Abstract
In the past several decades, agricultural management practices consisting of intensive tillage and high rate of fertilization to improve crop yields have resulted in the degradation of soil and environmental qualities by increasing erosion and nutrient leaching in the groundwater and releasing greenhouses gases, such as carbon dioxide (CO2) and nitrous oxide (N2O), that cause global warming in the atmosphere by oxidation of soil organic matter. Consequently, management practices that sustain crop yields and improve soil and environmental qualities are needed. This paper reviews the findings of the effects of tillage practices, cover crops, and nitrogen (N) fertilization rates on crop yields, soil organic carbon (C) and N concentrations, and nitrate (NO3)-N leaching from the soil. Studies indicate that conservation tillage, such as no-till or reduced till, can increase soil organic C and N concentrations at 0- to 20-cm depth by as much as 7–17% in 8 years compared with conventional tillage without significantly altering crop yields. Similarly, cover cropping and 80–180 kg N ha year fertilization can increase soil organic C and N concentrations by as much as 4–12% compared with no cover cropping or N fertilization by increasing plant biomass and amount of C and N inputs to the soil. Reduced till, cover cropping, and decreased rate of N fertilization can reduce soil N leaching compared with conventional till, no cover cropping, and full rate of N fertilization. Management practices consisting of combinations of conservation tillage, mixture of legume and nonlegume cover crops, and reduced rate of N fertilization have the potentials for sustaining crop yields, increasing soil C and N storage, and reducing soil N leaching, thereby helping to improve soil and water qualities. Economical and social analyses of such practices are needed to find whether they are cost effective and acceptable to the farmers.
Highlights
Increasing crop production to feed the growing population was a major challenge to the agricultural community in the past few decades
The results suggests that no-tillage may be as good as conventional tillage in producing yields of cereal crops but reduced tillage, such as chisel plowing (CP), may be needed to sustain yields of vegetable crops, such as tomato
Improved agricultural management practices, such as conservation tillage, cover cropping, and reduced rate of N fertilization, show promising results to improve soil and water qualities. These practices can improve soil C and N storage and reduce soil erosion and N leaching from the soil profile to the surface and groundwater without significantly altering crop yields as compared with conventional tillage, no cover cropping, and full rate of N fertilization
Summary
Increasing crop production to feed the growing population was a major challenge to the agricultural community in the past few decades. Sainju et al.[22] observed that legume cover crops, such as hairy vetch (Vicia villosa Roth) and crimson clover (Trifolium incarnatum L.), increased yields of silage corn, sorghum grain, tomato, eggplant (Solanum melogena L.), and bell pepper (Capsicum annuum L.) compared with nonlegume cover crops, such as rye (Secale cereale L.), or no cover crop (Tables 1 and 2) They observed that yield increases with hairy vetch and crimson clover were similar to those obtained with fertilization of 60–180 kg N ha-1. Because cover crops use residual fertilizer and soil nutrients, such as N, and assimilate in the plant biomass, they recycle soil inorganic N and increase organic N level at the surface soil[5,10]. LSD denotes least significant difference at p < 0.05[22]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
