Green Manuring Effect on Changes of Soil Nitrogen Fractions, Maize Growth, and Nutrient Uptake

Lu Yang,Naohua Zeng,Weidong Cao,Jinshun Bai,Jia Liu

doi:10.3390/agronomy8110261

Abstract

Green manure is a promising, at least partial, substitution for chemical fertilizer in agriculture, especially for nitrogen (N), which in soil can be radically changed by exogenous input. However, it is not well understood how, after green manure incorporation, soil N changes coordinate with crop N uptake and consequently contribute to fertilizer reduction in a maize–green manure rotation. A four-year field study was performed consisting of (1) control, no fertilization; (2) F100, recommended inorganic fertilization alone; (3) G, green manure incorporation alone; (4) F70 + G (70% of F100 plus G); (5) F85 + G; and (6) F100 + G. The results show that treatments with 15–30% reduction of inorganic fertilizer (i.e., F70 + G and F85 + G) had similar grain yield, dry matter (DM) accumulation, and N uptake as F100 treatment. F100 + G maize had 17% greater DM and 15% more N uptake at maturity relative to F100. Of the five soil N fractions examined, dissolved organic N (DON) and mineral N (Nmin) explained over 70% of the variation of maize DM and N accumulation. Partial least squares path modeling further revealed that soil N fractions had positive indirect effects on DM production through N uptake, which might be coordinated with improved DON and Nmin status at both early and mid-late stages of maize growth. Overall, the results highlight enhanced maize production with reduced fertilizer inputs based on green manure incorporation in temperate regions.

Highlights

Improving crop yield and nutrient use efficiency simultaneously is challenging due to the increasing demand for food and intensifying environmental issues [1,2]
Of the five N fractions examined in the present and N (DON) and mineral N (Nmin) together explained over 70% of the variation in Dry matter (DM) production and N uptake, i.e., there study, dissolved organic N (DON) and Nmin together explained over 70% of the variation in DM production and N uptake, was a greater contribution of these two N components than other variables
At Least 15–30% of Inorganic Fertilizer Input Could Be Reduced in the Orychophragmus violaceus (OV) Incorporation-Based Maize

Summary

Introduction

Improving crop yield and nutrient use efficiency simultaneously is challenging due to the increasing demand for food and intensifying environmental issues [1,2]. To pursue higher crop yields, farmers in some intensive agriculture areas of China apply excessively high rates of nitrogen (N) and phosphorous (P) fertilizer. The annual N fertilizer input in a maize–wheat cropping system in North. The substantial inputs do not reliably maintain the expected yields [3,4]. Much of the applied N fertilizer is lost to the environment [6], through nitrates leaching to groundwater [7] and greenhouse gas emissions [8]. It is of great importance to produce more grain yield with less environmental impact, e.g., lower nutrient losses [3,4]

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