Abstract:

【Objective】 The present experiment is aiming at studying how the coordination use of biogas slurry and potassium in apple orchard influences the physiochemical characteristics of its soil, the quantity of microorganisms in its soil, and its fruit quality, and thus providing a theoretical basis for properly use of biogas slurry in Weibei Rainfed Highland of Shaanxi. 【Method】The 10-year-old apple trees were used as test materials in the experiment and the effects of combined use of biogas slurry and potassium in apple orchard on the physiochemical characteristics of soil, the quantity of microorganisms in soil, and fruit quality were studied to screen the application rate of biogas slurry alone and the biogas slurry together with potassium. 【Result】 The results showed that biogas slurry dressing decreased soil bulk density and increased soil porosity, available nitrogen, and available potassium. Biogas slurry at 100 kg/tree decreased soil bulk density by 10.6% and increased soil porosity by 7.6% compared with the control. Biogas slurry at 50 kg/tree with potassium at 1 kg increased soil potassium by 20.5% compared with the control. Biogas slurry applied with potassium increased the number of soil bacteria, fungi, and antinomies. Biogas slurry applied at 100 kg increased the numbers of bacteria,fungi and actinomycetes by 132.7%, 38.3%, and 58.2% compared with the control. There was a promoting effect of combined application of biogas slurry with potassium on apple red fruit surface area rate, average single fruit weight, firmness, soluble solids and anthocyanin. Biogas slurry applied at 50 kg/tree and potassium applied at 0.5kg/tree increased anthocyanidin by 48%, colored area increased by 29.9% compared with the control. 【Conclusion】 The study proposed that biogas slurry applied at 100 kg per plant and biogas slurry applied at 50 kg with K fertilizer 0.5 kg per plant were the best for apple production and should be popularized.

Key words: apple, biogas slurry, potassium, orchard, soil properties, soil microorganism, fruit quality