| Ferrous, reducing sulfur and bivalent manganese are the major obstacles of cold waterlogged paddy field. It would have a severe impact on the growth and yield of rice. In order to study the effects of ferrous, reducing sulfur and bivalent manganese on the growth and yield of rice, zhongyou 849 was selected as experimental materials.To explore the dynamic characteristics, poisoning critical concentration, and the influence on the accumulation of nutrient and yield of rice, potted test and field experiment were carried out to provide a theoretical basis for improving the cold waterlogged paddy field. The main results are as follows:1.During the whole growth period of rice,the content of reducing matters, active reducing matters, ferrous, reducing sulfur and bivalent manganese were higher than yellow clayey paddy field and showed S-type changes. Before rice transplanting, the content of reducing matters, active reducing matters, ferrous, reducing sulfur and bivalent manganese in cold waterlogged paddy field were 3.34 times, 5.78 times, 4.67 times, 3.40 times and 4.49 times as much as yellow clayey paddy field. The content of reducing matters, active reducing matters, ferrous and bivalent manganese reached the maximum values in tillering stage, were 2.60 times, 6.20 times, 7.11 times and 8.36 times as much as yellow clayey paddy field, then were the lowest in heading stage.The content of reducing sulfur was the highest in heading stage,was 3.12 times as much as yellow clayey paddy field,the lowest in tillering stage.2.With the concentration of ferrous, reducing sulfur and bivalent manganese increasing, the extent of poison on rice was more serious. The high concentrations of ferrous, reducing sulfur and bivalent manganese lead to plant short, stem thinning,lodging easily, inhibiting root growth,decreasing root volume and root injury drop,reducing the number of green leaves and leaf area and SPAD values, and weakening photosynthesis rate.The high content of ferrum, sulfur and manganese, is not conducive to the accumulation of biomass and NPK of rice, resulting the decrease in panicle length and 100 grain-weight. When the concentrations of ferrous, reducingsulfur and bivalent manganese were 100 mg / L ~ 200 mg / L, 50 mg / L ~ 150 mg / L and 50 mg / L ~ 250 mg / L, the 100 grain-weight decreased by 13.1% ~ 29.1%, 68.2%and 18.3% ~ 10.5% ~ 40.9%. When the concentrations of ferrous, reducing sulfur and bivalent manganese exceeded 300 mg / L, 250 mg / L and 300 mg / L, rice was poison to death.3.It deduced the critical concentration range of ferrous, reducing sulfur and bivalent manganese poisoning of rice were 200 mg / L ~ 300 m / L, 50 mg / L ~ 100mg/ L and 50 mg / L ~ 100 mg / L by fitting the regression equation of the inhibition rate of plant height, fresh weight of shoot, fresh weight of root, dry weight of shoot, dry weight of root and 100 grain-weight against the concentration of ferrous, reducing sulfur and bivalent manganese.4.In the cold waterlogged paddy field, the high content of ferrous, reducing sulfur and divalent manganese would decrease rice biomass and inhibit nutrient absorption,and then result in effective panicles of rice, grain number, panicle and seed setting rate decreasing, and lead to lower production.Compared with lower content of ferrous(F1),the rice grains per panicle, grains per panicle, full grains, grain weight and yield of the high content of ferrous(F3) significantly decreased by 24.2%, 33.7%, 12.7% 12.9%and 40.3%. Compared with the control(L1), it significantly decreased by 22.9%,30.3%, 9.5%, 10.1% and 31.4% for the High content of reducing sulfur(L3).The rice grains per panicle, grains per panicle, full grains, grain weight and yieldThe high content of divalent manganese significantly decreased by 10.8%, 18.1%, 8.1%, 7.9%and 19.8% compared with the control(M1) was. |
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