Minor Heat Farming

During Minor Heat, crops across Northeast China enter vigorous growth, with maize, soybeans, and rice advancing simultaneously and full-scale field management underway.
Maize management from jointing to tasseling. Spring maize in Northeast China moves from jointing toward tasseling around Minor Heat, with stems elongating rapidly and the tassel about to emerge. This is a key stage for determining both ear number and kernels per ear. Management centers on applying 穗肥 at 8–10 kilograms of urea per *mu* to promote ear differentiation and yield formation; intertilling and earthing up together with fertilization to encourage root development and improve lodging resistance; ensuring adequate water because demand is high from jointing through tasseling and drought can reduce kernel number per ear; and controlling pests and diseases, with corn borer entering a critical treatment window and treated with phoxim or Bt preparations, while aphids, leaf spot, northern corn leaf blight, and other problems require simultaneous monitoring. Management from jointing to tasseling directly affects ear number and final yield.
Soybean management during flowering and pod setting. Soybeans in Northeast China enter flowering and pod setting around Minor Heat, with flowers opening and pod formation beginning. This is a critical stage for determining pod number and seed number. Management centers on applying 花荚肥 at 5–8 kilograms of compound fertilizer per *mu* to promote flowering, pod setting, and seed development; intertilling and earthing up to promote root growth and lodging resistance; controlling soybean pod borer, aphids, leaf spot, frogeye leaf spot, and other pests and diseases as they enter treatment windows; and ensuring adequate water because drought can cause flowers and pods to drop. Management during flowering and pod setting directly affects pod number and final yield.
Rice management during jointing and booting. Rice in Northeast China enters jointing and booting around Minor Heat, with stem internodes elongating and young panicles differentiating and developing inside the stem. This is a crucial stage for determining kernel number per panicle. Management centers on 晒田控苗 after unproductive tillers have been brought under control, draining and drying fields for 7–10 days to encourage deeper rooting and young-panicle development; applying 穗肥 after re-flooding, primarily potash, at 5–8 kilograms of potassium chloride per *mu* because potassium demand is high during booting and insufficient potassium can lead to smaller panicles with fewer grains; maintaining a shallow water layer of 3–5 centimeters after re-flooding; and controlling rice blast, sheath blight, planthoppers, and other pests and diseases as they enter treatment windows.
Pasture management. Pastures in eastern Inner Mongolia remain in vigorous growth and livestock grazing continues. Herders implement rotational grazing systems to make rational use of grassland resources.

During Minor Heat, Northwest China enters a critical stage of summer management: spring wheat moves from flowering into grain filling, cotton advances from budding into flowering, and orchards enter fruit enlargement.
Spring-wheat management from flowering to grain filling. In the Hexi Corridor of Gansu and the Yellow River irrigation districts of Ningxia, spring wheat moves from flowering into grain filling around Minor Heat. After flowering and pollination, the crop begins filling grain, making this a critical stage for both kernels per ear and thousand-kernel weight. Management centers on securing water supply because demand is high during flowering and grain filling; where soil moisture is insufficient, irrigation should be applied promptly at 40–50 cubic meters per *mu*, as drought during grain filling can severely reduce thousand-kernel weight. Wheat rust, aphids, and other pests and diseases enter important treatment periods, while 干热风 should be prevented through foliar fertilizer applications that strengthen stress resistance. Management from flowering through grain filling directly affects kernel number per ear and final yield.
Cotton management from budding to flowering. Cotton across Xinjiang advances from budding into flowering around Minor Heat, as flower buds develop and blossoms begin to open. This is a key stage for determining boll number and final yield. Management centers on applying 花铃肥 (*flower-and-boll fertilizer*) at 10–15 kilograms of compound fertilizer per *mu* to promote bud development, flowering, and boll formation; timely pruning through topping, removal of lateral growing points, and removal of unwanted shoots to control vegetative growth and promote reproductive growth; controlling cotton bollworm, aphids, cotton spider mites, Fusarium wilt, and other pests and diseases entering critical treatment periods, with cotton bollworm requiring particular attention during flowering and boll formation; and ensuring sufficient water because drought during this stage can cause flowers and bolls to drop. Management from budding through flowering directly affects boll number and final yield.
Orchard management. Apples, fragrant pears, grapes, and other fruit crops in southern Xinjiang enter fruit enlargement. Growers strengthen water and nutrient management through 膨果肥, mainly potash, and control pear psylla, aphids, spider mites, codling moth, oriental fruit moth, and other pests. Grapes enter fruit enlargement and require fruit thinning, summer pruning, and bagging to protect against pests and birds and improve fruit quality.
Specialty crops. Potatoes around Dingxi, Gansu, enter tuber enlargement and require stronger water and nutrient management through 结薯肥, mainly potash, together with late-blight control. Goji in Ningxia enters peak maturity and harvest, and farmers seize clear weather for picking, sun-drying, and mechanical drying. Processing tomatoes in Xinjiang enter fruit development and require stronger water and nutrient management.

During Minor Heat, North China enters a critical stage of summer field management: summer maize enters jointing, spring maize enters tasseling and silking, spring peanuts enter flowering and pegging, and full-scale field management unfolds.
Summer-maize management during jointing. Summer maize in North China enters jointing around Minor Heat, with stem internodes beginning to elongate rapidly and young ears starting to differentiate and develop. Jointing is a critical stage for determining ear number. Management centers on applying 拔节肥 at 8–10 kilograms of urea per *mu* to promote stem elongation and ear differentiation; intertilling and earthing up at 8–10 centimeters deep together with fertilization to promote root development and lodging resistance; controlling corn borer, aphids, thrips, and other pests entering critical treatment windows; and ensuring adequate water because demand is high during jointing and drought can reduce ear number.
Spring-maize management during tasseling and silking. Spring maize in North China enters tasseling and silking around Minor Heat, with tassels emerging, silks appearing from the female ears, and pollination and kernel formation beginning. This is a critical stage for determining kernels per ear and also the crop’s critical period of water demand. Water supply must therefore be ensured, because drought during tasseling and silking can cause poor pollination and a severe reduction in kernels per ear; where soil moisture is insufficient, irrigation should be applied immediately. 穗肥 is applied at 5–8 kilograms of urea per *mu* to promote kernel development. Under rainy or excessively hot conditions, artificial supplementary pollination may be carried out to improve seed set. Corn borer, aphids, leaf spot, and other pests and diseases also require control.
Spring-peanut management during flowering and pegging. Spring peanuts in North China enter flowering and pegging around Minor Heat, with large numbers of flowers opening and gynophores penetrating the soil to form pods. Management centers on applying 花针肥 (*flower-and-pegging fertilizer*) at 10–15 kilograms of compound fertilizer per *mu* to promote flowering, pegging, and pod formation; intertilling and earthing up to facilitate peg penetration and pod development; and controlling peanut leaf spot, aphids, cotton bollworm, and other pests and diseases.
Orchard management during fruit enlargement. Apple-, pear-, and peach-growing areas across North China enter peak fruit enlargement. Growers apply 膨果肥, mainly potash, at 10–15 kilograms of potassium sulfate per *mu* to promote fruit development and improve quality; carry out summer pruning by removing vigorous shoots and overcrowded branches to improve ventilation and light penetration and encourage flower-bud differentiation; and strengthen control of apple ring rot, anthracnose, pear scab, peach aphids, oriental fruit moth, spider mites, and other pests and diseases as they enter critical treatment windows. Early-ripening peach cultivars begin to mature and are harvested.
Vegetable management. Open-field vegetables across North China enter rapid growth and peak harvest, with cucumbers, beans, eggplants, peppers, tomatoes, and other summer vegetables reaching the market in large quantities. Water and nutrient management and pest and disease control need to be strengthened. As temperatures continue rising, protection against heat, drought, pests, and diseases becomes increasingly important.

Around Minor Heat, the plum-rain season approaches its end across the middle and lower Yangtze and “出梅” is imminent. Early rice moves from grain filling toward maturity, middle-season rice reaches peak tillering, and farming enters a stage in which flood prevention and summer field management remain equally important.
The plum-rain season approaches its end and preparations for “出梅.” Around Minor Heat, the plum-rain season approaches its conclusion across the middle and lower Yangtze, with “出梅” generally occurring from early to mid-July during the Minor Heat period. The end of the plum rains marks the transition from the humid heat of the meiyu season to the high temperatures of the 伏季 period. Farmers need to complete ditch clearing, drainage, and field management before the plum rains end, while preparing for the coming 伏旱 (*midsummer drought*). As rainfall decreases and temperatures rise after the plum rains, irrigation facilities should be inspected in advance.
Early-rice management from grain filling to maturity. Early rice across the Yangtze basin moves from grain filling toward maturity around Minor Heat, with kernels becoming full and panicles beginning to yellow. Management centers on keeping fields moist through shallow-water or moist irrigation without allowing them to dry; preventing heat-forced maturity by applying deeper water when temperatures reach 35°C or above; draining and drying fields 7–10 days before maturity to promote ripening and facilitate harvest; and controlling panicle-stage pests and diseases such as rice blast, sheath blight, and planthoppers. Early rice generally matures in mid- to late July, between Minor Heat and Major Heat, and farmers begin preparing harvesting tools and storage facilities.
Middle-season rice management during peak tillering. Middle-season rice enters peak tillering around Minor Heat, producing large numbers of tillers in a key stage for determining effective panicle number. Management centers on maintaining a shallow water layer of 3–5 centimeters without interruption; applying 分蘖肥 at 5–8 kilograms of urea per *mu*; carrying out 晒田控苗 when tiller numbers reach the target by draining and drying the field for 7–10 days to suppress unproductive tillers and encourage deeper rooting; and controlling rice blast, sheath blight, planthoppers, and other pests and diseases entering treatment windows.
Pest and disease control. High temperatures and humidity around Minor Heat bring rice pests and diseases into a high-incidence period. Key targets include rice blast—leaf blast and panicle-neck blast—treated with tricyclazole or isoprothiolane; sheath blight, treated with validamycin or difenoconazole + propiconazole; rice planthoppers, treated with imidacloprid or buprofezin; stem borers, treated with dimehypo or Bt preparations; and rice leaf roller, treated with abamectin or emamectin benzoate. Farmers need to strengthen field inspections and intervene promptly when pests or diseases are detected.
Vegetables and aquaculture. The Yangtze basin enters midsummer. Open-field vegetables reach peak growth but are also vulnerable to heat and drought, requiring stronger irrigation and shading for cooling. Greenhouse vegetables require stronger ventilation and temperature reduction. In aquaculture, high temperatures bring vigorous feeding but also increase the risk of oxygen depletion, pond overturning, and disease outbreaks, requiring stronger aeration, water-quality management, and disease prevention.

Around Minor Heat, agricultural activity across Southwest China enters a critical stage of summer management: spring maize enters heading, middle-season rice reaches peak tillering, and potatoes remain in tuber-enlargement management.
Spring-maize management during heading. Spring maize in Southwest China enters heading around Minor Heat, with tassels emerging, silks appearing from female ears, and pollination and kernel formation beginning. This is a critical stage for determining kernels per ear and the crop’s critical period of water demand. Water supply must therefore be secured, because drought during heading can cause poor pollination and a severe decline in kernel number per ear; where soil moisture is insufficient, irrigation should be applied immediately. 穗肥 is applied at 5–8 kilograms of urea per *mu*, while corn borer, aphids, leaf spot, northern corn leaf blight, and other pests and diseases require control.
Middle-season rice management during peak tillering. Middle-season rice in Southwest China enters peak tillering around Minor Heat and produces large numbers of tillers in a crucial stage for determining effective panicle number. Management centers on maintaining a shallow water layer of 3–5 centimeters, applying 分蘖肥 at 5–8 kilograms of urea per *mu*, beginning 晒田控苗 once tiller numbers reach the target, and controlling rice blast, sheath blight, planthoppers, and other pests and diseases.
Potato management during tuber enlargement. Spring potatoes in the main producing areas of Yunnan, Guizhou, and Sichuan enter peak tuber enlargement around Minor Heat, with underground tubers expanding rapidly in a critical stage for both yield and marketable quality. Management centers on applying 结薯肥, mainly potash, at 8–10 kilograms of potassium sulfate per *mu*; controlling late blight with mancozeb or metalaxyl; irrigating at the proper time to ensure adequate water; and intertilling and earthing up to prevent tubers from being exposed to the surface and turning green.
Orchard and tea-garden management. Citrus-producing areas across Southwest China enter fruit enlargement and require stronger water and nutrient management through 膨果肥, mainly potash, together with control of citrus red mites, leaf miners, canker, anthracnose, and other pests and diseases. Summer management of tea gardens continues.

#### (1) Mainland South China
Early-rice maturity and harvest—the opening of the “双抢” rush. Early rice across South China enters maturity and harvest around Minor Heat, with panicles turning fully yellow, kernels becoming plump and hard, and physiological maturity being reached. The “双抢”—the urgent harvesting of early rice and planting of late rice—is about to begin. Farmers seize clear weather for cutting, with combines working day and night and completing harvesting, threshing, and cleaning in a single operation; grain is then promptly dried and stored. The early-rice harvest window generally lasts only 5–10 days, making close monitoring of weather forecasts essential. If a typhoon or heavy rain is approaching, harvesting needs to be completed beforehand.
Late-rice sowing and nursery raising. Immediately after the early-rice harvest, late rice is sown and raised in nurseries, representing the “抢种”—urgent planting—part of the “双抢” rush. Sowing is concentrated between Minor Heat and Major Heat, using plastic-film-covered nursery techniques or dry-bed nursery raising. Seedling age is controlled at 20–25 days, with transplanting into the main field at the “三叶一心” stage, generally in early August. The earlier late rice can be sown, the better: every day of delay shortens the growing period and reduces yield.
Spring-peanut and spring-maize management. Spring peanuts enter maturity and harvest, with pods becoming full and harvesting beginning. Spring maize moves from grain filling into maturity, with kernels becoming full; adequate water supply needs to be maintained because drought can reduce thousand-kernel weight, while corn borer, aphids, leaf spot, and other pests and diseases require control.
Tropical-fruit management. Harvesting of early lychee cultivars such as “三月红” and “白糖罂” is largely complete, while middle- and late-season cultivars such as “妃子笑”, “桂味”, and “糯米糍” enter peak maturity and harvest. Mangoes also enter peak maturity and harvest. Longan moves from fruit enlargement toward pre-maturity and requires stronger water and nutrient management. Citrus enters fruit enlargement and requires control of excessive summer-shoot growth together with citrus red mites, leaf miners, canker, and other problems.
Vegetables and aquaculture. Open-field vegetables across South China enter rapid growth and peak harvest. Rising temperatures bring pests and diseases into a high-incidence period and require stronger control. In aquaculture, the hot season requires stronger aeration, water-quality management, and disease prevention, together with protection against typhoons and heavy rainfall.
#### (2) Taiwan
Rice: In central Taiwan—including Changhua, Yunlin, and the Chianan Plain—the first rice crop moves from full harvest toward the final stage around Minor Heat. In southern Taiwan, particularly the Kaohsiung–Pingtung region, harvest is completely finished. In northern Taiwan, including Taoyuan and Hsinchu, rice moves from grain filling toward maturity. Sowing and nursery raising begin for the second rice crop.
Vegetables: Around Minor Heat, summer vegetables across Taiwan enter peak harvest, with cucurbits such as watermelon, cucumber, and muskmelon, together with beans and fruiting vegetables, reaching the market in large quantities.
Fruit trees: Mangoes in southern Taiwan enter peak maturity and harvest. Lychees also enter peak maturity and harvest. Citrus enters fruit enlargement. Bananas in southern Taiwan move from flowering into fruiting.
Tea: Summer management continues across tea gardens in central and southern regions such as Nantou and Chiayi. In northern tea districts such as Wenshan and Sanxia, summer management likewise continues.
Fisheries: Catches in waters around Taiwan continue to increase during Minor Heat. With typhoon season approaching, coastal regions begin preparing for typhoon protection.
Farmer’s proverbs and folk customs: Taiwanese folk tradition preserves the saying “小暑過，一日熱三分”—after Minor Heat, each day becomes a little hotter. Another saying, “小暑驚蟄，熱得喘不過氣”, describes the oppressive heat of the Minor Heat period. Minor Heat also marks the beginning of “入伏”, and folk custom includes the dietary saying “头伏饺子二伏面”, linking dumplings with the first *fu* period and noodles with the second.