Improving Nitrogen Use Efficiency—A Key for Sustainable Rice Production Systems

Pauline Chivenge,Jon Hellin,Michelle Anne Bunquin,Sheetal Sharma

doi:10.3389/fsufs.2021.737412

Abstract

Fertilizer use and genetic improvement of cereal crops contributed to increased yields and greater food security in the last six decades. For rice, however, fertilizer use has outpaced improvement in yield. Excess application of nutrients beyond crop needs, especially nitrogen (N), is associated with losses to the environment. Environmental pollution can be mitigated by addressing fertilizer overuse, improving N use efficiency, while maintaining or improving rice productivity and farmers' income. A promising approach is the site-specific nutrient management (SSNM), developed in the 1990s to optimize supply to meet demand of nutrients, initially for rice, but now extended to other crops. The SSNM approach has been further refined with the development of digital decision support tools such as Rice Crop Manager, Nutrient Expert, and RiceAdvice. This enables more farmers to benefit from SSNM recommendations. In this mini-review, we show how SSNM can foster sustainability in rice production systems through improved rice yields, profit, and N use efficiency while reducing N losses. Farmer adoption of SSNM, however, remains low. National policies and incentives, financial investments, and strengthened extension systems are needed to enhance scaling of SSNM-based decision support tools.

Highlights

Optimal nutrient management in rice is important for food security, climate change mitigation, adaptation and transformation, and attainment of several sustainable development goals (Cakmak, 2002; Kanter et al, 2019; Lal et al, 2020)
Our analysis shows that on average, the implementation of site-specific nutrient management (SSNM) recommendations resulted in 644 kg ha−1 (11.4%) more rice yield compared to the farmer fertilizer practice (FFP; Table 1)
Our mini-review clearly shows that SSNM in rice cropping systems increases rice yield, profit, and N use efficiency while reducing N losses and greenhouse gas (GHG) emissions when compared with the farmer practice

Summary

Introduction

Optimal nutrient management in rice is important for food security, climate change mitigation, adaptation and transformation, and attainment of several sustainable development goals (Cakmak, 2002; Kanter et al, 2019; Lal et al, 2020). Fertilizer use has reduced agriculture expansion into natural ecosystems by increasing crop productivity on existing land. While yields increased with fertilizer use in the 1960s, they stagnated in intensive rice systems in the mid1980s despite the development of varieties with greater yield potential (Dawe and Dobermann, 1999). With increasing pressure to meet global food demand while fostering environmental sustainability, a paradigm shift is needed to a more judicious use of N fertilizer

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Conclusion