The abnormal phenomenon of rice is caused by improper selection of varieties or the influence of certain unfavorable factors during the growth and development of rice, resulting in a phenomenon that does not match the normal growth target of cultivation, seriously affecting the yield and quality of rice.
Mainly manifested as lodging, premature aging, and excessive youth.
1. Lodging
Overturning is a common phenomenon in rice production, and the earlier it occurs, the greater the angle of dumping, and the more severe the impact on yield.
Reason for occurrence: lodging is divided into root lodging and stem lodging. The root system of rice plants is often located in deep water, resulting in poor root development, fewer roots, shallow rooting, and poor root support. When slightly affected by wind and rain, they are prone to lodging on flat ground. The other is stem lodging, which occurs to varying degrees due to the low cellulose content in the base cells of the stem, thinning of cell walls, large intercellular spaces, soft tissue structure, weak stem, and inability to bear the weight of the upper part. From the perspective of cultivation management, the main reasons for lodging are shallow plowing layers, excessive watering, dense planting, poor root growth and development, and poor ventilation and light transmission conditions in the population. Another issue is improper management of fertilizer and water, excessive application of nitrogen fertilizer, excessive growth during tillering stage, large leaf area during elongation and elongation stage, and premature closure, resulting in excessive elongation of internodes at the base of the stem.
Preventive measures: Scientific irrigation should be carried out according to the different water requirements of rice at different growth and development stages. Shallow water transplanting, inch water tillering, and sun drying should be implemented at the end of tillering. On the premise of ensuring water demand, it is also necessary to ensure sufficient oxygen content in the soil to promote strong root growth. Reasonable sparse planting ensures sufficient nutrient area underground and a certain amount of space above ground, which is conducive to ventilation and light transmission. Reasonably fertilize, avoid biased application of nitrogen fertilizer, increase the application of phosphorus and potassium fertilizers, and microbial fertilizers to make the stems plump and strong, control the elongation of basal internodes, and enhance the ability to resist lodging.
2. Premature aging
Premature senescence refers to the premature decline of physiological functions in the leaves, stems, and other parts of rice during the later stages of growth, which weakens the photosynthetic capacity of functional leaves and reduces the source of grain filling substances. It is one of the main causes of grain rot.
Reason for occurrence: Some plants exhibit premature aging due to excessive growth in the early stages, which exacerbates conflicts between populations and individuals in the later stages of growth, accelerating the rate of root and leaf decay. Another reason is due to improper management of fertilizer and water in the later stage, premature water cut-off, insufficient supply of nitrogen and phosphorus fertilizers, which prevents nutrient supplementation for plant growth. Another reason is that the poor permeability of the soil, coupled with high levels of oxygen deficiency and toxic reducing substances, leads to poor root development in the later stages of rice cultivation, weakening the ability of the roots to absorb nutrients and resulting in weakened aboveground growth.
Preventive measures: Scientifically manage water, with a focus on increasing water temperature. During the filling period after heading, shallow water should be frequently irrigated to increase temperature and promote ripening. Intermittent watering is necessary from milk to yellow maturity to increase soil aeration, enhance root vitality, and nourish roots and leaves. Reasonable fertilization, as the physiological functions of leaves weaken in the later stage, it is necessary to prevent mid stage fertilization. In the later stage, it is necessary to apply foliar and granular fertilizers skillfully to improve the photosynthetic capacity of leaves.
3. Greedy youth
The organic nutrients produced by the leaves of rice in the later stage of growth are retained in the nutrient body, showing a clear preference for green. Especially during the grain filling period, nutrients from leaves and other nutrient organs are transported slowly to the ear, resulting in a decrease in thousand grain weight and an increase in empty grain rate.
Causes: Due to factors such as low temperature, cold damage, and soil drought, normal growth and development are hindered, reproductive growth is delayed, and nutrients cannot be transported to reproductive growth on time. Insufficient intensity of photosynthesis and light exposure time also exacerbate the degree of greediness. Excessive use of nitrogen fertilizer or delayed application time can lead to excessive growth of the nutrient body in the later stage, and also easily result in the phenomenon of excessive greening. Planting too many seedlings per unit area and poor ventilation and light transmission conditions can lead to excessive stem and leaf growth, which can also easily cause symptoms of excessive greening.
Preventive measures: Scientific irrigation to prevent drought. Reasonably plant densely, avoid planting too densely, which affects ventilation and light transmission, and leads to excessive plant growth. Nitrogen fertilizer should be supplied in a timely manner according to time and dosage, and should not be too much, to prevent the phenomenon of excessive nutrient growth in plants and the occurrence of green deficiency.