PRECISION IRRIGATION SCHEDULING FOR GREENHOUSE TOMATO BASED ON ANALYSIS OF ENVIRONMENTAL CHARACTERS AND THE PENMAN-MONTEITH MODEL

Precision irrigation offers excellent prospects in terms of saving water, reducing pollution and improving crop yield for greenhouse agriculture. However, the precision irrigation scheduling depends greatly on the environmental factors such as temperature, air pressure, wind velocity, etc. In this study, the environmental indicators in four greenhouses of Changle, Fuzhou (Jinan), Lianjiang, Fuqing in Fujian province of China were monitored, and the Penman-Monteith model was used to precisely calculate the irrigation amounts in these four typical areas. Results showed that the Penman-Monteith model could well satisfy the requirement regarding the irrigation amount calculation for the tomato under greenhouse conditions. According to the calculation result, the total irrigation amounts of Changle, Fuzhou, Lianjiang and Fuqing were 403.5, 376.7, 379.2 and 393.1 mm, respectively, and the averagely daily irrigation amounts were 1.79, 1.67, 1.69 and 1.75 mm, respectively. Similar calculation results for the four areas possibly due to that their locations were in the same province, which shared the semblable climates. Our study highlighted the importance of environmental factors when developing irrigation scheduling for greenhouse crops. This study could provide beneficial information for the precise irrigation of the greenhouse cultivation, and provide an important foundation for further development of precision agricultural decision system.