What is the best time for topdressing corn and for chemical control to suppress excessive growth?
Corn is a very common food, and it can now be seen in markets large and small across our country. Many people now grow corn, but when growing it, fertilizing is very important. However, when fertilizing, there are also some small tips, and special attention needs to be paid to timing. Let's take a look below!
The best time for topdressing corn
The best period for topdressing corn is from the jointing stage to the ear differentiation stage (June 20-27), when the corn has unfolded 7-12 leaves. This is exactly the period when the female ear grows and elongates to the female floret differentiation stage, and it is the key period that determines ear length and ear thickness. Topdressing at this time can meet the nutrient needs of jointing and booting, promote ear differentiation, and make the corn ears large with many kernels.
The best time for chemical control (growth suppression) of corn
The period in which corn growth suppression agents can be used is the 6-13 leaf stage (fully unfolded leaves), with 7-9 leaves, that is, when the corn height is about 60-70 cm (above the knees and below the waist), being the best period for use. This period is the early jointing stage of corn. After spraying, the corn stalk can become thicker, the internodes shortened, both the ear position and plant height reduced, and the number of layers and strands of “brace roots” increased. This can effectively prevent corn lodging, and can also promote the transfer of nutrients to the ear, reducing empty plants and bald tips.
Methods of topdressing corn
1. There are 3 commonly used topdressing methods in corn production, namely broadcasting on the ridge platform and then immediately plowing to cover with soil; digging pits between plants on the ridge platform for deep application by hand, covering with soil, and then plowing the land to cover; and topdressing in the furrow. Among these 3 topdressing methods, the best effect is achieved by digging pits by hand, plowing the furrow, and covering with soil. Because the fertilizer is applied deeply and covered tightly, the fertilizer utilization rate is high, and very good application results are obtained. It will increase yield by 2%-11% compared with broadcasting fertilizer on the ridge.
2. Next is topdressing in the furrow. The advantage of this method is that it saves labor and trouble. The shortcoming is that the fertilizer is slightly farther from the dense root zone, which is not conducive to the full absorption of fertilizer by the corn roots. Therefore, when using it, be sure to plow a shallow furrow before fertilizing and covering with soil, and cover the fertilizer tightly to avoid volatilization, loss, and waste. Broadcasting on the ridge platform sometimes results in the fertilizer being exposed outside because the ridge is not sealed tightly, causing serious loss and waste. The depth of corn topdressing and the distance from the plants should both be 7-10 cm. This is beneficial to the absorption and utilization by the corn roots. If it exceeds 10 cm, it will affect the effect of fertilizer application; if it is less than 5 cm, it will cause seedling burn. After fertilizing, cover with soil in time or cover with soil in combination with hoeing and ridging.
What chemical fertilizer to use for topdressing corn
Urea or compound fertilizer is mostly used for topdressing, and the amount used varies depending on whether it is spring or summer corn.
1. The amount used for spring corn is generally about 33.0% of the total nitrogen fertilizer amount. For soil that is rather sandy and poor at retaining fertilizer, the topdressing amount can account for about 50% of the total nitrogen fertilizer amount. Because summer corn is replanted after harvesting the previous crop, generally no base fertilizer is applied, and the amount of seed fertilizer is not large either, so topdressing becomes even more important. Generally, most or all of the nitrogen fertilizer is used as topdressing.
2. Topdressing must be guaranteed twice. The first time is after thinning to a stand, when the seedling-promoting fertilizer should be applied promptly. This topdressing should mainly use quick-acting nitrogen and phosphorus chemical fertilizers, which can achieve the goal of both promoting seedlings and stabilizing growth.
3. The second topdressing should be after jointing at the large trumpet stage, mainly with heavy nitrogen fertilizer application, using twice the amount of nitrogen fertilizer used the first time, to ensure the large demand for nitrogen during the ear differentiation stage. Topdressing should all adopt the method of hole application and soil covering, and broadcasting and surface application should be eliminated to prevent waste caused by volatilization.
The time when corn is most in need of fertilizer is generally in early summer, and fertilization should also depend on the conditions. There are also some choices for the fertilizer used in topdressing, and the fertilizer chosen is different in different periods. Growth suppression in corn is also one aspect of ensuring its quality, and growth suppression also depends on timing. There are some detailed introductions above, and I hope they can be helpful to everyone.