Grazing cover crops may increase land-use efficiency while promoting sustainability. We investigated how grazing intensity affects cover crop litter quantity, quality, decomposition, and cotton (Gossypium hirsutum L.) N uptake. Cover crops were a mixture of rye (Secale cereale L.) and oat (Avena sativa L.) managed as follows: no grazing +34 kg N ha(-1) (NG34), no grazing +90 kg N ha(-1) (NG90), heavy grazing (HG), moderate grazing (MG), and light grazing (LG). Grazed treatments received 90 kg N ha(-1). After cover crop termination, above- and belowground litter was collected and incubated in situ for 0, 4, 8, 16, 32, 64, and 128 days, with cotton plants sampled on the same days to estimate N recovery and synchrony between N release from litter and uptake by cotton. By Day 128, only 13% of initial NG34 aboveground biomass had disappeared, whereas 42% of HG disappeared. Nitrogen retained in aboveground litter of HG was less than NG90 (27 vs. 60 kg N ha(-1)), and aboveground final N stock (at Day 128) of HG was less than NG90 and LG (16, 47, and 41 kg N ha(-1), respectively). Belowground litter contributed 98 kg N ha(-1) versus 46 for aboveground. Belowground N disappearance from litter bags was greater from NG90 than NG34 (39 vs. 21 kg N ha(-1)). Cotton N uptake by Day 128 was similar across treatments (191 kg N ha(-1)). Grazing cover crops impact aboveground litter quantity, quality, and decomposition rates, and belowground litter plays an important role on the N cycling.

Carinata is a purpose-grown oilseed feedstock for renewable fuels, including sustainable aviation fuel (SAF) that can replace conventional aviation fuel (CAF). Given carinata is a new crop in the Southeastern United States, it is crucial to analyze its sustainability from a supply chain perspective. This study developed a mixed-integer linear programming (MILP) model and simulated it for 20 years, starting from a farm (county-level data) and ending at the airport. About 2.06 million ha in Alabama, Florida, and Georgia combined were found suitable for carinata production. Given the three-year rotation period, about 0.69 million hectares can be cultivated annually, approximately 65% of which was in Georgia. About 2.4% of the combined SAF annual demand of four major airports (about 210 thousand t) in the study area is satisfied at that level of carinata cultivation. However, all available SAF was supplied to the Atlanta airport as this decision minimizes the supply chain cost. A total of 1343 storage units, one oil extraction mill, and one biorefinery were needed to meet the overall demand. We found that SW Georgia is the top supplier of carinata seeds. The unit cost of production and carbon intensity were estimated to be $0.89 L-1 (or $26.79 GJ-1) and 0.91 kg CO2e L-1 (or 27.28 kg CO2e GJ-1), respectively. This carbon intensity of carinata-based SAF was 67.8% lower than that of CAF. With variations included in SAF demand, yield, and soil carbon sequestration, carbon savings remained between 66.5% and 67.8%. Given the GHG advantage of SAF over CAF, there is justification for subsidies required to make SAF competitive.

Integrated crop-livestock systems provide an array of benefits to agricultural systems, including a reduction in nitrogen (N) leaching. A farm approach to integrate crops and livestock is the adoption of grazed cover crops. Moreover, the addition of perennial grasses into crop rotations may improve soil organic matter and decrease N leaching. However, the effect of grazing intensity in such systems is not fully understood. This 3-year study investigated short-term effects of cover crop planting (cover and no cover), cropping system (no grazing, integrated crop-livestock [ICL], and sod-based rotation [SBR]), grazing intensity (heavy, moderate, and light grazing), and cool-season N fertilization (0, 34, and 90 kg N ha-1 ) on NO3 -N and NH4 -N concentration in leachate, and cumulative N leaching by using 1.5-m deep drain gauges. The ICL was a cool-season cover crop-cotton (Gossypium hirsutum L.) rotation, whereas SBR was a cool-season cover crop-bahiagrass (Paspalum notatum Flüggé) rotation. There was a treatment × year × season for cumulative N leaching (p = 0.035). Further contrast analysis indicated that cover crops decreased cumulative N leaching compared to no cover (18 vs. 32 kg N ha-1 season-1 ). Nitrogen leaching was lesser for grazed compared to nongrazed systems (14 vs. 30 kg N ha-1 season-1 ). Treatments containing bahiagrass had lesser NO3 -N concentration in leachate (7 vs. 11 mg L-1 ) and cumulative N leaching (8 vs. 20 kg N ha-1 season-1 ) compared to ICL systems. Adding cover crops can reduce cumulative N leaching in crop-livestock systems; moreover, warm-season perennial forages can further enhance this benefit.

Soil organic carbon (SOC) is closely tied to soil health. However, additional biological indicators may also provide insight about C dynamics and microbial activity. We used SOC and the other C indicators (potential C mineralization, permanganate oxidizable C, water extractable organic C, and beta-glucosidase enzyme activity) from the North American Project to Evaluate Soil Health Measurements to examine the continental-scale drivers of these indicators, the relationships among indicators, and the effects of soil health practices on indicator values. All indicators had greater values at cooler temperatures, and most were greater with increased precipitation and clay content. The indicators were strongly correlated with each other at the site-level, with the strongest relationship between SOC and permanganate oxidizable C. The indicator values responded positively to decreased tillage, inclusion of cover crops, application of organic nutrients, and retention of crop residue, but not the number of harvested crops in a rotation. The effect of decreased tillage on the C indicators was generally greater at sites with higher precipitation. The magnitude and direction of the response to soil health practices was consistent across indicators within a site but measuring at least two indicators would provide additional confi-dence of the effects of management, especially for tillage. All C indicators responded to management, an essential criterion for evaluating soil health. Balancing the cost, sensitivity, interpretability, and availability at commercial labs, a 24-hr potential C mineralization assay could deliver the most benefit to measure in conjunction with SOC.

Many ground beetle species (Coleoptera: Carabidae) prey on noctuid larvae and pupae. Therefore, agricultural practices that maintain or even en-hance carabid populations have the potential to reduce noctuid pest populations through predation. One such pest is the fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), a migratory pest of row, turf, and vegetable crops. Before migrating in spring from southern Florida and southern Texas, it feeds and develops on cover crops such as field corn and sorghum-sudangrass and expands its populations. Here we sampled the species and density of carabid populations that were active in cover crops with differing capacity to support fall armyworm development. Three cover crop species, sorghum-sudangrass, cowpea, and sunn hemp, were previously studied for their effects on fall armyworm populations, with sunn hemp showing high incompatibility with fall armyworm development. The cover crops were grown in 3 locations in north and north-central Florida and pitfall traps were used to compare numbers of carabid beetles caught in different cover crop treatments. Almost 2,000 predatory and omnivorous carabid beetles were collected. Three species in particular, Calosoma sayi Dejean, Tetracha carolina (L.), and Cicindela punctulata Olivier, are known predators of S. frugiperda in the laboratory and may aid in the reduction of populations in the field. There were no differences in beetle numbers among cover crop plants. In another trial, more beetles were collected in plots of a popular sunn hemp cultivar developed in the southeastern U.S., 'AU Golden', than in plots of another germplasm line, Tillage SunnTM. Further research should determine if the predatory species found in this study prey on S. frugiperda in the field and if this added mortality helps reduce crop damage.

In abiotic stresses, drought is the main problem in agricultural production which inhibits the plants to show off their genetic potential. Maize is not only the cereal crop of the world but also 3rd important cereal crop in Pakistan. Maize is drought-sensitive and affected at each growth and development stage. So, the organic amendment is not only the solution to mitigate the drought stress due to long-lasting moisture availability but also improves the growth, yield, quality, and nutrient uptake with improving soil properties. Therefore, a two-year field experiment during 2018 and 2019 was laid out at Agronomy Research Area, Department of Agronomy, Bahauddin Zakariya University, Multan, Pakistan. Treatments included pre-screened maize hybrids: P-1429 (drought-sensitive) and Dk-6724 (drought-tolerant); pre-optimized levels of each organic fertilizer source (OFS); recommended chemical fertilizer source (CS), 10 t/ha biochar (BC), 10 t/ha farmyard manure (F.M) and 10 t/ha poultry manure (P.M); and irrigation regimes i.e normal irrigation (Ck) 100% field capacity and severe drought (SD) 50% field capacity. The Experiment was designed in a randomized complete block design (RCBD) with a split-split plot arrangement and was replicated three times. Irrigation regimes were put in the main plot, organic fertilizer sources were put in the subplot and maize hybrids were put in the sub-sub plot. Different agronomic growth and yield attributes, quality attributes, crop physiology, soil physical properties, nutrient uptake, and activity of antioxidant enzymes were assessed. It resulted that in organic fertilizer sources application, 10 t/ha poultry manure and farmyard manure followed by biochar improved the growth and yield of maize hybrids significantly, under normal irrigation and severe drought. These also improve the quality of maize by improving the nutrient uptake and soil physical properties like increasing the soil porosity and decreasing the soil bulk density during consecutive years 2018 and 2019. It was also noticed that the application of organic fertilizers mitigated the adverse effect of drought by the antioxidant defense system with the production of SOD, POD and CAT.

The combination of subsoil compaction and injudicious usage of nitrogenous fertilizers are key factors that may lower crop yields, especially in soils with a shallow hardpan. Therefore, the objective of this study was to determine the effects of tillage and N application on carinata productivity in rainfed conditions. A 3-year field study was conducted at the North Florida Research and Education Center, Quincy, FL, USA. Treatments were four rates of N (0, 45, 90, and 135 kg N ha(-1)) and three tillage methods (disking, chiseling, and no-tillage). Maximum cone index measurements for no-tillage occurred at 15 cm but at 20 cm soil depth for both chisel and disk tillage. A hardpan at 15 cm restricted taproot growth but promoted lateral root growth. Subsoiling and N application improved carinata growth relative to no-tillage. Seed yield response to N application rate depended on the tillage method. The agronomic maximum seed yield occurred at 134, 128, and 125 kg N ha(-1) for chisel, disk, and no-tilled systems. Nitrogen agronomic efficiency was greatest at 45 kg N ha(-1) for the chisel method and 95 kg N ha(-1) for disk and no-tillage. Tillage has a greater potential to increase yields even at relatively low N levels. When tilled, carinata produces 8%-17% greater seed yield at 45 kg N ha(-1) than no-tilled carinata grown with 135 kg N ha(-1). These results indicate that tilling the subsoil and applying 90-135 kg N ha(-1) are required for carinata production in soils with a hardpan.

Brassica carinata is a non-food industrial oilseed crop that can be grown in the winter in the southeast US without impacting food, feed, or fiber crops. Carinata is a low carbon advanced renewable fuel feedstock and a good source of animal protein. Carinata research in the SE US through a public-private partnership has developed a comprehensive body of knowledge regarding carinata agronomics, life cycle analysis, best management practices and economics. This article aims to help growers and others interested in carinata to understand its biology, agronomy, and production aspects.

Carinata (Brassica carinata A. Braun) is an emerging oilseed crop with potential as a dual use winter cover/cash crop in the southeastern US region. Although carinata is historically cultivated as a spring crop in northern latitudes, incorporating carinata into southeastern US cropping systems can provide winter/cover ecosystem services and a bio-feedstock for a high value, renewable aviation fuel without displacing feed and food crops. In this study, our major objective was to quantify the agronomic performance and stability of selected carinata genotypes across several locations in the southeastern US. Extensive field evaluations of twelve, elite carinata genotypes, arranged in a randomized complete block design with four replications, were conducted from 2016 to 2019 across Mississippi, Alabama, Georgia, Florida, South Carolina, and North Carolina. Data was collected on days to 50% bolting, days to 50% flowering, plant height, grain yield, and test weight. Results demonstrated the ability to produce viable grain yields across the region, but also highlighted the impact of freezing temperatures on winter production. In total 20% of all environments were lost to mortality due to freezing temperatures. Overall, genotype 15 produced the highest grain yield across individual environments, topping the trial in 74% of all environments. However, both crossover and non-crossover genotype x environment interactions were detected for agronomic traits, with problematic crossover interactions more prevalent for days to 50% bolting and days to 50% flowering. Our results also suggest the southeastern US be separated into three mega environments to include 1) northern Georgia, South Carolina, and North Carolina, 2) southern and central Georgia and Alabama, and 3) northern Florida. Future efforts to identify advanced breeding lines and/or commercial seed products with adaptation to the region should consider field testing in each of these mega environments.

The burgeoning global market for soil microbial inoculants for use in agriculture is being driven by pressure to increase sustainable crop production by managing pests and diseases without environmental impacts. Microbial inoculants, based predominantly on bacteria and fungi, are applied to soil as alternatives to conventional inorganic fertilizers (biofertilizers) or to carry out specific functions including biocontrol of pests and diseases (biopesticides), or for bioremediation and enhancement of soil characteristics. While some soil inoculants such as rhizobia have a long and successful history of use, others have performed inconsistently in the field and failed to live up to their promise suggested by laboratory testing. A more precise understanding of the ecology and modes of action of inoculant strains is key to optimizing their efficacy and guiding their targeted use to situations where they address key limitations to crop production. This will require greater collaboration between science disciplines, including microbiology, plant and soil science, molecular biology and agronomy. Inoculants must be produced and formulated to ensure their effective establishment in the soil and practicality of implementation alongside existing cropping practices. New approaches to strain selection and construction of beneficial microbial consortia should lead to more efficacious inoculant products. Extensive and rigorous field evaluation of inoculants under a range of soil and environmental conditions has rarely been undertaken and is urgently needed to validate emerging inoculant products and underpin successful implementation by growers, especially in a market that is largely unregulated at present.

Management of cotton requires an understanding of the growth habit and responses of the plant to the environment. This publication provides basic information for understanding how a cotton plant develops and some of the factors that can alter the pattern of development. This document is SS-AGR-238, one of a series of the Agronomy Department and the North Florida Research and Education Center, Quincy FL. Original publication date February 2005. Updated May 2022 by David L. Wright, Isaac Esquivel, Sheeja George and Ian Small. SS-AGR-238/AG235: Cotton Growth and Development (ufl.edu)

Farmers, scientists, and other soil health stakeholders require interpretable indicators of soil hydraulic function. Determining which indicators to use has been difficult because of measurement disconformity, spatial and temporal variability, recently established treatments, and the effect of site characteristics on management practice differences. The North American Project to Evaluate Soil Health Measurements includes 124 sites uniformly sampled across a range of soil health management practices in North America in 2019. We compare and recommend indicators of hydraulic function that best characterize soil health. We assessed the relationship of each indicator to a suite of soil inherent properties and climate variables, the response of each indicator to soil health management practices, the effect that soil inherent properties (clay content, sand content, and pH) and climatic variables (10-yr mean annual precipitation and temperature) had on response to management practices, and the relationship among the responses of the indicators to soil health management practices. Field capacity measured on intact cores (theta(FC_INTACT)) was the best measure of soil hydraulic function, because it responded to management, represents a direct measure of soil hydraulic function, is proximal to stakeholder values, and its response to management was not significantly influenced by inherent and climatic variables. Other suitable indicators are bulk density, soil organic carbon (SOC), and aggregate stability, which are not direct measures of soil hydraulic function but do respond to management and may be practical in situations in which measuring theta(FC_INTACT) is not. This study informs selection of soil health indicators to measure soil hydraulic function.

Integrating two years of bahiagrass (Paspalum notatum Flugge) into the peanut (Arachis hypogea L.) and cotton (Gossypium hirsutum L.) cropping system improves soil quality and crop production as compared to a conventional peanut-cotton-cotton rotation (CR). However, it is unclear if this system, known as a sod-based rotation (SBR), affects soil biological communities (e.g., soil microorganisms and nematodes) and their trophic interactions. Furthermore, how soil trophic groups respond to agricultural management (e.g., irrigation) is understudied. In April 2017, we collected pre-planting soil samples (0-30 cm) from cotton plots located in Quincy (Florida, United States) that had been under CR (cotton grown in two consecutive years) and SBR (cotton grown only once) for 17 years. We used amplicon sequencing to investigate soil microbial communities and an inverted microscope technique to quantify nematodes. Compared to CR, SBR significantly increased nematode alpha diversity (one-way ANOVA; P < 0.05) and induced different nematode communities. In contrast, there were no significant differences in the diversity and structure of bacterial communities between SBR and CR. SBR plots were significantly enriched in Nitrospira, while the second of two consecutive years of cotton growth in CR had a higher relative abundance of Alphaproteobacteria (one-way ANOVA; P < 0.05). Plant-parasitic (848 counts per 100 g dry soil) and bacterial-feeding nematodes (798 counts per 100 g dry soil) had a similar abundance in SBR, while plant-parasitic nematodes (7772 counts per 100 g dry soil) were predominant in CR (<1000 counts per 100 g dry soil for all other taxa). SBR exhibited a greater number of significant paired Pearson correlations (P < 0.05) among functional groups of bacteria and nematodes compared to CR systems. Irrigation had no effect on the diversity and structure of bacterial and nematode communities in SBR, although some soil bacterial and nematode groups responded to irrigation. Overall, these results suggest that integrating bahiagrass to diversify the conventional peanut-cotton rotation is a sustainable approach to enhance soil biodiversity, with more diverse nematode communities and complex soil trophic interactions that will affect the response to crops and irrigation. Thus, future crop rotations should increase plant functional trait diversity (e.g., by adding perennial grasses) to maximize benefits to soil communities.

This publication discusses several aspects of field corn production in Florida, such as economics, land preparation, hybrid selection, fertilization, irrigation, and disease management. Written by David Wright, Ian Small, Cheryl Mackowiak, Zane Grabau, Pratap Devkota, and Silvana Paula-Moraes, and published by the UF/IFAS Agronomy Department, revised August 2022.

Currently accepted pedotransfer functions show negligible effect of management-induced changes to soil organic carbon (SOC) on plant available water holding capacity (theta(AWHC)), while some studies show the ability to substantially increase theta(AWHC) through management. The Soil Health Institute's North America Project to Evaluate Soil Health Measurements measured water content at field capacity using intact soil cores across 124 long-term research sites that contained increases in SOC as a result of management treatments such as reduced tillage and cover cropping. Pedotransfer functions were created for volumetric water content at field capacity (theta(FC)) and permanent wilting point (theta(PWP)). New pedotransfer functions had predictions of theta(AWHC) that were similarly accurate compared with Saxton and Rawls when tested on samples from the National Soil Characterization database. Further, the new pedotransfer functions showed substantial effects of soil calcareousness and SOC on theta(AWHC). For an increase in SOC of 10 g kg(-1) (1%) in noncalcareous soils, an average increase in theta(AWHC) of 3.0 mm 100 mm(-1) soil (0.03 m(3) m(-3)) on average across all soil texture classes was found. This SOC related increase in theta(AWHC) is about double previous estimates. Calcareous soils had an increase in theta(AWHC) of 1.2 mm 100 mm(-1) soil associated with a 10 g kg(-1) increase in SOC, across all soil texture classes. New equations can aid in quantifying benefits of soil management practices that increase SOC and can be used to model the effect of changes in management on drought resilience.

Cotton root microbiomes were investigated in two long-term rotation systems established in 2000, a bahiagrass (Paspalum notatum Flugge)-bahiagrass-peanut (Arachis hypogaea L.)-cotton (Gossypium hirsutum L.) rotation (sod-based rotation, SBR) and a peanut-cotton-cotton rotation (conventional rotation, ConR), from 2017 to 2019. Our results demonstrate that bacterial communities were primarily structured by interannual variability, while fungal alpha and beta diversity were significantly affected by both rotation and interannual variability, with greater fungal diversity and distinct fungal communities in SBR compared to ConR across three sampling years. Cotton roots in SBR also harbored more complex and stable microbial networks. These increased resistance to environmental changes driven by interannual variability, such as temperature and precipitation. Beneficial microbial communities (e.g., Opitutaceae, Pseudonocardiaceae, Rhizobiaceae, Bacillaceae, Comamonadaceae, Serendipitaceae, and Glomeraceae) that may promote plant growth, improve tolerance to abiotic stress, and enhance pathogen defense were associated with cotton roots in SBR, along with fewer pathogenic microbes. These beneficial microbial communities (core microbiomes) together with complex and stable microbial networks were significantly and positively correlated with cotton yield across three sampling years, suggesting that long-term conversion to SBR shaped root microbiomes in a way that increased cotton productivity. This study improves our understanding of the microbial mechanisms that underlie the agronomic and economic benefits observed when integrating perennial grasses to diversify the conventional peanut-cotton rotation.

Fall armyworm, Spodoptera frugiperda (J. E. Smith) is a migratory moth that annually migrates northward each spring from sites in southern Florida and southern Texas. This caterpillar pest feeds on and damages row, turf and vegetable crops in the eastern and central U.S. Before migrating in spring, it feeds on cover crops in central and eastern Florida and expands its populations. Our objective was to use multi-year studies to compare fall armyworm populations that develop in cover crop plants. A series of field experiments and a laboratory feeding study were conducted to compare infestation and feeding and of fall armyworm on different cover crop plants. Field experiments had plots planted with corn (Zea mays L.), sorghum-sudangrass [Sorghum bicolor (L.) Moench], a standard cover crop in Florida, and two alternative cover crops, sunn hemp (Crotalaria juncea L.) and cowpea [Vigna unguiculata (L.) Walpers spp. unguiculata]. Another trial compared populations in sorghum-sudangrass and in mixtures of sorghum-sudangrass with buckwheat (Fagopyrum esculentum Moench) or pearl millet (Cenchrus americanus (L.) Morrone). Fall armyworm larvae were fed and allowed to develop on different sunn hemp germplasm in a laboratory trial. Field populations of fall armyworm were highest on corn, followed by sorghum-sudangrass. Sunn hemp and cowpea had larval populations 70–96% less than on sorghum-sudangrass, suggesting replacement of this cover crop with either plant species might help reduce areawide populations of resident or migratory fall armyworm. Larvae collected from cover crop plots had parasitism levels that averaged 30%, with Chelonus insularis (Hymenoptera: Braconidae) emerging as the most commonly-collected species. Larval feeding on different sunn hemp germplasm lines resulted in no difference in weight gain. Replacing sorghum-sudangrass with sunn hemp varieties or germplasm should be acceptable as a replacement cover crop for areawide management of fall armyworm.

Potential carbon mineralization (Cmin) is a commonly used indicator of soil health, with greater Cmin values interpreted as healthier soil. While Cmin values are typically greater in agricultural soils managed with minimal physical disturbance, the mechanisms driving the increases remain poorly understood. This study assessed bacterial and archaeal community structure and potential microbial drivers of Cmin in soils maintained under various degrees of physical disturbance. Potential carbon mineralization, 16S rRNA sequences, and soil characterization data were collected as part of the North American Project to Evaluate Soil Health Measurements (NAPESHM). Results showed that type of cropping system, intensity of physical disturbance, and soil pH influenced microbial sensitivity to physical disturbance. Furthermore, 28% of amplicon sequence variants (ASVs), which were important in modeling Cmin, were enriched under soils managed with minimal physical disturbance. Sequences identified as enriched under minimal disturbance and important for modeling Cmin, were linked to organisms which could produce extracellular polymeric substances and contained metabolic strategies suited for tolerating environmental stressors. Understanding how physical disturbance shapes microbial communities across climates and inherent soil properties and drives changes in Cmin provides the context necessary to evaluate management impacts on standardized measures of soil microbial activity.

This 3-page publication discusses the benefits of using perennial grasses in peanut/cotton rotations for integrated management of nematodes, diseases, and weeds. Written by D. L. Wright, J. J. Marois, S. George, Z. Grabau, R. Barocco, and I. Small, and published by the UF/IFAS Agronomy Department, revised September 2022. SS-AGR-125/AG257: Use of Perennial Grasses in Peanut/Cotton Rotations for Integrated Management of Nematodes, Diseases, and Weeds (ufl.edu)