Detailed Explanation of Key Taro Cultivation and Management Techniques
Taro, also known as taro or taro, is the underground corm of a plant in the Araceae family. Its shape and flesh vary by variety, and the kind usually eaten is the small taro. It is a perennial tuberous plant, often cultivated as an annual crop. The leaves are shield-shaped, and the petioles are long and thick, green or purplish-red; at the base of the plant a shortened stem forms, gradually accumulating nutrients and enlarging into a fleshy corm, called “taro” or “mother taro”, which may be spherical, oval, elliptical or block-shaped.
Each node of the mother taro has a brain bud, but the axillary buds at the middle and lower nodes are the most active, producing the first tiller and forming a small corm called a “daughter taro”; from the daughter taro, “granddaughter taros” then develop, and under suitable conditions great-granddaughter or great-great-granddaughter taros and so on can form.
Taro Cultivation
1. Land preparation and trenching After the land is prepared, open trenches at a row spacing of 80—100 cm, with a trench width of 50 cm and a trench depth of 35 cm, then apply fertilizer in the trenches.
2. Fertilization Taro has a high fertilizer demand and a long growing period. First, sufficient base fertilizer must be applied: 2000 kg of high-quality organic fertilizer per mu, and 60 kg of 48% potassium sulfate compound fertilizer (16—16—16), applied in trenches opened according to row spacing. Topdressing should be applied in split applications, 2—3 times in total during the seedling stage, the vigorous growing stage and the peak corm growth stage, mainly with phosphorus and potassium fertilizers.
3. Sowing The sowing time is after Qingming (that is, early April), with a plant spacing of about 50 cm, the seed 3—5 cm from the ground, and a soil cover thickness of 5 cm. Plastic film mulching cultivation can also be used.
4. Watering Taro is averse to dry soil; when drought occurs, the leaves turn yellow and wither, but excessively wet, waterlogged soil is also unfavorable to root growth. During the seedling stage, the soil should have sufficient subsoil moisture, and watering should by no means be done just for the sake of it. During the seedling stage, keep the soil alternately dry and moist, and pay attention to drainage in rainy weather.
5. Intertillage and earthing up During the seedling stage, combine topdressing with intertillage to remove weeds and warm the soil; at the end of the seedling stage, carry out intertillage and make the cultivation trench level with the ground. After that, earth up once about every 20 days, to a thickness of 7 cm, for a total of two times. The purpose of earthing up is to inhibit the sprouting and growth of the terminal buds of daughter and granddaughter taros, reduce nutrient consumption, allow the taro to swell fully and produce a large number of adventitious roots, and increase drought resistance. As the farming proverb says: “If you don't earth up taro, it's as if you didn't plant it.” Along with earthing up, according to the density of leaf area distribution and the season, remove excess lateral buds as early as possible, so as to avoid consuming nutrients and limiting the growth of daughter taros.
Taro Management
1. Choosing the planting site and preparing the land before planting
Taro has a very long growing period, and the use of organic fertilizers before planting is one of the important factors affecting the quality of the taro produced later. In addition to applying traditional fully fermented organic fertilizers, it is recommended to apply plant-based organic fertilizers with a relatively high humic acid content, such as Feibao No. 2 and Kelaigen, as base fertilizer.
When choosing a taro planting site, continuous cropping should be avoided. If continuous cropping cannot be avoided, apply 750-1000 kg/mu of Wulu (calcium cyanamide) before land preparation. Besides providing a source of nitrogen and calcium for taro for more than 3 months, this fertilizer can also eliminate miscellaneous soil microbes and adjust the soil pH; it avoids a series of disorders caused in taro by continuous cropping, for example: soil acidification, bacterial and fungal wilt diseases, and so on. In addition, Wulu also has a considerable control effect on golden apple snails in taro fields. If Wulu is used, taro seedlings can only be planted after 15 days.
2. Seedling stage
Fertilization should be avoided during about the first 15 days after planting. Only after confirming that young roots have begun to grow should nitrogen fertilizer be applied in appropriate amounts; at this time 150-250 kg/mu of nitrogen-calcium fertilizer (calcium nitrate) is recommended, once every 10-15 days, for 2-3 consecutive times. If a cold wave strikes in the early planting period and the temperature drop causes taro growth to pause, do not apply heavy fertilizer because of a supposed fertilizer shortage; doing so may cause fertilizer burn, and when the temperature rises again growth may instead stop.
If the temperature is normal in the early planting period, in order to promote the early and sound development of young roots, it is recommended to use rooting agents at the right time and in the right amount, to establish a complete root system early for taro to absorb nutrients.
3. From the seedling stage to before taro corm setting
Taro is a shallow-rooted crop, and its root system often grows only at a depth of about 10 cm in the topsoil. Therefore, during its growth process the traditional fertilization method (intensive application of quick-acting fertilizers) is most suitable, but because its vegetative growth often lasts more than 120 days, the general traditional fertilization method has become a major burden on production costs.
Precautions for Fertilizing Taro Planting
Taro likes moisture and tolerates heat, and regions with fertile soil are more favorable for its growth. Before planting in winter, deep plowing should be carried out to freeze and aerate the soil, sterilize it and remove eggs, reducing the harm of diseases and insect pests. In spring, apply base fertilizer, mainly decomposed organic fertilizer and compound fertilizer. Per mu, 4000-5000 kg of decomposed organic fertilizer and 60-75 kg of potassium sulfate compound fertilizer can be applied. During the plant growth period, topdressing is also needed 2-3 times. For the first topdressing, quick-acting nitrogen fertilizer can be applied, for example 10-15 kg of urea per mu, to promote rapid growth of stems and leaves, enhance photosynthesis, and provide sufficient nutrients for the growth of the underground corm.
For topdressing during the taro growth and daughter taro swelling stages, phosphorus and potassium fertilizers should be the main choice, such as 30-45 kg of ammonium bicarbonate and 40-50 kg of monopotassium phosphate per mu, to promote the growth and swelling of the corm, and apply less nitrogen fertilizer, otherwise the stems and leaves grow rapidly and consume nutrients, which is unfavorable to corm growth. No more fertilizer should be applied in the late growth stage, to avoid waste.
Taro Cultivation Techniques in Paddy Fields
I. Rational fertilization and scientific water management
1. Rational fertilization. On the premise of applying sufficient base fertilizer, thin biogas slurry or manure water may be applied appropriately in the early stage. When the taro begins to swell in early June, use 1000 kg of farmyard manure, 50 kg of peanut shells, 15 kg of potassium sulfate, 50 kg of bio-organic fertilizer and 2 kg of boron-zinc-magnesium fertilizer per mu, compost them for 30-45 days, then apply them at the edge of the bed and cover with soil. Before the Great Heat in mid-July, use 25 kg of potassium sulfate compound fertilizer and 15 kg of potassium sulfate per mu, mix them evenly and apply them on the bed surface, covering the fertilizer with a little soil; before fertilizing, the weeds around the field should be pulled out. No more fertilizer should be applied after August. During the rapid swelling stage of taro (June-July), swelling agents plus monopotassium phosphate and the like can be sprayed together with pest and disease control, which can promote taro swelling and increase yield.
2. Scientific water management. Before fertilizing and removing the film, the bed surface should be kept moist; on rainy days, the standing water in the bed trenches should be drained; on sunny days with drought, running water should be let into the bed trenches to keep them moist. During the peak growth period (June-August), the bed trenches should keep 1 cun of water at the bottom or remain moist, and irrigation should be stopped 10 days before harvest (for harvest and marketing before October).
II. Timely application of chlormequat and removal of daughter taros
1. Applying paclobutrazol and seedling-strengthening agent. When the taro has grown 5-6 leaves and the plant height is about 45 cm, apply 5 kg of seedling-strengthening agent and 150 g of paclobutrazol mixed per mu as a drench, and after 20 days apply 150 g of paclobutrazol again as a drench or foliar spray. The dosage may be increased or decreased as appropriate according to the vigor of the plants. On a sunny day, add 15 g of paclobutrazol to 40 jin of water, and pour it into the heart leaves of 80-100 plants, with a plant height of 80 cm, more than 5 leaves, and the rows basically closed.
2. Removing daughter taros. Daughter taros begin to form when the taro has grown 7-8 leaves. To reduce the dispersal and consumption of nutrients and favor the swelling of the mother taro, when a daughter taro has one leaf and one heart, carefully cut off the growing point of the daughter taro with a small knife or small iron shovel, taking care not to cut and injure the mother taro. Daughter taros to be kept for seed should be left as three or four young shoots and not removed.
III. Making full use of taro fields for intercropping and relay intercropping
Plant taro early, harvest before the end of August, and make full use of the taro beds to relay intercrop vegetable corn; harvest the vegetable corn before the end of November, and use the corn stalks to relay intercrop sweet peas or snow peas. In this way, four harvests from the field can be achieved (mother taro, vegetable corn, daughter taro, and beans).