When is the latest time to plant and harvest autumn corn in the north? What kind of fertilizer is better?

Corn is one of the most widely planted food crops in the world, and it has different names in different regions, such as millet, sticks, corn, corn and so on. As growers in the north, what they most want to know is: when will autumn corn be planted and harvested in the north? What kind of fertilizer is better? The following information will be sorted out as follows.

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

I. Maize planting and harvesting in the north

1. Northeast China: in order to determine the sowing date of spring maize, the first thing to consider is the cold injury in flowering stage, the slow growth and development in cool summer, the cold injury in autumn in grain filling and mature stage, and the influence of first frost. When the temperature rises to 7-8 ℃ in spring, early-maturing varieties are selected in cold years, and middle and late-maturing varieties or late-maturing varieties are selected in warm years. Early maturing varieties were selected in the northern region and middle and late maturing varieties were selected in the central and southern regions. Early-maturing varieties are selected at high elevations.

two。 In North China, the sowing time of wheat stubble corn should not be too early, and the symbiotic period of wheat and corn should not be too long (usually 25 days). It is necessary to ensure that corn has entered the stage of ear differentiation when wheat is harvested, so that the key period of maize yield formation has a good growth environment, and the late growth stage of corn is not affected by low temperature, and the mature yield is high.

3. In autumn in North China, there are often cold autumn weather with low temperature and continuous rain or early cooling (from late August to September), which makes corn green and late ripening, poor grain maturity and low yield. The reason is that the seeds are sown too late and the varieties are not used properly. According to the long-term weather forecast, varieties with different maturity should be used according to different year types (warm autumn and cold autumn) to ensure a good harvest in different years.

4. Southwest region: two problems should be paid attention to in spring corn sowing. One is that the southwest region warms up early in spring and makes use of the heat conditions in early spring to avoid the effects of spring drought, early summer drought and high temperature damage. Second, we should pay attention to the "late spring" caused by the "late spring" weather, and we should seize the cold tail and warm head to sow seeds to avoid the impact caused by the spring cold at the end of the spring cold weather.

5. South China: especially in Hainan, in order to determine the sowing date of southern propagation of maize in winter, it is necessary to consider the low temperature of maize flowering and pollination period from January to early February, sowing from October 15 to November 15, and 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 and early May and can be harvested in late August. Autumn corn can be sowed no later than mid-July and harvested in mid-late October.

2. Corn varieties suitable for planting in North China

The corn varieties suitable for planting in the north are Zhongdan 909, Jundan 29, Tunyu 808, Delinong 988, Liyu 37, Jingke 968, Weike 702 and so on.

What kind of fertilizer is better for corn?

1. Base fertilizer

Base fertilizer is a long-term fertilizer to supply nutrients in the whole growth period of maize, which plays a very important role in the high and stable yield of maize. The application methods of base fertilizer are spreading, strip application and hole application. Generally, strip application and acupoint application have better effect. The base fertilizer is mainly farm manure and chemical fertilizer.

The main results are as follows: (1) under the condition of a large amount of base fertilizer and deep ploughing, spread the base fertilizer on the surface of the soil, and then bury the base fertilizer in the ploughed layer. The depth of fertilization should depend on factors such as soil, fertilizer, climate and agricultural technology. If full-layer fertilization or stratified fertilization is adopted under certain conditions, it can better adapt to the absorption of roots in different periods and make the yield-increasing effect of base fertilizer more obvious.

(2) when the amount of base fertilizer is small, especially when chemical fertilizer is used as base fertilizer, concentrated strip or hole application should be used to apply manure in ridges and furrows. This method of fertilization can make the fertilizer close to the root of corn, which is conducive to the absorption of corn, so there is a saying that "it is better to fertilize a large area than a line".

two。 Compound fertilizer

(1) the proportion of fertilizer required in the three stages of maize growth is different, accounting for 2% of the total fertilizer required at seedling stage, 85% at ear stage and 13% at grain stage. Corn from jointing to big cough mouth stage is the peak period of fertilizer demand, and reasonable fertilization should be achieved during fertilization, that is, the combination of base fertilizer, seed fertilizer and topdressing fertilizer, the combination of nitrogen fertilizer, phosphate fertilizer and potassium fertilizer, and the combination of agricultural fertilizer, chemical fertilizer and biological bacterial fertilizer. and cooperate with spraying Zhuangsuiling to increase the 1000-grain weight of corn. Base fertilizer should be fully applied, which is the basis. Generally, 2000 kg of rotten organic fertilizer, 7.5kg of phosphorus pentoxide and 5.5kg of potash fertilizer should be used as base fertilizer per mu.

(2) the topdressing of corn should be carried out as early as possible, the first method is to topdressing the front and the back to the ground, and the other is to use picks to dig the pit with a depth of more than 15 centimeters; when topdressing, it is necessary to combine chemical fertilizer and biological fertilizer to promote the good development of the root system. In general, 10kg urea per mu and 1 kg of biological bacterial fertilizer can promote the early ripening of corn.