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Poor soil health purportedly limits crop yield and on-farm profitability in environments with a history of intensive tillage. Research was conducted to determine if cover cropping improves basic soil physical properties, crop productivity, and economic parameters in conventionally tilled soils. The effects of irrigation and cover crop species on bulk density, water infiltration rate, cotton yield, and net returns were evaluated on a Dundee silty clay loam (Fine-silty, mixed, active, thermic type Typic Endoqualfs) near Tribbett, MS in 2017 and a Leeper silty clay loam (fine, smectitic, nonacid, thermic Vertic Epiaquepts) near Starkville, MS from 2017 through 2018. Relative to the fallow production system, cereal rye and crimson clover decreased bulk density 4.6% but had no effect on water infiltration rate. Pooled over year and location, cover crop had no effect on lint yield in either irrigated or non-irrigated environments. However, transitioning from conventional to a cover crop system reduced net returns for cotton $50.22/ha to $307.87/ha on average. Our data indicate that while transitioning from a conventional to a fall cover crop production system, modest improvements in some soil physical properties due to cover crop establishment will not increase cotton productivity but will decrease net returns.

Properly terminating furrow irrigation in mid-southern United States (U.S.) crops could reduce irrigation costs, the likelihood of adverse harvest conditions, and agricultural withdrawal from the Mississippi River Valley Alluvial Aquifer (MRVAA). This research was conducted to determine an optimum termination window for furrow-irrigated cotton (Gossypium hirsutum L.) in the mid-southern U.S. The effects of irrigation termination timing on cotton lint yield, net returns, and irrigation water use efficiency (IWUE) were evaluated on a Leeper silty clay loam (fine, smectitic, nonacid, thermic Vertic Epiaquepts) and on a Dundee silty clay (fine-silty, mixed, active, Typic Endoaqualfs). Neither terminating nor continuing to irrigate cotton from cutout (NAWF = 5) up to three weeks past first cracked boll had an effect on lint yield or fiber quality (p ≥ 0.6107). Irrigation water use efficiency declined when water was applied past cutout (p < 0.0001). Results indicate that irrigation in cotton can be terminated at cutout without adversely effecting lint yield and fiber quality if soil water potential does not exceed -130 kPa prior to first cracked boll. Terminating irrigation in cotton at cutout could reduce late season irrigation cost and reduce water withdrawal from the MRVAA thus improving it sustainability.

HighlightsAn integrated research and Extension program promoted adoption of computerized hole selection (CHS), surge irrigation, soil moisture monitoring, and multiple inlet rice irrigation (MIRI) for surface irrigators in Arkansas.Using a contest design, water use efficiency (WUE) was determined for maize, soybean, and rice fields, and report cards were provided to contest participants to provide feedback on their irrigation acumen.The highest yielding fields did not always result in the highest WUE.The contest was implemented on working commercial farms in the Arkansas Delta using flowmeters and in-field crop yield checks for the purpose of promoting adoption of irrigation water management (IWM).Abstract. The Arkansas “most crop per drop” irrigation contest is an integrated research and Extension program developed to assess water use, rainfall, and yield for the purpose of estimating water use efficiency (WUE). The irrigation contest resembles traditional yield contests, with the goal of documenting WUE and increasing adoption and awareness of irrigation water management (IWM) practices in the region. Adoption of IWM practices was greater for those who participated in the contest than their Arkansas peer average, with documented adoption increases of 33% for computerized hole selection, 28% for surge irrigation, and 51% for soil moisture monitoring. Keywords: Computerized hole selection, Soil moisture monitoring, Surge irrigation.

Highlights Within-field variability was larger for individual depths than for the profile average across multiple depths. Distributions of the profile average were approximately normal, with increasing variances as the soil was drying. Probability theory was applied to quantify the effect of sensor set number on irrigation scheduling. The benefit of additional sensors sets may decrease for longer irrigation cycles and for more heterogeneous fields. Abstract. Even when located within the same field, multiple units of the same soil moisture sensor rarely report identical values. Such within-field variability in soil moisture sensor data is caused by natural and manmade spatial heterogeneity and by inconsistencies in sensor construction and installation. To better describe this variability, daily soil water tension values from 14 to 23 sets of granular matrix sensors during the middle part of four soybean site-years in the Mississippi Delta were analyzed. The soil water tension data were found to follow approximately normal distributions, to exhibit moderately high temporal rank stability, and to show strong positive correlation between mean and variance. Based on these observations and the existing literature, a probabilistic conceptual framework was proposed for interpreting within-field variability in granular matrix sensor data. This framework was then applied to investigate the impact of sensor set number (i.e., number of replicates) and irrigation triggering threshold on the scheduling of single-day and multi-day irrigation cycles. If a producer’s primary goal of irrigation scheduling is to keep soil water adequate in a particular fraction of land on average, the potential benefit from increasing sensor set number may be smaller than traditionally expected. Improvement, expansion, and validation of this probabilistic framework are welcomed for developing a practical and robust approach to selecting the sensor set number and the irrigation triggering threshold for diverse soil moisture sensor types in diverse contexts. Keywords: Irrigation scheduling, Probability, Sensors, Soil moisture, Soil water tension, Variability, Watermark.

The termination timing of cover crops varies by farm. This research was conducted to determine whether the timing of cover crop termination alters cotton growth and development. The effects of cover crop (crimson clover, cereal rye, oat, and a blend of cereal rye + crimson clover) and termination timing (targeted dates 01 February, 01 March, 01 April, and 01 May) on cotton emergence, plant height, nodes above white flower and yield was evaluated near Starkville, MS on a Leeper silty clay loam (fine, smectitic, nonacid, thermic Vertic Epiaquepts) in 2017 and 2018 and near Tribbett, MS on a Dundee silty clay loam (Fine-silty, mixed, active, thermic type Typic Endoqualfs) in 2017. Timing of cover crop termination had a transient effect on cotton emergence. Relative to terminating cover crops in March or April, terminating in February or May decreased cotton emergence at 7 days after planting (DAP) by up to 26%. However, by 14 DAP, cotton stand averaged 74,190 plants/ha and there was no effect of cover crop termination timing on emergence. There were modest interaction effects of cover crop and termination timing on cotton development including plant height, number of nodes, and nodes above white flower. Cotton lint yield did not differ due to cover crop species but increased up to 8% when cover crop termination was delayed from February until May. This research indicates that April and May are the optimal times to terminate a cover crop in a Mississippi cotton production system, provided there is a suitable environment for healthy cotton growth.

The reniform nematode, Rotylenchulus reniformis, can be damaging in silt loam soils that have predominantly supported cotton (Gossypium hirsutum L.) production in the Mid-Southern United States. The objective of this research was to determine the profitability of integrated nematode management options in Mississippi cotton production in soils naturally infested with the reniform nematode. Experiments were conducted near Hamilton, MS, in 2016 and Oswego and Tchula, MS, in 2017. Commercially available seed treatments included a base seed treatment of azoxystrobin + fludioxonil + mefenoxam and seed-applied nematicides including thiodicarb + imidacloprid and fluopyram. In-furrow nematicides included aldicarb and fluopyram + imidacloprid. Lastly, 1,3-dichloropropene was applied preplant to soil followed by cotton seed with and without treatment. Cotton yield was 40 kg/ha greater when 1,3-dichloropropene was applied, and a base fungicide seed treatment was utilized compared with the base seed treatment alone. Cotton yield was at least 73 kg/ha greater when the base seed treatment was followed by aldicarb or fluopyram + imidacloprid in-furrow compared with seed treatments alone. Economic analyses suggested that seed treatment and in-furrow nematicides without 1,3-dichloropropene provided the greatest return on investment.

Management decisions are needed for producers who experience hail or wildlife damage to cotton when replanting is not an option. This research was conducted to determine if applications of foliar nitrogen (N) fertilizer had an effect on cotton growth, lint yield, lint turnout, or fiber quality to cotton that had eight nodes of growth, including the apical meristem, removed at pinhead square or first bloom. The effects of foliar N (no foliar N, foliar N applied at the time of damage, one week after damage, two weeks after damage, at the time of damage + one week after damage, at the time of damage + two weeks after damage, one week after + two weeks after damage, and at the time of damage + one week after + two weeks after damage) were evaluated on Phytogen 499 WRF planted in Mississippi in 2016 and 2017.

Developing a model for soybean seed emergence offers a tool producers could use for planting date options and in predicting seedling emergence. In this study, temperature effects on soybean seed emergence were quantified, modeled, and validated. The data for seed emergence model development was generated at varying temperatures, 20°C/12°C, 25°C/17°C, 30°C/22°C, 35°C/27°C, and 40°C/32°C, on two soybean cultivars, Asgrow AG5332 and Progeny P 5333 RY. Time for 50% emergence (t50%) was recorded, and seed emergence rate (SER) was estimated as reciprocal to time at each temperature in both the cultivars. No differences were observed between the cultivars in their response to temperature. A quadratic model (QM) best described the relationship between t50% and SGR and temperature (R2 = 0.93). Two sets of experiments were conducted to validate the model. In Experiment 1, 17 time-series planting date studies with the same cultivars were used by utilizing diurnal and seasonal changes in temperature conditions. In the second experiment, sunlit growth chambers with 3 different day/night temperatures, low—20°C/12°C, optimum—30°C/22°C, and high—40°C/32°C, and 64 soybean cultivars belonging MG III, IV, and V, were used. Air temperature and t50 were recorded, and SGR was estimated in all experiments. No differences were recorded among the cultivars for t50% and SGR, but differences were observed among seeding date and temperature experiments. We tested QM and traditionally used Growing Degree Days models against the data collected in validation experiments. Both the model simulations predictions agreed closely with the observed data. Based on model statistics, R2, root mean square errors (RMSE), and comparison of observations and predictions to assess model performance, the QM model performed better than the GDD model for soybean seed emergence under a wide range of cultivars and environmental conditions.

The addition of cover crops and minimum tillage to current row‐crop production practices in the mid‐southern United States could holistically improve the sustainability of these farming systems. This relatively short‐term study was conducted to determine if the addition of these practices into corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotational systems in the region would decrease irrigation water use while improving yield, irrigation water use efficiency, and net returns above production costs. The effects of cover crops and minimum tillage on these parameters were investigated from 2017 to 2019 on six pairs of production fields in northwest Mississippi. A pair was created by dividing a single field that had been under uniform management into two fields that were land leveled and hydrologically separated with an earthen berm. Control fields were managed according to standard practices within the region, which include winter fallow and multiple tillage passes, whereas treatment fields were managed with winter cover crops and minimum tillage. The addition of cover crops and minimum tillage had no effect on yield (p = .09), irrigation water use efficiency (p = .38), or irrigation water applied (p = .83). The net economic return on average across all site years was a loss of US$233 ha–1. These results reflect the short study period as changes resulting from these practices often occur on a greater time scale. The value proposition for adoption of a cover crop–minimum tillage system will be challenging in the mid‐southern United States if potential benefits are to be expected in the early years of adoption.

Soil fertility and reniform nematode (RN) directly affect earlyseason growth and physiology of cotton. The growth responses to soil fertility and RN may, however, vary across germplasm. A greenhouse study was conducted to gain information on the role that host plant resistance plays in influencing RN populations, and cotton growth and physiological response to a range of soil nitrogen (N) levels in the presence and absence of RN. RN-resistant cotton lines (08SS110-NE06.OP and 08SS100) along with susceptible cultivars (Deltapine 16 and PHY 490 W3FE) were subjected to four levels of N from planting until biomass harvesting, 60 days after planting(DAP), under the presence orabsence of RN. The linear and quadratic functions (r2 = 0.72 to 0.99) bestdescribed measured responses of cotton genotypes to soil N. However, the responses were not different among genotypes, except for plant height at 30 DAP. This study revealed significant increases in several morphological parameters with increasing rates of N. RN population in the pots grown with resistant lines was lower whencompared to susceptible cultivars at biomassharvest. Physiological responses indicated that 08SS110-NE06.OP was more resilient to RN stress than other genotypes. The information from this study could be useful in managing the early season growth of cotton.

This article identifies irrigated row-crop farmer factors associated with the adoption of water-conserving practices. The analysis is performed on data from a survey of irrigators in Mississippi. Regression results show that the amount of irrigated area, years of education, perception of a groundwater problem, and participation in conservation programs are positively associated with practice adoption, while number of years farming, growing rice, and pumping cost are negatively associated with adoption. However, not all factors are statistically significant for all practices. Survey results indicate that only a third of growers are aware of groundwater problems at the farm or state level, and this lack of awareness is related to whether farmers noticed a change in the depth to water distance in their irrigation wells. This evidence is consistent with a report to Congress from the Government Accountability Office (GAO) that recommends policies promoting the use of: (1) more efficient irrigation technology and practices and (2) precision agriculture technologies, such as soil moisture sensors and irrigation automation.

Optimizing overhead irrigation practices will ensure that water loss is minimized, and each unit of water is used most effectively by the crop. In order to optimize overhead irrigation setup, a study was conducted over two years in Mississippi to quantify the optimal overhead irrigation duration and intensity for six soil types commonly found in row-crop production regions in the state. Each soil type was transferred to containers and measured for total water infiltration and water infiltration over time using a two-nozzle rainfall simulator in a track sprayer. The rainfall simulator was calibrated to apply 2.1 mm of water per minute. The rainfall simulator ran on a 2.4 m track for 90 s, with 3.2 mm total water applied during that time. After the 90 s overhead irrigation event, each container was undisturbed for 150 s and assessed for irrigation penetration through the soil profile. Commercially available irrigation nozzles were measured for droplet size spectrum. Results showed that across soil type, organic matter was the primary factor affecting water infiltration through the profile, followed by soil texture. Irrigation nozzle volumetric median droplet sizes ranged from 327 &micro, m to 904 &micro, m. The results will improve overhead irrigation setup in Mississippi, improving irrigation water use efficiency and reducing losses from soil erosion over the application of water and reduced crop yield.

The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), is the most important insect pest of cotton in the states of Arkansas, Mississippi, Louisiana, Missouri, and Tennessee. Numerous insecticide applications are required during a growing season to manage this insect, and these associated costs are unsustainably high for growers. Cultural practices could provide an inexpensive means to manage the tarnished plant bug. Experiments were conducted at the Mississippi State University, Delta Research and Extension Center, to determine the impact of leaf pubescence on tarnished plant bug feeding that results in reduced cotton yields. Three separate varieties, each possessing differing levels of pubescence, were utilized to determine if there was any effect on tarnished plant bug density and damage. Varieties possessing high numbers of trichomes retained significantly more squares and yielded significantly higher than varieties with fewer trichomes. The variety with the fewest number of trichomes sustained significantly greater injury and yield loss than the other varieties utilized in this experiment. Variety selection could be an inexpensive cultural practice used to combat rising input costs associated with cotton production.

Effects of environmental stressors on the parent may be transmitted to the F1 generation of plants that support global food, oil, and energy production for humans and animals. This study was conducted to determine if the effects of drought stress on parental soybean plants are transmitted to the F1 generation. The germination and seedling vigor of F1 soybean whose maternal parents, Asgrow AG5332 and Progeny P5333RY, were exposed to soil moisture stress, that is, 100, 80, 60, 40, and 20% replacement of evapotranspiration (ET) during reproductive growth, were evaluated under controlled conditions. Pooled over cultivars, effects of soil moisture stress on the parents caused a reduction in the seed germination rate, maximum seed germination, and overall seedling performance in the F1 generation. The effect of soil moisture stress on the parent environment induced seed quality that carried on the F1 generation seed gemination and seedling traits under optimum conditions and further exasperated when exposed to increasing levels of drought stress. Results indicate that seed weight and storage reserve are key factors positively associated with germination traits and seedling growth. Our data confirm that the effects of soil moisture stress on soybean are transferable, causing reduced germination, seedling vigor, and seed quality in the F1 generation. Therefore, optimal water supply during soybean seed formation period may be beneficial for seed producers in terms of optimizing seed quality and vigor characteristics of commodity seed.

Recent improvements in climate modeling and consolidation within the agriculture and weather industries result in producers who are aware of relatively short-term weather patterns and can modify their cropping and irrigation strategies accordingly. Advances in breeding and genetics have improved stress tolerance of commercial corn hybrids and, along with seed treatment advances, allows seedlings to withstand cool, moist temperatures. Our work in the Mid-South USA region suggests that there are potential moisture savings with minor modifications to existing irrigation and agronomic practices. Data from over 14 farmer fields and four research stations over the 2013 to 2015 growing seasons suggest that by implementing minor irrigation modifications, we can improve yield by approximately 3 to 5 % (8 bu/A) and reduce the amount of water applied by 40 % all while increasing profitability. Planting date, plant population, and hybrid selection can also be optimized to improve the profitability of the system and lower risk.

Studies suggest that coincidental adoption of both herbicide-resistant genetically modified crops (GMC) and conservation management may be mutually complementary, but integrated conservation systems with GMCs need to be assessed to balance production goals with environmental concerns. Genetically modified glyphosate-resistant cotton (Gossypium hirsutum L.) was managed on replicated experimental plots as either no-till (NT) or minimum tillage (MT) and with either no cover (NC) or rye (Secale cereal L.) cover crop (CC) from 2001 to 2007 near Stoneville, MS. Rainfall simulations in 2007 were used to evaluate water quality in runoff as influenced by management at two critical times: (i) 24 h after fertilizer application in the spring; and (ii) 24 h after tillage following crop harvest. With the exception of MT-NC in the spring (with the lowest surface plant residue coverage, 2%), runoff was higher in fall than spring. Suspended solids and turbidity in runoff were higher for tilled soil (MT) and areas with no cover crop, particularly in the fall. Tillage in the fall was the largest contributor to erosion loss. Similarly, total orthophosphate and total Kjeldahl N losses were greatest with tillage in the fall, while the lowest dissolved organic C losses in runoff were in fall with NT. Overall, NT and CC treatments reduced nutrient and solids losses. Major factors contributing to these results include recent tillage (in the fall) and coverage of the soil surface by plant residues (NT > MT, CC > NC). This study demonstrated the effectiveness of integrating cover crop and conservation tillage in reducing runoff and nutrient losses in a GMC system.

Accurately delivering and precisely timing sprinkler irrigation improves peanut yield and profitability, but there are no data on how to achieve this in the mid-southern USA where furrow-irrigation dominates. This research was conducted to determine if soil water potential could be manipulated through land preparation method, irrigation delivery, and irrigation scheduling. The effects of land preparation method (flat vs bed), furrow-irrigation delivery (every vs every-other furrow), and irrigation scheduling [Food and Agriculture Organization and drainage paper 56 (FAO-56), - 50 kPa, -75 kPa, and -100 kPa] on peanut yield, net returns above irrigation costs, and irrigation water use efficiency were investigated near Stoneville, MS on a Bosket very fine sandy loam. Our data indicate that regardless of land preparation method, peanut yield, net returns above irrigation costs, and irrigation water use efficiency are most often optimized in the mid-southern USA by irrigating every other furrow at a threshold of -50 kPa.

A 4-yr field study was conducted from 2007 to 2010 at Stoneville, MS to examine the effects of rotating corn and soybean under reduced tillage conditions on soil properties, yields, and net return. The six rotation systems were continuous corn (CCCC), continuous soybean (SSSS), corn-soybean (CSCS), soybean-corn (SCSC), soybean-soybean-cornsoybean (SSCS), and soybean-soybean-soybean-corn (SSSC). Field preparation consisted of disking, subsoiling, disking, and bedding in the fall of 2005. After the fall of 2006, the raised beds were refurbished each fall after harvest with no additional tillage operations to maintain as reduced tillage system. The surface 5 cm soil from continuous soybean had higher pH than continuous corn in all four years. Unlike pH, total carbon and total nitrogen were higher in continuous corn compared to continuous soybean. Delta 15N tended to be higher in continuous corn compared to continuous soybean. Fatty acid methyl ester (FAME) indicated minor changes in soil microbial community in relation to cropping sequence, however there was a significant shift in rhizosphere community depending on crop. Corn yield increased every year following rotation with soybean by 16%, 31%, and 15% in 2008, 2009, and 2010, respectively, compared to continuous corn. As a result, net returns were higher in rotated corn compared with continuous corn. This study demonstrated that alternating between corn and soybean is a sustainable practice with increased net returns in corn.

Simazine is an important management tool for weed control in vineyards because of its relatively low price, reliable control of several problem weeds, and long residual activity. After repeated and extensive use of simazine, several growers in the Central Valley of California expressed concerns about reduced, residual weed control with this herbicide. Experiments were conducted to evaluate the rate of simazine dissipation in soils with differing simazine-use histories and to determine whether residual weed control differed among sites. Two raisin vineyards were used in all studies, one with extensive simazine-use history (adapted) and one with no recent simazine-use history (nonadapted). Results indicated that simazine dissipation from biotic processes was fourfold greater in soil with a long simazine-use history relative to soil with no recent simazine applications. In the field, simazine persisted longer at the nonadapted site, and weed-control duration was affected by dissipation rate. Central Valley vineyard soils that have had repeated simazine applications can develop enhanced, microbial degradation, and reduced, residual weed control is possible; however, weed control is also affected by environmental conditions and other crop management practices.

Simazine is commonly used to control broadleaf weeds and annual grasses in perennial tree and vine crops because of its relatively low cost and long residual activity. Simazine may be subject to enhanced biodegradation in some areas which can result in decreased herbicide persistence and reduced residual weed control. Laboratory studies were conducted to determine if rapid simazine degradation occurs in California citrus orchards and if degradation rates are correlated with simazine use history. In the Central Valley, simazine degradation curves indicate that simazine degradation rate is more rapid in soils with a simazine use history (adapted) compared to soils with no recent use (non-adapted). In these soils, simazine dissipation was two- to three-fold faster in adapted compared with the non-adapted soils. However, in southern California, simazine dissipation and mineralization were not substantially different among soils with different simazine use histories. Repeated simazine use in California orchards can lead to the development of enhanced microbial degradation of the herbicide. However, soil type and long-term cropping factors can affect persistence and distribution of herbicide-degrading microbial populations in California orchards.

a b s t r a c t Wetlands may be constructed to provide several ecosystem functions. A constructed wetland receiving agricultural runoff water was observed prior to, and for more than two years after, establishment. The excavated portion of this wetland was compared to an undisturbed, upland area and to an adjacent, natural, depressional, reference wetland. After construction the excavated cell was rapidly colonized by wetland plant species, including some exotic invasive weeds. Flourescein diacetate (FDA) hydrolysis and triphenyl tetrazolium chloride (TTC) dehydrogenase assays indicated that the soil microbial community was more active in the excavated wetland cell than either of the two reference areas. In 2003 and 2004 TTC activity was greater than twice as high in the constructed wetland than the reference wetland. FDA was greatly stimulated in the constructed wetland immediately after construction, but by 2004 the three systems were not significantly different. The soil microbial community of the constructed wetland rapidly decreased in the abundance of fungi and gram-negative bacteria and increased in gram-positive bacteria and overall bacteria, as measured by fatty acid methyl esters. These shifts in the microbial community were consistent with the differences noted between the communities of the upland system and the reference wetland. During the time of observation the constructed wetland did not sequester carbon relative to the upland system (P = 0.11) and did not significantly increase in carbon content (P = 0.41).

In the present study a branched serial first-order decay (BSFOD) model is presented and used to derive transformation rates describing the decay of a common herbicide, atrazine, and its metabolites observed in unsaturated soils adapted to previous atrazine applications and in soils with no history of atrazine applications. Calibration of BSFOD models for soils throughout the country can reduce the uncertainty, relative to that of traditional models, in predicting the fate and transport of pesticides and their metabolites and thus support improved agricultural management schemes for reducing threats to the environment. Results from application of the BSFOD model to better understand the degradation of atrazine supports two previously reported conclusions: atrazine (6-chloro-N- ethyl-N 0 -(1-methylethyl)-1,3,5-triazine-2,4-diamine) and its primary metabolites are less persistent in adapted soils than in nonadapted soils; and hydroxyatrazine was the dominant primary metabolite in most of the soils tested. In addition, a method to simulate BSFOD in a one-dimensional solute-transport unsaturated zone model is also presented. Environ. Toxicol. Chem. 2011;30:1973-1981. # 2011 SETAC