|Budget Amount *help
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1998 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1997 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1996 : ¥1,300,000 (Direct Cost : ¥1,300,000)
The objective of this study is to develop the real time control system which can predict the changes of soil moisture (pP value) in a greenhouse and appropriately control pF value. In 1996 and 1997, the soil moisture control system and the environmental supervisory system were constructed. Using the multiple regression analysis, changes of pF values were determined to be the dependent variable, and the temperature, the moisture and the amount of solar radiation were used for independent variables. In 1998, the automatic irrigation systems were constructed using two kinds of control methods. One is the multiple regression control mentioned above, and the other is the fuzzy control. These cultivation results were compared with those of farmer's manual irrigation work (the custom method). Cucumber, which frequently requires irrigation work, was chosen in this study.
Regarding the total amount of irrigation in the experimental periods, that of the custom area was I , 330 L, while that of the multiple regression control area was 641 L, and that of the fuzzy control area was 917 L.The ratios of A-quality during the whole experimental period showed 47% in the custom area, 43% in the multiple regression control area, and 47% in -the fuzzy control area. The yield of cucumbers per stock during the experimental period showed 2,006g in the custom area, white those in the multiple regression control area and in the fuzzy control area showed 2,067g and 2,338g. The earnings per stock are 847 yen, 885 yen and 1,026 yen, respectively, From the results mentioned above, these two control methods were proven to be useful for automatic irrigation control in the greenhouse.