Study On Spatio-temporal Characteristic Of Soil Nutrient And Effect Of Fertilization In Apple Orchard Of Shaanxi Weibei Area

Fertilization is an important part of the orchard management. Mean while soil availablenutrient is not only a sign of orchard soil fertility level, but also is the important basis offertilization. Due to the lack of effective evaluation standard and methods, there generally hasthe phenomenon of fertilizing blindly or only by experience during apple orchards nutrientmanagement in Loess Plateau of Shaanxi. As a consequence, lots of fertilizers are wasted, soas to affect the yield and further improving the economic benefits of the apple.Objects: Study on soil effective nutrients level status of apple orchards and itsgeographical features, temporal and spatial variation and their relationship with fertilizingeffect. Of this thesis, we select season orchards of Fuji apple whose yields more than15t·hm–2of30apple base counties in Loess Plateau of Shaanxi as research subjects.Methods: Combining the long-term fertilizer effect experiment of fruit trees, theconventional statistics, statistical and spatial analysis methods were used.Results:Part1:The results from the investigation of3752orchard fertilization （farmers） in13apple basecounties in the region of Weibei Plateau indicate that high fertilizer input production modewas widely used, and year average fertilizer dosages were pure N587kg·hm^-2,P₂O₅362kg·hm^-2 and K₂O255kg·hm^-2. In addition, average organic fertilizer dosage was6.1kg·hm^-2. Highest frequency distribution scope of fertilizer for orchard were pure N400～600kg·hm^-2, P₂O₅200～400kg·hm^-2 and K₂O0～200kg·hm^-2, and orchards of no usingorganic fertilizer occupied71.7%of total ones.Compared with early time, this results present increasing trend of nitrogen and potashconsumption, but the phosphate fertilizer consumption appears reducing trend, and the dosage of organic fertilizer on average was only about a quarter of that in early. The result also showsthat fertilizer amounts of N and P₂O₅was highest in the most suitable areas, was lowest inthe sub-suitable areas, and average K₂O dosage was highest in suitable areas, and also waslowest in the sub-suitable areas. However, the dosage of organic fertilizer on average washighest in the sub-suitable areas, was lowest in the most suitable areas.It presents significantly positive relationship between apple yield and nitrogen fertilizerin different ecological zones and different output levels of orchard types, but the relevancebetween apple yield and the phosphate or potash fertilizer are large difference by biome andby different types of output level.Evaluation results of excess or lack fertilization for orchards in Weibei region show thatnitrogen fertilizer application was mainly excessive, phosphorus was excessive or deficient,and potash fertilizer dosage is mainly insufficient in three climate zones. The proportion oforchard which nitrogen and phosphate application are excessive increases with rising, but theproportion of lack nitrogen and phosphate orchards presents downtrend with average appleyield decreasing. The orchards of lack of potash application are mainly distributed the mostsuitable and sub-suitable areas, whose proportion occupied in whole orchards accounted for74.6%and65.3%respectively, compared with most suitable, which is much higher than thatof the suitable areasPart2:Soil organic matter and available nutrient content analysis results of24608season ofFuji apple orchards in all30apple base counties of Weibei region in Shaanxi province showthat average soil organic matter content is11.7g·kg-1, and this level is lowest in all areas.The average contents of alkaline hydrolysis nitrogen, effective phosphorus and availablepotassium are62.7mg·kg^-1,15.8mg·kg^-1 and155.8mg·kg^-1 respectively, and effectivephosphorus and available potassium consumption mainly present deficiency, but alkalinehydrolysis nitrogen is given as moderate and high dosage.There are large differences for the average soil available nutrients content among threeecological zones, alkali-hydrolysable nitrogen and effective phosphorus content in the mostsuitable areas are the highest on average, organic matter content is lowest, andrapidly-available potassium content in sub-suitable areas is highest. With the improvement oforchard production levels, soil alkali-hydrolysable nitrogen, available phosphorus and available potassium content showed a trend of increase, however, the trend of organic mattercontent changes with apple production is not obvious.It is extremely significant correlation between soil alkali-hydrolysable nitrogen contentand apple production in all different yield levels orchards, but soil available potassium andorganic matter content are not significantly related to apple yields. In addition, correlationcoefficient, as a whole, is the highest between soil effective phosphorus and apple yield inmoderate yield orchards.The regression analysis results of nitrogen, phosphorus and potash application and soilavailable nutrient content in3752orchard tracking investigation show that these were verysignificant positive correlation between orchards nitrogen fertilizer and soilalkali-hydrolysable nitrogen content, and between amount of P2O and soil available p contentrespectively, it was significantly positive correlation between the dosage of K₂O andavailable k content, and it was significantly negative correlation between nitrogen fertilizerand soil available p content.Part3:The results of terrain features and geo-statistical analysis of soil available nutrientindicate that orchard soil organic matter, alkali-hydro nitrogen and available phosphoruscontent are all downtrend with the increase of slope, and soil organic matter and alkalisolution nitrogen is greater in Yin slope than that in Yang slope. Soil organic matter, availablephosphorus and available potassium all showed strong spatial correlation respectively becauseits inner factors,（structural factors） play a leading role. Alkali solution nitrogen presentsmedium spatial variability, which is the result of the interaction of the structural and randomfactors （human activities such as fertilizer）. Soil organic matter content presents zonaldistribution in the research area, which presents obvious decreasing trend from the south tonorth. Soil alkaline hydrolysis N and available P content shape patch distribution, which is atrend of decline from south to north and from west to east. However, the zonal characteristicof soil available K is not obvious.Soil nutrient interpolation results and accuracy analysis show that the forecast results ofsoil organic matter, alkali-hydro nitrogen and effective phosphorus are all larger than itmeasured, but that of available K, on the other hand, is opposite, and the margin of error ofthe predicted values and measured one is between3.4¹2.0%. The areas of soil available nutrients increased amplitude larger mainly distribute in the largest apple planting area recentyears and the famous area for apple industry.Recent25years, soil organic matter and available nutrients of apple orchards in Weibeiregion are mainly increasing trend, in which the area of the organic matter content accountedfor64.7%of total area, its increased amplitude is mainly between0¹0.0g·kg^-1. Foralkali-hydrolysable nitrogen, effective phosphorus and available potassium, the proportion ofits occupation in whole areas are73.8%,93.9%and94.6%respectively, whose increased rateof alkaline hydrolysis nitrogen is0²0.0mg·kg^-1, effective phosphorus0¹5.0mg·kg^-1and available potassium0⁵0.0mg·kg^-1 respectively.Part4:Test results of apple’s long-term fertilizer effect show that long time combinedapplication of nitrogen, phosphorus and potassium fertilizer made apple production increasedsignificantly, while the increased production effect in different production year changes muchbigger. The effects of fertilizer on apple yields and single fruit quality are all of N is greaterthan P and K.As regards as effects of fertilizer on the apple production, P was significantly greaterthan K in higher production years, and there was no significant difference for fertilizer effectsin medium and low yield years. Effects of fertilizer on the quality of single fruit, there was nosignificant difference in high and middle yield years for phosphate and potash, but K effectwas significantly greater than P in low yield years.Agronomy efficiency of nitrogen, phosphorus and potash fertilizer and contribution rateare of same order, which is N> P> K in high and middle production years; N> K> P in lowyield years. Long time combined application of nitrogen, phosphorus and potassium fertilizerincreased the orchard soil effective content of nitrogen, phosphorus and potassium, but theaccumulation of effective nitrogen, phosphorus and potassium in different soil layer changesbigger respectively. Among that, accumulation of effective nitrogen increased with theincrease of soil depth, on the other hand, accumulations of the effective phosphorus andeffective potassium decrease with the increase of soil depth.It is believed that available nitrogen and phosphorus nutrients accumulated in soil have asignificant impact on apple yield in next year, at the same time, the effects of fertilizer nutrient accumulation in soil on the apple production related to soil depth. Therein toavailable nitrogen and available phosphorus content in20⁴0cm depth soil wassignificantly positive correlation to apple yields.Conclusion: These research results can provide some references for providing acomprehensive grasp for orchard soil nutrient characteristics, guiding the rational fertilization,and improving the level of nutrient management in Weibei area in Shaanxi province.