A、Introduction of corn
Maize is one of the major food crops in China. The main areas that plant corn are in northern, northeastern and northwestern China Due to the different natural conditions in different places, corn planting system is also different. How to apply fertilizer scientifically according to the characteristics of corn growth and the law of fertilizer requirement. This is very important to improve corn yield.
According to its reproductive characteristics, corn can reach three main stages: the seedling stage, the ears stage and the kernel stage. The ears stage is from nodulation to tassel. This is the corn nutritional organs grow vigorously, male and female ears differentiation formation. Nutritional growth and reproductive growth at the same time to determine the size of the corn cob an important period. Male ears out to maturity for the flower kernel period, is the reproductive growth stage of corn.
3、Corn’s need for fertilizer
The amount of nitrogen, phosphorus and potassium absorbed by corn varies greatly depending on the soil, fertilizer, climate and planting methods. Roughly speaking, for every 100 kg of corn kernels produced, 2.5-4.0 kg of nitrogen, 1.1-1.4 kg of phosphorus and 3.2-5.5 kg of potassium need to be absorbed from the soil. The ratio is 1:0.4:1.3.
Spring corn absorbs 3.5-4.0 kg of nitrogen, 1.2-1.4 kg of phosphorus, and 4.5-5.5 kg of potassium per 100 kg of kernels produced. The ratio is 1:0.35:1.35.
Summer corn absorbs 2.5-2.7 kg of nitrogen, 1.1-1.4 kg of phosphorus and 3.2-3.8 kg of potassium per 100 kg of kernels produced. The ratio is 1:0.48:1.35. The maize in the crop absorbs 2.45 kg of N, 1.41 kg of P and 1.92 kg of K per 100 kg of kernels produced. The ratio was 1.7:1:1.4.
①N uptake by maize
Maize absorbs the most nitrogen during its lifetime, followed by potassium and less phosphorus. The uptake of nitrogen, phosphorus and potassium by corn is different at different stages of fertility. Research data show that nitrogen uptake at the seedling stage of spring corn is low, accounting for only 2.14% of the total nitrogen. The nitrogen uptake was higher during the ears stage, accounting for 32.21% of the total. Uptake during the tasseling and flowering stage accounted for 18.95% of the total. At the seed formation stage, the uptake accounted for 46.7% of the total.
Due to the short reproductive period, summer corn absorbs N earlier and at a faster rate. Seedling uptake accounted for 9.7% of the total. The uptake of nodulation and gestation accounted for 76.19% of the total. Uptake from tassel to maturity accounted for 14.11% of the total.
②Phosphorus uptake by maize
Spring maize absorbed 1.12% of the total amount at the seedling stage. However, 45.04% of the total uptake occurred during the plucking and gestation period. Finally, the stages of tassel fertilization and seed formation accounted for 53.84% of the total uptake. Summer corn also absorbed phosphorus earlier, with 10.16% at the seedling stage. However, 62.60% of uptake occurred during the plucking and gestation period. The tassel fertilization stage absorbed 17.37%. Finally, 9.51% of uptake during seed formation.
③Potassium uptake by maize
Spring corn is basically similar to summer corn. More than 70% gets absorbed before tasseling and 30% at the time of tasseling and fertilization. Maize dry matter accumulation and nutrient levels are closely related to the absorption of nitrogen, phosphorus and potassium, all three elements show the characteristics of fertilizer requirements at the seedling stage, with a significant increase at the nodulation stage and a peak from conception to tasseling. Therefore, corn fertilization should be based on this feature, as far as possible before the peak fertilizer demand fertilization.
B、Spring corn fertilization techniques
Spring corn according to the main base fertilizer, supplemented by chasing fertilizer. Agricultural fertilizer is the main, supplemented by chemical fertilizer. Nitrogen fertilizer is the main, supplemented by phosphorus fertilizer. Spike fertilizer is the main, supplemented by the basic principles of fertilization of grain fertilizer. Base fertilizer should generally account for about 70% of the total fertilizer application. Most of the phosphorus fertilizer should also be combined with the base fertilizer fertilization.
Generally in the first year combined with autumn plowing application. When applying base fertilizer, it should be evenly mixed with the soil. Generally, 37.5-60 tons of farmyard manure is applied per hectare of base fertilizer. If nitrogen fertilizer is used as base fertilizer, 375 kg of ammonium bicarbonate or 150 kg of urea can be applied per hectare. Be sure to apply deeply to prevent nitrogen volatilization loss. In phosphorus deficient soils, apply 450-600 kg of calcium superphosphate per hectare. While, in potassium deficient soils, apply 150 kg of potassium chloride per hectare. In zinc-deficient soil, apply 15 kg of zinc sulfate per hectare.
Before sowing in spring, use a small amount of farmyard manure. Also with the appropriate amount of nitrogen and phosphorus fertilizer applied in strips or holes. These serve as corn seed fertilizer.
Corn chasing fertilizer is an important measure for corn yield cultivation. Due to the long growth period of spring corn, the seedling growth is slow, absorbing less nutrients. Therefore, the spring corn fertilizer more “light before and heavy” fertilization method. That is, in the corn before the pulling of the node into the follow-up fertilizer 1/3, 75-150 kg of urea per hectare. Then, 150-300 kg of urea is applied per hectare. This will meet the nutrient needs of the corn female ears at the stage of spikelet and florets differentiation as well as seed formation. Experimental results confirm that spring corn using the “light before and heavy” fertilization method, than the “heavy before and light” fertilization method to increase yields by 13.3%.
C、Summer corn fertilization techniques
Hebei, Henan, Shandong and other provinces in the wheat harvest, combined with shallow tillage stubble. Apply 30-45 tons of high-quality stable fertilizer per hectare, base fertilizer 600-750 kg of phosphorus fertilizer. Some places use straw to return to the field. After the harvest of the previous crop of wheat, wheat straw is applied directly or when harvesting wheat, leaving a high stubble as a base fertilizer for summer corn. Generally, it is appropriate to apply 3000-4500 kg of wheat straw per hectare. In soils with low fertility, the application of wheat straw should be combined with a small amount of nitrogen fertilizer. This can regulate the carbon to nitrogen ratio. Therefore, it can accelerate the straw decomposition, when the season to play the proper effect.
Summer corn due to tight farming time when sowing. There are many places where it is not possible to give corn to prepare the ground and apply into the base fertilizer. But summer corn seedlings need to absorb a lot of nutrients from the soil. It is advisable to use the “heavy before and light after” method of fertilization. The total amount of fertilizer is 2/3 of the total amount of fertilizer applied in the pre-pulling period, and 1/3 of the total amount of fertilizer applied in the trumpeting period, focusing on meeting the nutrients needed for the differentiation of the female ears of it.
According to the national fertilizer network experimental results show that summer corn yield 5250-6750 kg per hectare. The amount of urea per mu is 30-40 kg, according to the “heavy before and light after” chasing fertilizer way. It is better to apply 20-25 kg at the nodulation stage of corn and 10-15 kg at the trumpet stage. However, we also according to the Chinese Academy of Agricultural Sciences Crop Institute test results. The “front heavy and then light” way than the “front light and then heavy” way of chasing fertilizer yield increase of 12.8%.
Summer corn fertilization should also consider the period and the distribution of fertilizer in different periods. Therefore, to choose the best application period and dosage, in order to get the best yield effect.
D、Fertilization of set corn
Crop corn is the main planting method of it in the Yellow Huaihai Plain. As corn is set 25-30 days before wheat harvest, the two crops have a long symbiosis period. And the amount of base fertilizer applied is small. The competition for water and fertilizer between wheat and it is more intense. Therefore, we need to apply fertilizer earlier.
According to Beijing, Hebei, Henan, Shandong and other places, experiments show that the set of it, no matter what varieties and places, fertilizer chasing is “before the heavy after the light” than “before the light after the heavy” yield is high, an average yield increase of 9.6%.
At present, the market with more fertilizers, is the company produced by Nagric.