerto Rico, through the assessment of cacao genotypic responses to soil acidity. The third and final year of a field study to evaluate selected elite cacao genotypic response to varying levels of soil acidity was concluded. In this study, data were collected on plant growth traits such as shoot and roots growth parameters and soil acidity tolerance index to assess the range of tolerance among the tested cacao genotypes. Plant and soil samples are being weighed to determine biomass accumulation and the samples will be further analyzed to determine the chemical composition in various plant tissues. Under Objective 1A and C, scientists at the Beltsville Agricultural Research Center in Beltsville, Maryland are studying the response of cacao genotypes from South America and Puerto Rico to abiotic stresses such as drought, low light, and elevated CO2. A growth chamber study with three cacao genotypes from CEPLAC and UESC Bahia, Brazil differing in drought tolerance were evaluated for their response (growth, physiology and biochemical) to adequate and deficit soil moisture levels. Plant samples were prepared and determination of nutrient composition for macro and micronutrients were completed. In collaborations with Crop Systems Global change Laboratory at Beltsville, Maryland, metabolites compositions in cacao leaf samples were completed. Water and nutrient use efficiency, drought tolerance indexes, growth and physiological parameters are being determined. In collaborations with scientists from Institute of Agriculture Research for Development (IRAD) of Cameroon, soil fertility status assessments for cacao farms from the South-Western region of the country were completed. To achieve sustainably high yielding cacao production it is essential to understand the nutrient status of plants subjected to abiotic stresses under different management systems. Changes to soil quality factors under different cacao management systems are critical to correct soil fertility limitations and to formulation fertilizer management practices. Collaborative research is being undertaken with scientists from the University of Florida Indian River Research and Education Center (IRREC) Fort Pierce, Florida, under a funded agreement. Under Objective 1, 2 and 3 considerable progress was made to evaluate elemental composition of macro (N, P, K, Ca, Mg) and micronutrients (B, Cu, Mn, Fe, Zn) of cacao grown in field and controlled conditions. Furthermore, in this collaboration research evaluations of the cadmium status in soil-plant systems of Southern Ecuador was conducted. Soil samples were collected under selected cacao plantations and were evaluated for various forms of soil cadmium, the levels of Cd in cacao beans and their relationship with soil cadmium levels. Accomplishments 01 Effects of different forms of iron on cacao nutrition and physiology. Cacao is grown on highly weathered acidic infertile Oxisols and Ultisols and in these soils iron (Fe) deficiency is one of the major nutrient responsible for reduction of yields and its sustainability. It is important to select the right source of Fe to improve its stability and availability to cacao in these acidic infertile soils. ARS scientists in Beltsville, Maryland reporting that right sources of iron fertilizers have significant effect on growth, photosynthesis, and nutrient uptake parameters of young cacao plants. Chelated forms of Fe are the best sources of Fe for improving growth, and physiological traits of cacao. This information will be useful in nutrient management to avoid iron nutrient deficiency and for improved sustainable production systems for cacao. Farmers, scientists and extension workers who need to develop improved nutrient management systems for infertile acidic soils will benefit from this research. 02 Long-term agroforestry cacao management systems have effects on soil quality. Slash and burning of native vegetation and planting of cacao is a traditional management system adopted by the farmers of the Peruvian Amazon region which leads to soil degradation and deforestation of native forest flora. For the first time ARS scientists in Beltsville, Maryland, are reporting the impact of long-term improved natural agroforestry systems (INAS) and an improved traditional agroforestry system (ITAS) of cacao management on soil physical and chemical properties in an area planted with different cacao accessions. Our results indicate that management practices have tremendous impact on soil properties. In both systems, soil organic matter, extractable phosphorous and exchangeable cations increased with years of cultivation. Therefore success of sustainable cacao production systems in the Peruvian Amazon is dependent on the proper management of the physical and chemical properties of these soils. Findings of this study will be useful to resource poor cacao farmers of the Amazon region to develop cacao management systems that enhance the fertility and productivity of these soils. 03 Zinc effects on the growth and nutrition of cacao in acidic and infertile tropical soils. Levels of Zn in tropical soils profoundly influence the production potentials and nutrition of tree crops such as cacao. Among the micronutrients, zinc (Zn) is one of the most limiting soil nutrients in Oxisols and Ultisols of South America especially where cacao is grown. ARS scientists in Beltsville, Maryland reporting that the growth and essential mineral nutrient levels in cacao genotypes are influenced by both deficient to excess levels of soil Zn in the acidic soils, and at all of the levels of Zn tested, cacao seedlings showed differences for biomass production and for foliar nutrient concentrations of P, K, Ca, Mg, Mn, Fe, Cu, and Zn. Information gained from this research will be useful to researchers, extension workers and farmers to design Zn fertilization practices and to improve sustainability of highly productive cacao in acidic infertile soils. 04 Cadmium (Cd) in cacao leaves and cacao beans and its relationship to soil Cd levels. Soils under cacao in Ecuador contain high levels of Cd. Cadmium poses a threat to food safety and human and plant health around the world. Plants can tolerate Cd concentration at low levels without showing any symptoms of toxicity, but accumulation of Cd in edible plant parts often causes adverse effects on human health. The range of total and extractable Cd in soil profiles of 19 cacao farms were assessed along with the relationship between soil properties and the soil Cd levels. ARS scientists in Beltsville, Maryland reporting that Cd accumulates in the surface soils (0-15 cm) and that 12 out of the 19 sampled sites exceeded the critical level. The distribution of Cd in cacao plants generally decreased in the order of beans > shell >> leaves. This information will be useful to farmers and traders of cacao beans faced with increased regulations to reduce cadmium contaminations. 05 Chemical speciation of soil cadmium (Cd); an approach to evaluate plant available Cd. Cadmium is one of the most plant-available elements in agricultural soils. Cadmium poses a threat to food safety and human and plant health. However there is no information relating to the forms of soil Cd and there bioavailability to plant and its accumulation in cacao beans. ARS scientists in Beltsville, Maryland used soil chemical analytical methods to identify various available Cd pools in the soils and determined relationship of these Cd pools with bean Cd concentration at several sites in Ecuador. The acid-soluble fraction was more closely related to bean-Cd levels. Such information will help scientists and researchers to select suitable chemical extraction method to identify plant available Cd in soils. This information is also useful to farmers either to avoid such areas for cacao cultivation or to find suitable management practices to reduce Cd bioavailability.
Impacts
(N/A)
Publications
- Chavez, E., He, H.E., Stoffella, P.J., Mylavarapu, R.S., Li, Y.C., Moyano, B., Baligar, V.C. 2015. Concentration of Cadmium in Cacao Beans and its Relationship with Soil Cadmium in Southern Ecuador. Science of the Total Environment. 533:205-214.
- Baligar, V.C., Sicher Jr, R.C., Elson, M.K., He, Z., Fageria, N.K., De Souza, J.J., Almeida, A.F., Ahnert, D. 2015. Iron sources effects on growth, physiological parameters and nutrition of cacao. Journal of Plant Nutrition. 38:1787-1802.
- Arevalo, E., Canto, M., Alegre, J., Loli, O., Julica, A., Baligar, V.C. 2015. Changes in soil physical and chemical properties in long term improved natural and traditional agroforestry management systems of cacao genotypes in Peruvian Amazon. PLoS One. 10(7):1-29.
- He, S., He, Z., Yang, X., Stoffella, P., Baligar, V.C. 2015. Soil biogeochemistry, plant physiology and phytoremediation of cadmium contaminated soils. Advances in Agronomy. 134:134-225.
- Cruz Neto, R.O., Souza Junior, J.O., Sodre, G.A., Baligar, V.C. 2016. Growth and nutrition of cacao seedlings influenced by zinc application in soil. Revista Brasileira de Fruticultura. 37:1053-1064.
- Chavez, E., He, H.E., Stoffella, P.J., Baligar, V.C. 2016. Chemical speciation of cadmium: an approach to evaluate plant-available cadmium in Ecuadorian soils under cacao production. Geoderma. 150:57-62.
- Fageria, N.K., Baligar, V.C. 2016. Growth, yield and yield components of dry bean as influenced by phosphorus in a tropical acid soil. Journal of Plant Nutrition. doi: 10.1080/01904167.2016.1143489.
- Barnaby, J.Y., Fleisher, D.H., Baligar, V.C., Reddy, V., Sicher Jr, R.C. 2015. Effects of CO2 enrichment and drought pretreatment on metabolite responses to water stress and subsequent rehydration using potato tubers from plants grown in sunlit SPAR chambers. Journal of Plant Physiology. 189:126-136.
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Progress 10/01/14 to 09/30/15
Outputs
Progress Report Objectives (from AD-416): The overall goal of this project is to develop sustainable management systems to improve the productivity and sustainability of cacao (Theobroma cacao L) cultivation. To accomplish this goal the following objectives will be addressed Objective 1: Identify cacao genotypes with superior ability for establishment under conditions of environmental stress. [NP 301, C1, PS 1A] Sub-objective 1A: Evaluate and identify cacao genotypes with superior tolerance to soil acidity. Sub-objective 1B: Determine key physiological and growth responses of selected cacao genotypes under different levels of irradiance (shade). Sub-objective 1C: Evaluate and identify selected cacao genotypes with superior drought tolerance. Objective 2: Characterize and manage soil nutritional components essential for optimal cacao yields. [NP 305, C1, PS 1C] Sub-objective 2A: Determine the residual effects of cover crops with and without NPK fertilizers on production potentials and bean quality. Sub-objective 2B: Determine the effectiveness of controlled release fertilizer formulations on improving growth, production, and cocoa bean quality of selected cacao genotypes grown in specific soil types. Sub-objective 2C: Determine optimum concentrations and nutrient use efficiencies of macro and micro-nutrients in selected cacao genotypes. Objective 3: Develop environmentally sustainable cacao management systems that improve soil quality and yield. [NP 305, C1, PS1C] Sub-objective 3A: Integrate improved canopy management, phytosanitation, and other management practices into cacao field experiments to evaluate their combined effect on yield. Sub-objective 3B: Develop an improved cacao rejuvenation system that integrates improved management practices and evaluates its effect on cacao yield. Approach (from AD-416): The major emphasis of this project is to identify cacao genotypes tolerant to abiotic stresses (drought, infertile acidic soils, and high/ low irradiance) and develop sustainable management systems to improve their productivity and bean quality. The residual effects of cover crop cultivation and improved management systems (agroforestry planting, high density planting, fertilization, sanitary and phyto-sanitary practices) on the changes of soil quality parameters (physical, chemical, biological) and bean yield and quality will also be determined. Nutrient use efficiency of macro-micronutrients of elite cacao genotypes and cover crops at various abiotic stresses and management systems will be evaluated. Enhanced nutrient use efficiency and sustainable high productivity of cacao will be achieved through improved management practices. To achieve these objectives we have established collaborative research programs under specific cooperative agreements with government and non-government organizations (NGO) and national and international agricultural universities in cacao growing regions of Peru, Brazil, and Ecuador, and the University of Florida at Fort Pierce as well as the USDA ARS in Puerto Rico to establish controlled studies in greenhouses and large scale field trials. University of Reading (UR), UK will be collaborating on abiotic stress assessment. Cacao genotypes with superior ability for establishment under abiotic stresses will be identified and incorporated in cacao improvement programs. Improved management systems will be developed, based on the results of this research, to enhance cacao yield potentials and bean quality and further improve soil fertility and halt the further soil degradation. Sustainable cacao production in the Andean region of South America is being affected severely by increasing abiotic stresses such as drought due to lack of rains, high light due to loss of shade trees and low fertility of the soil. Collaborative research was undertaken with scientists from Tropical Crop Research Institute (ICT) in Tarapoto, and National University of Agraria La Molina (UNALM) Lima, Peru under a Non Assistance Cooperative Agreement (NACA) to develop sustainable production systems for tropical tree crops and assess germplasm to improve cacao sustainability under various abiotic stresses. Progress was made toward Objectives 1.A, B, and C to assess the performances of cacao varieties or genotypes collected from various Peruvian river basins, national and international cacao genotypes to abiotic stresses (drought, soil acidity, and light quality). This research will assist in the identification of abiotic stress tolerant genotypes. Field experiments were completed at two different plantations that vary in their age, to determine the effectiveness of controlled released fertilizer on cacao production. In both plantations various fertilizers (controlled and regular formulations) did not have any significant effects on yields or on disease intensities. Progress was made (Objective 2A) to evaluate the effects of 10 years of cover crop residue incorporation on the performance of cacao genotypes. Initial soil samples collected from these field studies are being evaluated for soil quality assessments. Substantial progress was made to address Objective 3A through long term field studies that have been established to evaluate cacao genotypic responses to Andean and agroforestry management systems. At the end of the 8th year, soil samples were collected and analyzed for physical, chemical and biological soil quality assessments at ARS-Sustainable Agricultural Systems laboratory (SASL) in Beltsville, Maryland, University of Florida, Indian River Research Education Center (IRREC), Fort Pierce, FL and at the Tropical Crop Research Institute (ICT), Tarapoto, Peru. Field studies established at ICT, continue to evaluate cacao genotypic performance for growth, diseases and insect intensities, and yield. Improved canopy management and phytosanitory practices have been imposed on these field experiments. 305 C1 PS1C 2013-18 & 301 C1 PS1A 2013-17 In the Atlantic region of Brazil, there is a lack of suitable cacao genotypes adapted to various prevailing abiotic stresses and lack of proper management systems are preventing the development of sustainable cacao management systems. Collaborative research under NACA with scientists from State University of Santa Cruz (UESC), Brazilian Cacao Research Institute (CEPLAC),and Institute Cabruca, Bahia along with the National Rice and Bean Center of Empresa Brasileira de Pesquisa Agropecu�ria (EMBRAPA), Santo de Antonio, GO, Brazil has been implemented to evaluate the cacao genotypic and cover crop species response to abiotic stresses (drought, light, elemental toxicities and deficiencies) and the effects of cacao agroforestry management on soil quality factors. Progress was made to understand the role of anthocyanins (Objective 1B) during molecular and morpho-physiological responses to variations in light levels of cacao genotypes with differing anthocyanin contents. Substantial progress under Objective 1C was made to understand plant growth and nutrient uptake that could help to identify drought tolerant cacao genotypes under greenhouse conditions. Drought tolerant genotypes identified in greenhouse study were crossed in a diallel scheme and progenies of these are being evaluated at the Fazenda Juliana farm for their performance. Under Objective 2.A, substantial progress was made to complete the research on cover crop and cacao genotypes response to zinc. 305 C1 PS1C & 301 C1 PS1A Soil acidity complexes (low pH, deficiency of essential nutrients, toxicities of Mn and Al) are major growth limiting factors for cacao in low fertility soils of the tropics. Progress has been made to address Objective 1 in collaborations with a scientist of USDA-ARS Tropical Research Station, Mayaguez, Puerto Rico, through the assessment of cacao genotypic responses to soil acidity. The third year of a field study is being concluded to evaluate selected elite cacao genotypic response to varying levels of soil acidity. In this study, data is being collected on plant growth traits such as shoot and roots growth parameters and soil acidity tolerance index to assess the range of soil acidity tolerance among cacao genotypes. Plant and soil samples are being analyzed at Mayaguez to determine the chemical composition in various plant tissues. 301 C1 PS1A Under Objective 1A and C, scientists at the Beltsville Agricultural Research Center (BARC), Maryland are studying the growth, and physiological plant traits to identify cacao genotypes tolerant to abiotic stresses. A growth chamber study with three cacao genotypes that differ in their tolerance to acid soil were evaluated for their response (growth, physiology and metabolites) to deficient and adequate soil moisture and to adequate and excess lighting. Also at BARC, research was completed to assess the influence of soil potassium levels on macro and micro nutrient uptake parameters and use efficiency in cacao genotypes. 301 C1 PS1A Understanding of plant nutrient status under abiotic stresses and changes of soil quality factors under different cacao management systems is critical to correct soil fertility limitations and formulation of fertilizer management practices to achieve sustainable high yielding cacao production. Collaborative research is being undertaken with scientists from the University of Florida Indian River Research and Education Center (IRREC) Fort Pierce, Florida, under a NACA. Under Objective 1, 2 and 3 considerable progress was made to evaluate elemental composition of tropical crops subjected to abiotic stresses and soil chemical quality parameters of tropical soils under different cacao management systems. Furthermore, in this collaboration substantial progress was made to understand the soil cadmium chemistry, and nature of plant available cadmium in soils of cacao plantations in Peru and Ecuador. From Southern Ecuador soil samples were collected under selected cacao plantations and were evaluated for: (1) concentration of cadmium in cacao beans and its relationship with soil cadmium levels and (2) chemical speciation of soil cadmium: An approach to evaluate plant-available cadmium in Ecuadorian soils under cacao production. 305 C1 PS1C. Accomplishments 01 Molecular, physiological and biochemical response of cacao genotypes under soil water deficit. Frequent occurrence of long periods of drought in the cacao growing regions of South and Central America is severely affecting the yield potentials and health of the cacao trees. Planting of drought tolerant cacao types could help to alleviate the situation. This research identified molecular, physiological and biochemical responses of different cacao genotypes to soil water stress. Methods developed in this research could be useful in identifying drought tolerance in cacao genotypes. Information gained from this research could be useful to plant physiologists in identification of drought tolerant cacao genotypes and plant breeders in selection of drought tolerant crossing materials to breed drought tolerant cacao cultivars. 02 Zinc requirements of tropical legume cover crops. Soil and nutrient loss by erosion and leaching and weed infestations are the major soil degradation factors in reducing crop yield potentials in tropical regions. Cover crops are important components of plantation and row crops cropping systems because improve vegetative cover thereby reducing nutrient loss by erosion and suppressing weed infestations. Success of cover crops in acidic infertile tropical soils is influenced by the level of zinc in the soil with cover crop species having high zinc efficiency possibily producing higher yields and persisting longer when grown on infertile soils where the supply of zinc is limited. An ARS scientist in Beltsville, Maryland, identified interspecific differences in perennial legume cover crops for growth and zinc use efficiency at deficient to adequate levels of soil zinc levels in tropical acidic soils. Zinc efficient cover crops enhanced vegetative ground cover in early stages of plantation crop establishment thereby preventing nutrient loss by erosion, improving soil fertility, suppressing weed infestation and increasing yield potentials of crops. This information could be useful for row crop and plantation crop growers in selection of cover crops that will grow best in zinc deficient or zinc rich soils.
Impacts
(N/A)
Publications
- Santosdos, I.C., Anhert, D., Conceicaoda, A.S., Pirovani, C.P., Pires, J.L. , Valle, R.R., Baligar, V.C., Almeidade, F.A. 2014. Molecular, physiological and biochemical responses of Theobroma cacao L. genotypes to drought. PLoS One. 9(12):e115746. DOI:10.1371/journal.pone.0115746.
- Baligar, V.C., Fageria, N.K. 2014. Nutrient use efficiency in plants: An overview. In: Rakshit, A., Singh, H.B., Sen, A., editors. Nutrient Use Efficiency: from Basics to Advances. New Delhi, India, Springer Publications. p. 1-14.
- Fageria, N.K., Baligar, V.C., Heihemann, A.B., Carvalho, M.C. 2014. Nitrogen uptake and use efficiency in rice. In: Rakshit, A., Singh, H.B., Nutrient Use Efficiency: From Basics to Advances, New Delhi, India, Springer Publications, p. 285-296.
- Fageria, N.K., Baligar, V.C., Elson, M.K. 2014. Zinc requirements of tropical legume cover crops. American Journal of Plant Sciences. 5:1721- 1732.
- Li, Y., Elson, M.K., Zhang, D., He, Z., Sicher Jr, R.C., Baligar, V.C. 2015. Macro and micro nutrient uptake parameters and use efficiency in cacao genotypes influenced by deficient to excess levels of soil K. International Journal of Plant and Soil Science. 7:80-90.
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Progress 10/01/13 to 09/30/14
Outputs
Progress Report Objectives (from AD-416): The overall goal of this project is to develop sustainable management systems to improve the productivity and sustainability of cacao (Theobroma cacao L) cultivation. To accomplish this goal the following objectives will be addressed Objective 1: Identify cacao genotypes with superior ability for establishment under conditions of environmental stress. [NP 301, C1, PS 1A] Sub-objective 1A: Evaluate and identify cacao genotypes with superior tolerance to soil acidity. Sub-objective 1B: Determine key physiological and growth responses of selected cacao genotypes under different levels of irradiance (shade). Sub-objective 1C: Evaluate and identify selected cacao genotypes with superior drought tolerance. Objective 2: Characterize and manage soil nutritional components essential for optimal cacao yields. [NP 305, C1, PS 1C] Sub-objective 2A: Determine the residual effects of cover crops with and without NPK fertilizers on production potentials and bean quality. Sub-objective 2B: Determine the effectiveness of controlled release fertilizer formulations on improving growth, production, and cocoa bean quality of selected cacao genotypes grown in specific soil types. Sub-objective 2C: Determine optimum concentrations and nutrient use efficiencies of macro and micro-nutrients in selected cacao genotypes. Objective 3: Develop environmentally sustainable cacao management systems that improve soil quality and yield. [NP 305, C1, PS1C] Sub-objective 3A: Integrate improved canopy management, phytosanitation, and other management practices into cacao field experiments to evaluate their combined effect on yield. Sub-objective 3B: Develop an improved cacao rejuvenation system that integrates improved management practices and evaluates its effect on cacao yield. Approach (from AD-416): The major emphasis of this project is to identify cacao genotypes tolerant to abiotic stresses (drought, infertile acidic soils, and high/ low irradiance) and develop sustainable management systems to improve their productivity and bean quality. The residual effects of cover crop cultivation and improved management systems (agroforestry planting, high density planting, fertilization, sanitary and phyto-sanitary practices) on the changes of soil quality parameters (physical, chemical, biological) and bean yield and quality will also be determined. Nutrient use efficiency of macro-micronutrients of elite cacao genotypes and cover crops at various abiotic stresses and management systems will be evaluated. Enhanced nutrient use efficiency and sustainable high productivity of cacao will be achieved through improved management practices. To achieve these objectives we have established collaborative research programs under specific cooperative agreements with government and non-government organizations (NGO) and national and international agricultural universities in cacao growing regions of Peru, Brazil, and Ecuador, and the University of Florida at Fort Pierce as well as the USDA ARS in Puerto Rico to establish controlled studies in greenhouses and large scale field trials. University of Reading (UR), UK will be collaborating on abiotic stress assessment. Cacao genotypes with superior ability for establishment under abiotic stresses will be identified and incorporated in cacao improvement programs. Improved management systems will be developed, based on the results of this research, to enhance cacao yield potentials and bean quality and further improve soil fertility and halt the further soil degradation. 1245-21000-278-00D is a new project and initiated on 02/10/2014. Progress report of terminating project 1245-21000-266-00D from 04/21/2011 to 02/09/ 2014 has been reported on its FY 2014 report.
Impacts
(N/A)
Publications
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