Continuous applications of biochar to rice: Effects on nitrogen uptake and utilization

Min Huang,Long Fan,Yingbin Zou,Ligeng Jiang,Jiana Chen

doi:10.1038/s41598-018-29877-7

Min Huang, Long Fan + Show 3 more

Open Access

https://doi.org/10.1038/s41598-018-29877-7

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Abstract

Improving soil quality is critical for increasing rice yield, and biochar could be a beneficial soil amendment for high yield. This study was conducted to determine the effects of continuous (repeated seasonal) applications of biochar on nitrogen (N) uptake and utilization in rice. A fixed field experiment was done in Yongan Town, Hunan Province, China, in six continuous seasons (the early and late rice-growing seasons from 2015 to 2017). Results showed that biochar application did not significantly affect soil N uptake in the first four seasons. The effect of biochar application on fertilizer N uptake was not significant in three of the first four seasons. In the fifth and sixth seasons, biochar application resulted in 14–26% increases in soil N uptake but 19–26% decreases in fertilizer N uptake. Soil N availability did not explain the increased soil N uptake with biochar application. The decreased fertilizer N uptake with biochar application was attributed to both decreased fertilizer N availability and increased N loss through ammonia volatilization. As a consequence of a compensation between the increased soil N uptake and the decreased fertilizer N uptake, the effect of biochar application on total N uptake was not significant in the fifth and sixth seasons. However, biochar application led to 7–11% increases in internal N use efficiency in the fifth and sixth seasons and 6% increase in grain yield in the sixth season. Our study suggests that the effects of repeated seasonal applications of biochar on N uptake and utilization in rice depend on the duration of biochar application. Longer continuous applications of biochar can increase internal N use efficiency and grain yield in rice with insignificant change in total N uptake.

Highlights

Rice is the staple food for more than half of the world’s population[1]
0 Early Late Early Late Early Late biochar application may lead to changes in N uptake and utilization in rice. This was confirmed in previous studies of other crops such as wheat and maize[30,31] and in a one-season rice pot experiment by Huang et al.[32], who observed that biochar application increased fertilizer N uptake in rice
N uptake, internal N use efficiency, and grain yield were compared between rice grown with and without biochar application in a field experiment carried out in six continuous seasons

Summary

Introduction

Rice is the staple food for more than half of the world’s population[1]. Global rice production must be increased by about 1% annually to meet the growing demand for food resulting from population growth and economic development[2], and greater yield and sustainable intensification are required for this increase[3,4]. 60 ns Season biochar application may lead to changes in N uptake and utilization in rice This was confirmed in previous studies of other crops such as wheat and maize[30,31] and in a one-season rice pot experiment by Huang et al.[32], who observed that biochar application increased fertilizer N uptake in rice. It is still not clear how N uptake and utilization in rice will change in response to continuous applications of biochar under field conditions. The main objective of this study was to determine the effects of continuous applications of biochar on N uptake and utilization in rice

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