Stylosanthes and its cultivation practices
Stylosanthes (Stylo) is an erect growing perennial forage legume crop which is native to Brazil. Generally, stylosanthes reaches height of 2 meters. Stylosanthes, which is often grown on marginal land in the mid-hills of Nepal and is also intercropped with trees, can ease some of the pressure on tree fodder collection for livestock.
This perennial fodder legume is a sub-shrub, semi-erect or erect, with a strong tap root and small round root nodules. Some species of Stylosanthes are important green manure species, some are planted and harvested for commercial livestock feed whereas some can also be used as a nitrogen input into low input or organic cropping system. Some species have been used for land reclamation, soil stabilization and soil regeneration work because of their drought resistance, ability to restore soil fertility, improve soil physical properties and provide permanent vegetation cover. This crop can be grown in tropical climate.
Stylosanthes has a variable protein content, which is usually moderate (about 14% DM) but can be as low as 6% or exceed 20% DM. The fiber content is quite high (more than 25% DM crude fibre). Stylo contains condensed tannins. Poor palatability before flowering has been observed in Stylosanthes. The palatability improves after flowering. In November – December when the entire plot is ready for grazing has brownish appearance as the leaves come to senescence and have high palatability. Stylo has a low palatability during the rainy season, but is readily eaten in the dry season. It has a high proportion of moderately soluble proteins compared with other tropical legumes. The variety of Stylo found in Nepal is Palpa Stylo.
CULTIVATION PRACTICES OF STYLOSANTHES:
- Climate and soil
Stylosanthes is adapted to tropical climate and tolerant to low fertility soils, acidic soils and soils with poor drainage. It is drought resistant and a good pasture legume crop and requires low rainfall. It is drought resistant legumes coming up well in areas receiving a minimum rainfall of 450 – 840 mm annually but it does better between 1000 and 2500 mm for common Stylo. It is a warm season growing legume that thrives in places where annual temperatures are between 23 and 27°C.
- Field preparation
For good germination as well as production of Stylo, it is necessary to prepare field properly. Ploughing the field with cultivator twice before taking up sowing is preferable. This crop cannot withstand excess water. Drainage channels have to provided to remove excess water from the field.
- Time of sowing
The sowing season for Stylosanthes is from June – July to September – October.
The spacing of 0.5 – 1.0 m x 0.5-1.0m is beneficial for Stylo. Whereas, planting density should be kept 50,000 to 1,00,000 plants/ha.
- Method of sowing
It is done through line sowing and broadcasting method.
- Seed Treatment
The seed should be scarified, then soaked in water over night and then treated with rhizobium culture, shade dried and then sowings is taken up.
- Seed rate
For line sowing (30 x 15 cm), the seed rate is 6 kg/ha and for broadcasting 10 kg/ha is required.
- Fertilizer requirements
Fertilizer requirement for Stylosanthes is 20kg Nitrogen and 60kg P2O5 per hectare.
- Weed control
Weeds have to be controlled by using a blade harrow in between rows till the crop gets established.
The amount of irrigation depends on the type and temperature of land. 3 to 4 irrigation is required for good production. Drainage channels have to provided to remove excess water from the field.
First harvest can be taken 75 days after sowing at flowering stage and subsequent harvests depending upon the growth. It is to be noted that during the first year, the establishment after sowing is very slow and the yield is low. Later on when the crop establishes well due to self seeding it yields 30 to 35 t/ha per year from the third year onwards.