Detailed Explanation of Standardized Cultivation Techniques for Single-Crop Water Bamboo
Water bamboo, also known as high gourd, wild rice shoot, wild rice hand, water bamboo shoot, high shoot. It is a perennial root herbaceous plant of the genus Zizania in the grass family. It is divided into double-crop water bamboo and single-crop water bamboo (or divided into one-harvest water bamboo and two-harvest water bamboo); double-crop water bamboo (two-harvest water bamboo) has higher yield and better quality. The ancients called water bamboo “gu”. Before the Tang Dynasty, water bamboo was cultivated as a grain crop; its seeds were called wild rice or diaohu, and it was one of the “six grains” (tu, shu, ji, liang, mai, gu).
Morphological characteristics of water bamboo
Water bamboo is a perennial aquatic root plant of the grass family. The plant height is 1.6-2 m, with 5-8 leaves; the leaf is composed of two parts, the blade and the sheath. Where the blade meets the sheath there is a triangular leaf cushion, called the “water bamboo white eye”. The sheath wraps around itself layer by layer from the ground upward, left and right alternating, forming a false stem. The stem can be divided into two types: aboveground stem and underground stem. The aboveground stem is shortened and partly buried in the soil, and most of the tillers arise on it; the underground stem is a creeping stem that lies horizontally in the soil to overwinter, and several buds at its tip sprout into new plants the following spring, and the new plants can in turn produce new tillers. Because the water bamboo plant is parasitized internally by the smut fungus, its mycelium grows along with the plant; by early summer or autumn when the plant bolts, the flower stem tissue on the shortened stem of the main stem and early tillers is stimulated by the mycelial metabolite indoleacetic acid, and the meristematic tissue cells at the base nodes 2-7 proliferate and swell into a tender, plump fleshy stem (fungal gall), which is the edible water bamboo.
Male water bamboo refers to a small number of plants with especially strong disease resistance, into which the mycelium of the smut fungus cannot invade, so no water bamboo can be formed, and by summer and autumn the flower stem elongates, bolts, and flowers. Gray water bamboo refers to some plants that are overmature or whose mycelium grows rapidly, so that the interior of the water bamboo is already filled with dark brown spores, making the quality poor and inedible. The central bolt of male water bamboo rises above that of female water bamboo, making it relatively easy to identify; it should be pulled out with the roots in time, and the root stock must not be left in the soil.
Standardized cultivation techniques for single-crop water bamboo
Water bamboo can be divided into single-crop water bamboo and double-crop water bamboo. Single-crop water bamboo is also called one-season water bamboo; planting once yields only one harvest, generally harvested in September to October. Double-crop water bamboo is also called two-harvest water bamboo; planting once can yield two harvests. The first harvest is gathered in the autumn of that year, called autumn water bamboo; the second harvest is gathered in the summer of the following year, called summer water bamboo. The single-crop cultivation techniques are introduced as follows:
1. Site selection and land preparation
Water bamboo has no strict soil requirements. You can choose medium- and low-yield fields with deep soil layers and convenient irrigation, or fields at high altitude with good drainage and irrigation conditions, fertile soil layers, and strong water retention and drought resistance for planting. Before planting, plow and level the field until the field is level and the mud is soft, so as to facilitate deep rooting.
2. Seedling raising and transplanting
Single-crop water bamboo is generally planted in March to April. When using local old water bamboo clumps for seedling raising, generally before the winter solstice dig up the previously selected water bamboo clumps, lay them flat in a field corner or ditch, and fill with shallow water to overwinter. After lifting the clumps, cut off most of the surrounding old roots to favor new root growth the following year. After the Start of Spring, when temperatures rise and the water bamboo roots begin to sprout, splash-apply 20% human and livestock manure and urine once. Five days before planting, apply another starter fertilizer; appropriate amount of urea may be broadcast. Water bamboo is often planted in wide-narrow rows: wide rows 1.2 m, narrow rows 0.8 m, clump spacing 0.4 m, with 3-4 seedlings per clump, and 1300-1500 clumps planted per 667 sq m. Before inserting, cut off 0.2-0.4 cm of the old roots of the seedlings; the planting depth should be such that the seedlings do not float and do not lean, and it is essential not to plant too deep. In old water bamboo fields, around “Grain Rain”, thin and finalize the seedlings; thinning should follow the principles of “remove dense and keep sparse, remove weak and keep strong, remove inner and keep outer”.
3. Field management
1. Fertilization. Water bamboo has a long growth period and requires a relatively large amount of fertilizer; the base fertilizer must be sufficient and topdressing must be timely. ① Base fertilizer. In combination with land preparation, deeply rake in 1700-2000 kg of human and livestock manure per 667 sq m, or 50 kg of ammonium bicarbonate plus 40 kg of superphosphate as base fertilizer. ② Topdressing. 10-15 days after insertion, apply a “seedling-promoting fertilizer” by topdressing 400-500 kg of human manure and urine per 667 sq m, or 25 kg of ammonium bicarbonate plus 10 kg of superphosphate; note that ammonium bicarbonate should be applied on a cloudy afternoon and broadcast 0.2 cm away from the water bamboo seedlings to prevent burning the seedlings; one month after planting, apply another “tillering fertilizer”, with 10-15 kg of urea per 667 sq m; at the end of July, apply a “pregnan
2. Irrigation. Determine the irrigation depth according to the different growth stages of water bamboo. After planting water bamboo, maintain shallow water of 0.3 cm; as the water bamboo seedlings grow, gradually deepen the water layer; before tillering, maintain water 0.5-0.7 cm deep; in the late tillering stage, maintain water 1-1.3 cm deep to control ineffective tillering; during the pregnant water bamboo stage, deepen it to 1.7-2 cm so that the water bamboo flesh is white and tender.
3. Cultivation and leaf stripping. From planting to row closure, water bamboo requires 2 cultivations and weedings and 1 leaf stripping. The cultivations and weedings are carried out half a month after planting and before row closure respectively; leaf stripping mainly removes old leaves, yellow leaves, and diseased leaves from the plants.
4. Pest and disease control. ① The main diseases of water bamboo are rust disease, sheath blight, and so on. To control rust disease, spray with 12.5% hexaconazole wettable powder at 1600 times dilution, or 15% triadimefon wettable powder at 1500 times dilution, or 75% chlorothalonil wettable powder at 600-800 times dilution, once every 7-10 days, rotating the chemicals 2-3 times. For sheath blight, in the early stage of disease, spray with 20% tricyclazole at 500 times dilution or jinggangmycin at 3000 times dilution or 50% carbendazim wettable powder at 800 times dilution, once every 7 days, for a total of 2-3 sprays. ② The main insect pests of water bamboo are stem borers, the long green planthopper, thrips, and so on. During the larval hatching period of stem borers, spray with 0.1% matrine emulsion at 1000 times dilution or 0.6% miechongling at 1500-2000 times dilution 1-2 times to control stem borers. In early to mid-June and early to mid-July, spray with 10% imidacloprid wettable powder at 2000 times dilution or 25% buprofezin wettable powder at 1000 times dilution to control the long green planthopper. Spraying with 18% bisultap aqueous solution at 300 times dilution, or 10% imidacloprid powder at 2000 times dilution can control thrips.
4. Timely harvest
When the 3 outer leaves of the water bamboo have fully grown, the central leaf has shortened, the pregnant water bamboo part has swollen, and the leaf sheath has separated from its wrapping and exposed the white water bamboo flesh, it can be harvested for market. Be careful during the first harvest not to step on and injure the nearby young water bamboo. Also apply a quick-acting fertilizer once to promote the development and swelling of the second crop of water bamboo and increase the per-unit yield.