Detailed Explanation of Off-Season Broccoli Cultivation Techniques

Broccoli is currently a major variety of vegetables exported from China. In order to take advantage of the unique climate conditions in mountainous areas, adjust the vegetable industry structure, and develop export-oriented vegetable production for foreign exchange earnings, in 2002 Longquan City grew broccoli off-season on a contract basis in the high mountain areas of Longnan, Pingnan and other townships at an altitude of 750-1200 m, with an area of 2250 mu. The main cultivated varieties included Lufeng, Futulu, Ludai Zi, Shanshui, etc. The yield per mu reached 750-1000 kg, with an output value of 2000-3000 yuan and a net output value of 1800-2800 yuan. The cultivation techniques are introduced as follows:

1. Raising Strong Seedlings

1.1 Selection of Sowing Period

For off-season cultivation in high mountains, the harvest and marketing period of broccoli is required to be from late August to November, so the sowing period should be selected from mid-June to mid-July. For high altitudes and early-maturing varieties, the sowing period should be appropriately advanced; for low altitudes and mid-maturing varieties, the sowing period should be correspondingly delayed. According to the requirements of the contract enterprises, sowing can be carried out in stages and batches to achieve a balanced market supply.

1.2 Sowing and Seedling Raising

Rainproof seedling raising in greenhouses is adopted. The seeds are disinfected by soaking in warm water, mixed with chemicals and broadcast (Cai Feng Ning, chlorothalonil, etc. can be used). Every 15 g of seeds requires 10 sq m of seedbed; before sowing, water sufficiently to soak the bed, after sowing cover with 1 cm of fine soil, spread film flat to retain moisture, and set up shade nets to lower the temperature. 2-3 days after sowing, when 70% of the seeds have emerged, remove the film in the evening, and cover with shade nets from 10:00 to 16:00 on sunny days to lower the temperature. At the 2-leaf stage (8-10 days after emergence), transplant into 10×10 cm nutritional pots, and at the 6-leaf stage (about 30 days after seedling emergence), transplant to the field.

2. Land Preparation

2.1 Land Selection

Off-season broccoli can be planted in high mountain areas at an altitude of 750-1200 m. Deep soil layers, loose and fertile soil, and convenient drainage and irrigation are required. For plots at lower altitudes, it is better to choose sheltered plots facing east with a slight westward tilt, having a microclimate with morning sun and afternoon shade. High mountains have many terraced fields; make a pond at certain intervals, and use the natural drop to irrigate with hoses, reducing labor intensity.

2.2 Land Preparation and Bed Making, Applying Sufficient Base Fertilizer

After plowing the land, make beds 1.3 m wide (including furrows), open a furrow in the middle of the bed and apply base fertilizer. Generally, apply more than 1000 kg of farmyard manure per 667 sq m. Weeds from cleaning field ridges and field edges can be pressed in together as base fertilizer, combined with 25 kg of superphosphate, 10 kg of potassium chloride, 10 kg of urea, 2 kg of boric acid, or 30 kg of compound fertilizer and 2 kg of boric acid. Then spread 50 kg of quicklime on the bed surface and mix it evenly with the topsoil, and level the bed surface.

3. Field Planting and Management

3.1 Planting Density

Plant 2500-3000 plants per mu; early-maturing varieties should be denser, mid-maturing varieties sparser. Plant in diagonal arrangement, and after planting water sufficiently to settle the roots.

3.2 Cultivation, Weeding and Grass Mulching

From 7 days after planting until the rows close, carry out at least 2 cultivations and weedings, and cut grass for mulching, so as to lower surface soil temperature, maintain moisture, and reduce weed growth.

3.3 Fertilizer and Water Management

The fertilization principles for off-season broccoli in high mountains are: apply sufficient base fertilizer, apply topdressing early, apply heavy bud fertilizer, do not apply one-sided nitrogen fertilizer, and increase phosphorus and potassium fertilizer. Generally, 7 days after planting, apply a topdressing of dilute human excrement and urine once, or apply 3-5 kg of potassium sulfate compound fertilizer per 667 sq m; afterward, combined with cultivation and weeding, apply topdressing according to seedling condition; at the bud stage (when the curd is as big as a thumb), apply 10-15 kg of urea and 5-10 kg of potassium chloride along with watering. Combined with pest and disease control, spray Aiduoshou or Tianda 2116 disease-resistant yield-increasing agent or brassinolide or potassium dihydrogen phosphate, etc. every 7-10 days to increase yield and enhance resistance.

3.4 Pest and Disease Control

3.4.1 Pests The main pests include aphids, diamondback moth, cabbage caterpillar, armyworm, etc. Aphids can be controlled by spraying 10% Yibianjing 2000-fold solution or 1% insecticidal element 3000-fold solution, etc.; diamondback moth, cabbage caterpillar, and armyworm can be controlled by spraying 5% Yitaibao 2000-fold solution or 5% Rui Jin Te 3000-fold solution or 5% Ewanqing 1500-fold solution, etc.

3.4.2 Diseases The main diseases include black rot, soft rot, downy mildew, etc. For black rot and soft rot, in addition to seed disinfection by mixing with chemicals, during the disease occurrence period, 72% agricultural streptomycin 3000-fold solution or new plant mycin 100-200 ppm or 77% Keshade 500-fold solution, etc. can be selected for control; for downy mildew, 75% chlorothalonil 500-fold solution or 64% Shadufan 500-fold solution or 72.2% Pulike 600-800-fold solution, etc. can be sprayed for control.

3.5 Timely Harvest

Broccoli planted off-season in high mountains should be harvested when the curd has grown to full size and the edge has not yet cracked. Generally, harvest once every 1-2 days. On sunny days, harvest before 10:00 a.m. or after 4:00 p.m.; on cloudy days, it can be harvested all day. Grade and package promptly, and keep refrigerated during transport.