NGHIÊN CỨU ĐỘNG THÁI ẨM CỦA ĐẤT TRONG KỸ THUẬT TƯỚI NHỎ GIỌT PHỤC VỤ TƯỚI TIẾT KIỆM NƯỚC HỢP LÝ CHO CÂY TRỒNG CẠN VÙNG KHAN HIẾM NƯỚC (VÙNG KHÔ HẠN)

Abstract

During the experimental research on a suitable irrigation schedule of drip irrigation technique for Grape leaves at the water scarce region of Binh Thuan province, the author has concurrently experimented on soil moisture dynamic at two places: (1) Natural land (non crops) and (2) Cultivated one with Grape leaves in three crop seasons with 3 irrigation frequencies: 2days (CK2), 3days (CK3) and 4days (CK4). This article was presented at the Natural land. The observed results showed that: at the end of the irrigation frequency, water content of CK2 was larger than suitable min one for crops (θp), water content of CK3 (above layers) and the whole CK4 decreased lower than (θp), it sometimes approached the moisture at wilting point (θwp). The day water content decreased more greately than the evening and night ones, and the afternoon one decreased more greately than the morning one. The water content decrease was the greatest during 9:00÷15:00, the next ones were in period’s 15:00÷21:00, 3:00÷9:00 and the lowest one was in 21:00÷3:00 of the next morning. Establishing the equation system of homogeneous regression between pF and water content in each layer with all verificative results are satisfied and conformable. Therefore, based on these results, this equation system of homogeneous regression can be used to determine suitable water saving irrigation schedule following each development stage schedule for dry crops at the water scarce region (Droughty region) in the South Central part of Vietnam.