At the moment, summer harvesting and summer planting are about to begin, which is a good time to make rational use of straw and green manure. The following focuses on straw returning technology and green manure utilization methods.

Advantages of straw returning

The crop straw is rich in organic matter and mineral nutrients. After returning to the field, it can fertilize and change soil, save fertilizer, change straw burning to straw returning, and reduce smoke pollution and facilitate transportation.

Technical points of straw returning

Under the action of microorganisms, the straw returned to the field can be fertilized and soiled and absorbed and utilized by the crop after being rotted and releasing nutrients. Therefore, the key to straw returning technology is to create conditions for the biochemical reaction of microorganisms and to ensure that seedling growth is not harmed. The technical points are: 1 crushing the straw, and pressing it at the right time. The straw is cut into small pieces or pulverized to make water and the like easily immersed; the pressing time should be matched with the agricultural time, generally after the harvest of the current season crops, before the raking crops are planted. The depth of overturning is not less than 20 cm; 2 is applied with nitrogen and phosphorus fertilizer. The straw has a high carbon to nitrogen ratio and a low nitrogen and phosphorus content. In order to meet the needs of microbial decomposition and seedling growth, 200-300 kg of dry straw is generally returned per mu, and an additional 5 kg of urea is applied. 3 The soil moisture is regulated. The soil moisture which is conducive to straw rot and seedling growth is about 20%. For the straw returning before the planting of southern rice blast, the groundwater level should be reduced by shallow irrigation, timely drying and dredging. The straw is returned to the field, and the soil moisture should be improved by appropriate deep-plowing and pouring water.

Causes of yellow corn seedlings in summer after straw returning to the field

There are three main reasons for the yellowing of summer corn seedlings: 1 the straw is not cut enough, the pressure and the quality of the soil preparation are not high, so that the seeds are suspended, and sufficient water and nutrients cannot be obtained; 2 the fertilization is unreasonable, and no additional nitrogen fertilizer is applied. Or the proportion of nitrogen fertilizer used in the compound fertilizer is low; 3 soil moisture is insufficient, so that when the straw rots, the microorganisms compete with the seedlings for moisture. It is recommended to look at the above three points to find the cause and take corresponding improvement measures.

Rational use of green manure

To make rational use of green manure, the following must be done: 1 Rational planting. Green manure mainly provides nutrients for the post-crop crops, so it is necessary to select suitable green soil varieties suitable for local soil, climatic conditions and crops. For example, alfalfa, hibiscus is suitable for fertilizer, forage and green manure; Chinese milk vetch and green pecan can be used as rice sapling green manure; legume crops can fix nitrogen, can be rotated with gramineous crops or intercropped; 2 timely pressure . Green manure is too early to turn, the biomass and nutrient content are not high; the overpressure is too late, the stems and leaves are fibrotic or lignified, it is not easy to decompose and rot, and the feed value is reduced. Generally, it should be turned over during the bud period to full bloom; 3 right amount of pressure. The amount of overturning pressure is 1500-2000 kg and generally does not exceed 3,000 kg. Excessive over-pressure can easily cause crops to grow and soil nitrate accumulation or loss. 4 create conditions for green fertilizer decomposing. If the soil is dry before tumbling, it should be properly irrigated, or simmered in rain; in acidic soil, apply appropriate amount of lime when tumbling, neutralize the acidity produced by soil and green manure fermentation, in order to facilitate green fertilizer decomposing.

(Wang Xingren)