Substituting readily available nitrogen fertilizer with controlled-release nitrogen fertilizer improves crop yield and nitrogen uptake while mitigating environmental risks: A global meta-analysis

Abstract

ContextControlled-release nitrogen fertilizer (CRN) is considered as an efficient tool for improving crop total uptake of N (TUN) and crop yield by providing better synchronization of crop N demand, but its effects on crop productivity, greenhouse gases (GHG) emissions and N loss are variable across agroecosystems. Objective and methodsHere, we conducted a meta-analysis by synthesizing 8874 observations from 240 published studies to address the effects of substituting CRN for readily available N fertilizer on crop yield, TUN, profit, GHG emissions, and N loss in rice, maize, wheat, soybean, and rape, with focus on cereals. ResultsOverall, CRN could increase crop productivity (crop yield, 5.1 %; profit, 8.2 %; TUN, 7.1 %) and reduce environmental pollution (GHG emissions, −3.6 % to − 18.6 %; N loss, −32.6 % to −49.1 %). These efficacies varied among crops but showed similar trends in general. The effect of CRN on crop yield was modulated by the N rate and the ratio of CRN. The optimal N rate and CRN ratio to obtain higher crop yields and profits also varied with crops. The CRN efficacies for decreasing GHG emissions and N loss depended on the mean growing season temperature, mean growing season precipitation, background soil total organic carbon content and pH values, the regions, and the CRN ratio and coating materials. A synergy of CRN with other crop management practices, such as mulching and efficient irrigation, was an effective strategy for increasing both crop productivity and environmental benefits. ConclusionsSubstituting readily available nitrogen fertilizer with CRN could produce more food and obtain higher profits with less environmental risk in crops, especially in cereals. ImplicationsThis study provides new insights into the effect of plant-soil-climate-management systems on crop productivity and environmental benefits for Sustainable Development Goals.