沙漠地区麦田土壤养分运动特征

研究了干旱沙漠地区新垦沙地和耕种20年左右的灌淤土可溶性养分运动特征.结果表明,在小麦1个生长周期内土壤养分发生较大的衰减,表层养分呈梯级下降趋势,其明显吻合于灌溉周期;以灌溉导致养分淋溶造成土壤养分下降为主,以作物吸收利用造成土壤养分下降为辅.土壤下层存在养分截留层,当总灌水量由649mm(59mm/次)增至1998mm(111mm/次)时作物吸收利用养分量分别降低42%(沙土)和50%(灌淤土),土壤养分总消耗量分别减少40%(沙土)和49%(灌淤土).当灌水量太大时,许多土壤养分被水运移至土壤深层,致使作物难以吸收到这些养分.

Movement of soil nutrient of wheat field in arid desert area

The movement characteristics of soil nutrient of wheat field in arid desert area were studied. The results showed that the soil nutrient content reduced to a lower level after one growth season of wheat, and it decreased stage by stage. Every stage was synchronous with irrigation. Therefore, irrigation mainly induced the decline of soil nutrient in the soil layer. Most infiltrated nutrient was accumulated in sub soil. When total irrigation water amount was increased from 649mm to 1998mm, nutrient amount utilized by wheat crop was de clined 42%(sandy soil) and 50%(multi-soil) respectively and the total consumption of soil nutrient was declined 40%(sandy soil) and 49%(multi-soil) respectively. Much soil nutrient moved to deep soil layer where crop could not take any nutrient when the irrigating amount was too large.