Spatial Distribution Of Soil Nutrients In Main Apple Producing Areas Of The Loess Plateau And Methodology Of Fertilizer Recommendation Based On Yield Response And Agronomic Efficicncy For Apple

Fertilization is one of the important measures to achieve high yield of apples.As the most important apple eugenic area in China,the Loess Plateau has developed rapidly in recent years.However,the problem of excessive fertilization in apple orchards is becoming more and more widespread and intensified,which will inevitably lead to environmental problems such as low fertilizer utilization rate and atmospheric and groundwater pollution.Based on the Arc GIS geostatistics method,this paper studied the spatial variability of soil nutrients in the main apple producing areas of the Loess Plateau.Based on the yield response and agronomic efficiency,the apple recommended fertilization model was studied to provide theoretical basis and data support for rational fertilization of apples in the Loess Plateau.The main progress is as follows:(1)The soil p H,organic matter,total nitrogen,alkali nitrogen,effective scale and available potassium in the main apple producing areas of the Loess Plateau range from 6.30 to 9.90,4.2 to 29.0 g/kg,and 0.12 to 1.43 g/kg,respectively.20.00～145.18 mg/kg,2.80～79.40 mg/kg and 62.00～381 mg/kg,with average values of 8.02,11.56 g/kg,0.73g/kg,56.48 mg/kg,14.57 mg/kg and 167,respectively.Mg/kg;rainfall and temperature have significant effects on soil nutrients in apple orchards.On the whole,the soil organic matter and total nitrogen content in the main apple producing areas of the Loess Plateau were low,and the available phosphorus and available potassium were higher.(2)Based on the statistical data of 2001-2017,the QUEFTS model was used to analyze the nutrient absorption parameters of apples in the main apple producing areas of the Loess Plateau in China.It was found that the nitrogen,phosphorus and potassium nutrients of apples before the target yield of apples reached 80% of the potential yield.The absorption is relatively fixed;the nutrient uptake of nitrogen(N)phosphorus(P2O5)potassium(K2O)per plant per ton of fresh fruit is 1.0～2.4 kg,0.2～0.5 kg,1.3～2.7 kg,with an average of 1.4.Kg,0.2 kg and 1.8 kg;the NPK nutrient uptake per ton of fresh fruit is0.23～0.54 kg,0.85～1.48 kg,0.08～0.15 kg,with an average of 0.32 kg,0.11 kg,1.10 kg,respectively.(3)Correlation analysis showed that soil basic nutrient supply was positively correlated with soil nutrient content;apple yield response was significantly positively correlated with soil available potassium content,while correlation with alkali nitrogen and available phosphorus did not reach significant level;yield response There is a significant quadratic parabolic relationship with agronomic efficiency.Based on field trials and literature statistics,an apple-preferred fertilization model based on yield response and agronomic efficiency was established.The trial results showed that the apples could be provided with the corresponding apple recommended fertilization scheme.However,due to the small amount of data,the model still needs further correction.perfect.It can be seen that in the main producing areas of apples on the Loess Plateau,phosphorus and potassium should be controlled,and organic fertilizer input should be paid attention to.The apple-preferred fertilization model based on yield response and agronomic efficiency needs further improvement and field verification.