Key Management Points for Peanut Fields Under High Temperature and Rainy Weather

Once the rainy season arrives, especially after July, high-temperature overcast and rainy weather increases. Spring-sown peanuts are in the stage where vegetative growth and reproductive growth proceed together; the plants' pegging and vegetative growth are rapid, and fields with good water and fertilizer conditions are prone to excessive growth, with overly vigorous above-ground stem and leaf growth, which affects the transfer of nutrients to reproductive growth, resulting in fewer and less concentrated pods, small and unfilled peanut seeds, and many empty and shriveled pods, thereby affecting yield and quality. High-temperature overcast and rainy weather very easily causes the occurrence of peanut diseases and insect pests. After continuous rainfall, do a good job of peanut field management, promptly prevent and drain waterlogging, control excessive peanut growth, and do a good job of disease and pest control, laying a solid foundation for a bumper peanut harvest.

1. Promptly carry out chemical regulation to control excessive peanut growth. Good soil fertility, abundant rain, and high temperatures easily cause overly vigorous above-ground stem and leaf growth in the mid-to-late stage, consuming excessive photosynthetic products, inhibiting pod development, and affecting yield improvement. Therefore, according to the peanut field's growth condition and climate characteristics, timely and reasonable chemical regulation to prevent excessive growth and lodging of peanuts has a very obvious effect on increasing peanut yield. When the peanut plant height reaches 35-40 cm and the field begins to close the rows, apply it for the first time, around mid-July; according to the growth situation, when the plant height is 45-50 cm, apply it for the second time, around early August. Commonly used regulators include Zhuangbao'an and 15% paclobutrazol wettable powder, etc. When applying chemical regulators, note the following points: First, avoid a single excessive dose; a method of multiple small doses can be used, divided into 2-3 applications, among which the total amount of paclobutrazol applied should not exceed 40 g/mu, so as to avoid affecting peanut pod development due to an excessive dose and aggravating the occurrence of leaf diseases, causing leaves to wither and fall prematurely and leading to premature senescence of the plants. Zhuangbao'an can increase the chlorophyll content of peanut leaves, raise the photosynthetic rate, improve the distribution of photosynthetic products within the peanut plant, and promote pod development; improve root activity and delay root senescence; inhibit above-ground vegetative growth, dwarf the plant height, and prevent excessive growth and lodging, and can steadily increase yield by more than 10%. About 20 g per mu, diluted with 30-40 kg of water, sprayed on the foliage; for plants with obvious excessive growth, the dosage may be slightly increased or applied twice, but the total amount should not exceed 30 g per mu. For peanut fields with poor growth, the dosage may be appropriately reduced.

2. Drain waterlogging promptly to prevent pod rot. Days of continuous rainfall have already caused the soil moisture in peanut fields to become saturated, and some fields have already reached supersaturation. From the podding to maturity stage, vegetative growth gradually slows and even stops, and water demand decreases. However, excessive soil moisture is not conducive to pod development and may even cause pod rot. When soil moisture exceeds 80% of the maximum field water-holding capacity, drainage must be carried out. Flat low-lying fields prone to waterlogging should have drainage ditches promptly cleared, and in mountainous and hilly areas, ditches below the terraces should be dug well so that they connect with the cross ditches and peanut ridge furrows. This drains both surface water and subsurface water, solves "half-side waterlogging," and prevents soil erosion and terrace collapse, so that light rain does not cause waterlogging and heavy rain does not cause disaster.

3. Do a good job of disease and pest control. Peanut diseases mainly include peanut leaf spot (brown spot and black spot), net blotch, powdery mildew, scab, etc. Begin control with fungicides in early to mid-July. Spray with Pencozeb, mancozeb, carbendazim, chlorothalonil, etc., once every 7-10 days, for 2-3 consecutive times. Mixing the above agents for use gives a better disease-control effect. The main targets of insect pest control are cotton bollworm, aphids, and white grubs. For underground pests in peanut fields such as white grubs, where conditions permit, insect-killing lamps should be used for control; for chemical control, 48% chlorpyrifos at 250-300 ml per mu or 50% phoxim emulsifiable concentrate at 300-400 ml can be used, diluted with an appropriate amount of water, then applied to the root zone with a sprayer after removing the nozzle. For cotton bollworm, cotton semilooper, aphids, etc., beta-cypermethrin 1500-fold solution can be sprayed for control at the early stage of occurrence.

4. Prevent premature senescence and promptly spray foliar fertilizer. In peanut production, due to one-time fertilization, plastic film mulching causing premature and excessive podding, excessive chemical regulation, and poor vegetative growth in dry and barren land, peanut plants are all prone to premature senescence in the late growth period. If diseases and insect pests occur severely, premature senescence becomes even more serious, and premature senescence has become a major obstacle limiting further increases in peanut yield. In the late growth period of peanuts, spray the foliage with 1-2% urea or 0.2-0.4% potassium dihydrogen phosphate solution, or foliar fertilizer rich in NPK and multiple trace elements, 2-3 times, at intervals of about 1 week. When carrying out foliar topdressing, pay attention to mastering the timing and quality of spraying. First, do not spray in the morning when there is dew, at noon during high temperatures, or on overcast and rainy days; second, on the premise of fully and evenly stirring, spray evenly and thoroughly.