Recipient Organization
TEXAS TECH UNIVERSITY
(N/A)
LUBBOCK,TX 79409
Performing Department
(N/A)
Non Technical Summary
Rapid and uncontrolled extraction of groundwater from the Ogallala Aquifer and poor water-conserving agricultural practices are causing significant challenges to sustain the agricultural industry in the southwest High Plains. To sustain crop cultivation in regions limited by water, adopting grain sorghum and cotton rotation is proposed to be a pragmatic option compared to continuous cotton. However, a systematic analysis of the sorghum-cotton rotation considering it'simplication on soil health associated microbial (bacteria and fungi) changes, farm productivity and economic outcomes, particularly connecting the findings from research farm to the producer field has not been conducted. To facilitate producers to make well-informed decisions, the project objectives are designed to (i) Quantify changes in crop yield and quality with a sorghum-cotton rotation under different irrigation levels, management practices and soil types; (ii) Explore soil microbial changes and associated impact on soil health and crop productivity in a sorghum-cotton rotation compared to continuous cotton and (iii) Determine the economic outcomes and environmental sustainability of a sorghum-cotton rotation in the target region. In addition, the project will leverage TAWC (Texas Alliance for Water Conservation), a long term "Producer-Teaching-Producer" demonstration program in operation for 17 years, to disseminate project findings to a wider group of stakeholders in the High Plains. The comparative assessment of findings from the research farm and producer fields will facilitate developing an economically feasible pathway for incorporating sorghum-cotton rotation in water-limited environments of the southwest High Plains.
Animal Health Component
80%
Research Effort Categories
Basic
20%
Applied
80%
Developmental
(N/A)
Goals / Objectives
Long term goalDemonstarte soil health and microbial changes, economic outcomes, and associated environmental benefits by introducing grain sorghum into a continuous cotton system under semi arid conditionsSupportive objectivesObj. 1 - Quantify changes in crop yield and quality with a sorghum-cotton rotation under different irrigation levels, management practices and soil typesObj. 2 - Explore soil microbial changes and associated impact on soil health and crop productivity in a sorghum-cotton rotation compared to their respective continuous croppingObj. 3 - Determine the economic outcomes and environmental sustainability of a sorghum-cotton rotation under water limited environments of southwest High PlainsObj. 4 - Enhance awareness of the economic and environmental sustainability of sorghum-cotton rotation under semi-arid environments of the southwest High Plains
Project Methods
Agronomic approach Trials will be carried out on the university research farm in New Deal and producer field equipped with a pivot. On the research farm, we will establish four treatments (sorghum-sorghum, cotton-cotton, sorghum-cotton and cotton-sorghum rotations). The replicated trial will be established on a 9-acre field, with sub-surface drip irrigation. Three different irrigation levels will be maintained on the research farm trial i.e. 80% ET (Evapotranspiration), 60% ET and 30% ET, with 80% considered to be a true control for comparison with two reduced available water treatments. A similar approach will be carried out on the producer field, with a quarter of the pivot maintained under 60% ET and their other quarter per crop with 30% ET. The pivot (120 acres) will be managed under half circles of grain sorghum and cotton in rotation over the duration of the project. All trials, including those on the research farm and the producer field will be under a no-till system.Each replicate plot on the university farm and each quarter of the pivot on the producer field will be equipped with soil moisture probes that have the potential to acquire real-time soil moisture data at every 4-inch interval down to 48 inches. The weather stations on the experimental site and on the producer field (installed as a part of this project) will be used in combination with the soil moisture data to generate evapotranspiration-based irrigation scheduling from tools generated by the TAWC. During the course of the experiments detailed information related to management operations, soil parameters, fertilizer application, fuel usage, herbicides, amount of water applied, and others will be recorded. At the end of the season, crops on the research farm and on the producer field will be harvested mechanically and grain yield and quality in sorghum and lint yield in cotton will be recorded. On the research farm experiments, about 5 x 5 m2 area will be harvested manually at the ground level across all treatments and replications at two key developmental stages (50% flowering and harvest) to record the biomass per unit area. The above ground biomass data will be used to associate with changes in the microbial composition and parameters related to soil health. In addition, starting from 30 days after planting, aerial flights with UAV fitted with RGB, multispectral cameras and thermal imaging will be obtained at 15-day intervals to assess the crop health, canopy temperature and senescence across different irrigation treatments in all four-crop combination. At these 15-day intervals, SPAD-based chlorophyll content and stomatal conductance using a LI-600 porometer will be measured to provide ground-truthed data to support findings from aerial imagery.Microbial analysis Soils will be collected at 10 cm depth from three timepoints annually to the study microbial community dynamics: once in spring prior to the crop growing season, once in summer during the peak vegetative growth prior to grain filling phase, and once in the fall at the end of the crop growing season. We will record soil moisture and temperature in the field at the time of soil collection. After transporting samples to the Soil Microbial Ecology lab at TTU, each sample will be divided into two sub-samples and either air-dried to store for soil physical and chemical analyses or frozen, field-moist, at −80 °C to await microbial analyses. In air-dried soil samples collected at each of the three sampling dates for two years, soil pH, EC and soil organic matter will be measured in 1:1 soil: water extracts in the laboratory. We will extract soil inorganic nitrogen using a 1:10 ratio of soil: 2 M KCl solution and quantify the concentrations of NH4+ and NO3− in filtered extracts via spectrophotometric absorbance at 650 nm and 540 nm wavelengths, respectively. Routine soil test nutrients (including P, K, Ca, Mg, Cu, Na, S, Zn) will be measured via inductively coupled plasma (ICP) analysis in air-dried samples sent to a commercial laboratory.Total genomic DNA will be extracted from frozen samples collected at the final timepoint each year using a DNeasy PowerSoil kit (Qiagen). After quantifying DNA concentrations using a Qubit 2.0 dsDNA assay kit (Thermo Fischer, Waltham, MA, USA), these will be sent to the Texas Tech Center for Biotechnology and Genomics (TTU-CBG) for library preparation and MiSeq Illumina sequencing using the 16S rRNA V3-V4 and ITS 1 and 2 regions to assess soil bacterial and fungal microbiomes, respectively, within each site and treatment. The resulting 16S rRNA and ITS sequences will be classified into amplicon sequence variants (ASVs) using the dada2 pipeline. These will be pre-processed using R along with R packages dada2, Biostrings, and ShortRead. Taxonomic identification will be assigned using the assignTaxonomy function, referencing the SILVA database for bacteria and the UNITE database for fungi.Economic and environmental sustainability While sorghum is considered a lower value crop compared to traditional row crops like corn and cotton, it has many economic benefits. Previous economic studies from the team have analyzed the impact of irrigation timing on crop yield. In this project, economic budgets will be created to assess the short-term profitability of a sorghum-cotton rotation system compared to continuous cropped sorghum or cotton systems. To calculate profitability on the university research farm and the producer field, the economic budgets will include all revenue sources and a complete cost accounting of all field-management operations, including energy usage. Management data will be collected from field experiments and producer sites across all continuous sorghum, cotton and their rotation and irrigation treatments. Data related to seeding rates, tillage, chemical and fertilizer applications, energy use for irrigation, and other operations collected across research trials and producer field will be analyzed using well-established econometric models to determine the cost-benefit ratio and producer's revenue with the proposed rotation. Due to the current rise in market prices and input costs, a sensitivity analysis will be conducted to create a wide range of potential profitability scenarios. A Monte Carlo risk analysis will be performed using the economic budgets by creating stochastic yield and price distributions coupled with weather data to simulate the long-term probability that sorghum-cotton rotations compared to continuous sorghum and cotton systems will provide a positive net return. Once economic budgets have been created, the field data will be input into the Fieldprint Platform® and COMET-Farm tool to determine the impact of soil health on field-level sustainability.OutreachThe 17-year long term effort from the TAWC will be leveraged as an outreach platform and the relevance of the rotation system and the benefits captured through the project will be disseminated to a wider stakeholder community through the annual "Water College". In addition, TAWC organizes farm walks during the cropping season, which will be used to spread the project findings to a larger section of the producers/stakeholders in the region. About two in-season farm-walks/demonstrations will be organized on the research farm and on the participating producer field to engage producers from different counties in the Texas High Plains. Many of these producers associated with TAWC are leaders in their communities and in the agricultural industry, holding memberships on cooperative boards and state and national commodity associations, which will aid in the promotion of these technologies beyond the Texas High Plains. Utilizing farm and ranch shows, conferences, producer events, fact sheets, radio, and on-line media TAWC has reached a combined estimated impact to exceed 32,500 persons across the region.