Field Management Techniques for Rice During the Jointing and Panicle Elongation Stage

Rice jointing begins around the peak tillering stage and internode elongation does not stop until several days after heading; in production, this period is called the jointing and panicle elongation stage. The field management goals during the jointing and panicle elongation stage are: on the basis of preserving tillers and increasing panicles, promote strong stems and large panicles, and prevent excessive vegetative growth and lodging.

The main technical measures for field management are:

1. Scientific irrigation

Rice requires the most water during the jointing and panicle elongation stage, and it is especially sensitive to water during the meiosis stage. Therefore, the water requirements of rice should be met. However, when rice enters the jointing and panicle elongation stage, temperatures are generally relatively high, organic matter decomposition accelerates, microbial activity is vigorous, and oxygen consumption is at its greatest, causing accumulation of toxic substances and root oxygen deficiency, which is unfavorable for root growth, so prolonged deep-water irrigation is not appropriate. For this reason, the irrigation method for rice during the jointing and panicle elongation stage should be: in the early period, that is, at the late tillering stage or early jointing stage, drain the water appropriately for field drying to control the occurrence of excessive ineffective tillers and help control disease and insect damage. In the later period, maintain a water layer to meet the water requirements during the meiosis and pollen content filling period within 5-15 days before heading. During the remaining periods, intermittent moist irrigation should be the main method, that is, adopt the irrigation method of “old water not dry, new water not entering” to promote steady growth of the rice plants.

2. Scientific fertilization

Fertilization during the jointing and panicle elongation stage of rice can be divided into flower-promoting fertilizer and flower-preserving fertilizer. Flower-promoting fertilizer is applied about 30 days before heading, and flower-preserving fertilizer is applied about 15 days before heading. Topdressing flower-promoting fertilizer and flower-preserving fertilizer should depend on the seedling condition. If in the early stage the rice grows poorly, the number of seedlings is insufficient, and the leaf color turns yellow, 3-5 kg of urea per mu can be applied as flower-promoting fertilizer to strive for more effective panicles and increase the number of filled grains per panicle; otherwise, flower-promoting fertilizer should not be topdressed, to avoid causing late-season delayed maturity and lodging. As for flower-preserving fertilizer, as long as the field has normal growth vigor and appearance, it should be topdressed. Generally, 8-10 kg of potassium sulfate and 2-3 kg of urea per mu are applied to meet the nutrient needs of young panicle growth in rice. For high-fertility fields, such as fields where the previous crop was garlic, applying nitrogen fertilizer as flower-promoting and flower-preserving fertilizer is not recommended; instead, 5-8 kg of potassium sulfate should be topdressed at the rice jointing stage to ensure that the leaf color can naturally fade at the heading stage, preventing late-season lodging and delayed maturity.

3. Timely control of diseases, insects, weeds, and rodents

1) Disease and insect control. The main diseases during the rice jointing and panicle elongation stage are rice blast, bacterial leaf blight, stripe virus disease, and rice false smut; the corresponding control agents are sulfur triazole, Jun Du Qing, Jun Ke Du Ke, and Jinggangmycin, etc.; the main insect pests include rice stem borers and rice planthoppers, etc., and the corresponding control agents include Shachongshuang and Lesiben emulsifiable concentrate, etc. Disease and insect control should be based on forecasting and prediction, and at the same time one should go deep into the field to inspect carefully. If disease or insect conditions are found, one should “use the right medicine for the symptom” and carry out control early to avoid causing damage.

2) Weed control

The main weeds during the jointing and panicle elongation stage include various weeds such as barnyardgrass, and manual pulling should be adopted to thoroughly eliminate weed damage.

3) Rodent control

If field rats are found causing damage during the jointing and panicle elongation stage, “poison bait” prepared from different types of rodenticide should be placed promptly for control, to keep rodent damage to a minimum.