The Effect Of Applying Iron And Magnesium Fertilizer On Leaf Yellowing Of Plum

In recent years,due to the high economic value of plum in county Mao,the planting area gradually increase.However,most of farmers cannot grasp the plum fertilizing method,type and dosage correctly,which resulting in a large area of the plum leaves happened yellowing phenomenon,it has seriously affected the growth and development of plum.According to the analysis of the various elements of yellowing plum leaves and orchard soil,our research group found that lacking iron and insufficient magnesium is the main reasons of leaves yellowing.In this experiment,11-year-old Cuihong plum plants which leaf yellowing has appeared in Luoshan village of county Mao were used as materials to carry out related experiments to solve the problem of leaf yellowing by using iron and magnesium fertilizer.The results of the research are as follows:（1）According to the measured the content of mineral elements in leaves,we found that along with application amount of ferrous sulfate increased the content of active Fe,total Fe,total K,total Zn,total Cu are increasd in varying degrees,while the content of total Ca,total Mg,total Mn reduce in varying degrees and total Fe/total Mn increase,total Ca/total Mg are reduced firstly and then increased;however,along with application amount of magnesium sulfate increased the content of activity Fe,total Fe,total K,total Zn,total Cu are reduced in varying degrees while total Ca,total Mg,total Mn are increased in varying degrees,total Fe/total Mn is increased and total Ca/total Mg is reduced.The interaction between soil application of ferrous sulfate,soil application magnesium sulfate and foliar spraying was significant.（2）According to investigate about yellowing rate of plum leaves,we found the yellowing rate reduced with the increase of the amount of ferrous sulfate by soil application but decreased firstly and then increased with the increase of the amount of magnesium sulfate by soil application.The yellowing rate is also induced with foliar spraying of 0.3%ferrous sulfate,and increased with the foliage application of 0.3%Magnesium Sulfate.There is a significant negative correlation between the leaf yellowing rate and the content of active iron,and the correlation coefficient is 0.930.（3）Through the determination of chlorophyll content,we found along with the amount of ferrous sulfate by soil applicating increased the chlorophyll content of leaf is also increased but along with the amount of magnesium sulfate by soil applicating increased leaf chlorophyll content is increased firstly and then reduced;foliar spraying0.3%ferrous sulfate solution can increase the chlorophyll content but foliar spraying0.3%magnesium sulfate solution decreases chlorophyll content.The interaction between factors,except the interaction of S_Mg and F on chlorophyll b is not significant,the rest were significant or extremely significant.（4）Through the determination of chlorophyll fluorescence parameters of leaves,ferrous sulfate by soil applicating,foliar spraying 0.3%ferrous sulfate solution and proper amount magnesium sulfate by soil applicating can improve Fo、Fm、Fv/Fm、Yield、ETR、qP、qN.It tells that soil applicating and foliar spraying ferrous sulfate and soil applicating proper amount magnesium sulfate can help chlorophyll improve the absorption and transfer of light energy,also can increase the rate of electron transfer in photosynthesis,the utilization ratio of leaves to light energy,and strengthen the protection of photosynthetic system.（5）According to the measured antioxidant system,soil applicating ferrous sulfate and magnesium sulfate,foliar spraying have different degree effects to the antioxidant system by changing the rate of leaf yellowing.That’s to say,under the decreasing rate of leaf yellowing,SOD activity will induce,POD activity will induce slowly firstly and then increase quickly,CAT、APX activity will increase and the content of Pro,MDA will induce.Therefore,fertilize Fe and Mg can improve the ability of antioxidant system by helping plants grow healthily to improve the resistance of low temperature and strong light environment at high altitude.（6）According to all the results and principal component analys about all indexes,we get the best result of leaf yellowing integrated management is soil applicating 100g ferrous sulfate and 80g magnesium sulfate with organic manure in late October in addition foliar spraying 0.3%ferrous sulfate solution in April,June and August can prevent plum leaf yellowing effectively.