Research and Analysis of High-Efficiency Lotus Root Cultivation Models: A Case Study of Lotus Fields in Caidian District

Lotus root is one of the pillar agricultural industries of Caidian District, Wuhan City. In 2006, the planting area was 10,000 hectares, the total output was 200,000 t, and the total output value was 320 million yuan, accounting for 18.2% of the district's total agricultural output value. In order to improve the economic benefits of lotus fields, Caidian District promoted several high-efficiency lotus field cultivation models and achieved good results. In 2006, the promoted area of the models in the district reached 7,730 hectares, accounting for 77.3% of the district's lotus root planting area. The main models promoted and applied in recent years are introduced below.

1 Early Lotus Root - One Crop of Late Rice

Lotus root is planted from late March to early April and harvested in mid-July; late rice is sown in mid-to-late June and transplanted in late July. This model was applied relatively early in this district and has a relatively large area. It requires little investment and has stable benefits.

1.1 Technical Points

Strengthen the early-maturing cultivation management of lotus root, promote lotus root expansion, and ensure early yield and benefits. Late rice is managed conventionally.

Key points for lotus field management: ① Select early-to-mid-maturing varieties, such as Elian No. 1, Elian No. 5, and Wuzhi No. 2. ② Plant at a reasonable density, with a conventional seed rate of about 450 kg per 667 sq m. ③ Apply sufficient base fertilizer and topdress early. Apply 100 kg of ammonium bicarbonate, 50 kg of phosphate fertilizer, and 15 kg of potassium sulfate compound fertilizer per 667 sq m, and apply as much organic fertilizer as possible. When standing leaves begin to appear, topdress with 15 kg of urea per 667 sq m. ④ Since the base fertilizer in the lotus field is relatively sufficient, late rice can be given little or no base fertilizer.

1.2 Economic Benefits

Lotus root is harvested in mid-July, with a yield of 900 kg per 667 sq m, a price of 2.6 yuan/kg, and an output value of 2,340 yuan; late rice has a yield of 450 kg per 667 sq m, 1.6 yuan/kg, and an output value of 720 yuan. The total output value of the two crops per 667 sq m is 3,060 yuan. After deducting production costs, the annual profit is 2,300 yuan. In contrast, one crop of middle rice has an average yield of 650 kg per 667 sq m, 1.8 yuan/kg, an output value of 1,170 yuan, and a profit of 800 yuan. Compared with one crop of middle rice, this model increases income by 1,500 yuan per 667 sq m.

2 Early Lotus Root - Seleng Wormwood (Artemisia selengensis)

After the lotus root is harvested, seleng wormwood is planted as a follow-up crop. Lotus root is cultivated with heat-preservation facilities, planted in early March, and harvested in stages from early June to early July; seleng wormwood is planted in early August and harvested successively from late October to April of the following year (with heat preservation cover in winter). This is a new model promoted and applied in recent years, with a promoted area of more than 730 hectares in 2006.

2.1 Technical Points

① Use large tunnels or medium tunnels. Large tunnels use steel-frame tunnels, 6.0 m wide, 2.5 m high, and 50 m long. Medium tunnels use bamboo arches, 3-3.5 m wide, 1.5-1.7 m high, and 20-30 m long. The tunnels run north-south to facilitate ventilation. Because large tunnels require high investment, most areas in Caidian District currently use medium tunnels.

② For lotus root, choose early-maturing and mid-maturing varieties Elian No. 1 and Elian No. 5; plant early at the right time, in early March, 1 month earlier than in the open field; increase planting density, with a seed rate of 450 kg per 667 sq m; apply sufficient base fertilizer and topdress early, applying 75 kg of ternary compound fertilizer per 667 sq m, and topdress with 10 kg of urea when standing leaves appear; harvest and market in a timely manner, usually in 2 harvests.

③ For seleng wormwood, in early July, after the lotus root harvest, drain the field water, dry the field for 20 days, then plow and harrow to prepare the land, and apply 3,000 kg of decomposed organic fertilizer per 667 sq m. Make perimeter ditches and bed ditches well, with a ditch depth of 25 cm and a bed width of 1.2 cm. Cuttings are inserted in early August, with cutting length 8-10 cm, bearing 2 ungerminated plump axillary buds. Immediately after cutting, water thoroughly once and cover with a shade net. Water should be applied frequently to keep the bed surface moist; ditch irrigation is suitable, and topdressing should be combined with irrigation. In late November, cover with film for heat preservation, with the tunnel temperature preferably 18-20 °C, and pay attention to uncovering the film for ventilation and dehumidification. It can be harvested 5 times a year until April of the following year.

2.2 Economic Benefits

The first lotus root harvest is in early June, with a yield of 450 kg per 667 sq m, 8.0 yuan/kg, and an output value of 3,600 yuan; the second harvest is in early July, with a yield of 400 kg per 667 sq m, 3.0 yuan/kg, and an output value of 1,200 yuan. The total output value of lotus root from the 2 harvests is 4,800 yuan per 667 sq m. Seleng wormwood is harvested 5 times, with a yield of 3,000-4,000 kg per 667 sq m and an output value of 4,100 yuan. The total output value of the two crops, lotus root and seleng wormwood, is 8,900 yuan per 667 sq m. After deducting production costs, a profit of 6,570 yuan can be obtained. Compared with "large-tunnel lotus root - one crop of late rice," this model increases income by 2,900 yuan per 667 sq m. This model requires a certain amount of investment and more labor, but has high benefits and can alleviate the contradiction of having more people and less land.

3 Double-Crop Lotus Root (Lotus Root - Lotus Root)

Double-crop lotus root is a new model invented by lotus farmers in Caidian District for planting and harvesting lotus root twice a year, and it obtained a technical patent in 2001. The second-season lotus root in this model has the characteristics of a white, round, and smooth root body, uniform root nodes, and a crisp, sweet, and refreshing taste, and is very popular in the market. If the second season adopts trench harvesting, leaving part of the seed stock in the field and promptly strengthening field management, the lotus root can mature earlier the following year and be harvested and marketed in mid-June, obtaining a relatively high price and benefit. In 2006, the area of double-crop lotus root in this district was 1,200 sq m.

3.1 Technical Points

① Choose the early-maturing variety Elian No. 1, which is 15-20 days earlier than the mid-maturing variety Elian No. 5. The first-season lotus root is harvested in mid-June; take the large lotus roots for market, leave the small lotus roots as seed stock for the second season and transplant them into the field in a timely manner. For the second season, the seed rate is 900 plants per 667 sq m, with 1,200 effective buds, and trench harvesting is carried out in November-December. In the following year, strengthen field management in a timely manner, harvest again in mid-June, and cycle year by year.

② Because the first-season lotus root uses the original seed stock of the previous autumn lotus root, it emerges faster than transplanted stock. If water and fertilizer management are strengthened in a timely manner, it can expand and form lotus root by late May. Before emergence, combine intertillage and weeding, and apply 100 kg of ammonium bicarbonate, 50 kg of phosphate fertilizer, 20 kg of potassium fertilizer, 2 kg of boron fertilizer, 1 kg of zinc fertilizer, and 5 kg of carbendazim per 667 sq m. When there are 1-2 standing leaves, topdress with 20 kg of urea.

For second-season lotus root, sufficient base fertilizer should be applied, with 500 kg of bio-organic fertilizer and 50 kg of compound fertilizer per 667 sq m. When the first standing leaf appears, apply 15 kg of urea per 667 sq m.

③ In autumn, focus on controlling the tobacco cutworm; in winter, keep the water depth in the lotus field above 10 cm to prevent freeze damage.

3.2 Economic Benefits

First-season lotus root has a yield of 750 kg per 667 sq m and an output value of 3,000 yuan; second-season lotus root has a yield of 450 kg per 667 sq m and an output value of 1,800 yuan; the total output value of the two seasons of lotus root is 4,800 yuan per 667 sq m. After deducting costs, the average profit is 3,700 yuan per 667 sq m. This model requires little investment and has relatively high benefits.

4 Early Lotus Root - Chinese Water Chestnut

The "early lotus root - Chinese water chestnut" planting model has a long history in Caidian District. In 2006, the promoted area of this model was 1,000 hectares.

4.1 Technical Points

① Crop rotation: lotus root is planted in early April and harvested in mid-July; Chinese water chestnut is raised as seedlings in early April, planted in mid-to-late July, and harvested from December to March of the following year.

② Lotus root cultivation can refer to "early lotus root - rice."

③ For sprouting Chinese water chestnut, varieties such as Xiaogan water chestnut and Hangzhou fruit water chestnut can be selected. In early April, choose vegetable plots in front of and behind houses to prepare the land for sprouting. Prepare enough 200-250 seed Chinese water chestnut corms per 667 sq m of field (3.5-3.5 kg).

④ Temporary transplanting: when the Chinese water chestnut sprouts grow to about 6 cm, transfer them to the temporary transplanting field. In the temporary seedling field, make beds at 1.5 m, drain off the surface water, and plant the sprouted seed water chestnuts at a density of 13 cm x 17 cm.

⑤ Seedling division: in mid-to-late May, carry out seedling division and temporary planting. Apply 50 kg of compound fertilizer per 667 sq m as base fertilizer in the seedling division bed. After planting, manage with shallow water and topdress with urea 2 times, 10 kg/667 sq m each time.

⑥ Field planting: transplant to the field for planting in mid-to-late July. Before planting, combine with land preparation and apply 500 kg of bio-organic fertilizer and 100 kg of compound fertilizer per 667 sq m. The planting hole spacing is 0.5 m and the row spacing is 1 m, with 3-5 seedlings per hole.

① Field water and fertilizer management: early stage should be shallow water to promote tillering, with a depth of 3-5 cm being suitable. Later, gradually deepen the water layer to 5-10 cm to control tillering and promote Chinese water chestnut expansion. Topdress 3 times throughout the growth period: the first time 10 days after transplanting, apply 10 kg of urea per 667 sq m; the second time 20 days after the first topdressing, apply 10 kg of urea per 667 sq m; the third time before corm formation, apply 15 kg of compound fertilizer per 667 sq m to promote Chinese water chestnut expansion.

4.2 Economic Benefits

The previous crop lotus root has a yield of 800 kg per 667 sq m, an average price of 2.4 yuan/kg, and an output value of 1,920 yuan; the following crop Chinese water chestnut has a yield of 2,300 kg per 667 sq m, an average price of 1.2 yuan/kg, and an output value of 2,760 yuan. The output value of the two crops is 4,680 yuan per 667 sq m, and the profit is 3,700 yuan. This model has relatively high benefits, but requires more labor and a larger workforce.

5 Loach Polyculture in Lotus Fields

Loach polyculture in lotus fields is a form of ecological farming. The ecological environment of lotus fields is very suitable for loach survival, and loach burrowing into the mud to inhabit helps loosen the soil and decompose fertilizer, and can also prey on pests in the lotus field. Caidian District demonstrated this model in 2001 and promoted it year by year, with a cumulative promoted area of more than 330 hectares.

5.1 Main Techniques

① Field facilities: dig a perimeter ditch around the field ridge, 1.5 m wide and 0.5 m deep, raise the field ridge to 0.6 m, and install anti-escape facilities at the water inlet and outlet.

② Field selection: the field should have convenient irrigation and drainage, strong water retention, rich soil organic matter content, and a deep mud layer. Generally, the mud layer should be about 25 cm deep, and the area is preferably 334-667 sq m for easy management.

③ Lotus root management: plant in early April. Base fertilizer should be mainly base fertilizer, with topdressing as a supplement; base fertilizer should be mainly organic fertilizer, with inorganic fertilizer as a supplement. Apply 1,000 kg of bio-organic fertilizer and 50 kg of compound fertilizer per 667 sq m as base fertilizer, and 15 kg of urea as topdressing. The topdressing should be applied 10 days before stocking loach.

④ Loach stocking: when lotus root grows to 3-4 leaves, loach can be stocked, generally in mid-May. During stocking, maintain a water layer of 10-15 cm. Stock 1.0-15 kg of loach fry about 5 cm long per 100 sq m. Loach feed mainly includes mixed feed such as wheat bran, bean dregs, and @#@254@#@, fed once a day, with the feeding amount at 3%-5% of the total body weight of the loach, and the type and amount of feed should be adjusted at any time according to different temperatures.

⑤ Harvest: lotus root is harvested from November to March of the following year. Loach can be delayed until March of the following year for capture.

5.2 Economic Benefits

Lotus root yield is 1,500 kg per 667 sq m, 1.2 yuan/kg, and the output value is 1,800 yuan; loach yield is 180 kg per 667 sq m, 26 yuan/kg, and the output value is 4,680 yuan. The total output value of lotus root and loach is 6,480 yuan per 667 sq m. After deducting costs, the profit is 4,100 yuan.