Response of Rice Harvest Index to Different Water and Nitrogen Management Modes in the Black Soil Region of Northeast China

Sicheng Du,Zhongxue Zhang,Tiecheng Li,Zhijuan Qi,Zhongbo Wang,Xin Zhou,Zhaomei Gai

doi:10.3390/agriculture12010115

Sicheng Du, Zhongxue Zhang + Show 5 more

Open Access

https://doi.org/10.3390/agriculture12010115

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Abstract

Understanding the methods leading to rice yield increase is vital for sustainable agricultural development. Improving the harvest index (HI) is an important way to increase rice yield. To explore the effects of different water and nitrogen management modes on the rice HI in the black soil region of Northeast China, a field experiment was conducted in 2019 (Y1) and 2020 (Y2). Two irrigation methods, conventional flooding irrigation (FI) and controlled irrigation (CI), were established in the experiment, and four nitrogen application levels (0 kg/ha, 85 kg/ha, 110 kg/ha, and 135 kg/ha) were set during the entire growth period, named N0, N1, N2, and N3. The dry matter weight and the rice yield at the maturity stage were determined, and the HI was then calculated. The results showed that different irrigation modes and nitrogen application levels had significant effects on the rice HI. Under different irrigation modes with the same nitrogen application level during the two years, the comparison regular of HI was consistent. In Y1 and Y2, the HI of FN0 was 3.36% and 5.02% higher than that of CN0 (p < 0.05), and the HI of CN1 was 0.31% and 2.43% higher than that of FN1 (p > 0.05). The HI under CI was significantly higher than that under FI under N2 and N3 (p < 0.05), the HI of CN2 was 4.21% and 4.97% higher than that of FN2, and the HI of FN3 was 13.12% and 20.34% higher than that of CN3. In addition, during the two-year experiment, the HI first increased and then decreased with an increase in the nitrogen application rate under FI and CI. Under the FI treatments, the HI of N1 was the highest, and that of N2 was the highest under the CI treatments. A variance analysis showed that the irrigation pattern and nitrogen application level had significant interactions on the rice HI (p < 0.01), and the appropriate water and N management mode could increase rice the HI by 26.89%. The experimental results showed that the HI of the 110 kg/ha nitrogen application rate under CI was the highest, reaching 0.574 and 0.572, respectively, in two years. This study provides a data reference and theoretical support for realizing water savings, nitrogen reduction, and sustainable agricultural development in the black soil region of Northeast China.

Highlights

Licensee MDPI, Basel, Switzerland.Rice is one of the most important crops in the world and is the foremost staple food inAsia, providing 60% of the dietary calories for more than three billion people [1]
The results show that the dry matter accumulation of controlled irrigation (CI) was more at the low nitrogen application level, while that of flooding irrigation (FI) was more at the medium and high nitrogen application levels
The results showed that, under the same nitrogen application level, CI was more conducive to improving the rice harvest index (HI)

Summary

Introduction

Licensee MDPI, Basel, Switzerland.Rice is one of the most important crops in the world and is the foremost staple food inAsia, providing 60% of the dietary calories for more than three billion people [1]. China is the largest rice producer and consumer in the world. With the continuous growth of China’s population (1.4 billion ) [3], the rice yield has a direct impact on China’s food security. A lack of water resources has become an important problem that hinders agricultural development, and rice is the most water-consuming crop in agriculture. The irrigation water consumption of a paddy field accounts for greater than 65% of the total agricultural water consumption [4]. Based on the above status and problems, it has become important to explore the appropriate water and N management mode to improve the rice yield. The total rice yield still needs to be increased to feed the growing population under the current situation of increasing water resource shortages. China’s demand for agricultural water is rising sharply, and the contradiction between supply and demand is becoming increasingly prominent [8]

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