| 摘要: |
| 北京市在永定河、潮白河、温榆河两岸有沙荒地30余万亩。北京郊区要满足人民肉、蛋、奶的需要,必须重视充分利用沙荒地,低产田建设草地农业系统。本文根据土壤水分特征曲线、土壤不饱和导水率和保持土壤水的当量孔径,将沙荒地的土壤有效水,分为难动有效水、慢动有效水、快动有效水和速动有效水,以研究土壤水分状况与苜蓿生长的关系。据1984—1987年四年的观测,在自然降水条件下,3月下旬—4月中旬,正值苜蓿返青生长初期,表、心土层土壤水处于慢动一快动有效水范围,苜蓿生长正常。4月下旬——雨季前,正值苜蓿生长旺期,表、心土层土壤水多数时间处于慢动有效水状况,在特旱时期处于难动有效水状况,难以满足苜蓿对水分的需要,苜蓿生长缓慢,影响产草量。进入雨季后,表、心土层土壤水处于慢动一快动有效水状况,可以满足苗蓿的需水要求。底层轻壤土,常年处于快动有效水状况,对苜蓿抗旱保产有实际意义。在自然降水条件下,二年以上的多年生苜蓿,年收三茬,亩产鲜草2000公斤。加强水肥管理,亩产鲜草可达3000公斤。 |
| 关键词: 土壤水分性状 沙荒地 土壤水分状况 基模势 饱和导水率 草地农业系统 有效水 土壤水分特征曲线 苜蓿 自然降水条件 |
| DOI： |
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| STUDIES ON SOIL MOISTURE CONDITIONS OF A SANDY SOIL IN BEIJING REGION AND THEIR RELATION TO THE GROWTH OF ALAFALFA(MEDICAGO SATIVAL.) |
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| Abstract: |
| Determinations were made of soil moisture characteristic curves of various horizons of a sandy soil profile_n Measurements were also made of the seasonal soil moisture regimes during the period 1984-1987 under non-irrigated conditions.On the basis of parameters derived from soil moisture characteristic curves,soil moisture regimes were grouped into four categories differing in water availability and supply to pla- nts in the various growing seasons. Under conditions of the experiment,fresh weight yields of ... |
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