Key Points of High-Ridge Double-Row Potato Cultivation Technology
High-ridge double-row potato cultivation refers to a planting method using wide and narrow rows, where soil from the wide rows is hilled onto the narrow rows, forming raised beds that stand more than 25cm above the ground. Trials have confirmed that potatoes grown on ridges and beds have the advantages of earlier emergence, a higher proportion of large and medium tubers, and higher yields; ridge-bed cultivation increases yield by 19.1% compared with flat-bed cultivation. The specific cultivation techniques are as follows:
1. Fine seedbed preparation
Potato is a shallow-rooted crop. After the tubers are planted and before emergence, the better the root system develops in the soil, the stronger the plant growth after the seedlings emerge, and the higher the yield. In particular, the root systems of early-maturing varieties are generally less developed than those of late-maturing varieties and are distributed more shallowly. Therefore, the quality of seedbed preparation directly affects tuber growth. Choose a plot with deep topsoil, loose soil, medium or higher fertility, convenient drainage and irrigation, a previous crop that is not a Solanaceae crop, and ample sunlight. Deep plow 25-30cm, plow twice and harrow twice, and manually fill and press to break up clods, so that the soil is loose and the clods are fine and crumbly.
2. Seed selection and seed potato treatment
Select virus-free, healthy seed potatoes of high-yielding, high-quality new varieties such as Hui-2, Hezuo 88, and Hezuo 23.
After the seed potatoes are harvested the previous year, select healthy seed potatoes and spread them flat in 2-3 layers on a wooden board, and cultivate short, sturdy sprouts under scattered light. After sowing, they emerge quickly and the seedlings are sturdy.
3. Timely sowing and rational close planting
The sowing date should be determined by considering the following aspects: First, arrange the tuber formation period in a season suitable for tuber enlargement, that is, an average temperature not exceeding 23°C, daily sunshine hours not exceeding 14 hours, and moderate rainfall. Second, consider the time of the late frost. Generally, sowing should be done about 20-30 days before the late frost, when the temperature steadily passes 5-7°C, so as to avoid damage to the seedlings from late frost disease. Third, determine it according to varietal characteristics; early-maturing varieties should be sown appropriately earlier. Medium- and late-maturing varieties (the planted varieties Hui-2 and Hezuo 88 are both medium-late maturing varieties) have strong stress resistance and can be sown appropriately later, so that the tuber-setting period shifts accordingly to the low-temperature, short-day conditions suitable for tuber setting. Therefore, the sowing date should be determined by arranging the tuber-setting period in the most suitable season according to the time required for each growth stage of the plant. Based on the characteristics of winter fallow, drought, and the rainy season generally arriving in June, and late frost extending to April, sowing during the Jingzhe-Chunfen solar terms is most suitable.
Planting density should be rationally close according to varietal characteristics. The leaf area index for high-yielding potato is 3.5-3.5, and generally reaching 4 can achieve high yield. Varieties that mature earlier or have shorter plants and fewer branches should be appropriately densely planted. For example, Atlantic and Zhongdian Hongyan mature earlier and have fewer branches, so they should be appropriately densely planted, with 4000-4500 hills per mu being suitable; while medium-late maturing varieties such as Hui-2, Hezuo 88, and Hezuo 23 have more branches and a larger leaf area per plant, so 3500-4000 hills per mu is more suitable. Moreover, where altitude is low and water, fertilizer, light, and heat conditions are good, planting density should be sparse; as altitude rises and water, fertilizer, light, and heat conditions become poorer, planting can be densified.
4. High-ridge double-row cultivation
Use wide and narrow row planting, with wide rows 80cm and narrow rows 40cm. After fine seedbed preparation and leveling, open furrows at a row spacing of 40cm, with a furrow depth of 10-15cm, planting 2 rows and leaving 1 row empty. Then, at a plant spacing of 28-33cm, place the prepared seed potatoes into the furrows, apply seed fertilizer above the seed potatoes, and then break soil to cover the seed. When breaking soil, do not break the ridge between the 2 rows of potatoes, only break the ridges on both sides of the 2 rows of potatoes. Sowing depth should be determined according to soil moisture. Generally speaking, under loose soil texture and drought conditions, sowing can be deeper, with a depth of 12-15cm being suitable; if sown too shallow, it is easily affected by high temperature and drought, which is not conducive to plant growth and tuber formation and enlargement, affecting yield and quality. Under sticky, heavy soil and waterlogged lowland conditions, shallow sowing can be appropriate, with a depth of 8-10cm being suitable; if sown too deep, it easily causes seed rot or prolongs the emergence period, affecting full stand and strong seedlings. In addition, under drought conditions, placing seed potatoes with the eyes facing upward at sowing tends to promote earlier emergence.
5. Apply sufficient base fertilizer and apply topdressing early
Potato is a high-yielding crop and requires a relatively large amount of fertilizer. Among the three major elements, it requires the most potassium, followed by nitrogen, and less phosphorus. Fertilization should be mainly basal, with topdressing as a supplement; apply heavy basal fertilizer and early topdressing; apply more farmyard manure and appropriate nitrogen fertilizer. Under higher soil fertility levels, in order to avoid excessive vegetative growth, 2/3 of the total nitrogen fertilizer can be mixed into farmyard manure as basal fertilizer and applied together, leaving 1/3 for topdressing. Phosphorus and potassium fertilizers are generally applied as basal fertilizer. Topdressing should be early; especially for early-maturing varieties, early topdressing can promote early tuber setting, early harvest, and early marketing; late topdressing easily causes excessive vegetative growth, or delayed tuber enlargement and late maturity. Topdressing should be completed before the plants close the rows. Therefore, the basal fertilizer requirement is 1500-2000kg of decomposed farmyard manure per mu and 80-100kg of compound fertilizer with N:P:K=10:10:10, with the two fertilizers applied together once as hill-covering fertilizer. After full emergence, combine checking seedlings, replanting, and intertillage weeding for topdressing, applying 10kg of urea or 25kg of ammonium bicarbonate per mu to promote seedlings.
6. Whole-tuber sowing
Whole-tuber sowing can avoid the transmission of viral and bacterial diseases through the cutting knife, and avoid cut pieces rotting and causing missing plants. In addition, after sprouting, whole-tuber sowing emerges uniformly, the tuber-setting period among plants is relatively consistent, the grown tubers are uniform, and the marketable tuber rate is high. At the same time, compared with cut-piece sowing, whole-tuber sowing has stronger stress resistance, tolerates drought, has fewer diseases, has greater yield-increasing potential, and is conducive to high yield. According to trials, whole-tuber sowing can increase yield by 30-50% compared with cut-piece sowing. The tubers used for whole-tuber sowing should not be too large; otherwise, the seed quantity is large and the cost is high. Generally, seed potatoes of about 50g are used for sowing. However, the tubers should not be too small either; too-small tubers have weak seed quality and are prone to degeneration.
7. Strengthen intertillage management to ensure a bumper harvest
1. Check seedlings and replant to ensure a full stand. When seedlings grow to 5-10cm, if missing hills are found, thin out seedlings from nearby hills with more seedlings and transplant them into the missing hills.
2. Hill up soil in time and hill deeply. To avoid stolons extending above the ground (becoming exposed) and turning into ordinary branches in the early growth stage, and to avoid tubers becoming exposed and turning green after tuber setting, which can poison humans and livestock if eaten, soil should be hilled up in time during the early growth stage of potato. At sowing, cover with shallow soil, and then hill up soil in combination with intertillage weeding. Hilling up 2-3 times is required. Before the plants close the rows, the final hilling should be combined with clearing furrows and deep hilling, so that the ridge height is at least more than 25cm. Deep hilling stabilizes soil temperature, can reduce the production of deformed tubers, and can also prevent late blight spores from invading the interior of tubers in large numbers through lenticels, causing diseased or rotting tubers.
3. Control diseases and pests to ensure a bumper harvest. The main potato diseases include late blight, bacterial wilt, ring rot, and scab; the main insect pest is the cutworm. Late blight is a widespread and relatively serious disease. When it becomes epidemic, it can cause devastating disasters in non-resistant varieties; when late blight becomes epidemic in poorly resistant varieties, field yield losses can reach 30-50%, and after the pathogen invades tubers, it can also cause losses during storage, ranging from 5-10% in mild cases to more than 30% in severe cases, even causing cellar rot. High humidity and high temperature (24-30°C) are favorable conditions for late blight spore invasion. If sunny weather after rain occurs for 2-6 days in the middle and late growth stages, late blight is likely to occur and spread widely. First, light brown lesions appear at the tips or edges of leaves, and the outer part of the lesion has yellow-green symptoms. On mornings with high humidity and on rainy days, the lesions expand rapidly, and the leaf surface appears water-soaked and wilted, with white mold appearing outside the dead spots; the white mold is clearer on the underside of the leaves. Prevention should be the main approach to late blight control, and choosing resistant varieties is especially important. The varieties currently promoted in our county, Hui-2 and Hezuo 88, are relatively resistant varieties. Once central diseased plants of late blight are found in the field in the middle and late growth stages, spray immediately for control. Every 7-10 days, choose pesticides such as metalaxyl mancozeb, Shuwenxiao, Ridomil, and Jinglei Ridomil, and spray 1-3 times consecutively for good control results.
Bacterial wilt is the most difficult disease to control. When a plant becomes diseased, one main stem or one branch suddenly wilts and becomes green-wilted, while other stems and leaves temporarily continue to grow normally, but soon they also wither and die. At present, there are no immune varieties to bacterial wilt, and it can also be transmitted through soil, so comprehensive control measures are needed to be effective. Using whole-tuber sowing, practicing crop rotation, eliminating parasitic weeds in the field, eliminating diseased plants, prohibiting diseased and rotting tubers from being mixed into fertilizer, and trying not to injure the roots when hoeing weeds are important measures to prevent bacterial wilt by reducing root transmission of the disease.
If cutworm damage is found, poison bait with trichlorfon can be used to trap and kill them, or a 5000-fold dilution of 20% emulsifiable concentrate fenvalerate or 2.5% emulsifiable concentrate cyhalothrin can be sprayed 1-2 times.
4. Control excessive vegetative growth. Hezuo 88 and Hezuo 23 are tall plants. In years with abundant rainfall, they will produce a certain degree of excessive vegetative growth. Therefore, when canopy coverage reaches 95%, choose a sunny day to spray the leaf surface with a paclobutrazol solution at a concentration of 2 parts per ten thousand to prevent lodging and ensure high and stable yield.