Determination of crop co-efficients of cauliflower at different growth stages by drainage lysimeter

Abstract

Crop coefficient (Kc) values are essential in estimating the water requirements of crops. The Kc values depend on crop evapotranspiration (ETc) and reference crop evapotranspiration (ET0). Again, ETo is a function of climatic factors like temperature, humidity, wind speed, and sunshine hours, together with latitude, longitude, and altitude. These climatic factors vary from location to location, hence, the Kc values. So, location-specific Kc values are essential to determine crop water requirements on a regional basis. One of the most reliable methods of determining the Kc values of crops is the drainage lysimeter. Thus, the experiment was conducted in the research farm of the Irrigation and Water Management Division of Bangladesh Agricultural Research Institute, Joydebpur, Gazipur, to determine ETc using a drainage lysimeter during the rabi season of 2009-10. In the experiment, there were four irrigation treatments: irrigation at 15, 25, 35, 45, and 55 days after planting (DAP) (T1), irrigation at 15, 25, 35, 50 and 60 DAP (T2), irrigation at 15, 25 and 40 DAP (T3), and irrigation at 15, 30 and 45 DAP (T4). The highest curd yield (43.0 t/ha) of cauliflower was recorded from treatment T1 and was considered ideal for estimating ETc and Kc values. The seasonal ETc under the local agro-climatic conditions was 135 mm, and the Kc values were 0.37, 0.99, 1.29, and 0.84 for initial, development, mid- and late-season stages, respectively. The estimated mean Kc value was 0.87. These Kc values can also be required to calculate the crop water requirement for similar agro-climatic conditions in Bangladesh.

Bangladesh J. Agril. Res. 49(2): 145-156, June 2024