松嫩平原西部典型农田需水规律研究

采用联合国粮农组织最新推荐的模型方法(FAO56)，利用近10年的日气象资料对松嫩平原西部玉米、大豆、高粱等作物近10年的农田逐日需水量进行了系统研究。得出了本区不同作物的需水规律，并根据当地的有效降雨量，获得了不同作物不同时段的水分亏缺规律，为节水灌溉和提高作物产量提供科学依据.

Study on the Crop Water Requirements in Typical Farmlands in Western Songnen Plain

Based on the FAO56 method recommended by Food and Agriculture Organization of the United Nations, the last ten-year daily meteorology data and the related observed data in field, the daily water requirements of major crops(corn, soybean and grain )from 1992 to 2001 in farmland are calculated,and analyzed systematically in Western Songnen Plain.The results show that the different crop has the different water requirement law. The peak period of corn water requirement is from the late June to early August. The daily ETc is usually more than 5 mm. The corn total ETc varied between 490 and 574 mm in last 10 years, less in wet years and more in dry years. The maximum water requirement period of soybean occurred during early and middle July, with daily water requirement usually more than 5mm, when the plants are in the late floral differentiation and early flowering stage. In the last 10 years, soybean water requirement varied between 380 mm and 440 mm with an average of 400 mm. The average sorghum water requirement is 506.8 mm with the peak period from the late June to the late July, when the plants are in the elongation stage and booting and heading stages.Employing the local effective rainfall and the calculated crop water requirement, the water deficit is confirmed. It is found that the main reason for the low yield of corn in this area is the serious water deficit in the booting and heading stages and the milk stage, in which it lacks 28% and 46.7% of the ETc respectively. The water deficit of soybean mostly is in the podsetting and podfilling stages and the mature stage. The water deficit of sorghum is mainly in the elongation stage and milking stage, with the average water deficit of (66.8)mm and 65.9mm respectively. Therefore in order to increasing the crop yields in this area in the large scale, the crop water in summer and autumn should be met on the basis of the settled drought in spring by dibbling irrigation.