学术
不同施氮水平和杂草清除时间对氮肥利用及平衡的影响
南维鸽[1,2,3] 李世清[1,2] 侯红乾[1,2,4] 李生秀[2]
[1]西北农林科技大学中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100 [2]西北农林科技大学资源环境学院,陕西杨凌712100 [3]陕西理工学院,陕西汉中723001 [4]江西省农业科学院土壤肥料与资源环境研究所,江西南昌330200
摘 要:
以半湿润区中等肥力土垫旱耕人为土为供试土壤，在冬小麦不同生育期采集0～100cm土层土壤样品、作物及杂草的样品，研究不同施肥及杂草处理对半湿润农田生态系统氮肥损失及氮素平衡的影响。试验结果表明，土壤中残留NO3^--N累积量均随施氮量增加而增加；NH4^＋-N累积量随施氮量变化不显著，总矿质氮随施氮量的变化趋势与硝态氮基本一致；农田系统中杂草的存在，能在一定程度上增加土体残留矿质氮（Nmin）累积量，且在高施氮处理下影响较大；在全生育期不清除杂草（A）、越冬前清除杂草（B）、返青期清除杂草（C）和拔节期清除杂草（D）等杂草处理下，杂草吸氮量平均值分别为2．38、1．60、4．72和4．54kgN／hm^2，占农田植物地上部分（作物＋杂草）总吸氮量的1．97％、1．38％、3．98％和3．76％，返青期杂草吸氮量最高，其值是越冬期杂草吸氮量的2．94倍；氮肥损失随施氮量增加而呈线性相关，考虑杂草时，相关系数R^2=0．9802。不同杂草处理间氮素表观损失量为59．9～96．1kg／hm^2，不同施氮处理间表观损失量为32．9～128．0kg／hm^2；不同时期清除杂草对氮损失和氮肥利用率影响显著，而越冬期清除杂草的影响效果最大；本试验条件下，杂草的存在对氮素平衡影响不显著。[著者文摘]
文章出处:
《干旱地区农业研究》-2008年26卷1期 -18-24页
栏目信息:
分 类 号:
文献标识码:
A
文章编号:
1000-7601（2008）01-0018-07
Effects of different nitrogen fertilizer levels and time of removing weeds on nitrogen utilization and nitrogen balance
NAN Wei-ge, LI Shi-qing, HOU Hong-qian, LI Sheng-xiu （ 1. State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau ; Northwest A ＆ F University ; Institute of Soil and Water Conservation, Chinese Academy of Science and Ministry of Water Resource, Yangling, Shaanxi 712100; 2. College of Resources and Environment Sciences, Northwest A ＆ F University, Yangling , Shaanxi 712100; 3. Shaanxi University of Technology, Hanzhong , Shaanxi 723001 ; 4. Soil Fertilizer and Environmental Resources Institute, Jiangxi Academy of Agricultural Sciences, Nanchang , Jiangxi 330200, China）
Abstract:
Application of nitrogen （N） fertilizer is one of the most important measures that increase grain yield and improve grain quality of winter wheat. However, it is common that excessive N fertilizer is applied on fertility field, which not only causes the decline of N use efficiency and economic effects, but also results in larger amount of nitrate-N accumulated in soil, and so it is concerned to bring potential risk environment. Nitrogen （N） was manipulated through fertilizer application, to determine the extent to which these treatments alleviated a competition, and that this would be related to levels of resource availability, particularly available N. However, application of N fertilizer not only helped control weed but also increased mineralization of the residues. Therefore, the experiment was a randomized complete block design consisting of two different factors. Nitrogen and weed treatments were arranged in a split - plot design with three replicates. Within normal density treatments, five levels of nitrogen, 0, 45, 90, 135 and 180 kg N/hm^2 were applied. Within each of these treatment combinations, different weed treatments were imposed. This experiment was carried out in Eum-Orthic An- throsol located in the semi-humid farmland ecological system. Soil sample was collected from 0- 100 cm layer. Sample of crops and weed were collected from the winter wheat in different growth stage. The research was concerned to effects of different fertilizer and weed treatment on N fertilizer loses and N balance in semi-humid farmland ecosystem. This experiment showed that residual nitrogen accumulation in soil increased with addition of N fertilizer application, but the ammonium nitrogen accumulation was stable. The total N mineralization increased with addition of N fertilizer application. The average value of Nitrogen uptake by weed in treatment A, B, C and D was respectively 2.38, 160, 4.72 and 4.54 kg N/hm^2. Meanwhile, nitrogen uptake by weed accounted forl. 97 % 、 1.38 % 、3.98 % and 3.76 % of N uptake by aerial parts plant. N uptake of weed in the overwinter was the lowest. The N uptake of weed in the reviving stage is higher, which was the time 2.94 of N uptake by weed in over-winter. Nitrogen utilization rate decreased and apparent N fertilizer loss increased along with the increase of N fertilizer application. Apparent N fertilizer loss was the linear correlation with N fertilizer application, and the correlation coefficient R2 was 0. 9802, considering weed. The average of N fertilizer loss maintained between 59.9 and 96.1 kg N/hm^2 at different weed treatments. The average of N fertilizer loss was in the range of 32.9 to 128.0 kg/hm^2 at different fertilizer treatments. There was obvious effect of removing weeds on N utilization rate and apparent N fertilizer loss at different time, especial before over-winter. There was no significant effect of weed on N balance.[著者文摘]
Key words:
nitrogenous mineralization; weed; nitrogen utilization rate; apparent nitrogen loss
基金资助:
国家自然科学基金（30571116,30670326）;西北农林科技大学创新团队项目资助
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