Dissertation
Dissertation > Agricultural Sciences > Crop > Cereal crops > Wheat > Wheat

Comparison of Urease/Nitrification Inhititors and Influence of 3,4-Dimethylpyrazole Phosphate (DMPP) on Nitrogen Patch and Wheat Root Micro-Distribution

Author ChenHuan
Tutor LiHuiXin
School Nanjing Agricultural College
Course Ecology
Keywords urease and nitrification inhibitors DMPP urea patch fertilizer microsites roots of wheat micro-distribution
CLC S512.1
Type Master's thesis
Year 2010
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Because of the importance of nitrogen to plant, nitrogen fertilizer is the key factor to achieve high yield. Amount of nitrogen application induced many problems, such as low nitrogen effiency and environmental pollution. One of main approaches to resolve these problems was application of urease and nitrification inhibitors. In the study, we tested four urease and nitrification inhibitors on four typical soil, then investigated the influence of best nitrification inhibitor DMPP on urea nutrient patch and roots distribution of wheat. Results were shown as follows:Rate of urea hydrolysis, nitrification and variation of soil pH had a great relationship with soil property, both the urea hydrolysis rate and nitrification were the worst in red soil, because of its low urease activity. The inhibitory effect of nitrification inhibitors was better than urease inhibitors to the end of experiment. The inhibitory duration of NBPT and HQ was short, which was weaken after 7 days and invalid after 14 days, effect of HQ was worse than NBPT in paddy soil, black soil and alluvial soil but red soil. DMPP could maintain high activity in 14 days, but DCD could keep plenty of NH4+ in soil until the expetiment finished. Although the inhibitory effect of DCD was the best in four soils, DCD was probably harmful to plants and facilitated loss of NH3. In the end, we chose DMPP in the further research.We investigated the response of wheat roots to nutrient patch used special container in different environments (control, urea mixed application and row application).Soil inorganic nitrogen and total nitrogen in row application treatment were higher, the miro-distribution of inorganic nitrogen of urea mixed application and row application were respectively symmetrical and asymmetrical. Urea nutrient patch has a large impact on the growth of wheat roots, and there was a certain correspondence between root spatial distribution and ammonium, nitrate concentration distribution in the fertilizer microsites.We studied the influence of DMPP on urea patch and wheat root micro-distribution under different fertilization pattern by the special container. DMPP significantly increased content of NH4+, wheat nitrogen content, apparent fertilizer utilization, and significantly decreased content of NO3-, inhibitory effect of DMPP in row application was better than mixed application. In our research, DMPP accelerated the growth of wheat in mixed application but the row application. NH4+-N and NO3--N fertilizer microsites were affacted by DMPP, then the wheat root micro-distribution was affected by fertiliazer microsites.

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