Cover crops slow erosion, improve soil, smother weeds, enhance nutrient and moisture availability, help control many pests and bring a host of other benefits to your farm. At the same time, they can reduce costs, increase profits and even create new sources of income. You¿ll reap dividends on your cover crop investments for years, since their benefits accumulate over the long term. This book will help you find which ones are right for you. Captures farmer and other research results from the past ten years. The authors verified the info. from the 2nd ed., added new results and updated farmer profiles and research data, and added 2 chap. Includes maps and charts, detailed narratives about individual cover crop species, and chap. about aspects of cover cropping.

Corn (Zea mays L.) and soybean ( Glycine max L.) production in the Midwest US can result in significant nutrient leaching to groundwater and surface waters, which contributes to eutrophication and hypoxia in the Gulf of Mexico. A promising strategy to control nutrient leaching and sediment runoff loss during winter fallow period is the use of cover crops (CCs). In southern Illinois, CCs are not widely adopted by farmers due to economic constraints and the lack of scientific data that supports benefits of incorporating CCs into the corn-soybean rotation. This doctoral dissertation addresses the critical question of the feasibility of the use of CCs in southern Illinois and is divided into three overarching research studies with different objectives divided into six research chapters. Research study 1 was a field experiment conducted from 2013 to 2017 to examine the effect of CCs (CC vs noCC) under two tillage systems [(no-tillage (NT) and conventional tillage (CT)] on aboveground plant attributes [dry matter yield, C:N ratio and nitrogen uptake (N uptake)], crop yields, available soil N content and N leaching in the vadose zone. The experimental layout was a randomized design with three rotations including corn-noCC-soybean-noCC [CncSnc], corn-cereal rye (Secale cereale L.) -soybean-hairy vetch (Vicia villosa R.) [CcrShv], and corn-cereal rye-soybean-oats+radish (Avena sativa L. + Raphanus sativus L.) [CcrSor] and two tillage systems. Soil samples collected after corn or soybean harvest and CC termination were analyzed for standard soil fertility parameters. Pan lysimeters installed below the 'A' horizon with depth varying from 22 to 30 cm were used for measuring soil solution nutrient concentration on weekly or biweekly basis depending on the precipitation. In NT system, the corn yield was 14% greater with CcrShv compared to CncSnc, whereas no significant difference existed in corn yield due to CC treatments within CT. Both CC treatments under NT reduced soybean yield by 24 to 27% compared to noCC. The rotations CcrShv and CcrSor with hairy vetch and oats+radish as preceding CCs resulted in 89% (37.73 vs 19.96 kg ha-1) and 68% (33.46 vs 19.96 kg ha-1) more nitrate-N (NO 3-N) leaching than the CncSnc during cash crop season 2015. During the CC season in spring 2016, cereal rye CC in CcrShv and CcrSor reduced the NO 3-N leaching by 84% (0.68 kg ha-1) and 78% (0.63 kg ha-1) compared to the CncSnc, respectively, under the CT system. Overall, our results indicated that the CT system had greater N leaching losses compared to NT system due to higher N availability in the tilled soil profile. The goal of the second research study was to understand the mechanisms of N cycling by CCs. We applied 15N labeled urea fertilizer (9.2% atom) to corn that followed hairy vetch and noCC in May 2017 to evaluate the contribution of fertilizer and soil organic matter to N leaching and quantify the 15N content of surface runoff after storm events. During the 2017 corn season, repeated soil samples were collected and analyzed for 15N fertilizer recovery in soil at three depths. 15N recovery was higher in the corn that had hairy vetch as the preceding CC than the corn that had noCC by 13.13 and 3.68 kg ha-1 on soil sampling events of 7 and 21 days after planting of corn, respectively, at the depth 15-30 cm. Overall, the cumulative loss of 15NO 3-N during corn season 2017 was

Cover crops have potential to provide benefits to agricultural systems, such as improved soil productivity, nutrient scavenging, weed suppression, and livestock forage. There are several challenges associated with cover crop integration into traditional Midwest corn-soybean cropping systems. One of these challenges is timely establishment in the fall, which is limited by the relatively late harvest of corn and soybean. Cover crop effectiveness is related to the amount of biomass produced, thus maximizing the growth period in the fall is desired. To address this challenge, we evaluated the potential to utilize early-season soybean maturity groups (MGs) to allow for earlier soybean harvest and cover crop planting to maximize cover crop growth. In addition, an integrated cover crop and herbicide management program was evaluated to determine its effect on weed suppression and corn yield. Cover crops have often been shown to be most effective when integrated with other methods of weed management such as herbicides. Cover crops have also been shown to potentially reduce subsequent corn yield. Therefore, we evaluated the influence of cover crop planting date, termination date, and herbicide program on weed density, weed biomass, and subsequent corn yield. Field experiments were conducted in 2017-2019 across six different locations in Nebraska, Ohio, and Kentucky. Results suggest use of early-season soybean MGs allow cover crops to be planted up to 30 days sooner than late-season MGs. Cover crop biomass production was highest for early cover crop planting dates associated with early-season MGs across most site-years evaluated. Soybean yield often plateaued near a 3.0 relative maturity (RM) depending on the region, suggesting that soybean RM may be reduced to 3.0 to allow for earlier cover crop planting without sacrificing soybean yield. Results further suggest that use of a residual herbicide with a postemergence herbicide was necessary to obtain the largest reduction in both weed density and biomass. Weed biomass was occasionally reduced by the cover crop, however, results were inconsistent. Cover crops generally had minimal influence on overall weed suppression, and occasionally resulted in corn yield reduction, indicating the importance of other traditional methods of weed management. Abbreviations: MG, maturity group; RM, relative maturity.

Reducing groundwater withdrawals from the Mississippi River Valley Alluvial Aquifer is imperative to sustain future irrigated cropping systems in the mid-southern USA. This research was conducted to determine the impacts of cover crops and irrigation sensor thresholds on corn (Zea mays L.) and soybean (Glycine max L.) production, water productivity, irrigation water use efficiency, and soil physical properties in the Mississippi Delta. The cover crop treatments included cereal rye (Secale cereale L.), hairy vetch (Vicia villosa R.), wheat (Triticum aestivum L.)-radish (Raphanus sativus L.)-turnip (Brassica rapa L.) mix, and no cover crop. The irrigation thresholds included -40 kPa, -90 kPa, and no irrigation. In 2020, cover crops and irrigation thresholds showed minimal impacts on most of the measured parameters but showed improvements as the study progressed. After two years, it was determined that long-term evaluations are needed to make a recommendation to producers in the mid-southern USA.

No-till corn and soybean growers in the mid-Atlantic who use cover crops (CC) typically terminate the cover crops with an herbicide a week or more before cash crop planting. In the interest of extending soil health benefits longer into the spring, some growers are now planting green, (PG) or delaying cover crop termination until cash crop planting or later. Three experiments were conducted to quantify the effects of planting green on corn and soybean production in Pennsylvania. We had three overarching hypotheses across all of the studies: compared to early rye termination, PG would i) increase cover crop biomass, cool and dry soil at planting, and conserve soil moisture later in the growing season; ii) reduce slug damage on cash crops; and iii) not reduce cash crop yield. We conducted one experiment at two Penn State research stations for three years to evaluate cereal rye CC management influences on soybean production. We had three treatments in a split-split plot randomized block design. The main plot was rye seeding rate (34, 67, or 134 kg ha-1), the split plot was topdress nitrogen fertilization rate (34 or 67 kg ha-1), and the split-split plot was rye termination timing (early-killed or planted green). PG increased rye biomass by 48-169%. Soil (0-8 cm) in the PG treatment was generally drier at planting, wetter later and cooler for much of the growing season compared to early-killed rye. PG reduced slug damage compared to early-killed in three of four site-years measured. PG soybeans yielded similarly to the early-killed most consistently when the 2x seeding rate was combined with the lowest N rate. Our results suggest that for best results with PG soybeans, rye seeding rates should be reduced to 67 kg ha-1 or lower, N fertility should be maintained at conservative levels, and rye should be killed early in dry springs.We conducted a second experiment at the same two Penn State research stations for three years to evaluate cover crop management effects on corn production. We had two treatments in a randomized complete block design: cover crop species (crimson clover, cereal rye, or clover + rye mix), and termination timing (early-killed or planted green). We measured similar CC biomass and soil moisture effects of PG as in the soybean experiment, though we found that crimson clover also caused dryer and warmer soils compared to rye or the crimson clover + rye mix. Slug damage was not significantly influenced by PG or CC, contrary to our hypothesis. At Rock Springs, corn yield was 10% lower in PG compared to early across CC in dry 2015, and 12% lower in PG crimson clover compared to early across years, and the main predictors of corn yield were soil moisture and temperature at planting and corn population. We concluded that PG can help manage soil water and corn can maintain similar yields in early-killed CC and PG, but we caution against PG and crimson clover in dry springs due to excessive soil drying and stand establishment complications.The last experiment expanded to include three cooperating farm sites in addition to the two Penn State research stations for three years, and we evaluated cover crop termination timing (early-killed or planted green) effects on corn (4 sites) and soybean (5 sites) production across a range of crop rotations, soils, weather conditions, and equipment. Planting green increased CC biomass 94% to 181% compared to early-kill. Except for two site-years, soil was 8% to 24% drier, and 0.7 to 2.4C cooler at planting in PG compared to early-kill. Slug damage was not different, lower, or higher in PG corn, and not different or lower in PG soybeans compared to early-kill. Our yield stability analysis showed that corn yield was more likely to be reduced by PG in high yielding environments, but there was no difference to a slight benefit in yield at lower yielding environments; conversely, soybean yield was stable across environments regardless of treatment. We conclude that corn was more vulnerable to yield losses from conditions created by PG than soybeans, and growers in environments similar to Pennsylvania hoping to get the most out of their cover crops can plant soybeans green to increase cover crop biomass, and manage soil water, with little risk of yield reduction.