A Model–Data Fusion Approach for Predicting Cover Crop Nitrogen Supply to Corn

Abstract

C over crop use in the mid-Atlantic and other regions of the United States has expanded in recent decades because they are an eff ective tool for reducing erosion and nutrient leaching and because they are a source of recycled N and fi xed N 2 for ecological nutrient management (Drinkwater and Snapp, 2007;Hively et al., 2015). However, it remains a signifi cant challenge to explain the variability and predict the outcome of N cycling processes across a range of cover crop management practices (Ketterings et al., 2015), leaving farmers with few tools to support adaptive N fertility management when using cover crops. While simple mathematical models have been developed to predict N mineralization from crop residue decomposition in laboratory incubations and greenhouse studies (Vigil and Kissel, 1991; Th orup-Kristensen, 1994), these models have limited utility for N fertility management because they are not calibrated to predict relevant agronomic outcomes, such as crop yield response or N fertilizer replacement value. We have developed a model-data fusion approach that uses easily collected fi eld data to calibrate a simple, ecologically based, lumped-parameter model of the N cycle to predict how cover crops will aff ect the yield of a subsequent corn crop.Cover crops have the potential to aff ect subsequent crop yields and/or N fertilizer requirements through the processes of N mineralization and N immobilization that occur during cover crop residue decomposition, as well as the pre-emptive competition for soil inorganic N that occurs during cover crop growth (Th orup-Kristensen et al., 2003). Th e quantity and directionality (positive or negative) of net N mineralization from cover crop residues depends on the total N content (kg ha -1 ) and the C/N ratio of the cover crop biomass (Vigil and Kissel, 1991;Starovoytov et al., 2010). Because the N content and C/N ratio of cover crop residues can vary widely across different cover crop species and mixtures as well as across diff erent environments and management practices (Cherr et al., 2006; Poff enbarger et al., 2015;Finney et al., 2016), it is diffi cult to generalize the N supply potential of cover crops (Ketterings et al., 2015). Rather, site-specifi c measurements of cover crop biomass C and N contents may be necessary to accurately predict the eff ect of cover crop N cycling on subsequent crop yields and N fertilizer requirements. However, a major constraint to aBstractOne potential benefi t of cover crops (CCs) is that N mineralization from decomposing CC residues may reduce the N fertilizer requirement of a subsequent crop, but predicting this credit remains a signifi cant challenge. Th is study used a model-data fusion approach to calibrate a model of CC residue N mineralization and pre-emptive competition for soil NO 3 -that occurs during CC growth to predict the yield response of an unfertilized corn (Zea mays L.) crop. Th e model was calibrated with a data set of 199 observations from four CC experiments in central Pennsylvania. Th e most parsimonio...

Cover Crop Mixture Effects on Maize, Soybean, and Wheat Yield in Rotation

“…1D). These results are in keeping with previous findings that the mean effect of cover crop mixtures (mostly bicultures) on maize yield is relatively small (Marcillo and Miguez, 2017) and that there is a risk of maize yield loss following high-C/N cover crop mixtures (Kuykendall et al, 2015;White et al, 2016White et al, , 2017.…”

“…A small body of literature indicates that cover crop mixtures can strongly influence the yield of the following crop by affecting soil N availability, particularly for crops with high N demand, such as maize (Kuykendall et al, 2015; Finney et al, 2016; White et al, 2016, 2017). Plant residue with a C/N ratio below 25 is likely to result in net N mineralization when returned to the soil, increasing N supply, while residue with a C/N ratio higher than 25 is likely to result in net N immobilization, reducing soil N supply (White et al, 2016). In a tilled system with no fertilizer added, Finney et al (2016) found that cover crop mixtures with low‐C/N biomass increased maize yield by up to 47%, while high‐C/N mixtures decreased maize yield by up to 70%.…”

Ecosystem Services and Disservices Are Bundled in Simple and Diverse Cover Cropping Systems

“…by 20 cm deep) per plot were collected and composited for analysis on two dates, before (May) and after (July) cover crop termination. Nitrogen supply was calculated using a previously calibrated model that predicts the effects of cover crop residues and N uptake on N availability to subsequent maize crops, relative to a no‐cover control (White et al, 2016). The model inputs were fall and spring cover crop biomass N per unit area, spring biomass C/N ratio, and spring soil NO 3 − concentrations for each plot.…”

Using the cover crop N calculator for adaptive nitrogen fertilizer management: a proof of concept

“…White et al . (2016) used a model-data fusion approach to predict corn yield response to cover crops. The model uses a humification coefficient based on the C:N ratio of the cover crop residue to predict net mineralization/immobilization for conditions in Pennsylvania.…”