关键词: 辣椒秸秆, 还田, 西瓜, 土壤养分, 土壤微生物, 土壤酶, 品质

Abstract: In order to promote the recycling of pepper straw waste，improve the yield and quality of watermelon，Meixiu watermelon was used as the test material，and the method of single factor randomized block design was adopted，with no straw returning used as the control（CK），and different straw returning amount of 4 500，9 000，16 500 and 27 000 kg/ha used as treatments（denoted as L300，L600，L1100 and L1800 respectively），and the effects of different amount of pepper straw returned on soil nutrients，microorganisms，soil enzymes，single melon weight and quality of watermelon were studied.The results showed that the contents of available phosphorus，available potassium，ammonium nitrogen and nitrate nitrogen in rhizosphere soil of watermelon first increased and then decreased with the increasing of straw returning amount，and reached the maximum inL1100 treatment，which increased by 13.86%，19.50%，51.29% and 41.73% respectively compared with the control，while the content of organic matter increased with the increasing of straw returning amount.The number of bacteria，actinomycetes，fungi and the total amount of rhizosphere microorganisms in the rhizosphere soil of watermelon were increased by pepper straw returning significantly，and their number was the largest under L1100 treatment. At the same time，the number of bacteria in rhizosphere soil was the most，followed by actinomycetes and fungi. With the increasing of pepper straw returning amount，the invertase activity of watermelon rhizosphere soil increased gradually，and the activity was the highest under L1800 treatment.The activities of urease，phosphatase and catalase of the four straw returning treatments were higher than those in the control，but the activities of urease and phosphatase were the highest in L1100 treatment，and the activity of catalase was the highest in L600 treatment.Under L1100 treatment，the single watermelon weight was the largest，increased by 37.77% compared with the control，and the content of central and marginal soluble solids was the highest，increased by 9.85% and 30.57%，respectively. The median⁃marginal difference was the smallest，which was 28.68% lower than the control. There was no significant difference in peel thickness between the control and L300，L600，L1100，respectively.The organic acid content was the highest under L600 treatment.Therefore，when the amount of pepper straw returned to the field is 16 500 kg/ha，it can significantly improve the soil nutrients in the 0—20 cm plough layer，increase the number of soil microorganisms and soil enzyme activity，improve the weight of single melon and flavor of watermelon.It can be used as the appropriate amount of pepper straw returned to the field for watermelon farmland soil fertility and high quality and high yield of watermelon.

Key words: Pepper straw, Straw returning, Watermelon, Soil nutrient, Soil microorganism, Soil enzyme, Quality