When is the latest time to sow and harvest autumn corn in the north, and what fertilizer is best?

Corn is one of the most widely grown food crops in the world, and it goes by different names in different regions - baogu, bangzi, sumi, yushushu, and so on. As growers in the north, what you most want to know is: when is the latest time to plant and harvest autumn corn in the north? What fertilizer is better? The information is compiled below.

When is the latest time to plant and harvest autumn corn in the north?

1. Corn planting and harvesting in the north

1. Northeast region: In determining the sowing period for spring corn, the first things to consider are low-temperature chilling damage at the flowering stage, slow growth and development caused by a cool summer, and the effects of low-temperature chilling damage and early frost during the grain-filling and maturity stage in autumn. Corn can be sown once the spring temperature rises back to 7-8°C. In cold years, choose early-maturing varieties; in warm years, choose mid-to-late-maturing or late-maturing varieties. In the northern areas, choose early-maturing varieties; in the central and southern areas, choose mid-to-late-maturing varieties. In high-altitude areas, choose early-maturing varieties.

2. North China region: The sowing period for corn following wheat should not be too early, so that the period of coexistence between wheat and corn is not too long (generally 25 days is suitable), nor should it be sown too late. It is necessary to ensure that by wheat harvest time the corn has already entered the ear differentiation stage, so that the key period of corn yield formation has a good growth environment, and also to ensure that the later growth stage of corn is not affected by low temperatures, so that it matures well and yields high.

3. In autumn, the North China region often experiences low-temperature continuous rain or a cold autumn with early temperature drops (late August to September), which causes corn to stay green and mature late, with poor grain maturity and low yield. The reasons are sowing too late and using inappropriate varieties. Based on long-term weather forecasts, different maturing varieties should be used for different year types (warm autumn, cold autumn) to ensure a good harvest in every year type.

4. Southwest region: There are two issues to note when sowing spring corn. First, the southwest region warms up early in spring, so take advantage of the early spring heat conditions to sow at the right early time and avoid the effects of spring drought, early-summer drought, and high-temperature damage. Second, pay attention to the “late spring cold” weather causing a “late spring”; one should sow at the end of the cold spring weather, seizing the transition from the cold tail to the warm head, to avoid the effects caused by the spring cold.

5. South China region: Especially in Hainan, in determining the sowing period for winter corn seed production in the south, it is necessary to consider having the corn flowering and pollination period avoid the low temperatures of early to mid-January. Sowing from October 15 to November 15 is suitable, and it should not be postponed to late November to early December.

6. Corn is divided into spring corn and autumn corn. Spring corn is sown in late April to early May and can be harvested in late August; autumn corn should be sown no later than mid-July and is harvested in mid-to-late October

2. Corn varieties suitable for planting in the north

Corn varieties suitable for planting in the north include Zhongdan 909, Jundan 29, Tunyu 808, Delinong 988, Liyu 37, Jingke 968, Weike 702, and others.

What fertilizer is better for corn?

1. Base fertilizer

Base fertilizer is a long-acting fertilizer that supplies nutrients throughout the entire growth period of corn and plays a very important role in high and stable corn yields. The application methods for base fertilizer include broadcast application, band application, and hole application. Generally, band application and hole application are more effective. Base fertilizer mainly consists of farmyard manure and chemical fertilizers.

(1) Broadcast application: When the amount of base fertilizer is relatively large and deep plowing is used, broadcast the base fertilizer on the soil surface, then bury the base fertilizer into the plow layer together with deep plowing. The fertilization depth should be determined according to factors such as soil, fertilizer, climate, and agricultural techniques. If conditions allow the use of full-layer fertilization or layered fertilization, it can better adapt to root absorption in different periods and make the yield-increasing effect of the base fertilizer more obvious.

(2) Band application or hole application: When the amount of base fertilizer is relatively small, especially when chemical fertilizers are used together as base fertilizer, concentrated band application or hole application should be adopted, applying the manure in the furrows. This fertilization method can bring the fertilizer close to the corn roots, which is beneficial for corn absorption, hence the farming saying, “Fertilizing a big patch is not as good as a single line.”

2. Compound fertilizer

(1) In the three stages of corn growth, the proportions of fertilizer required differ: the seedling stage accounts for 2% of total fertilizer requirement, the ear stage accounts for 85%, and the grain stage accounts for 13%. From jointing to the large trumpet stage, corn is at its peak fertilizer demand. When fertilizing, achieve rational fertilization, that is, combining base fertilizer, seed fertilizer, and topdressing; combining nitrogen fertilizer, phosphate fertilizer, and potassium fertilizer; combining farmyard manure, chemical fertilizer, and biological bacterial fertilizer, and also spraying Zhuangsui Ling to increase the 1000-grain weight of corn. The base fertilizer must be applied sufficiently; this is the foundation. Generally, apply 2000 kg of decomposed organic fertilizer per mu, 7.5 kg of phosphorus pentoxide, and 5.5 kg of potassium fertilizer as base fertilizer.

(2) Corn topdressing should be carried out as early as possible. Method one is to topdress in front and hoe the soil behind, combining topdressing and hoeing; method two is to use a hoe to dig a hole and topdress deeply to more than 15 cm. When topdressing, combine chemical fertilizer and biological fertilizer to promote good root development. Under normal circumstances, topdress 10-15 kg of urea per mu, plus 1 kg of biological bacterial fertilizer, which can promote earlier maturity of corn.