| In order to find out the status of soil nutrient and leaf nutrient abundance and fertilization in orchards in the main apple producing areas in my country,scientifically guide the rational fertilization of apple orchards,and further improve the yield and fruit quality,this study was conducted in mid-to-late July 2021,based on 24 counties in the Loess Plateau(Shaanxi,Gansu,Shanxi,Henan),Bohai Rim(Liaoning,Shandong),Southwest Lengliang(Yun,Sichuan)and Xinjiang characteristic production areas.The apple orchard was the representative to investigate the management of the orchard,and a total of 284 survey forms were filled out.On the basis of a large number of investigations,representative mature apple orchards with high yield,medium yield and low yield were selected for sampling.A total of 260 soil samples of 0-20 cm and 20-40 cm and 98 leaf samples were collected.In this study,a total of 11 indicators of soil and 9 indicators of leaves were measured.The present situation of fertilization,yield,soil nutrient and leaf nutrient status of apple orchards in 4 producing areas were analyzed,and the abundance and deficiency of soil and leaf nutrient were evaluated according to the corresponding standards,and reasonable fertilization suggestions were put forward.The purpose of this study is to provide a basis for rational fertilization of apples in the four major apple producing areas in China,increase of fruit tree yields,and development of sustainable agriculture.The main conclusions are as follows:Through the investigation and analysis of the current situation of yield and fertilization,it is shown that the average output in China’s main producing areas was 32.49t·hm-2.The apple production in each main producing area is unbalanced,and the regional differences are large.The average yield of Xinjiang production areas is slightly higher than that of Bohai Bay production areas,and the average value of southwest cold and cool production areas is the lowest.The main apple producing areas in China generally have low output,and the potential for increasing production needs to be further explored.There is a big difference in the fertilization situation of each main apple-producing area.The insufficient and excessive fertilization of nitrogen,phosphorus and potassium fertilizers coexist,and the fertilization situation of each main apple-producing area is quite different.The N input of chemical fertilizers and organic fertilizers in the Bohai Bay area was 758.61kg·hm-2,which was 18.24%,45.20%,and 46.57% higher than that in the Loess Plateau,Southwest Lengliang and Xinjiang production areas.The input amount of chemical fertilizer and organic fertilizer P2O5 in Xinjiang characteristic production area was 542.07kg·hm-2,which were 7.48%,28.15% and 38.50% higher than those of the Loess Plateau,Southwest Liangliang and Bohai Rim respectively.The application rate of chemical fertilizer and organic fertilizer K2 O in the Loess Plateau production area was 637.62kg·hm-2,which were 62.94%,60.17% and 36.50% higher than those in Xinjiang,the Loess Plateau and the Bohai Rim,respectively.On the whole,the input amount of organic fertilizer in the Bohai Bay Rim and Southwest Cold and Cool production areas is higher than that in the Loess Plateau and Xinjiang characteristic production areas.The organic matter content of 0-40 cm in the Loess Plateau production area was 15.19g·kg-1,which was 32.21%,27.90% and 12.75% lower than that in the Bohai Bay,the cold highland in southwest and Xinjiang production areas,respectively.The available N content of 0-40 cm in the Loess Plateau was 39.76 mg·kg-1,and the content of available N in the cold highland in southwest and Xinjiang was 76.55% and 83.39% lower than that the Loess Plateau.The orchards with abundant and high levels of available P in the Loess Plateau and the Bohai Bay accounted for 72.46% and 92.59%,respectively.The content of available K in the Loess Plateau,the Bohai Bay,the cold highland in southwest and Xinjiang 0-40 cm soil were 318.19 mg·kg-1,213.81 mg·kg-1,242.70 mg·kg-1,289.58mg·kg-1,and the available K the orchards with rich and high content accounted for 92.75%,62.96%,73.91%,and 100% respectively.The content of exchangeable Ca 0-40 cm in the Loess Plateau was 9.34g·kg-1,which was 3.78 times,4.51 times,and 1.38 times that of the Bohai Bay,the cold highland in southwest and Xinjiang.The content of Fe and Mn in the Bohai Bay and the southwest the cold highland in southwest production areas were69.51mg·kg-1,25.17mg·kg-1 and 65.81mg·kg-1,118.93mg·kg-1,respectively.The content of available Cu of the Loess Plateau,Bohai Bay,the cold highland in southwest and Xinjiang production areas was 1.34mg·kg-1,4.46mg·kg-1,1.98mg·kg-1,0.91mg·kg-1.The orchards with low or very low available Zn content accounted for 100% in the cold highland in southwest.The proportion of orchards with moderate N content in the Loess Plateau,Bohai Bay,and Xinjiang production areas were 86.79%,55.56%,and 57.14% respectively.The proportion of orchards with low P content in the leaves of the Loess Plateau accounted for99.97%,the proportion of orchards with medium and low levels of P in the Bohai Bay area accounted for 92.59%,and the proportion of orchards with suitable levels of P in the southwest was 100%,The rich orchards in Xinjiang production area accounted for 85.71%.The leaf P content of the Loess Plateau and the Bohai Bay is relatively high,and the phosphorus content of the apple leaves in Xinjiang is rich.The K content in the Loess Plateau,the Bohai Bay and the southwest cold and cool production areas is at a moderately low content level of 100%,92.59% and 100%,respectively.The proportion of orchards with high K in Xinjiang is 100%,the K content in the Loess Plateau,the Bohai Bay Rim and the southwest cool and cool leaves was low,the K content in Xinjiang leaves was high,and the overall leaves of the four producing areas were high in Ca and Mg.The content of Fe in leaves was low,the content of Zn was generally low,and many orchards had excessive amounts of Cu in leaves.It was suggested to control the input of NPK in the Loess Plateau production area and increases the application of trace elements,increases the application of P fertilizer and K fertilizer in the Bohai Bay production area,increases the application of NP fertilizer and Zn fertilizer in the the cold highland in southwest,increases the application of N and P fertilizer and trace elements fertilizer in the Xinjiang production area.At the same time,the four regions should pay attention to the application of organic fertilizer. |
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