Performing Department
(N/A)
Non Technical Summary
Health soils are critical to sustainable agriculture. Currently, a variety of conservative farming practices are applied to agriculture soils to promote soil helath. Cover cropping is one of the most commonly used approach. However, a major knowledge gap is the uncertainty of the benefits of implementing cover cropping and the time that it takes for positive effects to become noticeable. In this project, our long-term goal is to better understand how cover cropping modulates soil health, crop performance, and microbial communities. By applying a space-for-time approach and control-treatment paired design, we will investigate the time scales at which cover cropping cascades into microbial community structure (mainly of bacteria, archaea and fungi), the associated nutrient processing including carbon and nitrogen, soil health, and crop yields.The key questions we try to answer here are: How do cover cropping alter microbial composition, soil health, and crop performance? And at what time scales do these effects manifest? Are soil health indices reflective of microbial structure and function, and do relationships among these measures vary through time? We will partiner with 48 farms (24 paired fields each year for 2 years) in Pennsylvania with time since implementation of conservation practice ranging 0-15+ years. We will (1) characterize detailed compositions of soil microorganisms such as bacteria, archaea and fungi; (2) measure nitrogen and carbon processes and dynamics with cover crops implemented in different duration of years; and (3) sutdy the how cover cropping impact soil health measurements and crop performance. This study will provide robust informationon how cover cropping contributes to improvement of microbial soil health and sustainable agriculture. Lessons from this study will be transferable to a broader agriculture audience and farming communities. This study will support the professional development and education of four researchers (two senior and two junior), one soil health coordinator, five technicians, and multiple undergraduate students.
Animal Health Component
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Research Effort Categories
Basic
100%
Applied
0%
Developmental
0%
Goals / Objectives
Healthy soils are the foundation of life. Soil degradation due to unsustainable agricultural practices (e.g., intensive tillage, bare ground after harvest) represents a major challenge to long-term agricultural productivity and food security. Soil microorganisms (e.g., bacteria, archaea and fungi) play a key role in maintaining soil structure and functions such as carbon and nutrient cycling and, therefore, have a direct impact on soil health and crop productivity (Figure 1). Implementing conservation practices such as cover cropping can improve soil structure, increase soil organic matter, and foster healthy soil microbial consortia. It can also bring other environmental benefits such as reducing erosion and improving water quality. However, the implementation of cover cropping remains low across most of the US, and adoption of cover cropping lags far behind use of no-till and reduced-till practices (Wallander et al. 2021). From the growers' perspective, a barrier to adoption is the uncertainty on when to expect the benefits of cover cropping to manifest. The time scales (within a year, over years) at which cover cropping may impact soil health, crop performance, microbial community structure, and the functions they mediate is largely unknown. In particular, detailed microbial community dynamics of multiple domains (bacteria, archaea and fungi) under cover cropping are rare in large scale field studies. Therefore, the main goals of this research are to (1) assess how cover cropping in fields managed with continuous no-till affects soil health, cash crop performance, and the community structure of soil microorganisms and their associated functions; and (2) determine the timescales at which these changes may occur. Filling this knowledge gap is crucial to advance the adoption of cover cropping by the next generation of growers and significantly increase the agricultural and environmental benefits of this practice.Our established network of cooperating farms in Pennsylvania includes farms with time since implementation of cover cropping varying from 0 to 15+ years. Of particular relevance to this project are farms within our network that have implemented continuous no-till practices with and without cover cropping. This representative swath of farms enables robust characterization of responses to cover cropping across a range of environmental and management contexts while also allowing a space-for-time substitution approach to address the question of when these responses can be expected to manifest. By collaborating with farmers as opposed to working on experimental farm trials, lessons from this study will be more easily transferable to a broader agriculture audience and farming communities. Results from preliminary work have shown that our choice of experimental fields with varying periods of cover cropping in a paired treatment vs control design is viable, informative, and robust. In addition to physical and chemical indicators of soil health, we will specifically characterize detailed microbial community structure (i.e., bacteria, archaea, fungi) and functions (i.e., carbon and nitrogen cycling) from field soil cores at two depths (0-15 and 15-30 cm) and evaluate the effect of cover cropping on carbon and nitrogen transformation activities, key soil health indicators, crop performance, and microbial community composition. In a nutshell, we will characterize soils from our network farms in Pennsylvania with time since implementation of cover cropping varying from 0 to 15+ years with the specific objectives to:1) Characterize soil functions, crop performance, and detailed microbial community structure under conservation practices (continuous no-till with and without cover cropping) on working farms.2) Determine the time scales at which the effects of cover cropping manifest in soil functions, crop performance and microbial community structure (bacteria, archaea, and fungi).3) Test if soil health indices are reflective of microbial community structure and functions and determine how these relationships vary through time.
Project Methods
Efforts:Experimental designThe proposed work will be conducted in Pennsylvania (PA), an ideal location for this study because it is one of the leading states in adoption of no-tillage practices and cover cropping (USDA, 2021). We will leverage the working networks and expertise of The Robin L. Vannote Watershed Restoration Team of the Stroud Water Research Center to recruit farmer collaborators. Our goal is to have a minimum of 48 pairs of fields. We will target 48 fields (yielding 24 treatment-control pairs) in year one and 48 fields (an additional 24 treatment-control pairs) in year two.Space for time substitution design: To address the question of when impacts of cover cropping on soil properties manifest, we will use a space for time substitution approach. Farms in our network have employed cover cropping 0 to 15+ years. We will incorporate control-treatment pairs that represent variation in time since cover crop implementation in four categories: 1-5 years, 6-10 years, 11-15 years, and 15+ years, an approach that was successful in our pilot study. The 48 treatment-control pairs sampled will be distributed acrossover two years of sample collection.Sample collectionIn each sampled field, a 40 m x 40 m plot will be established near the center. Twenty randomly located soil cores (3.0 cm i.d.) will be collected to a depth of 30 cm from each plot using aseptic procedures. Each core will be divided into two depth increments: 0-15 cm and 15-30 cm. Over two years, we will collect total 192 samples including control and treatment fields (96 fields by 2 depths =192). Cores from each depth increment will be homogenized within each plot to generate two composite samples. Soil samples will be stored on ice for transfer to the lab, where they will be sub-sampled in preparation for analyses detailed below.Soil microbial community structureDetailed bacterial, archaeal, and fungal biodiversity and community structure will be characterized by a high throughput sequencing platform (Illumina), and the raw sequence data will be processed and analyzed with standard bioinformatic pipelines (e.g., DADA2, Qiime 2 etc.).Soil functionsWe will assess two essential soil functions mediated by the soil microbial community, carbon and climate regulation and nutrient cyclingby measuring carbon and nitrogen pools and quantifying rates of carbon and nitrogen transformation and extracellular enzyme activity (EEA).Soil health indicesA soil health score will be determined for each field using the Cornell Assessment of Soil Health (CASH). The following attributes will be included in the score: soil pH, organic matter content, extractable phosphorus, potassium, micronutrients, soil texture, active carbon (e.g. permanganate oxidizable carbon), wet aggregate stability, soil respiration, total carbon, and total nitrogen. In addition to inclusion in determining an overall soil health score, individual metrics derived from the CASH will contribute to assessment of nitrogen (total nitrogen) and carbon (total carbon, soil respiration) cycling dynamics.Crop performance monitoringCrop performance will be assessed through collection of current and historical yield data. All sampled fields will be planted to corn, therefore, current yield data will be grain or silage yield in the fall following soil sample collection. Corn yield data will be collected through yield monitoring equipment cooperating farmers already have on harvest equipment or scales used in conjunction with harvest equipment.Data analysis and interpretationDr. Leslie New, senior statistician at Ursinus College and Stroud Center's Information Services team will provide data management and analysis services for all proposed work following the Data Management Plan.Evaluations:Evaluation of research activitiesMilestones: (1)identify farmers with applications of cover crops with different durationDefining (year 1); (2)samples will be collected from 48 pairs of fields, and all chemical and biological characterization will be conducted (year 1-2); (3) statistical analysis of the "space for time" data, and identify the time frame that when the soil benefits can be seen over time; (4) publish scientific results.Evaluation of research activities will adhere to a timeline forcompleteness of all milestones and expected project outcomes and achievements.Evaluation of education activitiesUndergraduate research experiences incorporated in this project will aim to increase participant knowledge of soil ecology and its applications to sustainable agriculture, enhance skills in field and laboratory research, and improve scientific communication skills, thus preparing students for careers in the field of agriculture. We will evaluate the effectiveness of summer research fellowships and academic year research in building relevant knowledge and skills using a pre- and post-survey approach. In addition, written and oral projects will be compared to established benchmarks for scientific communication used by Ursinus Biology and Statistics faculty. We will also share our findings with growers through our ongoing educational efforts at Stroud Center. Responses and evaluations from growers and attendees will be evaluated through pre-and post- event surveys.