1, topdressing period
The best topdressing period of maize is from jointing stage to ear differentiation stage (June 20-27), when maize has been sown 7- 12.
Leaf cutting is the key period to determine the ear length and ear diameter of maize, and it is the period from the growth and elongation of female ear to the differentiation of female floret. At this time, topdressing can meet the demand of nutrition at jointing and booting stage, promote ear differentiation and make corn ear bigger and more grains. ?
2. Topdressing method
There are three common topdressing methods in corn production, namely, fertilizing on ridge and terrace, and then immediately ploughing and covering the soil; Digging holes between artificial ridges, deep application, covering soil, and then ploughing and covering; Ridge and furrow topdressing. The best effect of these three topdressing methods is artificial furrow mulching. Because of deep fertilization, strict mulching and high fertilizer utilization rate, it will achieve good application effect, which will increase the yield by 2%- 1 1% compared with ridge fertilization.
3. Top dressing times
Most of the corn is topdressing once at 9- 1 1 leaf stage, about June 25th. If the amount of topdressing is large, it is best to topdress it twice (jointing, booting and ear fertilization). The distribution principle of two topdressing is that the first topdressing should account for 2/3 of the total topdressing, and the second topdressing should account for 1/3. Light soil such as sandy soil has poor water retention, so a small amount of topdressing is needed for many times to prevent nitrogen leaching. ?
4. Topdressing amount
Topdressing of maize should meet the needs of maize growth and development according to soil fertility, fertilizer demand characteristics of varieties and growth period of varieties. The amount of topdressing should be increased in plots with low soil fertility, otherwise it can be reduced appropriately.
5. Other matters
When the soil is dry, the topdressing time should be determined according to the weather forecast, and it is best to topdress before it rains. It is also necessary to apply fertilizer appropriately according to the growth of corn and seedling conditions, and the plots lacking fertilizer should be replenished in time to increase the amount of topdressing. For the green-greedy and late-maturing plots, more carbon should be applied to supplement phosphorus and potassium fertilizer to promote the maturity of corn as soon as possible.