Broken branch's mulching improving soil physical and chemical properties and enhancing quality of peach

Abstract: Cleaning peach branch residue need a great number of labor power and is also costly. The study aimed to investigate the effects of peach branch residue mulching on soil physical and chemical properties and peach quality. The field experiment was carried out from 2013 to 2015 in a peach orchard with dwarf peach trees in Ping Gu district, Beijing(116°59′E,40°11′N). Three treatments were designed including no cover (CK), rychophragmus violaceus cover (T1), and peach branch residue cover (T3). Rychophragmus violaceus was planted in April each year and cut in October for residue cover. The peach branch was crushed into pieces smaller than 5 cm, mixed with soil evenly, turned into soil 10 cm depth. During the experiment, the irrigation amount each year was 1350 L/hm2. Measured indicators included soil particle composition, soil density, moisture, organic matter, emission rate of carbon dioxide, and quality of peach fruits. The results showed that: 1) During the whole growth period of fruit trees, the residual branches cover could greatly affect soil properties. The T2 and T1 could significantly increase soil >0.25 mm aggregates compared with CK, and the T2 had larger effect on T1; 2) Overall, the soil compactness had the trend of CK>T1>T2. The compactness of CK was 30.2% higher than the T1 and 43.9% higher than T1 (P<0.05). The compactness of T1 was 10.54% higher than T2 (P<0.05); 3) The soil water characteristic curve for soils collected in June and October revealed that the soil water holding capacity of the T2 treatment was 10.16% higher than CK when the water suction was 30 kPa, and that of T2 and T1 treatment was 10.02% and 8.51% higher than that of CK when the water suction was 100 kPa; 4) Water infiltration rate decreased and stabilized with infiltration time. The stable infiltration rate of CK, T1 and T2 was 4.22, 8.41, and 10.01 cm/h; 5) Compared with CK, the soil organic matter content in T1 and T2 was increased by 119.8% and 183.2% (P<0.05), respectively; 6) Compared with CK, the T2 could increase the Vc content of peach by 43.5%, decrease titratable acid by 21.7%, increase soluble sugar by 20%, and increase the average single fruit weight by 7.9%(P<0.05). They were not significantly different between T1 and T2. In conclusion, the soil physical and chemical properties could be improved and the fruit quality was improved by peach branch residue cover. The peach branch residue cover had the similar effects with the rychophragmus violaceus cover. The study provides valuable information for peach orchard residue management.