Abstract:
Abstract: Fritillaria cirrhosa is one of the most precious traditional Chinese medicines. Some characteristics, like being fond of humidity and fearing of high humidity, have posed a great challenge to the artificial irrigation of Fritillaria cirrhosa. The intelligent precision irrigation system can be expected to realize the water-saving irrigation on demand in recent years. In this study, a partition system of variable rate Fritillaria Cirrhosa irrigation was developed using the wireless sensor network. An investigation was made on the impact of growth age, planting season, soil, and planting density on the required irrigation water of Fritillaria cirrhosa in the process of artificial cultivation between April 2018 and December 2020. A capacitance analyzer was also selected to detect the soil moisture content. The water demand was thus obtained for the Fritillaria cirrhosa growth and irrigation water in planting soil. As such, the required and planting soil moisture content model was established for the growth of Fritillaria cirrhosa. The results showed that the required soil moisture content of Fritillaria Cirrhosa growth increased, with the increase of planting density, in addition to the factor of Fritillaria cirrhosa growth age. A fuzzy control strategy model was established for the application of partition variable irrigation of Fritillaria cirrhosa. A double-input and simple-output structure was adopted for the fuzzy controller. The input variables were the planting density c and the difference value e between the required soil moisture content for Fritillaria cirrhosa growth and the planting one. The output variable was the increment of soil moisture content u during irrigation. Genetic Algorithm (GA) was utilized to optimize the quantification factors of fuzzy control, Ke and Kc, the scale factor Ku, the fuzzy control rules, as well as the membership function, in order to achieve an accurate decision on the irrigation water of Fritillaria cirrhosa. The irrigation water was also applied under the different planting densities, seasons, and growing ages. A field irrigation process was conducted in the greenhouse of Fritillaria cirrhosa using the partition variable irrigation technology, according to the increment of irrigation soil moisture content u. The experimental results showed that a better water-saving effect of irrigation was achieved using fuzzy control optimized by GA. The increment of soil moisture content was distributed between 5% to 7%, and the consumption of irrigation water decreased significantly. The error of optimized variable irrigation was around ±5% under the specific planting density of Fritillaria cirrhosa, where satisfied the irrigation demand as required water amount of Fritillaria cirrhosa growth. The required irrigation water also increased linearly, with the increase of planting density of Fritillaria cirrhosa. Correspondingly, there was a parabolic relationship between the water-saving rate of partition variable irrigation and the planting density ratio of Fritillaria cirrhosa. The optimum water-saving rate was achieved, where the standard planting density and the annual water-saving rate reached more than 27.6%. This finding can provide a sound reference and technical support to the strategy of planting density and water-saving irrigation for Fritillaria Cirrhosa.