Effect Of Chlorine-containing Fertilizer On Yield And Quality Of Apple And Distribution Characteristics Of Chlorine In Soil

Shaanxi Province is the largest province in China for apple planting area and yield.The proper management of nutrients in apple orchards is the key to increase of production and efficiency of the local apple industry.However,some unreasonable fertilization problems still exist in the apple production practice,such as“fruit trees inappropriate for chlorine”,which constrains the applying of chlorine fertilizers in apple orchards.This paper studied the effects of chlorine-containing fertilizers on apple yield,quality,distribution of chlorine,and soil nutrient content in apple orchards in different regions of the Loess Plateau,explored the reasonable application amount of chlorine-containing fertilizers in apples,and to provide scientific theoretical basis for the rational application of chlorine-containing fertilizers in apple orchards.1.After one year's applying potassium chloride fertilizer,in the 3-year-old Idared apple orchard in Weinan City,Shaanxi Province,there was no significant difference in the effect of different potash fertilizer treatments?KCl,K₂SO₄,KCl+MgK₂?SO₄?₂?on apple yield.In terms of improving soil available potassium,the effects of potassium chloride applied alone and in combination with diammonium are better than those of potassium sulfate.But potassium chloride in the soil significantly increased the Cl^-content in the soil.In order to ensure the safety of soil chlorine after the application of potassium chloride in apple orchards,when the amount of fertilizer is N:300 kg/hm²,P₂O₅:150 kg/hm²,and K₂O:200kg/hm²,it is recommended that the potash is provided in half by potassium chloride and potassium sulfate?or potassium magnesium sulfate?,and be used together with urea and diammonium?or MicroEssentials SE?.2.The 8-year-old Fuji apple orchard under two kinds of water conditions in dryland and irrigated land in the Loess Plateau was selected as the study object.Five chlorine-containing fertilizers were used in the field to treat CK,T1,T2,T3,and T4.The corresponding Cl^-input amounts were 0,113,226,763,and 1300 kg/hm²,respectively.Five chlorine-containing fertilizers were used in the field for treatment:CK,T1,T2,T3,and T4,Kg/hm² Cl^-,apple yield,quality,and Cl^-content in leaves,fruits at maturity and Cl^-content in 0-200 cm soil layers were measured.The results showed that there was no significant difference in apple yield and quality between different treatments of dry land and irrigated apple orchards.With the increase of Cl^-the Cl^-content in the fruits and leaves of apple trees in dry land and irrigated land increased.The content of Cl^-in fruits and leaves of dry land treated with T4 increased by 62.16%and 311.02%,respectively.On the irrigated land T4was significantly increased by 20.11%and 46.55%compared with CK,respectively.The vertical distribution pattern of Cl^-content in orchard soil of dryland and irrigated land is obviously different.Among them,soil Cl^-in the dry land apple orchard is mainly distributed in 0-100 cm soil layer,while irrigated soil is mainly distributed in 100-200 cm soil layer.Therefore,chlorine-containing fertilizers are more suitable for application in irrigation areas.3.For two consecutive years?2016-2017?,five chlorine-containing fertilizers treatments including four irrigation treatments CK,T1,T2,T3,T4 and one drought treatment T5?D?were set in Guanzhong Irrigation Area,the corresponding Cl^-input amounts were 0,113,226,763,1300 and 1300 kg/hm²,respectively.There was no significant adverse change in fruit yield and quality.The appropriate amount of Cl^-could increase the yield and quality,promote the absorption of N,P and K by the plants and increase the chlorophyll content of the leaves,However,excess Cl^-has inhibitory effect.At the mature stage,the content of Cl^-in the leaves reached 165¹80 mg/kg,and the Cl^-of the branch ranged from 19.68 to 26.29 mg/kg,which increased with the increase of chlorine application amount.There was no significant difference in the content of Cl^-?63.22⁶7.31mg/kg?among fruits.From T2 to T4,the Cl^-content in 0-200 cm each layer increased significantly with the increase of Cl^-application rate.And it is obviously affected by leaching:the Cl^-content in the 0-100 cm soil layer was lower than 100 mg/kg in mature period,and in the 0-60 cm in the was less than 15 mg/kg.The law of vertical distribution of NH₄⁺content in each treatment was not obvious,and NO₃^-was significantly affected by leaching.The SO₄^2-content ranking of each treatment is basically the same as the ordering of its input,and it was also affected by leaching.The pH of the soil is between 7.7 and 8.2,and the regularity between treatments is not obvious,but it decreases as the soil layer deepens.The EC content increased as the soil deepens.In summary,in the case of high-yield fertilization levels with N,P₂O₅,K₂O:480,300,600 kg/hm² in the irrigation area,potassium sulphate can be used instead of potassium sulphate for 2 years.