Effects Of Long-term Application Of Chemical Fertilizers On Availability Of Soil Microelements In Korla Fragrant Pear Orchard

In order to reveal the long-term application of chemical fertilizers on the distribution characteristics and spatial variability of the total amount and available content of soil trace elements in different ages of Korla fragrant pear orchards,three fragrant pear orchards（5 years,12 years,and 25 years old）with similar site conditions and fertility were selected.Sampling the soil within the canopy（0.80m from the trunk）,the edge of the canopy（1.50m from the trunk）,and outside the canopy（3.25m from the trunk）,and determine the total amount and effective content of soil trace elements at different sampling points Analyze the distribution characteristics and spatial variability of effective state content,and provide a scientific basis for constructing a soil nutrient management system that is conducive to high-quality and high-yield Korla fragrant pear.The main conclusions are:（1）Total contents of Fe,Mn,Cu and Zn in soil of Korla Fragrant Pear Orchard.The average soil Fe content of the 5-year-old Korla Fragrant Pear Orchard is 34.9g·kg^-1,the average 12-year-old tree is32.80g·kg^-1,and the average 25-year-old tree is 40.85g·kg^-1.The average soil Mn content in the 5-year-old Korla Fragrant Pear Orchard is 0.676 g·kg^-1,the average 12-year-old tree is 0.616 g·kg^-1,and the average25-year-old tree is 0.727 g·kg^-1.The average total Cu content in the soil of the 5-year-old Korla Fragrant Pear Orchard is 0.034 g·kg^-1,the average 12-year-old tree is 0.025 g·kg^-1,and the 25-year-old tree average is 0.036 g·kg^-1.The average total Zn content of the 5-year-old Korla Fragrant Pear Orchard is 0.083 g·kg^-1,the average 12-year-old tree is 0.065 g·kg-1,and the average 25-year-old tree is 0.090 g·kg^-1.The total amount of trace elements in the soil of the three-age Korla Fragrant Pear Orchard is 25 years old>5 years old>12 years old.At different sampling points（inside the crown,the edge of the crown,and outside the crown）,the total amount varies between soil layers.Large,no significant difference.（2）Available content of Fe,Mn,Cu and Zn in soil of Korla Fragrant Pear Orchard.The average soil available Fe content in the 5-year-old Korla Fragrant Pear Orchard is 16.70 mg·kg^-1,the average soil available Fe content in the 12-year-old Korla Fragrant Pear Orchard is 6.29 mg·kg^-1,and the average25-year-old tree is 16.34 mg·kg^-1.The average soil effective Mn content in the 5-year-old Korla Fragrant Pear Orchard is 9.52 mg·kg^-1,the average 12-year-old tree is 4.96 mg·kg^-1,and the 25-year-old tree average is 8.44 mg·kg^-1.The average soil available Cu content in the 5-year-old fragrant pear orchard is 2.17mg·kg^-1,the average 12-year-old tree is 0.59 mg·kg^-1,and the 25-year-old tree average is 1.61 mg·kg^-1.The average soil available zinc content in the 5-year-old Korla Fragrant Pear Orchard is 1.48 mg·kg^-1,the average 12-year-old tree is 0.37 mg·kg^-1,and the 25-year-old tree average is 0.96 mg·kg^-1.The content of microelement available in the soil of the three-age Korla Fragrant Pear Orchard showed that the 5-year-old tree>25-year-old tree>12-year-old tree.There was no uniform distribution of effective state content at different sampling points（inside the crown,edge of the crown,and outside the crown）of the three tree ages.（3）The average effective iron content of tree-age soil in 12 years was 6.29 mg·kg^-1,which was a deficiency level(<7 mg·kg^-1),and the average effective Mn content of 12-year tree-age soil was 4.96mg·kg^-1,which was a deficiency level(<7 mg·kg^-1);the average effective Zn content of 12 tree-age soils was 0.37 mg·kg^-1,which was a deficiency level(<1 mg·kg^-1),and the average soil content of 25-year-old pear garden was 0.95 mg·kg^-1,Nutrient grading is a deficiency level(<1 mg·kg^-1).Overall,trace elements of iron,Mn,copper effective content in 5 years and 25 years of tree-age pear garden soil rich,do not need to be replenished.12 years of planting years of pear garden soil effective Fe,Mn,Zn is relatively lacking,25 years of planting years of pear garden effective Zn content is relatively lacking,can be appropriately replenished the lack of the corresponding trace element fertilizer.