| Shaanxi province is one of the most important producing areas in China.And Northern Shaanxi is a major area for manufacturing dehydrated jujube dates,while Dali county is famous for fresh winter jujube production.However,problems such as unknown soil nutrient status of orchard,fertilization imbalance and extensive management seriously restricted jujube date production in Shaanxi province.How to keep efficient growth of the jujube production has become an important subject.In present study,a survey was conducted on the nutrients inputs of the jujube orchards in the area of Dali County.The nutrients input of nitrogen,phosphorus and potassium were analyzed and soil nutrient such assoil nitrate nitrogen,phosphorus,potassium,and bioavailable iron,manganese and zinc contents in the soil were determined and evaluated.And ten varieties of jujube from northern Shaanxi,Jiaxian Date,Yanliang-Xiang Date,Jianghuai 1 Date,QiyuexianDate,Fucuimi Date,Jun Date,Goutou Date,Fengmiguan Date,Zhuyaoyao Date,Lingwu Date plus one variety of winter jujube of Dali were selected for calcium chloride and boric acid application to investigate the effect of calcium and boron on the cracking of jujube.The main conclusions were as follows:1.The average yield of Dali jujube was 24656kg·hm-2 in 2015 and 2016,and the yield range of most farmers produce were between 15,000 and 30,000 kg·hm-2.The average application amounts of nitrogen（N）,phosphorus（P2O5）and potassium（K2O）fertilizers were 380.0,423.9 and 398.3kg·hm-22 respectively.Nitrogen and potassium are higher than recommendation in the region(300.0kg·hm-2 for N and 271.0kg·hm-2 forK2O).Phosphorus was similar as the recommendation,412.2 kg·hm-2.There was imbalance among nitrogen,phosphorus and potassium.The nutrients application method is mainly basal fertilization,supplemented by topdressing fertilization.The ratio between basal application and topdressing of nitrogen and phosphorus fertilizer were9:1 and potassium was 8:2.The mean soil available nitrogen was 89.2 mg·kg-1,with large variances among farmers.The average soil available phosphorus is 18 mg·kg-1,which was ata reasonablelevel.The average soil available potassium was 215.8 mg·kg-1,with half of jujube orchards above recommendation level.Insufficient organic manure input,overuse of chemical fertilizers,imbalanced input of nitrogen and potassium,and irrational fertilization application ratio were the main problems in the nutrients management of jujube in Dali area.2.The average soil available calcium and boron were 3079 mg·kg-1 and 1.47 mg·kg-1,respectively.The average soil available iron and manganese were 6.9 mg·kg-1 and 6.3 mg·kg-1,respectively.About 11.8%soils were available iron deficient and 25.7%soils were deficient in available manganese.Over all,soils were rich in available copper and zinc,the average of which were 1.1 mg·kg-1 and 1.6 mg·kg-1,respectively.3.Calcium and boron foliar spray experiments were conducted in the year of 2015 and2017,The results showed that cracking rate of Jiaxian Date in 2015 decreased significantly after spraying calcium And,the fruit cracking rate of Qiyuexian Date,Jiaxian Date,Goutou Date,Yanliang-Xiang Date were all significantly reducedin 2017.With boron foliar fertilization,the rate of cracking of Qiyuexian Date,Jiaxian Date,Jianghuai 1 Date was significantly reduced in 2015.And only the Qiyuexian Date cracking rate were decreased significantly in 2017.However,there were no significant increment of calcium either in leaves,peels,or pulp with the calcium treatment,which may be due to the transferring difficulty of calcium in jujube;While spraying boron significantly increased boron concentration in leaves,peels and pulp by 40%to 80%. |
