Preliminary Mechanism Of Raising Yield Of "Zaosu"pear By Application Of Pruning Compost

Pruning compost was a cmposting pruduct that made from lots of pruning branches,it was a way that can turn the solid waste of the fruit orchards into a new organic fertilizer containing comprehensive nutrients and realize the utilization of the pruning branches.Application of organic fertilizer can improve soil quality,increase soil organic matter and mineral nutrients,as well as improve fertilizer utilization.The benefical effects on tree growth had been gradually foucused.However,the effect of application of the organic fertilizer made from pruning branches is not clear.In this paper,based on the equal mineral nutrients and organic matter,the experiment set sheep manure(SM)and chemical fertilizer as control(CF)to study application of pruning compost(PC)on the yield,soil properties,growth and distribution of roots.Furthermore,the experiment was designed to explore the dissolved organic matter compostion which was related to growth promotion effect.The main results are as follows:1 PC and SM treatments significantly increased the content of alkali-hydrolysable nitrogen in the soil,which were 1.78 and 1.44 times of the control treatment,respcetly.PC increased soil available P contents by 30.3%compared with the control.SM and PC increased soil available K by 19.5%and 7.5%,respectively.The soil organic matter content under PC treatment was 25.7%higher than control.The number of bacterial and actinomycete were increased by 46%s and 56%under PC.SM treatment significantly increased the number of actinomycetes by 35%.Application of PC had a significant effect on weight of single fruit,which was 20.7%higher than that of the control.The yield of PC and SM were 1.31 times and 1.36 times of control.PC significantly increased the content of soluble solids in the fruit,and the ratio of sugar and acid was 1.23 times of control.Otherwise,SM decreased soluble solids in the fruit.2 Compared with CF,PC and SM significantly increased the total root length,total root surface area and the number of root tip of pear tree.All root feature parameters mentioned above were PC>SM>CF.In horizontal direction,two organic fertilizations increased the distribution of root in the range of 0～40 cm 120～160 cm and 160～200 cm,and PC performed better than SM.In vertical direction,applications of two organic fertilizer increased root length,surface area and volume in 0～30 cm and 30～60 cm soil layers.In 30～60 cm soil layers,application of organic fertilizers increased the density of absorbing root and coarse root.PC contributed more absorbing root and SM contributed more coarse root.The results also showed that the relative length,surface,volume of absorbing root were increased by applying organic fertilizers,and very fine root was most obvious.Furthermore,fine root relative volume was significantly increased under PC,and the relative length,surface area and volμme of coarse root were highest under CF,followed was SM.3 The promoting effect of pruning compost was related to the active organic matter,and dissolved organic matter was the most active component.The experiment was conducted to study the effects of different molecular weight and different oxidation states compost extract on the growth of seedling so as to explore the mechanism of root growth promoted by pruning compost.The results showed that the promoting effect of the compost was mainly related to the small molecular weight dissolved organic matter contained in it.The effect of different oxidation state compost extract on the growth of the seedling was studied,and physical and chemical properties and spectral properties of dissolved organic matter were analyzed.The results showed that the promoting effect of pruning compost was related to small molecular weight dissolved organic matters which had redox activity in the compost.In conclusion,applying pruning compost for 4 consecutive years improved the soil properties,promoted the growth of pear roots and the distribution of roots in the soil,increased pear yield and improved fruit quality.The beneficial effects of the application of pruning compost on fruit trees may be related to the small molecule organic matter with redox activity in compost.