| Shaanxi Province is the world’s best eugenics zone for apple cultivation due to its unique natural climatic conditions,and its cultivation area and total production have ranked first in the country.The apple industry has become an economic pillar in the Weibei dry plateau region,which relies on its natural endowments to vigorously develop the apple industry.However,the widespread bagging,sloppy orchard management,and irrational fertilization in the region have led to increased production costs,decreased fruit yield and quality,and reduced soil fertility.For this reason,two types of quality and efficiency fertilization techniques were studied in this paper: bag-free fertilization technique and organic alternative fertilizer reduction and efficiency technique for apples.The bagging-free fertilizer application technology is based on the comparison of the effects of bagging-free water spray(CK1),bagging-free water spray(CK2)and bagging-free foliar fertilizer spray(T1 and T2)on the internal and external quality of bagged apples,while the organic alternative fertilizer reduction and efficiency technology is based on a long-term localization experiment to study the effects of bagging-free fertilizer(CK),organic fertilizer alone(M),chemical fertilizer alone(NPK)and organic-inorganic combination(MNPK)on the quality of bagged apples.(MNPK)on apple yield and quality,plant and soil nutrients,and soil profile nutrients.The aim is to explore the quality and efficiency technologies for apple production and management,and to provide technical support and theoretical basis for the green and sustainable development of dryland orchards.The following main conclusions were obtained:(1)Compared with no bagging,the spraying of bagging-free foliar fertilizer can significantly reduce fruit hardness,improve fruit color,significantly improve the red-green color of ’Qincui’ apple and yellow-blue color of ’Ruixianghong’ apple,and reduce the color angle;compared with bagging,the spraying of bagging-free Compared with bagging,spraying bag-free foliar fertilizer could improve soluble solids,soluble sugar and vitamin C content of fruits,and had little effect on single fruit weight,fruit shape index and titratable acid content,in addition,it could save 25.5% of production cost,and it also showed good performance in ’Qincui’,’Fuji’ and ’Ruixianghong’.In addition,25.5% of production cost can be saved and the performance is basically the same in ’Qincui’,’Fuji’ and ’Ruixianghong’.(2)Organic alternative to chemical fertilizer application reduction and efficiency technology can improve fruit tree yield and fruit quality.The single application of organic fertilizer,single application of chemical fertilizer and organic-inorganic combinationtreatment increased the fruit weight by 16.7%,25.0% and 8.3%,respectively,compared with the no fertilizer treatment,with little effect on the number of hanging fruits.The single chemical fertilizer application had the most significant effect on the improvement of single fruit weight and single plant yield;the apple quality in the organic fertilizer application treatment(single chemical fertilizer and organic-inorganic combination)was better than that in the no fertilizer and single chemical fertilizer application treatments.Compared with other fertilizer application modes,the organic fertilizer application alone had the most significant effect on the enhancement of soluble solids and Vc content and reduction of hardness of fruits.(3)The effect of organic alternative to chemical fertilizer application reduction and efficiency technology on plant nutrient content and fruit nutrient uptake was significant.The highest N,P,and K contents were found in the organic-inorganic treatment,with 3.85 g kg-1,0.74 g kg-1,and 8.47 g kg-1,respectively,and the highest N,P,and K nutrient uptake was found in the chemical fertilizer treatment alone,with significantly higher N,P,and K contents in the M and MNPK treatments than in the NPK treatment.(4)In the 0-40 cm soil layer,soil organic matter,total nitrogen,effective phosphorus and fast-acting potassium contents were significantly elevated under long-term fertilization treatments,and soil p H was significantly lower.Among them,soil p H was significantly lower in the M treatment than the other treatments,with an average reduction of 0.39 units.In addition,the soil organic matter,total nitrogen and effective phosphorus contents were significantly higher in the treatments with organic fertilizer addition(M and MNPK)than in the treatments without organic fertilizer application(CK and NPK).(5)There was a correlation between leaf 100 leaf weight,100 leaf thickness and plant nutrient content and fruit quality.Leaf index mainly had significant effects on fruit hardness,fruit shape index,titratable acid and solid acid ratio,and fruit nutrient content was mainly related to fruit shape index and titratable acid.Soil nutrient content significantly influenced fruit yield and quality,with several soil nutrient factors acting together on the same fruit quality index,and with different magnitudes of influence.Yield and its constituents correlated well with soil water content,and hardness,soluble solids,solid-to-acid ratio,and Vc correlated well with each soil nutrient factor.(6)After 13 years of continuous fertilization in apple orchards,nutrients from long-term organic fertilization(M and MNPK)migrated downward to deeper soils,and the depth of cultivation increased,but mainly clustered in the 0-20 cm soil layer.Soil phosphorus of long-term organic fertilizer application was concentrated in 0-60 cm soil,and the Olsen-Pcontent of 0-20 cm soil of long-term organic fertilizer application might exceed the environmental threshold of phosphorus,and there was a risk of phosphorus leaching.In conclusion,bag-free fertilization technology can reduce production costs,improve fruit flavor,and help orchards transform from bagged to bagless cultivation,while organic fertilizer alternative to chemical fertilizer reduction and efficiency technology is an effective way to achieve quality and efficiency improvement,soil fertilization and green development in orchards,and the above two fertilization technologies are worth promoting. |
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