Abstract:
Objective To investigate the effects of nitrogen fertilizer combined with nitrification inhibitor on grass production in natural grassland mowing, in order to improve the nitrogen utilization efficiency of grassland, and to provide theoretical basis and practical reference for grassland managers and decision makers for sustainable grassland management.
Methods In this study, the natural mowed grassland of military horse farm in Zhaosu County was selected as the research object. Field investigation and sampling method were adopted, and the split-plot experiment design was adopted. Urea was added in the main zone, and 6 application gradients (urea, nitrogen content was 46.7%) were set. They were 0, 3.32, 9.96, 29.87, 59.74, 59.74 g/m2, respectively. In the secondary area, nitrification inhibitor (DCD) was added. Six gradients (0, 0.332, 0.996, 2.987, 4.482, 5.974 g/m2) were set according to 10% of urea nitrogen application, and the quantitative characteristics of above-ground vegetation communities and soil nutrients were measured and analyzed.
Results (1) Nitrogenous fertilizer alone and nitrogenous fertilizer combined with nitrification inhibitor could significantly increase plant height, coverage, density, Simpson index, Pielou index, above-ground biomass and nitrogen use efficiency. (2) Under the same nitrogen application rate, the total biomass and nitrogen use efficiency of 0.332 g/m2 DCD were increased by 14% and 25% respectively. (3) Nitrogen fertilizer combined with nitrification inhibitor had no significant effects on soil organic carbon, total nitrogen and total phosphorus, but 0.332 g/m2 DCD reduced soil nitrate nitrogen content by 12% compared with urea alone.
Conclusion The combination of 3.32 g/m2 and 0.332 g/m2 DCD is the best for natural grassland cutting in Zhaosu County.
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