| In order to study organic solid waste composting substrate used in the production of soil-free turf, this article studies on regulation of the waste composting substrate permeability, water retention, fertilizer conservation and explores the effects of different dosage of bark compost on sludge compost permeability, different particle size mushroom compost on water retention and physiological characteristics of tall fescue under drought stress, combined application of controlled-release fertilizer and compound fertilizer on substrate nutrient holding capacity and nutrient leaching respectively. The main results are as follows:1 The study of using bark compost to regulate sludge compost permeability showed that the total porosity, aeration porosity and permeability coefficient were increased by 2.7%~9.1%?217%~440% and 184%~510% in adding bark compost than that of pure sewage sludge compost respectively, while the bulk density, water holding porosity, WAP/AP, EC were decreased by 8.1%~35.1%?10.66%~29.65%?58.85%~84.06% and 19.04%~75.83% gradually with the increasing amount of bark compost. The emergence rate, height, growth rate, number of tillers and root activity of ryegrass were the best in the 50% bark treatment and increased by 10%, 52.5%, 31%, 61.9% and 53.9% compared with the pure sewage sludge compost.2 The study of water retention property of different particle size mushroom compost showed that volumetric water content at particle size <5mm was the lowest and decrease amplitude was the biggest. At the end of drought stress, the SOD activity and proline content of the plants grown at particle size <5mm were the highest, which were 1.45, 1.73 times of the control respectively. The leaf relative water content, water potential,WUE, POD activity, CAT activity, soluble protein content and root activity of the plants grown at particle size <3mm were the highest, which were 1.21, 1.22, 2.13, 1.26, 1.28, 2.07, 1.61 times of the control respectively. However, the lawn ET, Tr and MDA content were the lowest and decreased by 31.55%, 27.64% and 33.25% respectively when compared with the control. Volumetric water content at particle size <2mm was the highest and decrease amplitude was the least. The chlorophyll content, Pn and soluble sugar content of the plants grown at particle size <2mm were the highest, which were 1.31,1.96,1.41 times of the control respectively. In addition, its leaf relative conductivity was the lowest and decreased by 20.03% compared with the control.3 The study of combined application of controlled-release fertilizer and compound fertilizer regulating substrate nutrient holding capacity showed that NPK leaching rates in controlled-release fertilizer treatments(T2, T3, T4 and T5) are 1.80%~24.74%, 0.07%~0.72% and 0.03%~0.30%, while 25.59%~94.59%, 53.25%~95.45% and 3.23%~90.32% lower than those in compound fertilizer treatment, respectively. Among them, 100% controlled-release fertilizer was the lowest and 25% compound fertilizer plus 75% controlled-release fertilizer took second place. Combined application of controlled-release fertilizer and compound fertilizer improved white clover's nutrient uptake and fertilizer use efficiency, 25% compound fertilizer plus 75% controlled-release fertilizer had the better upgrading effect, its NPK use efficiency was 273.32%, 82.06%, 234.26% higher than those in compound fertilizer treatment. While the proportion of controlled-release fertilizer was 50%~75%, white clover's emergence stage was the earliest, dry weight per plant, emergence rate, plant height, branch plant, chlorophyll(a+b) and root activity were significantly higher than those in compound fertilizer treatment., its stem-leaf ratio and Specific leaf area were significantly lower.4 Comprehensively consideration production practice, the addition of 50% bark compost is suggested for the adjustment of sludge compost permeability. Mushroom compost particle size <3mm has better effect on drought-resistant ability of Festuca arundinacea under sustained drought stress. Under the same N, P and K nutrient inputs, an application ratio of 3:1 controlled-release fertilizer to compound fertilizer is recommended in the studied area. |
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