Performing Department
(N/A)
Non Technical Summary
In the Southern US, the adoption of cover crops is crucial for addressing sustainability issues in corn-fallow systems. However, winter annual cover crops often struggle to grow enough biomass due to weather constraints and the short growing season before corn planting, limiting the benefits of cover cropping.To address this, this project is focused on evaluating a living mulch system that incorporates cool-season perennial crops, allowing corn to be planted directly into the living mulch. The hypothesis is that using a perennial legume cover crop as a living mulch can seamlessly integrate with current corn management practices. This integration is expected to increase cover crop biomass, improve nitrogen recycling, and provide other ecosystem services.Our multi-institutional collaborative research aims to assess the feasibility of a living mulch system in three southern US states (Texas, Mississippi, and Florida). It will compare the biomass production of perennial cover crops in living systems to traditional annual cover cropping. It will also evaluate potential yield trade-offs in corn grown within the living mulch system and determine the nitrogen benefits of the living mulch compared to traditional fallow-corn and annual cover crop-corn systems.This is a benchmark study to test the possibility of such a system in the Southern US. If successful, it will open several avenues for further research, including system compatibility, optimized fertilizer programs, inter and intra-specific competition, irrigation strategies, pest management, and more.
Animal Health Component
0%
Research Effort Categories
Basic
10%
Applied
80%
Developmental
10%
Goals / Objectives
The goal of this project is to establish sustainable agroecosystems in the southern United States, where cover crops and corn cultivation work synergistically to enhance soil health, environmental quality, yield, and overall profitability.Specific objectives of the project are:1) Evaluate the feasibility of managing perennial cover crop as living mulch within corn production systems across three ecoregions of southern US, assessing agronomic viability and biomass production capabilities2) Investigate the yield implications and nitrogen credits of living mulch system to the corn production.
Project Methods
Field experimental sitesThe specific objectives of this project will be achieved through two-year (2024-2026) field research experiments conducted at three different locations in the southern US: (1) Temple, TX, (2) Starkville, MS, and (3) Jay, FL. These regions represent a wide range of southern US soil types and climatic conditions. The Temple site is located within the Blackland Prairie region of Central Texas, which is a major corn producing region in the state with an average annual precipitation of around 890 mm and its prominent soil classified as black clay. The Starkville site is located within the eastern part of Mississippi, with a Leeper silty clay loam and annual precipitation of around 1420 mm. The Jay site is situated in North Florida, with a typical soil profile of fine sand with an annual precipitation of around 1675 mm. All three sites will be rainfed following the common practice in respective regions.Experimental treatments and designAt each site, the experiment treatments will consist of a full factorial among cropping systems and nitrogen (N) rates. The three different cropping systems include: fallow-corn rotation (control), an annual winter cover crop-corn rotation, and a perennial winter cover crop as a living mulch into which corn will be planted. Crimson clover (Trifolium incarnatum L.) and white clover will be annual cover crop and the perennial cover crop used for the experiment, respectively. Each of the three cropping systems will receive four N rates: 0, 80, 160, and 240 kg ha-1, to investigate nitrogen dynamics of various systems under N gradients. The experimental design will be a split-plot design, with cropping system treated as a main plot and N rate as a sub plot, replicated four times. Each plot will be a minimum of 10 m × 4 m at all three sites. Depending upon the weather conditions at each site, crimson clover will be planted between September-October in both years and white cover will be established in the first year of the project. Crimson clover will be terminated two weeks prior to corn planting, as per local recommendations. All plots will be planted with corn in March-April following strip tillage. Corn will be planted at the recommended seeding rate using the best performing hybrid at each location. Except 0 kg ha-1 N rate treatment plots, all plots will be supplied with 40 kg ha-1 N at the planting and remaining N dose will be applied at side-dress at V5- V7 stage of the corn crop. All nutrients other than N will be managed based on pre-plant soil testing and will follow local university recommendations.Data CollectionDuring the cover crop growing season, green canopy coverage will be recorded on all plots at a weekly interval using the Canopeo mobile app. For living mulch treatments, canopy cover measurements on the perennial cover crop will be continued throughout the corn growing season at a biweekly interval. Cover crop above-ground biomass will be collected from random 0.25 m2quadrats at the stage of crop termination for annual cover crop (crimson clover) treatment. The perennial cover crop (white clover) will be sampled at five times: two weeks before corn planting, corn planting, V6, VT, and corn harvest. The cover crop biomass will be oven-dried at 60°C to estimate dry biomass weights, and then grounded to pass through a 1 mm screen. Percent N and C concentration in cover crop biomass samples will be estimated using the flash combustion method (Thermo Scientific FlashSmart NC Analyzer) at the Blackland Research & Extension Center at Temple. Plant biophysical characteristics such as plant height, ear height, stalk diameter, final plant population, and leaf area index will be collected at VT growth stage. Moreover, corn biomass samples will be hand harvested from a 1-m segment of two center rows in each plot at the maturity stage. Harvested samples will be dried at 60°C to obtain the dry biomass weight. Corn ears will be then separated, and grain weight will be estimated after husking and shelling. The yield will be adjusted to 15% moisture. Corn biomass and grain samples will also be grounded and analyzed for N content using the flash combustion approach,Data analysesStatistical software R will be used to analyze all exploratory data (R Core Team, 2023). Within R "Tidyverse package" will be used for data handling, manipulation and visualization, and data will be subjected to analysis of variance using "lme4" and "lmerTest" packages via a linear mixed effect model. The ANOVA analysis will be employed to determine the main effects of cropping systems and N rate or their two-way interaction effects on dependent variables such as yield and N uptake. Moreover, agronomic optimum N rate (AONR) by cropping system will be calculated by fitting yield to applied total N rate in linear plateau and quadratic plateau models in R using "easynls" and "agroreg packages". The best model will be selected based on coefficient of determination (R2 ), the Akaike information criterion (AIC) and the root mean square error (RMSE).