The role and application method of spraying paclobutrazol on rice

Paclobutrazol is a highly active plant growth retardant and broad-spectrum fungicide. Its internationally used code is pp333, and the code for the product made in China is MET. Its physiological effects on rice are mainly dwarfing, promoting tillering and improving stress resistance. Moreover, after transplanting, the seedlings turn green quickly, tiller early, the number of effective panicles increases, and the seed-setting rate and 1000-grain weight increase. It is a simple, easy and effective measure to increase yield.

Experiments in various places in Liaoning in recent years have found that rice seedlings sprayed with paclobutrazol show the following changes compared with the control:

1. The seedlings become shorter. After spraying paclobutrazol at the rice seedling stage, the seedlings turn green quickly and become shorter. The seedlings are sturdy, the leaves are upright, and the stems become shorter. Generally, the seedlings are 3.4-4.8 cm shorter than the control, the leaves are 3.2-5 cm shorter, and the leaf width is about 0.04 cm. Tillering increases by 0.9-1.8.

2. The root system develops well and stress resistance is enhanced. The root system of seedlings sprayed with paclobutrazol is well developed, with many white roots, thick and strong, and long. The total number is 2.5-3.5 more, and there are 3.8-6.4 more white roots, and the root activity is vigorous. After transplanting, the seedlings turn green 34 days earlier, are more drought-tolerant and cold-resistant, and have less disease.

3. The effective tillering rate increases, the panicle-forming rate is high, and the seed-setting rate is high. In seedlings treated with paclobutrazol, tillering occurs early and the effective tillering rate increases, and the leaves are upright. According to surveys, the number of effective panicles per mu increases by 10,000-27,000, and the panicle-forming rate increases by 2.5%-4.8%.

4. Yield increases. The yield increases by 20-40 kg per mu.

Methods of using paclobutrazol in rice seedling raising:

1. Spraying time. Spray the pesticide after seed soaking or at the 1-leaf-1-heart stage of the seedlings.

2. Dosage standard. According to the results of experiments and applications in various places, generally 100-150 g of 15% paclobutrazol is used per mu, diluted with 50 kg of water, and evenly sprayed on the seedlings.

3. Precautions. Drain the seedling field 1 day before spraying. Liaoning mostly uses dry seedling raising, and there is no water in the seedling-raising period. After spraying, re-water the next day for normal management. If it rains on the day of spraying, spray again, but the dosage can be appropriately reduced. During spraying, the liquid medicine should be stirred frequently, stirring while spraying.

It is strictly forbidden to prepare the concentration and dosage of paclobutrazol solution according to the instructions, as excessive amounts will inhibit plant growth and cause yield reduction.