Prevention of lodging, premature senility and greed in the late growth stage of planting rice

The abnormal phenomena such as lodging, premature senility and greed for green of rice are due to the improper selection of varieties or the influence of some unfavorable factors in the process of rice growth and development, which is not consistent with the normal growth of cultivation objectives. the yield and quality of rice were seriously affected.

1. Lodging

Cause: lodging is divided into root lodging and stem lodging. However, because the rice plant is in deep water for a long time, the root system is underdeveloped, the root is shallow, the root support is poor, slightly attacked by wind and rain, it is easy to lodge on the ground. However, the stem has different degrees of lodging due to the less cellulose content at the base of the stem, the thinning of the cell wall and the weakness of the stem, which can not afford the weight of the upper part. From the point of view of cultivation management, the main causes of lodging are shallow ploughing layer, deep irrigation, high planting density, poor root growth and poor ventilation and light transmission. The other is improper management of fertilizer and water, one-sided heavy application of nitrogen fertilizer, overgrowth at tillering stage and early closure, resulting in excessive growth of basal internodes of stem.

Preventive measures: scientific irrigation should be carried out according to the different water demand of rice in different growth and development stages, transplanting rice seedlings in shallow water, tillering in an inch of water, and setting up the field at the end of tillering. Under the premise of ensuring water demand, it is also necessary to make enough oxygen content in the soil to promote the root system to grow strong. Reasonable close planting is beneficial to ventilation and light transmission. Reasonable fertilization can not be partial application of nitrogen fertilizer, increase the application of phosphorus and potassium fertilizer, make the stem rich and strong, control the elongation of basal internodes, so as to enhance the ability of lodging resistance.

2. Premature senility

Premature senescence refers to the premature decline of physiological functions in leaves, stems and other parts of rice in the late growth stage, which weakens the photosynthesis of functional leaves and reduces the source of filling materials, which is one of the main reasons for blighted grains. Cause: the premature senescence of some plants is due to the overgrowth in the early stage, which aggravates the contradiction between the population and individuals in the later stage of growth, and accelerates the decline and death of roots and leaves. The other is due to improper fertilizer and water management in the later stage, water cut off too early, and insufficient supply of nitrogen and phosphorus fertilizer, so that the growth of plant nutrients can not be supplemented. In addition, due to the poor permeability of soil, hypoxia and toxic reducing substances, the root system of rice developed poorly in the later stage, weakened the ability of root system to absorb nutrients, and led to the decline of aboveground growth.

Preventive measures: scientific water management, mainly to improve the water temperature, after heading to the filling stage, frequent irrigation in shallow water to increase temperature and promote ripening. From milk maturity to yellow maturity, intermittent irrigation is required to increase the ventilation of the soil, enhance the vitality of the root system, and maintain roots and protect leaves. Reasonable fertilization and skillful application of spike and grain fertilizer can improve the photosynthetic ability of leaves.

3. Greed for youth

Causes: due to the influence of low temperature, cold injury and soil drought, the normal growth and development is hindered, the reproductive growth is delayed, and the nutrients can not transfer to the reproductive growth on time. The intensity of photosynthesis and light time are not enough, which also aggravates the degree of greed. If the amount of nitrogen fertilizer is too much or the application time is too late, the vegetative growth is too prosperous in the later stage, and the phenomenon of greed is easy to appear. If the population density is too large and the ventilation and light transmission conditions are not good, the stems and leaves are too luxuriant, it is also easy to produce greedy symptoms.

Preventive measures: scientific irrigation to prevent drought. Reasonable close planting, avoid planting too close, affect ventilation and light transmission, resulting in overgrowth of plants. Nitrogen fertilizer should be supplied timely according to time and dosage, and should not be too much, so as to prevent greedy green phenomenon due to excessive growth of plant nutrients.