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作 者 ：尹飞,毛任钊,傅伯杰*,陈明灿

期 刊 ：生态学报 2009年 29卷 1期 页码：325~331

关键词：枣粮间作；全氮；硝态氮；分布；空间异质性；

Keywords:jujube-crop intercropping ecosystem, total nitrogen, nitrate nitrogen, distribution, spatial heterogeneity,

摘 要 ：基于枣粮间作复合生态系统内部异质性，通过在不同位置采样测定，探讨了枣粮间作系统内土壤氮素空间分布特性。结果表明：（1）枣粮间作生态系统中，在小麦收获期和玉米收获期两个时期，土壤全氮和硝态氮含量均存在明显的垂直和水平两个方向空间变异性。而土壤铵态氮含量极低且没有明显的空间变异；（2）与全氮相比，枣粮间作系统中硝态氮空间变异性更强，且随着时间变化其空间分布特性有明显变化；（3）氮素施用量对土壤全氮和硝态氮空间变异有正向作用，而植株对氮的吸收利用可以降低土壤氮素分布空间差异程度。各因子对土壤全氮空间变异影响强弱顺序为氮吸收量＞氮素施用量＞土壤含水量；对土壤硝态氮空间变异影响强弱顺序为氮素施用量＞土壤全氮含量＞氮素吸收量＞土壤含水量。

Abstract:The widely cultivated jujube-crop intercropping ecosystem (JCIE) is an important pattern of agro-forestry in North China. The spatial distribution of soil nitrogen in this system has not been well documented yet. In order to understand the spatial heterogeneity of this intercropping system, an experiment was carried out at Dashujin village, Nanpi County, Hebei Province during 2005-2006. Soil samples were collected from different sites in JIE, i.e. 0.25 m, 1 m, 2 m, 3 m, 4.5 m, and 6.5 m away from the jujube row, in five successive soil depths, i.e. 0-20, 20-40, 40-60, 60-100 and 100-150 cm, to determine the spatial distribution of soil total nitrogen (TN), nitrate nitrogen (NO3 -N), and ammonium nitrogen (NH+4-N). The results showed that both horizontal and vertical variances of the distribution for soil TN and NO-3-N in JIE were significant at harvest of wheat and maize However, no spatial variance was found for the distribution of soil NH+4-N. The variance in soil NO-3-N was greater than that in TN and the characteristics of their spatial variance was also different. Along the 0-150 cm soil profile, soil TN first decreased, then increased with the increase in soil depth. The lowest soil TN concentration occurred in 60-100cm soil layer. The characteristics of spatial variance of NO-3-N were more complex than that of TN. Within 2m (at wheat harvest) or 3m (at maize harvest) to the jujube tree row, soil NO-3-N concentration was the highest at 40-60 cm, then it decreased with the increase in soil depth. The variance of NO-3-N was greater closing to jujube row, whereas TN was more consistent. The results showed that fertilizer application positively affected the horizontal variance of soil TN and NO-3-N, while N uptake had a negative effect on it. N uptake, followed by N application rate and soil water content, was important factors influencing the spatial variance of soil TN. To the spatial variance of soil NO-3-N, order of the influencing factors in importance was N application rate ＞soil TN concentration ＞N uptake ＞soil water content.

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