Effects Of Pouring And Spraying Molybdenum On Yield,quality And Nutrient Utilization Of Citrus

Molybdenum(Mo)is an essential element for plant growth and development,and Mo deficiency is common in acidic soils..Citrus growing areas in China are mainly distributed in the south,its acidic soil and insufficient Mo fertilizer application are one of the factors that limit the development of high quality of Citrus.Based on the current situation of Mo deficiency in the soil of citrus orchards,a two-year field experiments were carried out to analyze the effects of pouring and spraying Mo fertilizer on the yield,quality and nutrient utilization in two citrus varieties Satsuma mandarin and W·Mercotte.This study provides a theoretical basis for the scientific application of Mo fertilizer in the citrus orchards soil of Mo deficient and the improvement of fruit quality in China.The main results obtained are as follows:(1)The fruit yield of Satsuma mandarin and W·Mercotte were increased by Mo application.The yield of Satsuma mandarin was increased by pouring and spraying Mo applications with the pecentages of 24.60% and 25.85%,respectively;and the yield of W·Mercotte was increased by 27.77% and 6.49% due to the applications of pouring and spraying Mo,respectively.The increased yields caused by Mo application were confirmed by the increased single weight of fruit.Totally,the effects of pouring Mo fertilizer in increasing yield were better than those of spraying Mo.(2)The fruit quality were improved by Mo applications.The fruit color,fruit edible rate,the ratios of soluble solid(TSS/TA)and titratable acid(TA),vitamin C(Vc)concentrations were improved by Mo applications,but the concentrations of titratable acid were decreased in citrus.The decreased rates were 6.09% and 4.71% in TA;the increased rates were 15.20% and 16.27% in the ratio of TSS/TA,25.36% and 42.12% in the concentration of Vc by pouring and spraying Mo in Satsuma mandarin,respectively.The decreased rates were 2.29% and 2.92% in TA;the increased rates were 8.28% and0.84% in the ratio of TSS/TA,15.07% and 16.50% in the concentration of Vc by pouring and spraying Mo in W·Mercotte,respectively.Further study showed that the concentration of citric acid was decreased by Mo application,which was in line with the decreased TA concentration.Mo application significantly increased the activities of L-galactosid-1,4-endolipid dehydrogenase(GLDH)and mono-dehydrogenascorbate reductase(MDHAR),suggesting that the synthesis and regeneration of ascorbate were improved by Mo application,and thus increased the concentration of Vc in fruits.(3)Application of Mo fertilizer decreased Cu concentration and increased Mo concentration in leaves.Mo application increased the concentrations of N and Mo in fruit peel and the concentrations of N,P,K,Cu,Zn and Mo in fruit pulp.