Tuber Mustard Cultivation Techniques and Key Points of Crop Management
Tuber mustard (zha cai) belongs to the phylum Angiospermae and the class Dicotyledoneae. Most are herbaceous plants. Tuber mustard is a type of mustard, generally referring to the leaf mustards, such as nine-head mustard, potherb mustard, pig-blood mustard, tofu-skin mustard and so on. Tuber mustard is a semi-dry, non-fermented pickled vegetable made by pickling stem mustards as the raw material. It is one of China's famous specialty products and, together with French pickled gherkins and German sweet-and-sour cabbage, is known as one of the world's three great famous pickles. It first appeared in 1898 in Fuling, Sichuan, China (now Fuling District, Chongqing), and was then called "Fuling zha cai". Because the processing requires pressing out the water from the vegetable, it is called "zha cai" (pressed vegetable).
Planting Methods
1. Timely Sowing
The sowing time of tuber mustard is crucial and is an important factor in whether a high yield can ultimately be obtained. In China, tuber mustard is mainly sown in autumn, generally starting around October, with the specific time depending on weather conditions and the growing environment. Sometimes even a three-day difference in sowing time can cause a large difference in yield. The timing of sowing affects the quality and yield of tuber mustard. If sown too early, it may lead to severe viral disease and may also cause premature bolting. If sown too late, the tuber of the tuber mustard will become smaller, reducing the yield.
2. Raising Seedlings and Transplanting
Raising good tuber mustard seedlings is also a key factor for high yield and quality later on. Before sowing, the seeds should first be washed and soaked. Generally, 50 g of seeds is mixed evenly with 10 kg of mud ash, then broadcast, and the mustard seeds are covered with burnt mud ash, and finally covered with straw to retain moisture. After the seeds sprout and emerge, the straw can be removed and transplanting can begin. After transplanting, when the seedlings have produced their first leaf, thinning can be carried out. During thinning, care should be taken to pull out the fast-growing, large-leaved variant seedlings. At the second and third leaf stage, a second thinning is carried out, removing poorly developed weak and diseased seedlings, maintaining a reasonable density and ensuring normal growth.
3. Land Preparation and Fertilization
The seedbed should be chosen as sandy soil with convenient irrigation and drainage. Each mu of seedbed requires 30 loads of human and livestock manure, 50 kg of phosphate fertilizer and 20 kg of ammonium bicarbonate, applied deeply as base fertilizer. The seedbed is divided into beds 2.5 m wide including the ditch, with the soil finely prepared. After sowing, 30-40 loads per mu of finely crushed soil-and-manure fertilizer is used as covering fertilizer for the seeds.
4. Rational Fertilization
Tuber mustard has a relatively large fertilizer requirement during its growth process and also has relatively high requirements for base fertilizer. The amount of base fertilizer used should be determined according to the planting area. Generally, the base fertilizer for one mu is about 4000 jin, and pigsty manure is best for the base fertilizer. During the growth period, topdressing should also be carried out in stages. The first topdressing is carried out 30 days after transplanting, using fully decomposed farmyard manure. Then, before winter, a second topdressing is applied, which can also be farmyard manure. After topdressing, cultivate and earth up the soil to prepare for winter. While keeping the soil moist, it must not alternate between dry and wet. The purpose is to prevent premature loss of fertilizer leading to flowering. Fertilization is stopped one month before harvest to prevent excessively fast growth that causes hollow hearts.
5. Pest and Disease Control
The main pest and disease problem of tuber mustard is aphids. Aphids can also trigger viral disease in tuber mustard, and outbreaks are especially severe in dry weather, so timely control must be carried out when summer drought occurs. Especially at the seedling stage and the early stage after transplanting, these two stages are the key periods for aphid control. Pesticides such as pirimicarb and dimethoate should be used for control, and great attention must be paid to this. After harvest, the soil should immediately be plowed and disinfected, and the land exposed to the sun, to kill bacteria and parasites in the soil, reduce pathogens and the disease incidence in the coming year, and also to avoid continuous cropping.