Study On The Genotype Of Rice With Low Accumulation In Cd Pollution Paddy Soil And Its Amelioration

Combined with the practical farming production, with the aim to recover the farmland which was polluted by heavy mental Cd, an investigation and risk assessment of the pollution situation was carried out to farmland around industrial park in Xiangtan, Hunan province. The paper also has selected the genotype of rice with low accumulation of Cd, and compared the Cd-pollution restoration effect to soil of the three modifiers (Sepiolite, Bone char, and Silicon fertilizer). Real, objective test data were got. The study has selected the conventional rice and hybrid rice in ten genotypes of rice from Hunan market whose Cd content is relatively low. To provide scientific theory and practical techniques for the screening of rice cultivars with low Cd accumulation and reasonable improvement of heavy metal Cd pollution of farmland, high dose(2250 kg·hm-1)silicon fertilize was suggested to use to improve Cd pollution farmland soil conditions.The main conclusions as follows:Chapter I gives an introduction to the purpose, significance, content and anticipated target of this research, and summarized the research progress of selecting rice cultivars with constantly low accumulation of Cd at home and abroad, and the research progress of three kinds of improvers (Sepiolite, Bone char, silicon fertilizer applied) applied to the heavy metal pollution management field.ChapterⅡevaluated the pollution situation and potential risks of paddy soil around industrial park in Xiangtan, and health risk assessment to local adults were analyzed. The results showed that the rice paddies around the industrial park in Xiangtan were suffered heavy pollution by Cd and suffered ecological hazard. The late rice produced in paddy soil around the industrial park also probably impact human health, and the potential health hazard of Cd pollution was obvious.Chapter III discussed the accumulation and dynamic distribution of Cd in ten genotypes of rice from Hunan market. The results showed that the Cd concentration in various plant parts was in the order of root> leaf and stem>husk>brown rice. The dynamic change of the Cd concentration was different in root of selected conventional rice varieties and hybrid rice, and similar in leaf and stem. The fertility cycle length of rice directly or indirectly impacted the accumulation changes of rice to heavy metal Cd. Cd content in brown rice is relatively low in conventional rice and hybrid rice were Xiang Zao-xian 42 and T-you 705.Chapter IV compared the Cd pollution restoration effect of soil of the three modifiers (Sepiolite, Bone char, and Silicon fertilizer). Research found that these three modifiers could all restore distribution of Cd in soil. As the dosage adds, the restoration effect bigger, at the same time they can lower the Cd content of the rice plant and also can reduce the Cd accumulation of the rice grain especially the unpolished rice. The high dose of Silicon fertilizer'restoration effect is remarkable. The high dose of Bone char's can lower the Cd content of the unpolished rice evidently, next is Silicon fertilizer of high dose and middle dose. Silicon fertilizer can promote growth and development of rice, bone char can increase pH of the paddy soil significantly. Overall, Silicon fertilizer can not only promote the growth and development of rice, but also reduce Cd accumulation of rice. Improvement effect is relatively stable, which is optimization conditioner of repair Cd pollution of farmland. Applied dose is 2250 kg·ha-1 for the Appropriate.Chapter V summarized and discussed the results of this study, and pointed out that the innovation of this study and problems need to explore.