What are the causes and control methods of premature senescence in rice?
Premature senescence can occur when rice is grown. So-called premature senescence means aging before growing old, and it mainly refers to the phenomenon that occurs in the late heading stage of rice, when stems and leaves wither, grain filling is poor, and the number of blighted grains increases, reducing yield. Among farmers it is called “standing stalk death” or “straw return”, so what are the causes of premature senescence in rice? What should be done? Let's find out together.
I. Causes of premature senescence
1. Low-lying terrain with poor ventilation can cause excessive accumulation of harmful substances in the soil, which harms root growth and development, reduces vigor, and in severe cases causes black roots and root rot. In addition, when the soil lacks a certain element, the plant suffers from a lack of nutrients and develops premature senescence.
2. During planting, because the soil is prone to compaction and has poor permeability, root growth is poor, resulting in weak absorption capacity, and in the later stage the plant develops premature senescence due to fertilizer depletion.
3. During cultivation, if the planting density is too high, the rice grows thin and weak. In addition, if nitrogen fertilizer is applied in a one-sided way during fertilization, with too little phosphorus and potassium fertilizer applied, it will cause excessive vegetative growth of rice and make it prone to premature senescence in the later stage.
4. Long-term flooding irrigation without draining for aeration; planting in saline-alkali and infertile land, where root growth is poor; draining water too early before harvest or planting late-maturing varieties too late, and other such reasons can all cause premature senescence in rice.
5. During the grain-filling stage of rice, if the temperature is too low or light is insufficient, the formation and translocation rate of assimilates will weaken. When grain filling encounters a low temperature of 5-6 degrees, varieties with lower cold tolerance will show discoloration and premature senescence.
6. In addition, premature senescence is also related to some extent to the variety. Experiments have shown that generally short-stalked and early-maturing varieties are prone to premature senescence. This is because short-stalked varieties have poorer aeration than tall-stalked varieties, while early-maturing varieties have thinner leaves and shorter lifespans than late-maturing varieties, so they are prone to premature senescence.
II. Control methods
For low-lying or saline-alkali land, drainage works can be built before planting, which can enhance infiltration. Then improve the soil by applying a large amount of farmyard manure when preparing the land to improve soil structure. During planting, plant at a reasonable density and cultivate in time to promote root growth and development. For fields highly prone to root rot, first of all, do not apply or apply less fertilizer containing sulfate radicals. Nitrogen fertilizer should be applied less each time but more times, and basal fertilizer and tillering fertilizer should not be applied too much at once. In addition, fertilize according to the seedling stage, apply more phosphorus and potassium fertilizer to improve disease resistance, and topdress with farmyard manure high in potassium before the heading stage, which can prevent root rot.
The above are the causes and control methods of premature senescence in rice. We hope it can help you. If you want to learn more related knowledge, please follow us.