Detailed Explanation of Cultivation Points for the Late Growth Stage of Rice

Pest and disease control:

Diseases: The main disease requiring attention in the late growth stage of rice is rice blast. After rice heading, seize the opportunity to apply pesticide 2---3 times, with an interval of about 7 days. Apply about 100 grams of tricyclazole wettable powder per mu, mixed with 30 kg of water for foliar spraying.

Insect pests: The main insect pests in the late growth stage of rice include white-backed planthopper, brown planthopper, armyworm, and rice leaf roller. All four of these pests have long-distance migratory and sudden outbreak characteristics, and timely control should be noted. You may choose the Shoulei insecticide series produced by Guangxi Jiuhe ---- a dedicated insecticide for rice leaf roller mixed with a dedicated insecticide for rice planthopper, with a dosage of 30 ml per mu for each, mixed with 45----60 kg of water for foliar spraying. The control effect is especially excellent.

Water and fertilizer management:

Strengthening irrigation management in the late stage of rice is very important for preventing premature senescence of rice, raising soil temperature to promote early maturity, controlling rice blast, and increasing yield. Rice requires more water in the late stage and the root system requires more oxygen. Both water and oxygen are supplied by the soil, which easily creates a contradiction between water and air in the soil. To resolve this contradiction and achieve the goal of nourishing roots and preserving leaves, we should start from three aspects:

1. Reinforce the field ridges, clear drainage channels, lower the groundwater level, and enhance the vertical permeability of the soil. Through vertical percolation, harmful substances such as salt, alkali, and hydrogen sulfide in the soil are carried away, while oxygen dissolved in the water is brought into the lower soil layers, enhancing root vitality.

2. Implement shallow water irrigation, and in the late grain-filling stage implement intermittent irrigation with alternating wet and dry conditions. The water layer should be 2---3 cm; wait for it to naturally seep dry until the field does not sink underfoot and the soil does not crack, then irrigate the next round of water. The water cutoff period should be well controlled, generally about 40 days after full heading of rice, or 7---10 days before harvest. For rice fields with a high groundwater level and relatively heavy salinity and alkalinity, water retention should be the main approach, and the water cutoff period should be appropriately delayed to prevent soil salinization and premature senescence of rice.

3. Apply topdressing of foliar fertilizer and plant growth regulators. After full heading of rice, it is not advisable to apply nitrogen fertilizer to the root zone; instead, applying foliar fertilizer and plant growth regulators is an auxiliary measure to prevent premature senescence and delayed maturity with excessive vegetative growth in rice. Spraying foliar fertilizers such as rare earth dihydrogen potassium at the conventional dosage can promote grain filling, promote early maturity, and increase yield; generally 1---2 applications are sufficient. Due to the relatively frequent rainy weather this year, especially the continuous rainy and low-temperature weather during the heading period of rice, rice grain filling is slow. For a small number of rice fields with a relatively long growth period and very late sowing and transplanting, 40% ethephon 400----800 times solution can be sprayed in the early grain-filling stage of rice. Ethephon has the effect of accelerating rice grain filling and advancing maturity. After applying ethephon, nutrients in rice leaves rapidly transfer to the panicle, thereby making leaf color lighter and accelerating the timing of yellowing. However, it should be noted that ethephon is only a plant growth regulator and does not increase yield for rice that can mature normally. Generally, rice fields should avoid using ethephon as much as possible, especially rice sprayed with ethephon must not be retained for seed use.