Release Of Nutrients During The Decomposition Of White Clover Combined With Ryegrass As Green Manure And Their Effetcs On Fruit Yield And Quality In Apple Orchard In Weibei Highland

Orchard green manure as a pollution-free organic fertilizer in apple orchard is benefit forthe soil and apple trees. The nutrients released by decomposition and mineralization afterturning over the green manure, and can increase the soil organic matter and available nutrients,reduce the amount of chemical fertilizer, improve the soil fertility and reduce environmentalpollution. It is of great significance for developing sustainable of apple industry in Weibeidryland. However, the decomposition and nutrient release of the mixed with white clover andryegrass turn over in orchard are not been reported. The manures of100%white clover,75%white clover+25%ryegrass,50%white clover+50%ryegrass,25%white clover+75%ryegrass,100%ryegrass (Abbreviation: B, B3H1, B1H1, B1H3, H) were prepared. The nylonmesh bag method was used to monitor the nutrient release from the manures to soil whosedepth in0cm,10cm,25cm during215days. At the same time, the manures also directlyplowed into the soil as the above three kind of depth between the lines of fruit trees. Thenbegin to study on nutrient release during the decomposition of different green manure and theeffects on fruit yield and quality. The result is useful for the technology of turning over theorchard grass; a suitable and new management for orchard soil is selected for Weibei orchard.The main conclusions are as follows:1. The results indicated that under the same depth, the different ratio of white clover andryegrass were decomposed fast in the first month after incubation, and the nutrient werereleased fast in the first month too. We can also find that the degrees of decomposition andnutrient release are distinguished in different green manure throughout the experiment. It isshowed that the decomposition rate, C, N, P, K and Mg release rates of the five kinds of greenmanure were B>B3H1>B1H1>B1H3>H during the whole incubation. The release rate of Ca,Fe, Mn, Cu, Zn were inconsistent with the whole experiment due to the phenomenon ofenrichment. At the end of the experiment, the highest release rate of Fe, Mn, Cu, Zn were inwhite clover (B)(B3H1was the highest in25cm depth), followed by B3H1, and the highestrelease rate of Ca were in ryegrass(H)(B1H1was the highest in25cm depth)(P<0.05). 2. The decomposition and nutrient release in each ratio of white clover and ryegrass weredifferent under the different depth. It is indicated that green manures in10cm depth thedecomposition rate and the release rate of large number of elements are the fastest, deepplowing in25cm are faster, and covering the surface are the slowest. At the end of theexperiment, compared10cm depth treatments with25cm depth and cover of the surface, thedecomposition rate were higher2.9%and12.4%, respectively, C release rate were higher2.1%and10.9%, respectively, N release rate were higher2.7%and8.9%, respectively, Prelease rate were higher13.5%and22%, respectively, K release rate were higher1.8%and8.2%respectively; due to the enrichment of nutrient in mid-elements and micro-element, inaddition to calcium, the release rate of Mg, Fe, Mn, Cu, Zn in10cm incubation were lowerabout1%than deep plowing in25cm, compared with the covering surface treatment, therelease rate of Ca, Mn, Cu were lower about21.1%,3.6%,5.7%, respectively, the release rateof Mg, Fe, Zn were higher4.4%,4.4%,1.3%, respectively(P<0.05).3. The release rate among different elements of the same green manure in the same depthwas different, and they were all showed different characteristics during whole incubation. Theprocess of C release was consistent with the dry matter decomposition, and the releaseprocess were obviously different among N, P and K, the release rate of K was the highest andfollowed by P, N. N was released fast during the first21d(covered surface was in35d), andit almost in a straight line on the figure; P release during the first35d (covered surface was in80d) was from fast to slow, and then kept unchanging until the end of experiment; K releasewas radical, the release rate has reached80.2%~89%after50d; Ca, Fe, Mn, Cu, Zn werereleased fast during the first14d, and later the release of each treatment were different andhave appeared enrichment in the nutrient one after another; the release process of Mg wassimilar to K, which didn’t appeare enrichment during the experiment.4. The incubation of green manures (different ratio of white clover and ryegrass) hadobvious influence on fruit yield and quality and performed as follows: compared with the baresoil (CK), the fruit weight, the yield, the fruit firmness, the soluble solids content, and thesoluble sugar content were increased by the incubation of the same green manure under thethree kinds of depth, and the titratable acid content was declined. Each of the measurementindicators changed greatly in10cm depth, then was the25cm, and covering the surface wasthe last; we can also concluded that compared with the bare soil (CK), B3H1has the greatestinfluence for the same depth of five green manure treatment on apple fruit weight, yield, andsoluble sugar content. Fruit firmness and soluble solids content were B3H1> B1H1(thedifference was not significant). The titratable acid content reduced most in ryegrass (H), and it contrast in white clover (B), the other three green manures (B3H1, B1H1, B1H3) werebetween of them, the difference was not significant (P<0.05).5. According to the demand ratio of Apple’s nutrient (take the Weibei Fuji apple forexample), combined the nutrient release characteristics among the five green manuresincubated in three depth during the experiment (white clover released more nitrogen thanryegrass, but released less phosphorus and potassium than ryegrass, the nutrient release inother three manures were between of them), comprehensive analysis above factors and theimpact on fruit yield and quality, we can conclude that B3H1(white clover75%+ryegrass25%) incubation in10cm depth is the most conducive for decomposing and nutrient release,and the most benefit for improving fruit yield and quality. Considered from the root growthcharacteristics, the mode of B3H1green manure shifting cultivation in10cm and25cmdepth is the most suitable in Weibei orchard.