How much chemical fertilizer and urea per mu for corn and peanuts to achieve high yield? When is the best time to fertilize

Corn and peanuts are both annual herbaceous plants and are widely planted and eaten crops, so how much chemical fertilizer and urea per mu do they need to achieve high yield? When is the best time to apply them? Let's take a look below.

How much chemical fertilizer and urea per mu are needed to achieve high yield?

1. Corn

(1) Chemical fertilizer

Corn is a grain crop with a relatively large fertilizer requirement. During its growth, corn needs to absorb large amounts of nutrient elements from the soil, among which nitrogen and potassium are needed in the greatest amounts. Generally, to produce 100 kg of corn grain per mu, it needs to absorb 2.5 kg of pure nitrogen, 1.2 kg of phosphorus pentoxide, and 2.0 kg of potassium oxide. The ratio of nitrogen, phosphorus, and potassium is 1:0.48:0.8. The fertilizer requirement increases as the yield increases. Generally, the whole growth period of corn requires 10-16 kg of pure nitrogen, 3-5 kg of phosphorus pentoxide, and 5-8 kg of potassium oxide. Medium and trace elements such as zinc, boron, and manganese should be used in a targeted way according to the soil nutrient supply status, supplementing whatever is deficient.

2. In potassium-rich areas, the amount of potassium applied can be appropriately reduced. Corn is relatively sensitive to zinc, so zinc sulfate (0.1-0.3%) or other zinc-containing foliar fertilizers can be sprayed on the leaves at the jointing stage. Corn needs less fertilizer before jointing, the most from jointing to the large trumpet stage, and then gradually less afterward. According to this pattern, the number and amount of topdressing should be reasonably adjusted. Topdressing is generally carried out in two applications, which can be done 10 days after jointing and 10-15 days before tasseling at the large trumpet stage, with the first application lighter and the second heavier (maintain a ratio of 2:3). For fields that are topdressed all at once, it can be applied at the early large trumpet stage.

3. In the three stages of corn growth, the proportion of fertilizer required differs: the seedling stage accounts for 2% of the 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 period. When fertilizing, rational fertilization should be achieved, that is, combining base fertilizer, seed fertilizer, and topdressing; combining nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer; and combining farmyard manure, chemical fertilizer, and biological bacterial fertilizer. The base fertilizer must be applied sufficiently, as this is the foundation. Generally, 2000 kg of decomposed organic fertilizer, 7.5 kg of phosphorus pentoxide, and 5.5 kg of potassium fertilizer are applied per mu as base fertilizer.

4. Corn topdressing should be carried out as early as possible. Method one is to topdress in front and cultivate the soil behind, combining topdressing and soil cultivation; method two is to dig holes with a hoe and apply deeply more than 15 cm. When topdressing, chemical fertilizer and biological fertilizer should be combined to promote good root development. Under normal circumstances, 10-15 kg of urea per mu plus 1 kg of biological bacterial fertilizer can promote early maturity of corn.

(2) Urea

Nitrogen fertilizer (urea) requirement (kg/mu) = (500/100×2.9-17×50%)/(46%×40%) = 32.16 (kg/mu)

If 2000 kg of barnyard manure is applied per mu as base fertilizer, and the barnyard manure contains 0.45% nitrogen with a seasonal utilization rate of 30%, then it is equivalent to 2.7 kg of nitrogen (2000×0.45%×30%), equivalent to 5.87 kg of urea.

Actual urea application per mu: 326-587-26.74 (kg)

2. Peanuts

1. Peanut base fertilizer should mainly be phosphorus and potassium fertilizer. Generally speaking, compound fertilizers produced by legitimate manufacturers circulating on the market can all be used as base fertilizer. The application amount of base fertilizer should be determined according to soil fertility. Usually, the amount for a small mu (667 sq m) is 20 kg, and for a large mu (1000 sq m) it is 30 kg. To achieve precise fertilization, soil testing and formula fertilization can be carried out to apply fertilizer according to need. In addition, continuous peanut cropping will affect yield. If crop rotation is not possible, it is recommended to apply as much fully decomposed farmyard manure as possible. Although agents such as continuous cropping agents have certain effects, it is not recommended to use them too much.

2. In terms of fertilizer types, organic fertilizer must be combined with chemical fertilizer. Organic fertilizer not only contains relatively rich and relatively complete nutrient elements, but also contains organic matter that can improve soil structure. Chemical fertilizer contains single nutrient elements and has high quick-acting nitrogen content. Applying the two together can promote each other, improve fertilizer efficiency, improve soil structure, and continuously build up soil fertility.

3. Combine fertilization for the previous crop with fertilization for the current crop.

When is the best time to apply?

1. Corn

1. Conventional corn topdressing methods include splitting topdressing into two applications during the whole growth period or the ‘one-shot’ topdressing method. 1) Split topdressing into two applications: the first is at the 3-5 leaf stage of corn, applying 20-25 kg of high-nitrogen compound fertilizer per mu (to promote root development and the growth and development of stems and ear differentiation).

2. 3-5 days before the female ear silks and pollination of corn, apply 15-20 kg of urea per mu. The main purpose is to promote larger ears, improve pollination quality, reduce bare tips, increase thousand-grain weight, and increase yield. 2) One-shot topdressing: at the 6-9 leaf stage of corn, apply 35-40 kg of high-nitrogen compound fertilizer or 22-25 kg of urea per mu. Note: when soil moisture is poor, irrigation must be done before topdressing.

2. Peanuts

1. Fertilization principles: combined application of organic fertilizer and inorganic fertilizer. Reasonable matching of nitrogen, phosphorus, potassium, and trace fertilizers, with sufficient base fertilizer and appropriate topdressing.

2. Fertilization amount: peanuts need large amounts of nutrients throughout their life. Generally, for a yield of 300-400 kg of peanuts per mu, apply 3000 kg of organic fertilizer, 15-25 kg of urea, 15-20 kg of potassium chloride, and 15-20 kg of diammonium phosphate per mu. Or use peanut special fertilizer with a content of 45% (10-18-17) at 25 kg per mu.

3. Fertilization methods: for plastic-film peanuts, all fertilizer is applied as base fertilizer, with no topdressing; for open-field peanuts, phosphorus and potassium fertilizers are applied together with organic fertilizer as base fertilizer, and nitrogen fertilizer generally accounts for 50%-80% of the total base application, with the rest applied at the early flowering stage; for wheat-intercropped peanuts, it is applied once at the early flowering stage. In the middle and late stages, foliar spraying should be carried out according to growth conditions. For example, boron, zinc (0.2%), and monopotassium phosphate (0.1%-0.2%) can play a role in protecting leaves, protecting roots, and prolonging the functional period of the top leaves.