The Influence Of Chemical Agents On Rice Growth And Development

The rice as the one of the most important cereal crop, much attention has been paid to its yield and quality.Whatever the quality of rice seedlings, the existence of the field weeds will be restricted influence on its.The growth of rice affected chemicals on rice needs cannot be underestimated. The use of improper or wrong operation will cause injury to rice. In my experiment I used 7 kinds of chemical agents and treatment with different concentration on rice,comparison of physiological and biochemical changes between each treatment, determination of rice phytotoxicity phenomenon, symptoms and safety of concentration. The results are as follows:1. In Seedling Stage the application of butachlor should control the amount of dosage. When the concentration was 4 times the recommended dosage, the Seedling quality were significantly lower than control group; When the concentration was 8 times the recommended dosage, rice had different degrees of injury; When the concentration was 16 times the recommended dosage, caused Plants dwarf serious, plants uneven and no tillers. Transplantation to paddy fields, they showed weakness:seedlings slow, plants growing short, leaf number reduce significantly, less tiller number, less accumulation of dry matter and yield decreased.2. Butachlor and prometryn combination is another seedbed herbicide. It focuses on the advantages of the two herbicides, Weed control effect and the degree of the phytotoxicity is heavier. When the concentration was 4 times the recommended dosage, the quality of seedlings began to decline, too much butachlor and prometryn combination will not make the plant produces too many yellow leaves, but plant height is severely inhibited, and causing a decrease in fresh weight and dry weight of 100 strains. Transplantation to paddy fields, plant height, tiller and yield were affected, but the 1000 grain weight increased.3. In Rice Seedling rice needs strong seedling powder, it provides a good acid environment and nutrients for the germination of seeds. There was no harm to the seedlings growing vigorous growth and strong.4. At the two leaves a heart stage in order to ensure good growth of seedlings need additional ammonium sulfate, but excessive use of ammonium sulfate will cause harm to the seedlings. When the concentration was 2 times the recommended dosage, caused harm to the seedlings. When the concentration was 3 times the recommended dose, plant leaf wilt, rapid dry, water loss, difficult to recover. With the increase of the amount of fertilizer, the burning of the seedlings was more and more serious.5. Bensulfuron is inhibition of broad-leaved weeds herbicide. Different concentrations of Bensulfuron had certain effects on rice. When the concentration was 10 times the recommended dosage, last leaf of SPAD value was low but it existed short time. When the concentration was 30 times the recommended dosage, this phenomenon existed 15 days. High concentration of herbicide application has markedly improved the weed control effect, in does not produce the phytotoxicity cases, increasing the concentration of Bensulfuron can helps the field grass and weeds.The use of a single agent, within the 10 times concentration the plants were safe.6. Bensulfuron and pyrazosulfuron belong to the same kind of herbicide. Pyrazosulfuron weed control effect was stronger than Bensulfuron. When the concentration was over 10 times the recommended dosage, there were no weeds in the field, rice appeared slight injury, in the first few days of administration, the plants didn’t grow and appeared yellow leaf than recovered gradually. The use of a single agent, within the 5 times concentration the plants were safe.7. Two chloroquine phosphate is control weed of herbicides. It is relatively safe for rice, When the concentration was over 10 times the recommended dosage, the field without any gramineous weeds, When the concentration was 20 times the recommended dosage, last leaf of SPAD value was low, but a week or so and restored. If the jointing stage use when the medication reach 8 times the recommended dosage will seriously affect the grain grouting. When transplanting of single agent, within 10 times the recommended dosage for plants were safe, applied at jointing stage single agent, concentration of not more than 4 times the recommended dosage of, otherwise easy to affect production.