1. Nutritional demand characteristics. Forage grass is more common in China, mainly used as feed for animal husbandry. The cultivated pastures are mainly leguminous and grassy pastures. Forage growth requires a large amount of carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, sulfur and other elements, but also requires trace elements such as boron, manganese, zinc, iron, molybdenum. Gramineous forage and leguminous grasses have similarities in nutrient requirements, but there are also differences. Gramineous forage has a strong need for nitrogen and is more sensitive to the application of nitrogen fertilizer. Because of the symbiotic nitrogen fixation of leguminous grasses, it is only necessary to apply a small amount of nitrogen fertilizer before the formation of nodule in the seedling stage, so its response to nitrogen fertilizer is not as sensitive as that of grass crops. The leguminous grasses are more sensitive to nutrients such as phosphorus, potassium and calcium than grasses. The type and quantity of nutrients absorbed by the pasture from the soil is determined by the soil conditions, the growing environment and the type and yield of the pasture. The nutrients absorbed by the forage from the soil are far from meeting the needs of its growth. Only by scientific fertilization can the nutritional needs of the growth and development of the pasture be met.
2. Forage and fertilization techniques. The type, quantity and application period of forage fertilization are mainly determined according to the soil fertility status and the amount of fertilizer required for different types of pasture.
(1) Base fertilizer: The base fertilizer is applied in two ways. First, prior to sowing, high-quality farmyard manure, such as manure, compost or slow-acting fertilizer, should be used in combination with ploughing and ploughing to meet the needs of the whole growing season of the pasture. Generally, 1000-2500 kg of organic fertilizer per acre and superphosphate 10- 20 kg or 20 mg of calcium magnesium phosphate fertilizer, 8-10 kg of potassium chloride, sprinkled before ploughing, ploughed after sown; second is fertilized, applied simultaneously with seeds at the time of sowing to meet the needs of forage seedling growth. The fertilizer can be applied in the seeding ditch or in the hole, covered on the seed, or used for soaking seeds and seed dressing. The fertilizer used, whether it is farmyard manure or chemical fertilizer, can not affect the seed germination and emergence.
(2) Topdressing: After the forage is emerged, during the growth period, the topdressing is carried out according to the growth of the pasture. Topdressing is mainly based on chemical fertilizers. Topdressing methods can be applied, applied, applied, fertigation or foliar spray. The time of top dressing is generally in the tillering and jointing stage of grasses, the branching and bud stage of legumes. In order to improve the grass production rate, it should be topdressed after each harvest. Perennial pasture, every spring to chase 1 fat, to promote early and long. In autumn, the topdressing is mainly based on phosphorus and potassium fertilizer, so that the pasture can safely overwinter. Gramineous forage grass topdressing is mainly based on nitrogen fertilizer, with a certain amount of phosphorus and potassium fertilizer. In addition to the nitrogen fertilizer in the seedling stage, the leguminous grasses were mainly phosphorus and potassium fertilizers in other periods.