Ammonia Volatilization Reduced by Combined Application of Biogas Slurry and Chemical Fertilizer in Maize–Wheat Rotation System in North China Plain

Md Arifur Rahaman,Hailing Zeng,Yuting Long,Shuqin Li,Shengmei Lv,Qingwen Zhang,Xiaoying Zhan

doi:10.3390/su12114400

Abstract

Digestate and biogas slurry (BS) are the byproduct of biogas engineering that could be used for elevating plant growth. However, the consequent emissions of ammonia from BS are considered a severe threat to the atmosphere. Herein, we conducted two consecutive field experiments with wheat–maize rotations to find out the optimum ratio of BS to combine with chemical fertilizer (CF) to reduce ammonia volatilization (AV) while keeping the stable crop yield. In maize season, 226.5 kg N/ha of CF was applied. In wheat season, 226.5 kg N/ha was applied at different ratios (100%, 80%, and 50%) between BS and CF. Our results found that the maximum yield of 6250 kg/ha was produced by CF, and this yield could be obtained through a combined application of 38% BS mixed with CF. Highest AV produced of 16.08 kg/ha by CF. BS treatments significantly reduced the emission from 18% to 32% in comparison to CF. The combined application of BS-CF produced the highest yield due to essential nutrients coming from both BS-CF. Subsequently, it reduced the AV depending on fertilizer type and fertilizer rate. An optimal ratio of 38% BS was recommended to produce the highest yield and lowest ammonia emissions. The application of BS together with different ratios of CF could be an alternative agricultural strategy to obtain desired crop yield and reduce AV in North China Plain (NCP).

Highlights

China is one of the major agricultural countries and provides nearly one-fifth of calories to humans worldwide [1]
The main ambition of this study was to systematically evaluate and forecast NH3 losses during maize and wheat season after biogas slurry was applied in the field, compared with the chemical fertilizer (CF) practice at North China Plain (NCP)
Different emissions were found in maize season, the amount of fertilization was the same and only CF was applied at that time

Summary

Introduction

China is one of the major agricultural countries and provides nearly one-fifth of calories to humans worldwide [1]. The use of digestate slurry from anaerobic digestion as fertilizer in crop production is an important strategy for minimizing NH3 emissions. Sole application of organic fertilizer could only reduce NH3 emission, but the desired crop yield cannot be achieved [30]. Some studies showed that crop productivity could be significantly increased if slurry is applied together with CF [31,32]. For this reason, the optimum ratio of BS and CF should be developed to simultaneously reduce the loss of N through AV, and improve the crop yield of summer maize and winter wheat rotation system. It has been demonstrated that over application of digestate can be avoided under controlled conditions, and it is an environmentally promising option still in spite of being an expensive option for farmers [33]

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