Construction and application of a weighing feedback-based irrigation system for facility tomatoes

To An innovative irrigation system was proposed for facility cultivation tomatoes using weight feedback, in order to improve the accuracy of irrigation. Among them, the weighing feedback module was used to monitor the water requirements of tomato plants. Multi-source information acquisition and transmission were to collect and transmit the environmental information in the greenhouse. An irrigation decision module was to issue the irrigation commands for the switch of water pumps. A water-fertilizer actuation module was to configure and transport the nutrient into the crops. Initially, a satellite positioning module was employed to ascertain the latitude and longitude of the irrigation site, which was facilitated the automatic calculation of the sunrise, sunset, and solar noon times. Four phases of dynamic irrigation were autonomously segmented the day, according to the water absorption of coco coir strips and the diurnal transpiration patterns of tomato plants within the greenhouse. Furthermore, general mode of irrigating nutrient or desalination mode of irrigating pure water (or low-concentration nutrient solution) was formulated, according to the greenhouse temperature and humidity information, as well as the feedback on the root information of tomato plants that obtained from drainage conductivity. Experimental design was involved the radiation accumulation and timed irrigation as controls, in order to validate the applicability, in terms of cultivation, irrigation, and application benefits. The results indicate that the weight feedback system increased irrigation volume by about 1.8%, compared with the radiation accumulation. The fertilizer usage, drainage ratio, and drainage EC value were reduced by 7.3%, 7.9%, and 9.3%, respectively. The irrigation volume, fertilizer usage, drainage ratio, and drainage EC value decreased by approximately 11.3%, 20.0%, 17.9%, and 4.9%, respectively, compared with the timed irrigation. Cultivation results show that when the coconut coir strip-cultivated tomatoes were irrigated under this weight feedback irrigation system, there were no significant differences (P>0.05) in the stem thickness, relative chlorophyll content of leaves, sugar content, and single ear mass, compared with the radiation accumulation. Additionally, the plant height increased by 4.8%. There were no significant differences (P>0.05) in the plant height, stem thickness, relative chlorophyll content of leaves, sugar content, and single ear mass, compared with timed irrigation. It was expected that 15 solar greenhouses (1.22 hm²) were contributed to save 27.6 thousand yuan per month and 22.6 thousand yuan per hectares per month using the weight feedback system, compared with the radiation accumulation; The park can save 22.47 thousand yuan per month in application benefits, compared with the timed irrigation and 18.47 thousand yuan per hectares per month. As such, the previous cumbersome calculation of water demand was greatly simplified to achieve the precise detection of tomato water and precision irrigation for the Rockwool cultivation and the mixed substrate potted cultivation.