Summer drought of planting Maize and its Comprehensive Prevention

Summer days usually refer to the three-volt period from mid-July to mid-August, during which the drought is commonly known as summer drought. At this time, the drought caused the most serious damage to corn, so the drought in this period is called "stuck neck drought". Card neck drought will affect the heading, flowering and silking, pollination and fruiting of summer corn, resulting in a serious reduction in yield.

1. The precipitation standard of summer maize drought in summer drought is that in the three ten days from late July to mid August, the rainfall of more than 20 days in a row is less than 50mm, and the total rainfall of 30 days is less than 100mm.

The standard of soil moisture in summer drought is mild drought when soil moisture decreases to 65%-70% of the maximum water holding capacity, moderate drought when 55%-65%, and severe drought when it is less than 55%.

The morphological index of summer drought was that the temporary curl wilting of the lower leaves of maize at booting, flowering and pollination stage and grain formation stage at noon was mild drought, and the temporary wilting of upper and lower leaves of maize plant at noon was moderate drought. The permanent wilting of upper and lower leaves of maize plant (which can not return to normal at night) was severe drought.

Second, the characteristics of summer drought and summer maize harmful to summer days in Anhui Province are in the period of booting, flowering and pollination and grain formation, and it is also the period when summer corn needs the most water and is the most sensitive to drought in its life. The period from booting to grain formation is the most drought-intolerant period in maize life, and the effect of drought in this period has a long-term persistence, especially in the flowering and fruiting stage. Once the severe drought is encountered for a long time, the pollen will die, the filaments will dry up, and the pollination will not be able to bear fruit, resulting in a substantial reduction in yield. Therefore, there is an agricultural proverb that "the first drought is not drought, but the summer drought is reduced by half." A large number of experimental results show that there are great differences in the extent of yield reduction in different growth stages after severe drought disasters, such as 25% at jointing stage, 30% at booting stage and 40% at flowering stage.

Third, measures to deal with summer drought in maize must be irrigated as soon as possible when the summer drought reaches the moderate standard, so as to facilitate the normal flowering, pollination and fruiting of corn, or to ensure the smooth progress of grain formation and grain filling. It is worth noting that the summer drought is caused by the control of the western Pacific subtropical high, which has a wide range of influence and often lasts for a long time, resulting in high severity, long time and serious damage. Therefore, once the summer drought occurs, it is necessary to irrigate the "bumper harvest water" in time while the water source is abundant, so as to play the role of irrigation to ensure a bumper harvest. Otherwise, when the drought is serious, the seedlings are scorched and the water source is exhausted, then pour "life-saving water", often get twice the result with half the effort.