Analysis of the Benefits of Rice-Water Bamboo Crop Rotation and Water Bamboo Cultivation Techniques
Chongxian Town, Yuhang District, Hangzhou City, is located in a plain water-network area and was originally mainly engaged in rice cultivation, along with some aquatic crops such as water bamboo, arrowhead, and lotus root. During agricultural development and industrial restructuring, Chongxian Town utilized local water and soil resources to vigorously expand the rice-water bamboo rotation area, and treated water bamboo production as a high-efficiency agricultural undertaking within the vegetable basket project. The district, town, and village invested 2 million yuan to establish the Chongxian Village water bamboo demonstration park. In 2005, the Hangzhou Municipal Agricultural Comprehensive Development Office designated it as a national agricultural comprehensive development high-tech demonstration project (aquatic vegetable demonstration zone), and in 2006 it was also designated as a pollution-free water bamboo base in Zhejiang Province. The town government also invested 1 million yuan to establish a water bamboo trading market and invested more than 1.5 million yuan to build a cold storage facility for water bamboo, providing favorable conditions for stabilizing grain production, developing water bamboo, and increasing efficiency and income.
1. Multiple Cropping Patterns and Benefit Analysis
The rice-water bamboo rotation cultivation area in Chongxian Town has reached more than 6,500 mu (1 mu = 667 sq m, the same below), mainly using two patterns: "early rice-water bamboo" and "water bamboo-late rice." The former involves planting water bamboo after the early rice harvest; the latter involves planting late rice after the summer water bamboo harvest, implementing a two-year rotation system.
Practice has proven that rice-water bamboo rotation achieves high yields and high benefits. In Chongxian Town, more than 8,000 mu of early rice exceeded 400 kg per mu for three consecutive years, and 7,000 mu of late rice exceeded 550 kg per mu, with grain yield per mu being 50 kg higher than rice monoculture; planting rice in water bamboo fields can also reduce fertilizer use and save costs. In 2006, the average yield of more than 6,500 mu of water bamboo in Chongxian Town was 3,500 kg per mu (yield of shelled water bamboo retaining 2-3 short leaf sheaths), of which summer water bamboo was 2,400 kg and autumn water bamboo was 1,100 kg. Calculated at an average price of 1.40 yuan per kg for the two seasons, the output value per mu was 4,900 yuan; after deducting costs of 750 yuan per mu, the net profit was 4,150 yuan.
2. High-Yield and High-Efficiency Cultivation Techniques
For rice cultivation, early rice mainly uses the Hang 959 variety, with management carried out according to conventional practices, focusing on field drying and prevention and control of sheath blight. Late rice mainly uses the Jiahua No. 1 variety, with cultivation management generally carried out according to conventional practices, focusing on: breaking up and leveling old water bamboo clumps after digging them up, cultivating strong seedlings, appropriately sparse planting, cautious application of topdressing, and proper field drying. Only the water bamboo cultivation techniques are introduced below.
(1) Selection of excellent varieties. Water bamboo varieties should possess high-yield and high-quality characteristics as well as a maturity period that meets market demand. We selected double-cropping water bamboo varieties, among which the mid-late maturing Zhejiao No. 2 white-shell variety accounted for 60%, the purple-shell variety accounted for 35%, and the early-maturing Miantiao variety accounted for 5%.
(2) Seedling Raising Techniques
1) Mother clump selection. In the early stage of autumn water bamboo harvest (early to mid-October), select clumps that set bamboo early, uniformly, and with white, tender, and plump shoots for seed retention, and insert markers; around the following Qingming Festival, conduct a second selection, using clumps with uniform tillering and consistent leaf height as seed seedlings.
2) Seedling raising period and density. Raise seedlings from Qingming to Guyu, dig up "seed clumps" and divide them for planting. Plant as single plants, with row spacing of 50 cm x 50 cm; before planting, cut off the upper leaves of the seedlings, leaving 30 cm at the base to reduce water evaporation and improve survival rate.
3) Timely weeding, fertilizing, and field drying, with alternating dry and wet conditions to promote growth.
4) Pest and disease control. During the seedling stage, plants are tender and green, and are susceptible to damage from rice thrips, aphids, and stem borers. For control methods, refer to rice pest control; for disease prevention during the seedling stage, adopt comprehensive control methods mainly involving stripping off old leaves and diseased leaves.
(3) Field Planting
1) Field selection. Select rotation rice fields with convenient irrigation and drainage and fertile soil, which helps improve soil, reduce the occurrence of "gray water bamboo," and alleviate pest and disease damage.
2) Land preparation. Before transplanting, plow and level the field, and one day in advance apply 50 kg of ammonium bicarbonate per mu as base fertilizer.
3) Planting period, method, and density. The transplanting period is late July. Dig up the cultivated water bamboo seedlings, divide them into plants, cut off the upper leaves, and keep seedling length at 30 cm; planting row and plant spacing is 80 cm x 75 cm, with 1-2 seedlings per hole, and maintain shallow water to protect seedlings after planting.
(4) Fertilization Techniques
1) Seedling-promoting fertilizer. 7-10 days after planting autumn water bamboo, apply 1,000 kg of human manure per mu, or 50 kg of ammonium bicarbonate; for overwintering old water bamboo clumps, cut off remnant leaves and apply sufficient organic fertilizer in early to mid-February, using 2,000 kg of cow manure or 1,000 kg of chicken or duck manure refuse fertilizer, to promote bud development and growth.
2) Tillering and stem-thickening fertilizer. In the early tillering stage, apply 1,000 kg of human manure per mu or 50 kg of compound fertilizer. Apply in mid-August for autumn water bamboo and in mid to late March for summer water bamboo.
3) Bamboo-shoot-bearing fertilizer. In the late tillering stage, that is, mid-September for autumn water bamboo and mid-April for summer water bamboo, apply 50-75 kg of ammonium bicarbonate per mu, adjusting appropriately according to soil fertility. During fertilization, maintain a 6-7 cm water layer on the field surface to prevent fertilizer from damaging roots or being lost.
(5) Water management. According to seedling growth and season, from autumn transplanting to the peak tillering stage, and from overwintering old water bamboo clumps to the peak tillering stage of summer water bamboo, irrigate with shallow water of 3-5 cm, which favors early root and tiller development and prevents freezing in winter; for autumn water bamboo in mid-August, drain the field for 2-3 days and lightly dry it once to promote rooting and tillering; during the bamboo-shoot-bearing period, maintain a water depth of about 15 cm to suppress ineffective tillering and ensure that the water bamboo is white and tender.
(6) Clump pressing, seedling thinning, and weeding. Around Qingming, for overly dense water bamboo clumps, press small pieces of mud in the middle of the clumps to suppress some small tillers and thin the seedlings, which favors bamboo shoot formation. At the same time, promptly pull out weeds in the field and strip off yellow and diseased leaves at the base of water bamboo seedlings.
(7) Pest and disease control. Common water bamboo diseases include Helminthosporium leaf spot, rust, and sheath blight. For Helminthosporium leaf spot, use 40% isoprothiolane 600x solution, or 50% carbendazim wettable powder 600x solution for spraying; for rust, use 40% Fuxing fungicide 8,000-10,000x solution, or 1.5% triadimefon wettable powder 1,000x solution, or 25% Tilt emulsifiable concentrate 3,000x solution for spraying; for sheath blight, use 5% Jinggangmycin aqueous solution 1,000x solution for spraying, requiring spraying on leaf surfaces with fine spray, just enough to wet the leaf surface, so as not to affect bamboo shoot formation. Pests mainly include striped stem borer, pink stem borer, thrips, aphids, and leafhoppers. For control methods, refer to rice pest control; use 20% triazophos emulsifiable concentrate 600x solution, or 40% dimethoate 1,000x solution for spraying. Pesticides are prohibited during the bamboo-shoot-bearing period.
(8) Timely harvesting. The standard for harvesting water bamboo is: the leaf collars of 3 outer leaves are level, the bamboo flesh at the base is significantly swollen, and the surface of the bamboo flesh is white. Generally harvest once every 2-3 days to prevent the surface of the bamboo flesh from turning green and aging.