Straw Application Strategy to Optimize Nutrient Release in a Southeastern China Rice Cropland

Weiqi Wang,Jordi Sardans,Congsheng Zeng,Josep Peñuelas,Derrick Lai,Mireia Bartrons,Chun Wang,Ting Pan

doi:10.3390/agronomy7040084

Abstract

The management and improvement of paddy soils fertility are key factors for the future capacity of rice production. The return of rice straw to paddy soils is the best alternative to the application of industrial fertilizers for rice production sustainability. The best strategy for applying rice straw to improve soil nutritional capacity during rice growth has not yet been investigated. We compared straw decomposition in the ditches and ridges in paddy fields subjected to a typical crop management in southeastern China. Straw spread on the ridges provided lower residual straw carbon (C) concentration and mass, lower nitrogen:phosphorus ratio N:P, C:N, and C:P ratios, and lower soil salinity, as well as higher temperature, and higher N- and P-release capacity during the rice crop in comparison to the straw spread in the ditches. Therefore, applying rice straw to the ridges is better strategy than applying it to ditches to enhance rice production.

Highlights

Rice is one of the most important food crops globally, with more than half of the world population fed with rice [1]
During the straw-decomposition experiment, the proportion of the mass of the straw that remained in the nylon bag, the straw nutrient concentrations, the straw stoichiometry, the proportion of residual nutrients in the straw, and the soil traits all varied seasonally, apart from P concentration and soil pH and salinity (Figures 1, 2 and A2, Tables A1 and A2)
We used structural equation modeling (SEM) to analyze the factors explaining the maximum variability of the biomass; residual straw C, N, and P concentrations; soil C, N, and P concentrations; and C:N, C:P, and N:P ratios throughout the study period as functions of the habitat and the other soil traits

Summary

Introduction

Rice is one of the most important food crops globally, with more than half of the world population fed with rice [1]. Global rice production is projected to increase from 473 million tonnes in 1990 to at least 781 million tonnes by 2020 [2]. Paddy fields in China account for 23% of all cultivated land and nearly 20% of the global rice production [3]. High doses of chemical fertilizers have been used in rice cultivation to increase production in order to meet the increasing demand [4]. The long-term use of chemical fertilizers, acidifies the soil and compromises the sustainability of paddy production [5]. The excessive use of fertilizers increases the risk of pollution [6] and may generate nutrient imbalances in soils and crops, between nitrogen (N) and phosphorus (P) [7]

Methods

Results

Conclusion