施氮和不同栽培模式对半湿润农田生态系统冬小麦根系特征的影响

在陕北黄土丘陵沟壑区对清耕和问作沙打旺(Astragalus adsurgens)6年、4年、2年仁用杏园0～500cm土层土壤水分、有机质、全氮、全磷、速效氮、速效磷、速效钾含量及树体生长状况进行了测定,结果表明,间作沙打旺,除了在秋季提高了0～100cm土层土壤水分以外,在春季、夏季和秋季均显著降低了0～500cm土层土壤水分,且间作沙打旺年限越长,降低越显著。间作沙打旺提高了0～100cm土层土壤有机质和全氮含量,间作年限越长效果越显著,但对100cm土层以下的土壤有机质和全氮无显著影响。间作沙打旺对土壤全磷含量无显著影响。间作沙打旺显著降低了土壤速效养分含量,其中速效氮降低深度达500cm土层,速效磷、速效钾达300cm土层,且间作年限越长,降低越显著。间作沙打旺显著削弱了树体的长势,降低了坐果率和杏仁产量。间作沙打旺存在着与仁用杏争水争肥的矛盾,黄土丘陵沟壑区仁用杏园不宜间作沙打旺。

A field experiment was carried out on the soil located in the south part of loess plateau soil with 632 mm precipitation and Xiaoyan No.22 used as indicating crops to study the effects of nitrogen fertilizer(no nitrogen application and nitrogen application 120 kg/hm2) and planting modes(control-C,plastic sheet-mulching-PSM,ridge-furrow tillage-RFT and plastic sheet-mulching on ridge-PSMR) on root characteristic of winter wheat.The results showed,the root weight was gradually increased from reviving stage to...