Experience and Practical Tips for Rice Field Management
1. Water management
Rice water management should adopt intermittent irrigation: shallow water to protect roots, one-cun water for tillering, drain water to control seedlings when sufficient seedlings are established, shallow water at booting and heading, and moist conditions to plump the grains. During the green-turning stage, rice roots have weak water absorption capacity and high water requirements, so water management should ensure deep water for green-turning (at least 1 cun deep); during the tillering stage, the field should be neither drought-stressed nor flooded, so shallow water should be applied frequently, and at the end of tillering the field should be drained and sun-dried or left to dry; the panicle development stage is the period of greatest water demand in the entire life cycle, especially from the pollen mother cell division stage to the pollen grain formation stage, when the plant is very sensitive to water; this is the first critical water period for rice, so shallow water should be used to promote differentiation and one-cun water should be maintained to protect the pregnant panicle; from heading and flowering to the milk-ripe stage is the second critical water period for rice, so the field should be kept alternately dry and wet, mainly wet, with timely irrigation.
2. Nutrient management
Rice continuously absorbs various elements during different growth and development processes, among which N, P, K, and Si are the main ones, with the ratio of N, P, and K being 2:1:3. Japonica rice requires more N and less K than indica rice, and late rice requires more N and less K than early rice.
The absorption of the three major elements varies greatly among different growth stages of rice. Most of the inorganic nutrients required are absorbed during the tillering stage and the panicle development stage before heading. Compared with late rice, early rice absorbs more in the early stage and absorbs more N in the early stage.
According to the soil structure characteristics of Mangshi, on the basis of increasing organic fertilizer application, N-P-K compound fertilizer should be selected, boron and zinc elements should be supplemented, and silicon fertilizer should be promoted; the amount of various fertilizers should also be adjusted according to altitude; P and K fertilizers should all be applied as base fertilizer, while N fertilizer cannot be applied entirely as base fertilizer or entirely as topdressing. N fertilizer should be 30% as base fertilizer and 70% as topdressing, and topdressing is best applied twice: the first time 5—8 days after rice transplanting (tillering fertilizer), with an application rate of 10 kg urea per mu, and the second topdressing after an interval of 5—7 days, with the amount accounting for 40% of the total topdressing amount; foliar spraying should be carried out during the booting and grain-filling stages of rice.
3. Chemical weed control
6—8 days after transplanting, apply 100 g butachlor per mu mixed with soil and broadcast, or apply 1 kg weed control agent mixed with soil or fertilizer and broadcast.