The Study Of The Effect Of Soil PH On The Growth Of Apple And Its Mechanism

Contraposing the actuality of soil acidification becoming more serious in orchards, Malus hupehensis Seedlings and Gala were used as materials in this study, Effect of soil pH on the growth and element cumulation of apple tress weres studied. The distributing of siol pH and available nutrition of apple orchard in jiaodong and the relationship between the soil available nutrition and pH were studied. The main results is following:1. With the soil acidification became serious, pH from 6.44 to 5.91,root matter accumulation,number,length,area,root vigor and NR activity increased and decreased from 5.91 to 3.82 and decreased markedly at less than 5.0 and finally root growth of Malus hupehensis Seedlings was reduced markedly.2. With the soil acidification became serious, pH from 6.44 to 5.84 , matter accumulation,plant height,leaf area,stem diameter and the number of leaf were increased and decreased from 5.84 to 3.82.The soluble gugar concent of Gala leaves markedly decreased when PH was less than 5.5. With the PH of the soil less and less depressed(PH was less than 5.0 ), the NR acivity and Pr concent in Gala leaves markedly decreased.The soluble gugar concent and the NR acivity of the Malus hupehensis Seedings Organs began to markedly decreased(PH was less than 5.0)and the Pr concent began to markedly decreased(PH was less than 4.5)With the decrease of PH, the SOD activity decreased and the MDA concent markedly increased.The SOD, POD and CAT activity of Malus hupehensis Seedings Organs and Gala leaves markedly decreased,but the MDA concent of Malus hupehensis Seedings Organs markedly increased.Gala MDA concent began to markedly increased(pH was less than 4.5).With the decrease of pH, Pn of Gala and Malus hupehensis Seedings Organs began to decreased.P(pH was less than 5.0). Thus it can be seen pH of the soil markly effected Pn of Malus hupehensis Seedings Organs and Gala leaves.3. ZRs content in the root of seedling decreased slowly with low acidification and increased larger with high acidification. The content of IAA and ABA and (IAA+ZRS+GAS)/ABA in the root of seedling increased with high acidification,but the content of IAA, GAS, ZRS, ABA and ( IAA+ZRS+GAS ) /ABA in the stem and shoot tip deceased with acidification decreasing.4. The effect of soil pH on element cumulation in Malus hupehensis Seedings was different markedly, for example:N,K,Ca,Mg,Fe decreased markedly, treatment1 showed largest changes, decreasing more than 60%, Zn 51.79% and Cu 47.27%. The cumulation of Mn in the root were increased markedly, but the leaf was opposition. The cumulation of P in the stem were increased with soil pH decreasing, and the leaf was opposition.The effect of soil pH on element concentration in Malus hupehensis Seedings Organs was different markedly, for example P, Ca, Mn. The effect of soil pH on concentration of N, P, K, Ca, Mn, Cu, Zn in the root of Malus hupehensis Seedings was largest, P, Ca, Fe, Mn, Zn in the stem larger, while P, Ca, Mn in leaves large. The concentration of N and Ca in the root were decreased markedly when soil pH less than 5.0, while P, K, Mn, Cu increased markedly; The concentration of Ca decreased markedly while Fe, Mn in the stem increased markedly. The concentration of P and Zn in the stem and P in the leaf were increased while Ca in the stem decreased markedly when soil pH less than 4.5. The concentration of Cu in the stem were increased and Ca in the leaf decreased markedly. The rule of element concentration change in the leaf of Gala was similarity with Malus hupehensis Seedings, P, Mn, Zn increased with soil pH decreasing,while Ca, Mg, Fe decreased.5. The percent of orchards that soil pH less than 5.6 was 28.8%. There was marked negative correlation between pH and alkali hydrolysable N; especially while pH4.5~5.0. There were marked negative correlation between available P, available K and pH. There was marked positive correlation between pH and organic matter at pH4.5~5.0, but negative correlation at pH6.1~6.5 and correlation was significant at the 0.01 level. The chemical equations were: y=0.057x2-0.8043x+3.8981, y=-8.477x+ 118.73, y=0.857x2-14.169x+81.698 and y=25.132x2-330.63x+1170. Their R2 were respectively 0.046, 0.0539, 0.0178 and 0.1496.6. The results showed that the average content of organic matter in apple orchard of Jiao Dong was 1.14%, the content of the alkaline hydrolytic nitrogen was 74.9mg.kg-1, the content of the available phosphorus was 40.9mg.kg-1,and the content of the available potassium was 122.7mg.kg-1. The characteristic of soil nutrition is that the content of organic matter and available potassium was comparatively low , while the content of the available phosphorus was comparatively high, but the alkaline hydrolytic nitrogen assumes the polarization. The content of the available nutrition is different in different apple main production area. It is much lower in organic matter ,middle in alkaline hydrolytic nitrogen and lower available potassium but higher available phosphorus in Qi xia ,while is higher organic matter ,polarization and higher alkaline hydrolytic nitrogen higher available phosphorus and higher available potassium in Wen Deng ,but lowest organic matter , lower alkaline hydrolytic nitrogen ,higher available phosphorus and lower available potassium in Huan Cui. An analysis about the relationship between the available nutrition and the yield was made in the 248 orchards of Qi Xia city. There was positive correlation between organic matter and yield in the determination scope. Organic matter could increace the yield . There was marked positive correlation between the yield and alkali hydrolysable N, available phosphorus, available potassium while they were less 100,70 and 150 mg.kg-1 , or else, there was marked negative correlation. The soil available nutrition in orchards of high yield was higher than that in orchards of mid and low yield. The contents of phosphorus and potassium in soil in the orchards of high production, compared with low production, was increased significantly. Soil Phosphorus and potassium were the major factors. The proportion of nitrogen, phosphorus, potassium1:0.65:1.34 is suggested.