Effect Of Earthworms On Iron In Soil And Growth Of Orange

Fruit trees' iron deficiency is a worldwide problem and a global question that attracting many people's attention. In order to search an effective and economic approach, researchers have done much research job, but by now, they haven't found a recognized and effective way to deal with this problem .This paper used earthworms as biologic translation, translating the iron in organic matter and delivering to plants' roots. It studied the growth of orange and N,P,K,Fe accumulated in the root ,the change of content of Fe,N,P,K and chlorophyll in leaves, studied the effect of earthworm on iron enrichment and translation in organic matter and effect of iron in the red soil and calcareous soil. It also studied the effect of fertilizing vomicompost and lime on the growth and iron absorbing of orange, expect to explore the effect of earthworm on iron and other correlative index of plant , providing the theory ground base of usage of earthworm in the iron nutrient problem in fruit trees. Results as follow:1. Hole fertilizing cattle dung and inoculating earthworm could facilitate the growth of plants' roots, the roots it induced was 100.62% and 126.27% more than fertilizing cattle dung only and control in weight individually. The roots in treatment of fertilizing cattle dung and inoculating earthworm absorbed much more nutrient elements, it is 21.13%,35.44%? 76.31% and 35.37% more than the control individually.2. Treatment of fertilizing cattle dung and inoculating earthworm increased the leaves' content of N,P,K and chlorophyll, but it had little effect on the content of total iron and active iron in leaves, it was better than treatment of root inserted and treatment of hole fertilizing cattle dung only. The root inserted treatment could improve leaves' content of total iron and active iron in short time, but the addiction was not stable after long time. In the long run, hole fertilizing cattle dung could well improve the iron level in plants' leaves.3. Earthworms could transform and enrich iron element in organic matter, the straw treated with different configuration and different concentration iron solution, had high content of available iron after it conformed into vomicompost. Its value was increase according to the increasing of the concentration of iron solution treated with. In the meanwhile, earthworms' activity was restrained in the condition of high iron content, the straw treated with FeCl₃ hurt the earthworm more than the straw treated with FeSO₄.Earthworms absorbed and accumulated much iron in the condition of high iron content, along with the increasing of concentration of iron solution treated with, the earthworms absorbed and accumulated more iron, but the addition was decreased when the iron concentration reach a certain high degree.4. Covering straw and inoculating earthworms can improve the organic matter in the soil it covered distinctly, the value of soil pH was increased and to some extent it increased the content of active iron in soil. Straw treated with iron solution and transformed by earthworms increased the pH value and distinctly increased the available iron in the soil it covered. The treatments treated with different configuration and different concentration iron solution and inoculating earthworms can increase the content of available iron in 0 to 5 cm soil layer, it could increased the content of available iron in 5 to 10 cm soil layer too, but the addiction was not distinct, it had little effect on the content of available iron in the 10 to 15 cm soil layer.5. Fertilizing cattle dung and inoculating earthworms in different alkali soil, can increased the content of soil organic matter distinctly and to some extent decreased the pH value, the soil bulk density and content of HCO₃^-were decreased too, it increased the content of available iron while improving the soil condition. Along with the higher degree of soil'alkali, the increasing of the active iron in the treatments of fertilizing cattle dung and inoculating earthworms became larger. Soil pH value and content of HCO₃^- soil have distinct correlation with the content of available iron.6. Fertilizing vomicompost in red soil could increase the pH value, content of organic matter was increased and content of available iron was decreased, at the same time ,it induced much roots. The improvement was contacted with the quantity of the vomicompost fertilized in soil. In this experiment, the treatment of 40 percent vomicompost induced the most roots in weight, higher than the treatment of 60 percent vomicompost, but their difference was not distinct. With the increasing of content of vcmicompost, the roots induced by the plant were increased distinctly and the roots activity was strengthened.7. Employing lime in red soil can increased the pH value and content of HCO3" distinctly, available iron in soil was notably decreased, and the new roots absorbed less iron.8. Employing lime in red soil could facilitate the growth of roots; the effect of improvement was related to the quantity of the lime. In this experiment, the treatment of 6g/kg lime induced the most roots in weight. the root activity was improved by employing lime, but it had grate difference in orange's roots activity by employing lime, the roots activity in treatment of 6g/kg lime was the highest.