Biochar and Nitrification Inhibitor (Dicyandiamide) Combination Had a Double-Win Effect on Saline-Alkali Soil Improvement and Soybean Production in the Yellow River Delta, China

Abstract

Salt stress and nutrient deficiency strongly limited the productivity of coastal saline-alkali land in the Yellow River Delta. Biochar has been widely used to improve soil health and promote crop yield, and the positive effects of nitrification inhibitors on fertilizer use efficiency, especially nitrogen, were also verified. However, there were few types of research on the combined application of biochar and nitrification inhibitor dicyandiamide (DCD) on saline-alkali soil of the Yellow River Delta, China. In this study, five treatments, including no nitrogen (CK), normal NPK (N), NPK + 1%biochar (B), NPK + 2%DCD (D), and NPK + 1%biochar + 2%DCD (BD) were set to investigate the single and combined effect of biochar and DCD on nitrogen transform, soil properties, bacterial community structure, and soybean production. Results showed that BD application inhibited nitrification and increased the soil’s nitrate supply at the flowering stage, which reduced nitrogen waste and met the nitrogen demand for soybean growth. Biochar addition increased the soil’s pH and decreased the soil’s electrical conductivities and accelerated the soil’s macroaggregates formation, with the soil’s average mass diameter and geometric average diameter increasing by 78.69% and 30% in B, and 71.29% and 29.34% in BD relative to CK. Positive effects of inhibitors on soybean production were found in increasing soybean yield, hundred-grain weight, aboveground biomass, etc. Proteobacteria was the dominant phylum in the bacterial communities detected, and bacterial community diversity was significantly explained by nitrate content and soil aggregates (p < 0.05). Soil pH and DCD addition mainly influenced the abundance of the bacterial community, especially Actinobacteria. Biochar with DCD could be a feasible fertilization scheme for the coastal saline-alkali land in the Yellow River Delta, China.

Nitrogen acquisition and retention pathways in sustainable perennial bioenergy grass cropping systems

“…The option of applying synthetic chemical nitrification inhibitors to mitigate N loss in agricultural fields has been available since 1960s (Slangen & Kerkhoff, 1984). Commonly used inhibitors, such as nitrapyrin, dicyandiamide, and 3,4‐dimethlypyrazole phosphate, were all shown to increase agronomic N use efficiency and crop yields (Byrne et al., 2020; Peixoto & Petersen, 2023; Subbarao et al., 2006; Yu et al., 2022). However, drawbacks including the increased economic costs and environmental concerns such as promoted ammonia volatilization, have limited the adoption of synthetic inhibitors (Lam et al., 2017; Pan et al., 2016; Sahrawat, 1989).…”

A Novel Approach to Detecting the Salinization of the Yellow River Delta Using a Kernel Normalized Difference Vegetation Index and a Feature Space Model

“…These elements interact and accumulate, aggravating the degree of salinization. Salinization leads to the inability to cultivate saline-alkaline land, which is detrimental to the growth and development of crops, affects the quality and yield of crops, and severely restricts the sustainable development of agricultural production [4]. Salinization has also caused damage to the ecological environment.…”

Nanoattapulgite reduces the stimulation effect of nitrogen fertilizer on ammonia‐oxidizing microorganisms in salinized fluvo‐aquic soil

“…The nitrification rate is negatively correlated with N‐use efficiency and positively correlated with the denitrification rate in saline soils (Zhang et al, 2023). Reducing soil nitrification rate can improve crop biomass and nutrient utilization (Yu et al, 2022). Ammonia volatilization loss is more difficult than denitrification and nitrate nitrogen leaching loss in saline soil.…”