Effects Of The Interaction Between Soil Moisture And Boron On The Growth And Development Of Soybean

Boron (B) is an essential micronutrient for the normal growth of plants. With the development of modern agriculture, the popularization of new cultivars, the improvement of cultivation measures, as well as with the increase of the cropping index, crop yield is increasing. More and more boron has been taken away from soils by the crops, which often results in the occurrence of B deficiency in some soils. The availability of B is affected by soil conditions. Soil moisture is one of the most important and complicated factors to the availability of B. It is generally accepted that the effect of water on the B availability is the most outstanding of all the nutrient elements. Therefore, in order to conduct the agricultural production, it is urgent to study the effect of the soil moisture on the availability of B.The study showed:1 the vegetative and reproductive growth of soybean were different under different soils and water treatments. The plant height and the dry matter accumulation were all decreased under the water distress. The number of pods and seeds per plant was less and the seeds weight was lighter under the water distress treatments than that under the normal water treatments. Especially under the dry treatment, the effect was enormous. But the effect was less impaired on the per hundred seeds weight. We got the heaviest per hundred seeds weight under the dry-wet treatment on the three soils and the lightest one under the wet treatment on the fertile and sterile soils.2 in general leaf B content were higher under the normal water treatment and lower under the dry treatment than those under the other treatments. It is more obvious under the dry treatment when growing on the soils applied B. this is in accordance with the water soluble B in soils. Leaf B content was all decreased on the three soils at July 20' owing to the dilution caused by the quickly growth of the plant.3 Boron adsorption and desorption reactions with the soils were affected by the water treatments. Drying was in favor of B adsorption, which resulted in the lower water soluble B in soils. B adsorption was less impaired by wet treatment. B was apt to desorption in the soil which was rich in organic matter in wet condition for a long time.4 applying B to the soil can reduce the impairment of water distress. In dry condition, the weight of dry matter and the weight of per plant seeds were heavier than those didn't applied B. and the number of per plant seeds was as the same. In wet condition, the effect of improving the endurance of soybean plant to water distress by applying B was much obvious. The plant height, dry matter weight, the number of per plant seeds, per plant pods and the weight of per plant seeds, per hundred seeds were all higher than those sterile soils and fertile soil which was not applied B.5 water-soluble B, CaCh-extractable B, mannitol exchangeable B and NH:OH.HCl extractable B were all correlated with the B content in plant tissue. These four forms of Bwere available to the soybean plant.6 the available B in sterile soil was lower than the fertile soil. It may be the reason that caused the abortion of the flower of soybean.Postgraduate: Song Shi-Kui Crop Culture and Farming System Tutor: Li Wen-Hua...