[Rice] Irrigation    Research has shown that rice is particularly sensitive to temperature fluctuations during the critical growth stage of booting, heading, and flowering. This sensitivity is most pronounced 10 days before and after these stages. The optimal temperature range for this period is between 25°C and 30°C. When daily temperatures exceed 30°C, it can cause significant damage to pollination and fruit set. Prolonged exposure to temperatures above 35°C during the booting phase may result in underdeveloped flowers, poor pollen quality, and reduced fertility. During the heading and flowering stage, continuous high temperatures can lead to heat stress, causing rapid water loss, impairing pollen germination, and preventing proper pollination. In extreme cases, this can result in empty grains, often referred to as "flowers not setting." At a constant temperature of 38°C, rice plants may fail to produce viable pollen, which can severely impact yield.    As the saying goes, “rice is broken by water.†In our province, the heading and flowering stage of rice typically occurs during the hot summer months, making it highly susceptible to drought and high temperatures. To mitigate these effects, it's essential to maintain a water depth of 6–7 cm in the field. This helps regulate temperature and reduce heat stress. Additionally, foliar applications of 3% calcium superphosphate or 0.2% potassium dihydrogen phosphate solutions can enhance the plant’s resilience to heat. When the number of tillers reaches the expected level, it’s time to dry the field slightly until small cracks appear on the surface. This practice helps control excessive tillering, promotes root development, and improves nutrient absorption. If possible, nighttime irrigation or continuous flowing water can be used to cool the crop and prevent “high-temperature ripening.†Farmers with the resources can also use water spray methods to lower the temperature in the ear area by 4–5°C within a short time.    [Corn] Assisted Pollination    Experiments have demonstrated that high temperatures can significantly reduce photosynthesis in corn, block pollen release, accelerate growth processes, and decrease the number of ears formed. These conditions also increase the likelihood of various diseases. Given the recent high temperatures and soil moisture depletion in our region, it's crucial to implement timely irrigation and strengthen the plant’s resistance to heat stress. Sprinkler irrigation can be used to directly apply water to the leaves, helping to preserve the natural pollination process. If pollen dispersal is limited, artificial pollination techniques such as using bamboo stalks or applying pollen coatings can be employed to increase the amount of pollen reaching the stigma, thereby improving fertilization rates and reducing the negative impacts of high temperatures. These methods can generally increase seed set by 5–8%.    Chemical management strategies are also effective. For instance, external fertilizer application involves using urea, potassium dihydrogen phosphate solution, superphosphate, and ash to create a leaching solution during key growth stages—such as the tasseling and grain-filling periods—to maintain moisture levels and supply necessary nutrients. This not only helps cool and humidify the plants but also enhances grain filling. Another method is scientific fertilization, emphasizing the role of trace elements like zinc and copper, which promote the development of reproductive organs in corn. These elements can be applied as base fertilizer or sprayed on the foliage during the bell mouth stage to improve heat resistance. Foliar sprays should be diluted appropriately and applied in sufficient quantities to ensure maximum benefit.    [Cotton] Row Intercultivation    Currently, cotton is in its flowering and boll-setting phase, which is the period of highest water demand throughout its life cycle. Continuous high temperatures can cause internal plant temperatures to rise, leading to leaf burns, wilting, and curling. If combined with drought, it can result in flower drop. Excessive rain, on the other hand, can hinder root development. To alleviate the adverse effects of high temperature and drought, farmers can lay straw or vegetable residues between rows to help retain moisture, cool the soil, suppress weeds, and enhance fertility. If severe drought is observed, especially when plants show signs of wilting before 11 am or after 5 pm, timely irrigation should be carried out to improve the microclimate. It’s best to irrigate in the early morning or late evening to avoid sudden temperature differences between the water and the soil, which could cause the cotton buds to fall. Combining irrigation with drought-resistant agents like "dry land dragons" can further protect the crop.    Foliar application of micro-nutrients, particularly boron, can provide the essential elements needed by cotton during this critical period, promoting flowering, fertilization, and bud development. A typical application involves spraying a solution of 0.1% to 0.2% borax at a rate of 50–70 kg per acre, repeated every 7 days, sometimes up to 3–4 times, yielding excellent results. At the same time, it's important to monitor and manage pests such as red spider mites and bollworms to prevent further damage.    [Tomato] “One Drop Two Defenses†   During the hot season of tomato production, improper management techniques can lead to significant losses. It is important to focus on the “one drop two defenses†strategy:    Water spray cooling: High temperatures can cause leaf edges to burn and chlorophyll to fade, leading to dry leaves. To counteract this, water can be sprayed while cooling the plants, especially between 11:00 AM and 2:00 PM, when temperatures exceed 35°C or 40°C for more than four hours. This helps prevent damage to stems, leaves, and fruits.    Controlling flower and fruit drop: When daytime temperatures exceed 34°C and nighttime temperatures exceed 20°C, or when high temperatures reach 40°C for over four hours, the elongation of the style may surpass that of the anther, causing ovary shrinkage and failure in pollination and fertilization. Preventive measures include using formula fertilization, applying nitrogen fertilizer, avoiding large-scale flooding, and ensuring proper water and temperature coordination. If pollination is inadequate, auxins like 2,4-D can be used to enhance fertilization.    Preventing 2,4-D phytotoxicity: When using 2,4-D, it's important to control the concentration to avoid damaging the plants. The recommended concentration varies depending on the temperature. For example, at 15–20°C, the concentration should be 10–15 mg/kg. As temperatures rise, it should be reduced to 6–8 mg/kg. Avoid direct application to young shoots or leaves, and if the field is large, use anti-fall agents at 25–40 mg/kg. Always follow safety guidelines to prevent unintended harm to the crop. 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Strengthen field management to prevent high temperature and heat damage
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