Abstract
Improved agronomic management strategies are needed to minimize the impact that current maize (Zea mays L.) and soybean (Glycine max (L.) Merr.) production practices have on soil erosion and nutrient losses, especially nitrogen (N). Interseeded cover crops in standing maize and soybean scavenge excess soil N and thus reduce potential N leaching and runoff. The objectives were to determine the impact that pennycress (Thlaspi arvense L.) (PC), winter camelina (Camelina sativa (L.) Crantz) (WC), and winter rye (Secale cereale L.) (WR) cover crops have on soil N, and carbon (C) and N accumulation in cover-crop biomass. The cover crops were interseeded in maize at the R5 growth stage and in soybean at R7 in four replicates over two growing seasons at four locations. Soil and aboveground biomass samples were taken in autumn and spring. Data from the maize and soybean systems were analyzed separately. The results showed that cover crops had no effect on soil NH4+-N under both systems. However, winter rye decreased soil NO3−-N up to 76% compared with no-cover-crop treatment in the soybean system. Pennycress and WC scavenged less soil N than WR. Similarly, N and C accumulation in PC and WC biomass were less than in WR, in part because of their poor growth performance under the interseeding practice. Until PC and WC varieties with improved suitability for interseeding are developed, other agronomic practices may need to be explored for improving N scavenging in maize and soybean cropping systems to reduce nutrient leaching and enhance crop diversification.
Highlights
Maize and soybean are the two most economically important crops in the upper Midwest US.Despite short-term economic advantages of growing these crops, recurrent practices used for their production in the upper Midwest US have led to unintended environmental consequences including water pollution resulting from off-site nutrient losses, mainly nitrogen [1,2,3]
At relayed soybean harvest (RSH), cover crops had no effect on soil NO3 − -N at all locations for both soil depths (Table 2)
At Morris when data were compared over years, winter camelina (WC) as well as winter rye (WR) decreased soil NO3 − -N
Summary
Maize and soybean are the two most economically important crops in the upper Midwest US.Despite short-term economic advantages of growing these crops, recurrent practices used for their production in the upper Midwest US have led to unintended environmental consequences including water pollution resulting from off-site nutrient losses, mainly nitrogen [1,2,3]. Increased N fertilizer application rates for maize production but with reduced N use efficiency in the last few decades [12] may explain the increased nitrate loads to streams. This is aggravated in the absence of growing crops immediately following maize harvesting which would enhance residual nutrient uptake and minimize runoff. Growing crops following maize harvesting to cover the soil and enhance residual nutrient uptake has been suggested as a solution to reduce nutrient loads to streams [10]. Limited crop diversification costs soybean producers in four U.S states (Iowa, Michigan, Minnesota, and Wisconsin) an estimated USD 58 million y−1 in reduced yield and increased pesticide use [2]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
