A cover crop of vetch can cut down the cost of weed control and help conserve the soil and water.
Types of Farmland Suitable for Vetch
There are two kinds of agricultural area that are well suited to a crop of vetch.
- Paddy fields which are left fallow after the second crop is harvested (in Taiwan this is in December) ( Fig. 1). The following crop of vetch has five months to grow, from December to May. During this time, the vetch produces a high level of organic matter.
- Apple orchards or citrus orchards with a sprinkler irrigation system have good seed germination and good growing conditions for a crop of vetch ( Fig. 2).
What Happens When the Seeds Are Sown
The seeds of woollypod vetch need moisture for the first 5 - 7 days after planting in order to germinate. They then grow very slowly at first. The vetch crop may need a little fertilizer (urea and phosphate) to promote plant growth. Moisture at the germination stage is a key factor in growing a successful crop of woollypod vetch.
The time when the beautiful small purple flowers come into bloom is when the crop reaches its highest level of biomass. Vetch is not a climbing vine, and there is no danger that the plants will climb up into the fruit trees.
It is suggested that growers should not spray any pesticide or fungicide, because the young shoots of vetch are a delicious vegetable for stir frying.
Can the Vetch Be Used As a Perennial Crop?
Vetch is adapted to a temperate climate. Taiwan's high summer temperatures are too hot for this crop, and most of the vetch plants die, so that weeds begin to spread. If the vetch is being used in orchards, during this summer period the orchard will grow a cover crop of natural grasses. Farmers can control weeds by mowing. When autumn comes, another crop of vetch is sown (usually in late October) ( Table 1).
How Much Seed Is Needed?
You will need 150 kg per hectare. In Taiwan, vetch seed is sold in packages of 1.5 kg. These can be ordered by mail for US$3.57 per pack.
Index of Images
Figure 1 Field Demonstration of Vetch Growing in a Fallow Paddy Field. the Vetch Crop Produced 50 MT/Ha (Fresh Weight) during the Three Months' Growing Period
Figure 2 Field Demonstration of Vetch Grown As a Cover Crop in an Apple Orchard. the Vetch Grows Well from November to June, and Reduces the Cost of Weed Control during This Period
Table 1 Summary Advantage of Woollypod Vetch Grown As a Green Manure Crop, Assuming a Fresh Weight Yield of 40 MT/Ha