Optimal Nitrogen Management Enhanced External Chemical Nitrogen Fertilizer Recovery and Minimized Losses in Soil-Tomato System

Huimin Jiang, Jianfeng Zhang, Juncheng Yang

Abstract


Excess chemical nitrogen (N) fertilization is widespread in intensive greenhouse vegetable production in China and has resulted in low recovery efficiency and high losses of chemical N fertilizer. Understanding the fate of chemical N fertilizer is crucial for best management of chemical N fertilizer. Using the technique of stable isotope 15N-labeled urea, a micro-plot experiment was conducted to estimate the recovery of 15N-labeled urea in tomato, residues in soil and losses in soil-tomato system. The treatments included the conventional N management with chemical N rate (1000 kg N/ha), named FP and optimal N management with chemical N rate (500 kg N/ha), combined with maize straw and drip irrigation, named OPT. Compared with the FP, total dry matter yield increased by 6.5%–9.3% for the OPT in the autumn-winter season (AW) and winter-spring seasons (WS), respectively. There was a significantly higher recovery efficiency (20.7%) of 15N-labeled urea in the OPT compared to the FP (11.3%; P < 0.05). The amount of residual NO3--N derived from 15N-labeled urea was significantly higher in the FP than in the OPT (P < 0.05). More inorganic N derived from 15N-labeled urea was incorporated into the stable fraction of organic matter in the OPT and had a positive effect on reducing the N leaching with increased time during the season. The loss rate of N derived from 15N-labeled urea was 46.8% in the FP, 25.8% greater than in the OPT. Optimal N management improved tomato yields, enhanced chemical N recovery efficiency, while minimizing losses in the soil-tomato system. It will be practical for maintaining the sustainability of greenhouse-based intensive vegetable systems.


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DOI: http://dx.doi.org/10.5539/jas.v7n3p179

Journal of Agricultural Science ISSN 1916-9752 (Print) ISSN 1916-9760 (Online)

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