Effects of equal chemical fertilizer substitutions with organic manure on yield, dry matter, and nitrogen uptake of spring maize and soil nitrogen distribution

TLDR

Replacing chemical fertilizers with organic manure has gained attention to sustain yields and protect the environment. The study evaluated the impact of equal‑amount mineral fertilizer substitution with organic manure on spring maize yield, dry matter, nitrogen uptake, and soil mineral nitrogen distribution over two years. Treatments comprised chemical fertilizer, varying amounts of maize straw, cow manure, chicken manure, and an unfertilized control. Substituting 25 % of mineral fertilizer with cow or chicken manure increased yield, while full straw return reduced production; nitrogen and dry‑matter accumulation followed the order chicken manure > cow manure > chemical fertilizer > straw > control, and higher Nmin application raised soil nitrogen at depth, indicating potential leaching but overall improved yields and soil health.

Abstract

In order to maintain high yields and protect the environment, the replacement of chemical fertilizers with organic ones has received increasing attention in recent years. A 2-year field experiment (2015-2016) was carried out to assess the effects of substituting equal amounts of mineral fertilizer with organic manure on the yield, dry matter (DM), and nitrogen (N) uptake of spring maize (Zea mays L.) and on the mineral N (Nmin) distribution in the soil profile. The treatments included chemical fertilizer; different amounts of maize straw, cow manure, and chicken manure; and an unfertilized control (CK). Compared with the chemical fertilizer treatments, equal amounts of substitutions with cow manure or chicken manure increased production, and a 25% nutrient substitution resulted in the best yield increase. Straw return had no effect on maize production, and 100% straw return resulted in reduced production. The N accumulation and DM content both exhibited a slow-fast-slow growth trend throughout the various growth stages, and the average N uptake and DM accumulation in response to the treatments followed the order of chicken manure > cow manure > chemical fertilizer > straw return > CK. The Nmin content in the profile not only increased as the Nmin application rate increased but also showed greater increases at certain depths than at the surface, indicating that excessive N led to leaching. These results suggest that an appropriate proportion of organic substitution not only provides enough nutrients but also improves the soil environment and leads to increased yields. This technique represents a practical method of continuously increasing production and reducing the risk of N leaching.