INTRODUCTION It is an interesting research area using urease inhibitors to curb urease activity in soil,to decrease the rate of urea hydrolysis and to increase the recovery of urea nitrogen(Zhou,1984;Guan,1985).Few st...INTRODUCTION It is an interesting research area using urease inhibitors to curb urease activity in soil,to decrease the rate of urea hydrolysis and to increase the recovery of urea nitrogen(Zhou,1984;Guan,1985).Few studies have been conducted on the relationship betweenthe effectiveness of the inhibitors applied to rice and the environmental conditions and展开更多
Effects of urea amended with urease and nitrification inhibitors on soil nematode communities were studied in a Hapli- Udic Argosol （Cambisol, FAO） in Liaoning Province of Northeast China. A completely random design...Effects of urea amended with urease and nitrification inhibitors on soil nematode communities were studied in a Hapli- Udic Argosol （Cambisol, FAO） in Liaoning Province of Northeast China. A completely random design with four treatments, i.e., conventional urea （CU）, slow-release urea amended with a liquid urease inhibitor （SRU1）, SRU1 ＋nitrification inhibitor dicyandiamide （SRU2）, and SRU1 ＋ nitrification inhibitor 3,5-dimethylpyrazole （SRU3） and four replicates were applied. Thirty-nine genera of nematodes were identified, with Cephalobus and Aphelenchus being dominant; and in all treatments, the dominant trophic group was bacterivores. In addition, during the growth period of spring wheat （Triticum aestivum L.）, soil urease activity was lower in SRUs than in CU. The numbers of total nematodes and bacterivores at wheat heading and ripening stages, and omnivores-predators at ripening stage were higher in SUR3 than in CU, SRU1 and SRU2 （P 〈 0.05）.展开更多
Laboratory incubation experiment was conducted to study the effect of lime nitrogen(LN) on transfor-mation of iirea-N in three paddy soils. The results showed that LN had an inhibitory effect on urease activityin thes...Laboratory incubation experiment was conducted to study the effect of lime nitrogen(LN) on transfor-mation of iirea-N in three paddy soils. The results showed that LN had an inhibitory effect on urease activityin these soils especially in the first 5 days, and that in the first 20 days of incubation, the amount of NH-Nderived from urea was lower in the soil with LN than in the soil without LN. While after 30 days the ainountof NH-N was higher in the mature haplic paddy soil developed on Quaternary red clay(MHPS) with LNthan that in the soil without LN. The amonnt of NH_3-N volatilized was decreased in the earlier stage andincreased in the later stage of incubation in the MHPS by the addition of LN.展开更多
To increase fertilizer use efficiency （FUE） and to minimize its negative impact on environment have been the focal points in the world for a long time. It is very important to increase FUE in China for its relativel...To increase fertilizer use efficiency （FUE） and to minimize its negative impact on environment have been the focal points in the world for a long time. It is very important to increase FUE in China for its relatively low FUE and serious losses of nutrients. Recent advances of the technologies to increase FUE are reviewed in this article. These include site-specific and real-time nitrogen management, non-destructive quick test of the nitrogen status of plants, new types of slow release and controlled release fertilizers, site-specific nutrient management, and use of urease inhibitor and nitrification inhibitor to decrease nitrogen losses. Future outlook in technologies related to FUE improvement is also discussed.展开更多
文摘INTRODUCTION It is an interesting research area using urease inhibitors to curb urease activity in soil,to decrease the rate of urea hydrolysis and to increase the recovery of urea nitrogen(Zhou,1984;Guan,1985).Few studies have been conducted on the relationship betweenthe effectiveness of the inhibitors applied to rice and the environmental conditions and
基金Project supported by the National Key Basic Research Support Foundation of China (No. 2005CB121105) and the National High Technology Research and Development Program of China (No. 2005AA001480).
文摘Effects of urea amended with urease and nitrification inhibitors on soil nematode communities were studied in a Hapli- Udic Argosol （Cambisol, FAO） in Liaoning Province of Northeast China. A completely random design with four treatments, i.e., conventional urea （CU）, slow-release urea amended with a liquid urease inhibitor （SRU1）, SRU1 ＋nitrification inhibitor dicyandiamide （SRU2）, and SRU1 ＋ nitrification inhibitor 3,5-dimethylpyrazole （SRU3） and four replicates were applied. Thirty-nine genera of nematodes were identified, with Cephalobus and Aphelenchus being dominant; and in all treatments, the dominant trophic group was bacterivores. In addition, during the growth period of spring wheat （Triticum aestivum L.）, soil urease activity was lower in SRUs than in CU. The numbers of total nematodes and bacterivores at wheat heading and ripening stages, and omnivores-predators at ripening stage were higher in SUR3 than in CU, SRU1 and SRU2 （P 〈 0.05）.
文摘Laboratory incubation experiment was conducted to study the effect of lime nitrogen(LN) on transfor-mation of iirea-N in three paddy soils. The results showed that LN had an inhibitory effect on urease activityin these soils especially in the first 5 days, and that in the first 20 days of incubation, the amount of NH-Nderived from urea was lower in the soil with LN than in the soil without LN. While after 30 days the ainountof NH-N was higher in the mature haplic paddy soil developed on Quaternary red clay(MHPS) with LNthan that in the soil without LN. The amonnt of NH_3-N volatilized was decreased in the earlier stage andincreased in the later stage of incubation in the MHPS by the addition of LN.
文摘To increase fertilizer use efficiency （FUE） and to minimize its negative impact on environment have been the focal points in the world for a long time. It is very important to increase FUE in China for its relatively low FUE and serious losses of nutrients. Recent advances of the technologies to increase FUE are reviewed in this article. These include site-specific and real-time nitrogen management, non-destructive quick test of the nitrogen status of plants, new types of slow release and controlled release fertilizers, site-specific nutrient management, and use of urease inhibitor and nitrification inhibitor to decrease nitrogen losses. Future outlook in technologies related to FUE improvement is also discussed.
