Key Technical Points for Autumn Potato Cultivation with Rice Straw Mulching (Part 2)

4. Timely early sowing. Potatoes prefer a cool climate, and the sowing period should be when the daily average temperature steadily drops below 25°C. In plain and hilly areas below 500 m in altitude, the suitable sowing period is from late August to early September; in low mountainous areas at 500-800 m in altitude, the suitable sowing period is in late August.

5. Reasonable close planting and sufficient base fertilizer. For fields with rice stubble potatoes intercropped with rapeseed, both potatoes and rapeseed are planted in wide-narrow row patterns. For potatoes, the wide row is 0.6 m, the narrow row is 0.2 m, the hill spacing is 0.22 m, and about 7,000 hills of potatoes are sown per mu. In mid-October, 2 rows of rapeseed are transplanted into no-till holes opened in the middle of each wide row of potatoes. Density and fertilizer trials on different varieties show that for sole cropping of rice stubble potatoes, the sowing density per mu should reach 10,000-11,000 hills, with a row spacing of 0.33 m and a hill spacing of 0.16-0.18 m. When sowing potatoes, there is no need to dig holes; simply press the seed potatoes by hand onto the surface soil of the bed at the specified hill and row spacing, so that the seed potatoes are in close contact with the soil. The growth period of autumn potatoes is short, and topdressing is difficult after rice straw mulching, so a one-time application of base fertilizer is generally adopted. The general requirement is to apply 1,100-1,500 kg of organic fertilizer, 10-15 kg of urea, 25-30 kg of superphosphate, and 150 kg of plant ash (or 15 kg of potassium chloride) per mu, or 1,100-1,500 kg of organic fertilizer plus 30 kg of 35% compound fertilizer per mu. At the full flowering stage of potatoes, 50 kg of 0.35% potassium dihydrogen phosphate solution can be sprayed twice, with an interval of 7-10 days each time.

6. Rice straw mulching. Research on straw mulching trials for sole cropping of rice stubble potatoes shows that corn straw and sorghum straw have a high unit weight and do not cover completely, affecting the commercial characteristics and nutritional value of potatoes. Rice straw, however, is economical, readily available, low in cost, and easy to promote. Therefore? The best mulching material for quiet rice cultivation is rice straw, and the best mulch is continuous cropping with dry rice? 000-1,300 kg. The specific method is: after sowing and fertilizing potatoes, immediately cover the entire bed surface evenly with rice straw perpendicular to the bed, tip to tip, and make the straw mulch thickness reach 10-15 cm.

7. Pest and disease control. The most serious pests damaging potatoes are aphids and white grubs. In the early stage of aphid occurrence, spray with 2.5% deltamethrin diluted 2,500 times with water; to prevent white grubs, dissolve 500 g of 90% crystal trichlorfon in water and spray it onto 35 kg of fine soil, then broadcast it onto the bed surface at sowing. The main diseases damaging potatoes are late blight, bacterial wilt, ring rot, and viral diseases. Generally, viral diseases, ring rot, and bacterial wilt are prevented by selecting disease-resistant varieties, producing virus-free seed potatoes, implementing reasonable crop rotation, and avoiding continuous cropping with solanaceous vegetables. In the early stage of late blight, that is, when potatoes enter the initial flowering stage and central diseased plants appear in the field, immediately spray 25% metalaxyl WP at 500 times dilution or 100 g of Shu Wen Xiao for control, spraying once every 7-10 days for a total of 2-3 sprays.