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Nitrogen balances and nitrogen use efficiency of intensive vegetable rotations in South East Asian tropical Andisols 总被引:1,自引:0,他引:1
Ladiyani Retno Widowati Stefaan De Neve Sukristiyonubowo Diah Setyorini Antonius Kasno Ibrahim A. Sipahutar Sukristiyohastomo 《Nutrient Cycling in Agroecosystems》2011,91(2):131-143
Nitrogen fertilizer application rates in intensive vegetable production in (South) East Asia have increased exponentially
over the past decades, including in the low income countries. While there have been reports of excessive N inputs from e.g.
Vietnam, Thailand and Indonesia, very little quantitative knowledge exists on the real extent of the problem. We calculated
N balances and agronomic N use efficiencies (ANUE) for a number of typical intensive vegetable rotations in the highlands
of Central Java, Indonesia, on fertile Andisols, both for individual cropping cycles (short term) as for 6 consecutive cropping
cycles (long term). This was done for farmers practice (FP) treatments, and improved practice (IP) treatments, where N fertilization
was significantly reduced. Yields were in general similar in FP and IP, but tended to be slightly higher in IP, with some
significant differences. Both the short and long term N balances were always positive and usually very high. Short term N
balances ranged from 9 to 559 kg N ha−1 and 219 to 885 kg N ha−1 in IP and FP, respectively, while short term ANUE ranged from 8 to 67 and 4 to 39% in IP and FP, respectively. Long term
N balances ranged from 627 to 1,885 kg N ha−1 and 962 to 3,808 kg N ha−1 in IP and FP, respectively, indicating a massive excess of N supply especially in FP. N balances can thus be drastically
reduced with no negative impacts on yield, on the contrary. Soil mineral N in the 0–25 cm layer was in general not very high
(6.5–38.8 mg N kg−1 soil) and not systematically different between IP and FP, probably as a result of excessive NO3
− leaching. Therefore, topsoil mineral N seems to have only limited indicator value under these conditions. Because denitrification
losses in these soils are not very high, most N in excess of the crop requirements will be lost by leaching. Quantitative
data on N balances as obtained here may be used to sensitize policy makers and farmers about the threat of current farming
practices to the environment, and to improve economic performance. 相似文献
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