Optimizing Biochar and Fertilizer Application to Improve Rice Production in Reclaimed Coastal Saline Soils Using the ORYZA_V3 Crop Model

Abstract

【Background and objective】 Fertilization and soil amendments are common agronomic technologies to improve soil properties and safeguard crop production, but how to optimize their applications to save fertilizers without compromising crop yield is an issue that remains largely elusive. The objective of this paper is to fill this knowledge gap. 【Method】 We took rice grown in the reclaimed coastal saline soils as an example, and simulated its growth in response to biochar and nitrogen fertilization using the ORYZA_V3 crop model. Lysimeter experiments were conducted and the experimental results were used to calibrate the model. The calibrated model was then used to evaluate the impact of different nitrogen fertilizations and biochar amendments on crop growth and yield. 【Result】 The ORYZA_V3 model was capable of simulating the growth and yield of rice grown in the saline soils. When nitrogen application was low, amending the soil with biochar can increase the rice yield at significant level. However, the improvement depends on nitrogen application rate. When nitrogen application was more than 235 kg/hm2, nitrogen did not appear to be a limiting factor for the crop and the efficacy of amending the soil with biochar for improving crop growth and yield was also waning. For example, when the nitrogen fertilization was 235 kg/hm2, adding 2% of biochar (w/w) gave a yield 8 680.1 kg/hm2, while when the nitrogen fertilization was 141 kg/hm2, add 5% of biochar could increase the rice yield to 8 834.1 kg/hm2. Amending the saline soil with biochar is hence an effective way to reduce nitrogen application without compromising crop yield. 【Conclusion】 The efficacy of amending the reclaimed coastal saline soils with biochar to improve rice yield was when nitrogen fertilization application was low, and its efficacy waned as the nitrogen application increased. These results have important implications for rice production in regions with salt-affected soils.

Keywords

• nitrogen fertilization
• saline soil
• rice yield
• oryza_v3 model
• biochar amendment