The Variation Of Calcium In Orchard Soil And Apple Quality In Loess Plateau

Ca is an important quality element in apple,and it is one of the indispensible secondary nutrients.For the past many years in the fruit producing field,great attention paying to the application of N and P fertilizer but ignoring the Ca and others made it a phenomena that the fruit trees were absent of Ca.And plant diseases become increasingly common,such as bitter bit,variola,water core and so on.These diseases affected the fruit quality and storage, bringing too much economic loss to fruit tree producing process and influencing the sustainable development of manufacturer and supplier of fruits.Soil,as an important factor supplying the fruit trees with Ca,being studied about the Ca varying and the conditions of Ca supplying with influence of environment,revealing the theory mechanism of fruit trees Ca absence in limy soil.After analyzing the apple quality of Weibei area,the study fond the advantage and disadvantage of the apples and provided basis for high quality apples producing.By a study of nutrients distribution and varying in different soil profiles in different aged orchards,to attempt to reveal the theory of soil nutrients depleting and supply scientific application to orchard soil a basis,we studied the concentration and distribution of soil Ca and fond out that:1.These apples in Weibei basically corresponds Fuji apple physiochemical indexes, hardness,sugar content and acidity reached a success rate of 94.1%,64.7%and 82.4%.but first-class fruits had a low success rate of 17.6%.There among,the hardness was well.Sugar content was the middle,but it seemed lower with the local advanced conditions;acidity was a little higher.The Vc content was low,less than 3.7 mg/100g mostly;the minimum of Ca content was 3.04 mg/100g,with the maximum of 5.85 mg/100g,and these were far below the normal content in general.And it was because of Ca absence,the apples were prone to water core and bitter bit;protein content ranged from 0.109%to 0.197%,and it was a little low; water content was a little higher than normal(84%),with an average of 85.60%.Through the analysis between apple rigidity and tree age,the apple rigidity decrease sharply while the tree age increase.To maintain the trends of decreasing tree ages is the key factor to guarantee the high quality of apple production.2.The evolution characteristics of soil fertifilty was more significant in Weibei orchard.The organic matter content in the orchard soil profile decreased with the increase of soil depth,and especially soil organic matter below 40 cm decreasing sharply was a symbol of soil degradation.The organic matter content in 8 to 15 years decreased as the age of orchard increased,however,the organic matter content increased slightly with the age of 19 when the fruit trees become to their obviously degrade phase.Among all the orchards in Weibei area,available N accumulation increased sharply at the layer of 20 to 40cm.The depletion of N nutrient in degrade orchard was obvious.And the depletion in 40 to 100cm soil layer in 15 year old orchard was obvious but it was better in the later 19 years old orchard.P in orchard soil increased significantly as the orchard age increased,and the mainly position was above 40 cm soil layer.The available P content in 8 year old orchard was merely 2.9 mg/kg,with the 19 years old orchard as high as 9.8 mg/kg. Though,the supplying of available N and available P was not high.From the location of available N and available P,we can find that the problem in fruit trees nutrients management in Weibei area was the depth of application.In arid area where are short of water,only a proper deep-application can make the fertilizer a full use.3.Soils in Weibei area are rich in Ca,and which can be used by fruit trees are far more than the Ca content in soil.But,the Ca content in apples are far less than the normal ones.The absence of Ca is caused by absorption,translocation and using ineffectively.Different limy orchard soils with the different ages had the trend of exchangeable Ca declining,especially below the 60cm layer in the soil.The increasing of water soluble Ca in the soil was greatly related to inorganic fertilizer.The decreasing of exchangeable Ca and increasing of water soluble Ca made the soil a low buffer capacity,having a trend of acidification.And it was also a symbol of soil degradation,also a factor inhibiting the sustainable development of fruit trees.