Reasonable tillage Tillage measures are an important part of nursery, and rational tillage can improve soil physical and chemical properties. Rational tillage can increase soil porosity, enhance soil aeration, and facilitate root respiration and nutrient uptake. The increase of air in the soil is also easy to increase the ground temperature, reduce the temperature difference between day and night, promote the soil microbial vigor, and accelerate the decomposition of organic matter. Rational farming can also improve soil structure, enhance soil water permeability and water storage capacity, and to a certain extent eliminate weeds and pests.
Farming includes land preparation and cultivating. The purpose of land preparation is to improve soil structure, improve soil fertility, maintain moisture, eliminate weeds and pests and diseases, and facilitate seedling growth. It is best to carry out the autumn ploughing in the fall of the nursery, or to cultivate in the autumn. If it is necessary to prepare the land in the Spring, it is advisable to cultivate the land when the soil is frozen to a certain depth, so as to ensure the depth of the soil preparation, and the depth of the soil preparation is about 20 cm. In order to make the soil structure good, the soil moisture is very important when the soil is prepared. When the soil cohesion, plasticity and adhesion are small, the soil preparation effect is good. When the soil water content is 50%-60% of the saturated water content, the cultivated land resistance is the smallest and the highest efficiency. The best quality. If the soil is hard or there are many clods after the shovel and can not be broken, you can pour water once, when the topsoil is dry and the bottom soil is tidal. If the soil is too wet, the adobe is easy to destroy the physical properties of the soil, so the soil It is not advisable to prepare the soil when it is wet. After the nursery is cultivated, it must be thoroughly smashed, and there should be no large clods to eliminate grass roots and stones.
When cultivating, the best tilling time should be selected. When the soil moisture is too high, the cultivating will destroy the soil structure. The soil porosity, permeability and aeration conditions of the cultivated soil are obviously deteriorated, which has a bad influence on the growth of the seedlings, generally as the soil water content exceeds Withered water content, and less than 70% of the field water holding capacity, it is most suitable for farming, heavy loam does not exceed 37%, light loam does not exceed 30%, sandy loam does not exceed 22%, soil is too wet and strictly prohibited farming.
Leisure rotation is an effective method to restore the nursery soil. After the nursery has been cultivated for a certain period of time, the soil fertility will decrease. The best solution is to take a trip to the seedlings for a year or a round of leisure. The land is idle, and the weeds on the ground are turned into the water during the rainy season, allowing it to rot as a fertilizer. The time for turning over is too early, and weeds will grow after tumbling. The time is too late, the weed seeds are ripe, and it is easy to cause the second year of nursery ridiculous. Rotation is to plant a year's crops or cultivate different types of seedlings with the seedlings of the seedlings after the seedlings are out. The crops are generally grown with soy crops such as soybeans and mung beans. After the harvest of the autumn crops, the combination of the base fertilizer is used for tillage, leveling and finening, and the second year of spring seedling production. Seedlings are generally replaced by coniferous and broadleaf species, alternating between deep roots and shallow roots, cultivating seedlings and cultivating large seedlings.
Organic Fertilizer The most effective means of using land, raising land and protecting the land during the nursery process is to increase soil organic fertilizer. Increasing the organic matter content of the soil plays an important role in improving the ground temperature, maintaining a good soil structure, and regulating the fertilization and water supply capacity of the soil. After the soil is applied with a certain amount of organic fertilizer, it creates favorable conditions for the growth and reproduction of microorganisms. It can also form organic colloidal structures such as humus, pectin and polysaccharide through decomposition and biochemical action. These gels and soils are combined to form different sizes. Agglomerates and agglomerate structures of different shapes. The methods of applying organic fertilizer mainly include three types: base fertilizer, top dressing, and green manure.
The base fertilizer includes charcoal, manure, compost, etc. The base fertilizer must be decomposed. The fertilizer should be evenly spread before the preparation of the soil, and then the soil should be turned into soil. Before the seedling, the base fertilizer should be applied. According to the soil condition of the nursery and the different types of seedlings, The amount of fertilizer applied is generally 66.6 kg/133.3 kg per hectare.
The application of organic fertilizer mainly consists of decomposed manure and urine. The top dressing should be applied in a dispersed manner. It can be applied by strip digging and fertilization, or combined with cultivating. The large seedlings can be burrowed or round or radiated around the roots. Digging trench application, watering should be timely after applying organic fertilizer.
Planting green manure can be combined with the leisure or rotation of the nursery. The legumes such as alfalfa, soybean and Amorpha are the best, and the planting density is large. When the plant is fresh and the seeds are immature in the rainy season, it is turned into the soil. It rots as a fertilizer.
Although there are many types of tapping screws, they all have the following similarities:
(1) are generally made of carbonized carbon steel (accounting for 99% of total production). It can also be made of stainless steel or non-ferrous metals.
(2) The product must be heat treated. Carbon steel tapping screws must be carbonized and stainless steel tapping screws must be solution hardened. In order to make tapping screws to meet the requirements of the standard of mechanical properties and performance.
(3) The product surface hardness is high, the core toughness is good. That is, "soft inside strong outside". This is a major feature of tapping Screw performance requirements. If the surface hardness is low, it can not be screwed into the matrix; If the core toughness is poor, a twist will break, can not be used. So "inside soft outside steel" is self-tapping screw to meet the use of performance, very important requirements.
(4) The surface of the product needs surface protection treatment, generally electroplating treatment. Some product surface must be treated by phosphate (photostatting), such as wall panel self - tapping screws for photostatting.
(5) Production by cold heading process. It is recommended to use high-speed cold heading machine and high-speed wire rolling machine or high-speed planetary wire rolling machine. High speed is emphasized here to ensure product quality. Only the head of tapping screw produced by high-speed machine is well formed and the thread quality is high.
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