Effects Of Ca, Mg And B Fertilizers On Yield, Quality And Nutrient Accumulation Of Changshanhuyou Fruit

Field experiments involving application of calcium, magnesium and boron fertilizers were conducted in two consecutive years on a Changshanhuyou(Citrus changshanensis) orchard soil. To prove the effects of applying calcium, magnesium and boron fertilizers on the Changshanhuyou fruit growth processes, to lay a foundation for Changshanhuyou fruit quality nutrition diagnosis, and to provide a theoretical basis for fertilizer recommendations for both average and high yields of high fruit quality, we further study the effects of different fertilization treatments on soil and leaf nutrient concentrations, fruit yield and quality, and on calcium, magnesium and boron concentrations and uptake of the whole fruit, fruit pulp and peel in the early, middle and late, turn color period and mature period. The main results are as follows:On average fruit yields with the each treatment were in order: Mg+Ca+B>Mg+B≥Mg≥B≥Mg+Ca>Ca>CK, and the yields of various fertilizer treatments increased by 7.34%-29.83%. The yield of Mg+Ca+B was significantly higher than for the other treatments, and Mg had the hightest yield for a single nutrient application. The concentrations of calcium, magnesium and boron in soil and leaves improved on the basis of the application of calcium, magnesium and boron fertilizers respectively, and magnesium concentrations of soil and leaves reached significant level. The soil and leaf calcium, magnesium and boron concentrations were the highest to Mg+Ca+B in the acid red soil with lacking of calcium, magnesium and boron.Mg+Ca+B was the optimal quality one. Fruit Vc and titratable acid of Mg+Ca+B were lower than other treatments, and juice yield, edible rate and solid acid ratio were significantly higher than the control. To provide a comprehensive evaluation of fruit quality, we used the cluster analysis that it showed Mg, Ca, Mg+Ca and Mg+Ca+B were the optimal group of fruit quality, and the principal component analysis showed different treatments on fruit quality were in order: Mg+Ca+B>Mg>Mg+Ca>Ca>Mg+B>B>CK. As the fruit gradually matured, the fruit soluble solids concentrations and shape index(aspect ratio) first decreased and then increased. The concentrations of fruit titratable acid first ascend, then decreased and ascend, decreased again. Vitamin C(Vc) concentrations first raised, later dropped and then raised. Fruit juice yield and edible rate showed an increased tendency before they remained constant. The skin thickness decreased first, and then remained unchanged. Fruit diameters showed an increasing tendency, but the fruit aspect ratio showed a sustained decreased trend.Calcium, magnesium and boron accumulation amounts of each fruit part of Mg+Ca+B were higher than for the other treatments during fruit growth, and magnesium accumulation amount of the whole mature fruit reached significant level. The concentrations of calcium, magnesium and boron of fruit had been less affected by applying calcium, magnesium or boron fertilizers, only magnesium concentrations of whole fruit and fruit peel of Mg+Ca+B and Mg+B were significantly higher than for the other treatments. As the fruit gradually matured, calcium, magnesium and boron concentrations of each part of the fruit showed a change trend of gradual decline, but their accumulation amounts showed a gradually increasing trend, and calcium accumulation amount of fruit pulp decreased between color turning and mature. Calcium, magnesium, and boron accumulation amounts of each fruit part in the fuit late growth stage had reached more than 50% of corresponding part of the mature fruit.Soil exchangeable magnesium concentrations, leaf calcium and magnesium concentrations, calcium and magnesium accumulation amounts of whole fruit and peel before color turning, boron accumulation amounts of whole fruit, peel and pulp before late growth stages increased significantly or extremely significantly, and the titratable acid decreased significantly or extremely significantly during fruit growth by the calcium-boron interactions.In conclusion, Mg+Ca+B can not only improve soil fertility, enhance leaf nutrient concentrations and fruit nutrient uptake, but also increase production and improve quality of Changshanhuyou fruit.