Peanut management should focus on early leaves

The late growth stage of peanuts refers to the period from the first full fruit pod to the mature harvest, that is, the ripening period of fruit ripening, which lasts about 45~55 days. During this period, the new leaves are no longer added, and the lower and middle leaves begin to fall off. The focus of field management is to prevent early leaves, especially the upper leaves, maintaining a large green leaf area and maintaining a long functional period, thereby increasing the number of effective results, increasing the degree of solidity and increasing yield.

The main causes of early defoliation of peanuts are: pre-fertilization and premature aging, and more serious sandy areas; leaf spot hazards, especially black spot and brown spot disease, spread rapidly once they occur, often causing a large number of leaves to fall off within a few days. Premature and excessive spraying of plant growth regulators, especially longer than the long-acting and paclobutrazol and containing this component-based regulator. The main measure to prevent early defoliation is disease prevention and fattening.

1. Strictly prevent leaf spot disease Peanut leaf spot disease is mainly black spot and brown spot disease, both of which are dominated by harmful leaves. When peanuts develop, symptoms begin to appear from the lower leaves, and then gradually spread to the upper leaves. In the early stage of the disease, brown spots are produced, which gradually develop into round or irregular lesions. Brown spot disease lesions are large, there are yellow halos around the lesions, while black spot disease lesions are smaller, the color is lighter than brown spot disease, the edges are neat, and there is no obvious halo. The weather is wet or long-term rainy, the lesions can be combined into irregular large spots, and the leaves are scorched, which seriously affects photosynthesis. If it occurs on the petiole, stem or fruit needle, it will produce an elliptical dark brown or brown lesion, but the whole stem or fruit needle will be black and dead, which will greatly reduce the peanut yield. From the peanut to the late growth stage, there are many kinds of leaf spot diseases that cause early leaves to cause damage to the leaves. The main damage is brown spot and net spot disease. It can be sprayed in time at the beginning of the disease. The better drugs are: 80% of mancozeb 800 times solution, 70% methyl thiophanate 800~1000 times solution, agricultural anti-120 water agent 200 times solution, 50% colloidal sulfur 200 times solution, 1:2: 200 times Bordeaux mixture. When spraying, pay attention to spray and spray, prevent leakage, spray once every 8~10 days, even spray 3~4 times, which can basically control the occurrence of the disease.

2. Foliar sprayed peanuts reached the late growth stage, the ability of roots to absorb nutrients from the soil and the ability of root nodules to fix nitrogen began to weaken, while the ability of leaves to absorb nutrients was enhanced. Foliar spray fertilizer supplement nutrients have many advantages such as fast absorption, rapid action and high utilization rate. It is a good measure to prevent premature aging and cause early leaves. The soil is sandy, the soil is thin, the base fertilizer is insufficient, the plant is short, the growth is weak, and the leaf yellowing has the phenomenon of de-fertilization. The 1% urea solution can be used for foliar spraying. Miaowang Zhujian has a field with a strong tendency to grow, and it is not necessary to spray urea. Peanut leaves have a strong ability to absorb phosphorus. In the middle and late stages of growth, 2%~3% of superphosphate leaching solution per acre is sprayed (immersed in 14~16 hours) 60 kg, sprayed once every 7~10 days. , even spray 2~3 times, generally increase production by 7%~10%. Or use 100~150g of potassium dihydrogen phosphate per acre, 50kg of water, spray it in the evening or cloudy afternoon after it is fully dissolved, preferably spray 3 times, every 7 days, if within 8 hours after spraying In case of rain, it is necessary to spray again. Peanut is extremely sensitive to iron. It is planted on alkaline soil and is prone to iron deficiency. It shows symptoms of yellow leaves and whitening. If iron fertilizer is sprayed in time, it can turn green after a few days. It can be sprayed once every 5~6 days with 0.2% ferrous sulfate solution, and sprayed continuously for 2~3 times.