Abstract
Abstract: This study aims to examine the effect of matrix water on the expansion of mushroom shape, thereby determining the efficient water application of Agaricus bisporus in a greenhouse. A matrix water stress test of Abisporus bisporus during the whole growth period was conducted in the greenhouse in Henan University of Science and Technology of China in August 2020. The "Aoji No. 1" variety was taken as experimental material. An environmental control system was developed to adjust the temperature, air humidity, and CO2 concentration in the greenhouse. Four groups of matrix moistures were set at the saturated water holding rate of 80%-90% (full water treatment, T1), 70%-80% (light stress, T2), 60%-70% (moderate stress, T3), and 50%-60% (severe stress, T4). A sensor of soil moisture RS485 was selected to monitor the water content of substrate soil. The key parameters were determined, including the development morphological index, single mushroom quality, regional mushroom quality, yield, and water use efficiency of Agaricus bisporus during the fruiting period. The results showed that: 1) The thickness of mushroom cover and the stalk diameter were evidently reduced with the increase of soil water stress. There was no significant influence of soil water stress on the height of mushrooms. The maximum thickness of mushroom cover and stalk diameter decreased by 26.1% and 24.9% under severe stress of soil water. The harvest time was delayed by 16.5 h, when the size of mushroom cover was used as the index of fruiting, compared with full water treatment (P < 0.05). 2) The gradual, rapid, and slow growth stages were included in the development of cover thickness, stalk diameter, and mushroom height. Soil water stress reduced the peak of growth rate for the thickness of mushroom cover. The peak growth rate of mushroom stalk and cover were gradually advanced, whereas, the rapid growth time was prolonged significantly with the aggravation of soil water stress. Compared with full water treatment, the rapid growth time for the thickness of mushroom cover under light stress, moderate stress, and severe stress delayed by 4.1, 5.4, and 10.6 h, respectively, whereas, the rapid growth time of stalk diameter delayed by 10, 4.2, and 7.6 h, respectively, (P<0.05). 3) The overall quality, yield, and water use efficiency of Agaricus bisporus reduced with the increase of soil water stress. The number of diseased spots and malformed mushrooms increased sharply under moderate and severe water stress, resulting in the decrease of high-quality mushroom yield. The yield of Agaricus bisporus under the mild, moderate, and severe soil water stress decreased by 5.5%, 26.3%, and 39.1%, respectively, (P < 0.05), compared with full water treatment. Water use efficiency and the number of Agaricus bisporus reached the highest under the mild water stress, increasing by 2.3%, and 9.2%, respectively, compared with full water treatment (P < 0.05). Fruiting- and high-quality mushroom ratio under the mild water stress were slightly lower than those of full water treatment. 4) The soil water stress during the whole growth period of Agaricus bisporus led to the changes of fruiting body and texture of monomer, as well as the reduction of yield and high-quality ratio. Appropriate soil water stress prolonged the period of rapid growth stage without affecting the quality of Agaricus bisporus. Mild water stress can be carried out in the gradual growth stage (0-40 h), and slow growth stage of mushroom to increase water use efficiency. The sufficient water content of the substrate should be maintained during the rapid development period (40 h-100 h). Water deficit treatment should not be carried out to improve the development rate and quality of Agaricus bisporus. This finding can offer an efficient application of water control in fungi substrate suitable for the precise management of water in Agaricus bisporus production.
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