How to remedy herbicide damage in rice?
What should you do if herbicide application to rice causes phytotoxicity? To increase the weed-killing effect and broaden the herbicidal spectrum, most compound herbicides contain bensulfuron-methyl, pyrazosulfuron-ethyl, acetochlor and the like. If farmers do not know how to use them, phytotoxicity is easily caused. 1. Judging phytotoxicity. Rice may show symptoms similar to herbicide phytotoxicity because of root suffocation, nutrient deficiency, or pests and diseases...
What should you do if herbicide application to rice causes phytotoxicity?
To increase the weed-killing effect and broaden the herbicidal spectrum, most compound herbicides contain bensulfuron-methyl, pyrazosulfuron-ethyl, acetochlor and the like. If farmers do not know how to use them, phytotoxicity is easily caused.
1. Judging phytotoxicity
Rice may sometimes show symptoms similar to herbicide phytotoxicity because of root suffocation, nutrient deficiency, or pests and diseases, but through investigation and analysis it can still be determined whether the symptoms are herbicide phytotoxicity.
1. Judge from the timing and rate of application: if pesticides for pests and diseases are applied 1-2 days after rice transplanting (or seedling throwing), the rice is relatively sensitive and phytotoxicity sometimes occurs. High-dose application of some pesticide products also easily causes phytotoxicity.
2. Check fertilizer, water and soil conditions: flooding too deeply after application (submerging the growing point) easily causes phytotoxicity. Check whether poor growth symptoms are caused by improper fertilization, application of undecomposed organic fertilizer, or improper retting of rice straw green manure in the field.
3. Check pests and diseases: rice plants damaged by rice tube thrips and rice root leaf beetles become short and clustered, with leaf tips rolled into tubes and turning withered yellow, and short, small fibrous roots. The symptoms of common rice dwarf disease are mainly yellowing and withered rolling of leaves, stunted plants, fading starting from the top leaf tips, and the appearance of fragmented spots, but the leaf veins remain green, and the leaves often show obvious alternating yellow-green stripes.
4. Look at the growth of the seedlings before and after application: after rice transplanting (or seedling throwing) has normally revived (become established), if abnormal symptoms occur after application while seedlings of the same seedling quality and same variety in adjacent fields grow normally, it may be phytotoxicity.
2. Remedial measures
1. Replant (or throw seedlings again): if diagnosis confirms severe phytotoxicity, with more than 80% of the seedlings yellowed, gather seedlings and replant (or throw seedlings) immediately. Method: first drain the field water, lightly plow once, then drain off the muddy water, and then transplant (or throw seedlings). In recent years, sowing and transplanting (or seedling-throwing) seasons have been 7-15 days earlier than the traditional season. From discovering phytotoxicity to replanting is generally 5-10 days, so the seasonal conflict is not prominent.
2. Strengthen fertilizer and water management and intertillage: for fields where phytotoxicity is found, first drain the field water to which the herbicide has been applied, and irrigate with fresh living water. Next, carry out intertillage in the field, turning the herbicide adsorbed by the surface soil into the deeper soil to reduce the herbicide's effect on rice roots. 2-3 days after intertillage, apply 2-4 kg of imported compound fertilizer per mu to promote root growth and leaf development and speed up growth.
3. Apply rooting agent: after drainage, intertillage and fertilization, it is best to apply 200 kg per mu of rooting agent ABT at a concentration of 200 mg/kg, which has a good effect on promoting roots, can increase the number of roots by 25%-40%, and can speed up the growth rate.
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