Detailed Explanation of Key Cultivation Techniques for Upland Rice in Spring in Both Northern and Southern Regions

I. Early-Stage Management Techniques for Early Rice Production in the South China Rice Region

At present, it is necessary to focus on drought resistance and protecting spring plowing, and to seize the opportunity for transplanting and planting. In the southern region, early rice should be transplanted around Qingming; in the central region, around Guyu; and in the northern region, before "May Day." The following technical measures should be mainly adopted:

1. Apply sufficient basal fertilizer and transplant sufficient seedlings, and apply tillering fertilizer early and heavily. On the basis of applying good seedling-departure fertilizer to the seedling field, apply 30 kg of ordinary superphosphate, 7.5 kg of potassium chloride, and 25 kg of ammonium bicarbonate per mu as basal fertilizer. Where conditions permit, apply 1000-1500 kg of high-quality farmyard manure per mu. Throw or transplant 21,000-25,000 hills per mu; for hybrid rice, two seedlings per hill (two grains), and for conventional rice, 4-6 seedlings per hill. 5-7 days after throwing or transplanting, apply 5-6 kg of urea per mu as tillering-promoting fertilizer; 12-15 days after throwing or transplanting, apply about 7.5 kg of urea and 7.5-10 kg of potassium chloride per mu, or 12.5-15 kg of compound fertilizer per mu as strong-tillering fertilizer.

2. Transplant in shallow water and return to green in shallow water. During transplanting, maintain a thin water layer of 1.5-2 cm in the field, and after transplanting, irrigate the field with 3-4 cm of water. For fields with thrown seedlings, no water layer should remain during throwing; after the seedlings stand, re-irrigate with a shallow water layer of 1.5-2 cm. After returning to green and entering the tillering stage, the field water layer should be kept below 2 cm. 15-20 days after transplanting (or throwing), when the number of tillering seedlings in the field reaches 200,000 per mu, begin draining and sun-drying the field.

3. Control diseases and insect pests. Actively carry out integrated control of rice blast (leaf blast), rice sheath blight, striped stem borer, rice leaf roller, and other diseases and insect pests.

II. Management Techniques for Double-Cropping Early Rice at the Seedling Stage in the Middle Reaches of the Yangtze River

In early to mid-March, this region is mainly affected by rainy weather, and the sowing time of early rice has been somewhat delayed. However, because temperatures remained relatively high after sowing, the seedlings emerged quickly and grew robustly. If clear and favorable weather continues later, early rice will be transplanted normally in mid- to late April.

The following technical measures should be adopted during the seedling field period of early rice:

1. Pay attention to irrigation in the seedling field. After the weather turns from low temperature to clear, the seedling field should be sprinkled or irrigated in a timely manner. Especially for dry-raised seedlings, more sprinkling is needed to prevent bacterial wilt and seedling death.

2. Ventilate and harden seedlings in a timely manner. When the temperature steadily rises again, promptly uncover the film at both ends of the seedling bed for ventilation and seedling hardening. Especially when high-temperature weather occurs, uncover the film even earlier and water or irrigate in a timely manner to protect the seedlings.

3. Apply seedling fertilizer scientifically. After uncovering the film, apply uniform seedling fertilizer before and after irrigation or watering, generally applying 3-4 kg of urea per mu of seedling field; apply starting fertilizer 3-5 days before transplanting, generally applying 4-5 kg of urea per mu of seedling field.

III. Seedling-Raising Management Techniques for Single-Season Rice in the Southwest Rice Region

In this region, the current temperature is suitable, water sources are abundant, and meteorological conditions are better than in ordinary years. The seed market @#@125@#@ is sufficient, which is favorable for rice seedling management. However, because this year has a leap seventh lunar month, some farmers delayed sowing by 2-3 days compared with ordinary years; the quality of seeds used for production this year is not as good as in ordinary years, and in some places emergence is uneven, with seedling emergence rate and seedling survival rate declining somewhat; seed soaking with chemicals for dry-raised seedlings has not been fully implemented, and infection by "bakanae disease" in seedbeds has become more serious; in addition, some farmers have relaxed management of seedbeds, reducing seedling quality.

The following technical measures should be adopted at present:

1. Scientifically arrange the sowing period and transplanting period. Winter fallow fields and green manure fields should be sown on time, and favorable weather should be seized for timely transplanting. If possible, vigorously promote the enhanced cultivation technique for super-high-yield rice. In wheat (rapeseed)-rice double-cropping areas, the seedling age of conventional wet-raised seedlings is shorter than that of dry-raised seedlings. The seedling-raising period for mechanical transplanting generally does not exceed 25 days, and for tray-raised thrown seedlings it does not exceed 40 days. The sowing period should be reasonably arranged according to these standards. In areas that traditionally wait for rain to transplant rice, according to the technical requirements for cultivating "long-age, multi-tillering strong seedlings in dry land," effective technical approaches such as reducing sowing rate and spraying paclobutrazol should be adopted to increase the flexibility of seedling age.

2. Carefully carry out pre-sowing seed treatment. This mainly includes technical steps such as sun-drying seeds, seed selection, chemical seed soaking, and sprouting, so as to improve seed germination vigor and uniformity, prevent diseases during the seedbed stage, and ensure sufficient sowing rate.

3. Timely check the seed sprouting and germination rate and the seedling emergence rate in the seedbed. In areas about to raise seedlings, the sowing rate should be determined according to the seed germination rate. If the germination rate is below 80%, the sowing rate may be increased. In areas where seedlings have already been raised, the number of established seedlings should be evaluated. If the number of seedlings per mu of main field is about 80% of the planned number, seedbed management may be strengthened to cultivate multi-tillering strong seedlings and use tillers to replace seedlings; if it is below 80% of the plan, reseeding should be carried out in a timely manner.

4. Be alert to high-temperature seedling scorching and low-temperature cold damage. The focus is to strengthen film management and regulate water and fertilizer. For dry-raised seedling beds encountering high temperatures during emergence, cover with rice straw and other coverings to avoid direct sunlight on the film causing seedling scorching. If water is lacking, appropriately replenish water in the evening.

5. Actively prevent and control diseases and insect pests. According to disease and insect pest forecasts, control thrips, stem borers, and rice blast.

IV. Seedling-Raising Management Techniques for Single-Season Rice in the Northeast Rice Region

In recent years, single-season rice seedling raising in the Northeast Rice Region has been affected by unfavorable low-temperature and humid climates. In March this year, the temperature was on par with normal years and higher in some areas, but precipitation was 1 times more than in normal years; it is expected that in early April, temperatures will be lower than in ordinary years, precipitation will be higher, and there will be more windy days.

The following technical measures should be adopted at present for rice seedling raising:

1. Persist in raising seedlings in garden fields. To ensure the temperature needed for seed germination and rooting, areas with conditions must persist in raising seedlings in vegetable fields or courtyards, and as far as possible not raise seedlings in the main field. If seedlings can only be raised in the main field, be sure to choose a field with high, dry terrain, high soil organic matter content, and good permeability, preferably build a raised platform more than 30 cm high, and gradually improve it so that it becomes a permanent seedling field.

2. Carry out seed treatment well. Under early-spring low-temperature conditions, seeds that have been sprouted root quickly after sowing, tiller early, and emerge uniformly. Therefore, seed treatment procedures such as sun-drying seeds, saltwater selection, disinfection, sprouting, and drying sprouts must be strictly followed.

3. Prepare high-quality nutrient soil. The nutrient soil ratio is: 60%-70% foreign soil with organic matter content above 3% and 30%-40% fully decomposed, crushed, and sieved high-quality farmyard manure, while adjusting the pH value of the nutrient soil to 4.5-5.0. For every 100 kg of nutrient soil, add 150-200 g of ammonium sulfate, 300 g of calcium superphosphate, and 100 g of potassium sulfate. If a strong-seedling agent is used, omit the steps of acid adjustment and fertilizer addition. However, note that nitrogen fertilizer should be supplemented between the 3.5-leaf and 4.0-leaf stages, or seedling-departure fertilizer should be applied before transplanting at 40-50 g per square meter.

4. Sow sparsely to grow strong seedlings. According to the different needs of ordinary dry seedling raising, isolation-layer seedling raising, pot-tray seedling raising, and soft-tray seedling raising, control the sowing rate at 150-300 g per square meter.

5. Control temperature and harden seedlings. In the Northeast region, high-temperature periods often occur in late April and early May. To prevent excessive seedling growth, ventilate and harden seedlings at the 1.5-leaf to 2.0-leaf stage, with bed temperature controlled at 25-30°C; at the 2.5-leaf to 3.0-leaf stage, control bed temperature at 20-25°C.

6. Prevent and control diseases and insect pests well. Pay close attention to the occurrence of bacterial wilt and damping-off at the seedling stage, and carry out timely control.