South floods and north drought possible in April, agricultural disaster prevention guide released

In March, the overall impact of agrometeorological disasters was relatively light, with the main disaster being overcast and rainy weather with insufficient sunshine in the middle and lower reaches of the Yangtze River. In April, close attention should be paid to and defenses made against the adverse effects of drought in the north on the growth and development of winter wheat, spring plowing and spring sowing, and the effects of continuous rain, waterlogging damage and pests and diseases in the middle and lower reaches of the Yangtze River on rapeseed yield formation.

The agrometeorological disasters in March were overcast and rainy weather with insufficient sunshine in the middle and lower reaches of the Yangtze River, localized strong winds and hail disasters, and localized drought in the northern winter wheat region.

Overcast and rainy weather with insufficient sunshine occurred in the middle and lower reaches of the Yangtze River. From late mid-February to mid-March, the middle and lower reaches of the Yangtze River continued to experience overcast and rainy weather with insufficient sunshine, with sunshine 40% to 90% below normal; among this, most of Jiangnan had 15 to 29 rainy days, with precipitation more than 50% above normal, and low-lying fields in Jiangxi, southern Anhui and other places experienced mild to moderate waterlogging damage, affecting the transformation of the seedling condition of summer-harvested grain and oil crops and the bolting and flowering of rapeseed; this caused rapeseed sclerotinia stem rot to appear early and to be more severe than in normal years and last year, among which the leaf disease plant rate in Jiangxi and Hunan increased by 31.2% and 16.9% compared with last year. Based on a comprehensive analysis of the intensity of overcast and rainy weather with insufficient sunshine and the number of station-times, the overcast and rainy weather with insufficient sunshine in the middle and lower reaches of the Yangtze River was heavier than the same period last year, but lighter than in normal years.

In April, summer-harvested grain and oil crops will successively enter the key period of yield formation and have a relatively large water demand, and spring sowing across the country will unfold on a large scale. In April, priority should be given to defending against the adverse effects of drought and late frost in the north, and continuous rain and waterlogging damage in the south on the yield formation of summer-harvested crops, fruit tree flowering and spring sowing.

First, North China, the Huang-Huai region and western Northeast China should pay attention to drought prevention and drought resistance. It is expected that in April, temperatures in the wheat regions of North China and the Huang-Huai region will be relatively high, there will be many windy spring days, soil moisture loss will accelerate, and in addition drought conditions have already appeared in some areas, so wheat should be watered in a timely manner at the jointing and booting stages to defend against the effects of drought; western Northeast China should make preparations for sowing by creating soil moisture.

Second, the middle and lower reaches of the Yangtze River should pay attention to defending against continuous rain and waterlogging damage. It is expected that in April, precipitation in the Jianghuai region, the central and eastern parts of Jianghan and northern Jiangnan will be 20% to 50% above normal, so periodic overcast and rainy weather with insufficient sunshine and waterlogging damage must be guarded against, and after rainfall, moisture should be drained and waterlogging reduced in a timely manner to avoid premature root senescence of rapeseed and winter wheat, lodging in the later period and obstruction of spring sowing.

Third, the north should pay attention to defending against strong winds, sand and dust and late frost. April is a period when strong winds, sand and dust weather occur frequently in the north, so facility agriculture greenhouses should be reinforced to prevent facility damage and freezing of vegetables in the greenhouses. Before cold air arrives, measures such as covering should be taken to prevent frost damage during the flowering period of fruit trees. Spring sowing and plastic film mulching operations in cotton fields should avoid strong winds, sand and dust weather to prevent losses.

Fourth, summer-harvested grain and oil-producing areas should do a good job in monitoring and controlling pests and diseases. The northern winter wheat region should focus on preventing wheat aphids, and the middle and lower reaches of the Yangtze River should prevent the occurrence and development of wheat scab and rapeseed sclerotinia stem rot.