Inditrades

It is a deep-rooted fast going legume with moderate drought resistance and shade tolerance. It forms a thick luxuriant cover and suppresses all weeds. The dried leaf form thick mulch and is less palatable to cattle. Propagation of Mucuna Bracteata is through seeds and rooted cuttings.

The seeds are comparatively big and the seed rate is 200g/ha. Fruits are covered by stinging hairs. However the plant does not bear fruits in low elevation situations. Nitrogen fixing capacity of this was found to be high. It grows fast and covers the field very quickly thus, it suppresses all weeds.

Characteristics

The desirable characteristics of Mucuna Bracteata

Very vigorous growth.
Easy establishment and low seed rate
Non-palatability to cattle
High-drought tolerance
Shade tolerance
Presence of alleolo chemical to enhance competitive ability against weed growth
High biomass productions
Low labour and chemical requirements for its establishment
Tolerance to pest and diseases
Good control against soil erosion

Pretreatment

Pretreatment of Mucuna Bracteata Seeds As a part of value addition to the Mucuna Bracteata seeds exported by us, we have been constantly experimenting with methods to improve the germination of the seeds. Described below is the method that we found to give the best results, so far and improves germination by about 50-75%:

Take cleaned Mucuna Bracteata seeds (free from soil and other debris) in an acid resistant container (Glass or Plastic)
Add Concentrated Sulphuric acid (85%) gently while stirring with a wooden stick till a thin layer of acid coating is formed over the seeds
Approximately for every kilogram of seeds 50cc. of Sulphuric acid is needed
Continue the stirring for 30 minutes. By this time the outer hard coating which prevents the absorption of water by the seeds is dissolved and forms a black substance
Transfer the treated seeds to another container/bucket containing cold/normal water. Please ensure that the seeds are added to water and not water to seeds
Decant the water and add fresh water
Now rub the seeds between two hands to remove the scars on the seeds
Repeat this for two more times till the seeds are free from acid
Spread the seeds over any absorbent surface, like sack and cloth and dry them under shade
Sow them as early as possible

Method of Sowing

We have also observed that the following method of sowing gives the best results in case of Mucuna Bracteata.

Plant Density - 200 to 300 grams per hectare
Mark the areas in which seeds are to be planted
Dig a one cubic feet pit
Fill it with loose sand mixed with Supplements for early modulation/ growth
Sow two seeds per pit, taking into consideration, 50% germination probability

Materials

M. Bracteata seeds were imported from Kerala, South India on obtaining the Import Permit from Crop Protection Branch at Kuala Lumpur and Phytosanitary Certificate from Government of India in 1991.

The seed treatment, germination, method of planting, seeding rates, manuring and maintenance of cover and growth characters were studied under field conditions. This material was evaluated as follows :-

a. M. Bracteata x 4 replicates - Fld 90 - Flat area
b. 2 types* of LCP x 4 replicates - Fld 90 - Flat area
c. M. Bracteata x 4 replicates - Fld 91 - Terraced

Pueraria phaeseoloides and Calopogonium caeruleum Plot size was 10 m x 30 m

Establishment

Details on the establishment of M. Bracteata x Seeds

The seeds are large, weighing 99 to 190 mg each and are black in colour with a hard seed coat (see Appendix A). In view of hard seed coat, the seeds did not germinate under ambient conditions. Thus after treatment with Concentrated Sulphuric acid for 30 minutes a germination rate of 70 percent was obtained in three days. Scarification of seeds mechanically on a rough surface or sand paper recorded 95 percent germination success in three days. Mechanically scarified seeds were raised in mini polythene bags (12.7 cm x 17.7 cm), which were filled with top soil. Six weeks after sowing, the seedlings were transplanted to the palm rows, which were free from other vegetative growth.

Planting density

Three seedlings of M. Bracteata of six weeks old were planted in between two palms (in conjunction with palm planting). Lower seed rate of two seedlings took 30 percent longer time for longer coverage. In a stand of 136 palms per hectare, only 408 M. Bracteata seedlings or 75g of seeds were required per hectare. Care was taken to plant the seedlings during wet weather. M. Bracteata's growth at the initial period of 12 months was slow; subsequently it took over and exhibited it's vigorous growth. (To provide faster soil coverage Mucuna conchinchinensis is recommended to be sown along with M. Bracteata for the initial temporary ground cover or along with conventional covers e.g. Pueraria phaseoloides).

Manuring

M. Bracteata is very sensitive to inorganic fertilizer. It is recommended to apply Bayfolan (trace elements-foliar fertilizer) after two months of planting in the field. At the eighth month 50kg per hectare rock phosphate followed by 100 kg per hectare rock phosphate at the 14th month was used. No further application was required after the 14th month.

Maintenance

In the initial three months, a zone free of vegetation of 1m around each seedling of M. Bracteata was maintained. In the view of the low seedling rate per hectare, care was taken not to spray herbicide directly in order to prevent its drift on the M. Bracteata seedlings. Thereafter, only eradication of 'woody' plants was carried out. M. Bracteata gave full coverage of the field from second year onwards. Monthly circle sprayings of palms were very pertinent as the vigorous growth of M. Bracteata would otherwise engulf the palms.

Growth Characters

Results : Growth Characters

The vines grew very fast by branching from each node. Dark green trifoliate leaves grew to a size of about 14 cm to 10 cm. The leaves are thermonastic - when temperature rises or falls the leaves close up. The three seedlings of M. Bracteata planted between two palms grew and covered about 20 m2 in 10 months and suppressed the noxious weeds.
The dead older leaves shed and formed thick mulch over the ground.
A sampling after three years of establishment showed that the dry matter productions from M. Bracteata was 8 to 10 tons compared with 4.4 tons with conventional covers (Table 1). Leaf litter was 3.4 to 7.3 tons under M. Bracteata and only 1.5 tons under conventional covers (Table 2). The thickness of the green vegetation of M. Bracteata on the ground ranged from 39 cm to 90 cm. Such a luxuriant growth of cover plants will be much value in smothering weeds and reducing soil temperature. The probable presence of alleolo-chemicals in the tips of young vein inhibits the growth of engulfed weeds.

The mulch of dried leaves would increase the microbial activity and enrich the nutrient status of the soil. Roots developed from the nodes of vines touching the ground are fibrous. Nodules formed on such roots are small and round. The nodules that developed on the roots of established plants were irregular in shape measuring 0.2 cm to 2 cm. The nodules on aging turn black indicating presence of oxyhaemoglobin (Cloonan, 1963), which can serve the function of leghaemoglobin.

Drought & Shades ( Drought & Shade tolerance ):

This plant did not dry during hot spells (4 months drought). Only older leaves shed during the dry months and new shoots came out about 30 years later. Under shade, this cover plant also grew, but the growth was comparatively less.

Pest & Diseases

So far no serious pest or disease problems were noticed in this cover plant. In the months of December/ January, insect infestation was manifested by tiny holes on the leaves of this cover plant, however the infestations were mild as high levels of phenolic compounds deter the insects (Kothandram et al., 1989). It is also non-palatable to cattle due to presence of high levels of phenolic compounds and there is no menace for cattle.

Propogation

Propogation of M. Bracteata is possible through seeds and stem cuttings. As seeds are not easily available, propagation by cuttings or tissue culture could be adopted.

Based on the initial establishment of M. Bracteata since 1 June, 1991, the following points of interest in relation to its cultivation and its reaction to environment is noted.
In view of the low seed rate, the initial growth is comparatively slow thus sowing together with Mucuna cochinchinensis for an initial quick ground cover is advocated.
The thick biomass is conducive to beneficial microbes e.g. Actinomycetes, Tricoderma.
The alleolopathic property of this cover plant should be further investigated.
The high level of phenolic compounds deters insects and cattle.
As it does not flower in the plains, its cultivation for seed purpose should be attempted in the high ranges e.g. Cameron Highlands.
In the view of low success rate of stem cuttings, propagation by tissue culture should be attempted.
There is no need to determine an indigenous Rhizobium strain which further promotes nitrogen fixation.
This cover grows well on decayed organic matter, hence it would do well in zero burn areas.
One year after establishment of M. Bracteata the only weed maintenance required is regimented monthly circle weeding/ spraying.
One year after establishment of M. Bracteata the only weed maintenance required is regimented monthly circle weeding/ spraying.
Its drought resistance and shade tolerance is far superior to conventional covers thus poses less of a fire hazard in the dry weather.
Its deep root increase the fertility of surface soil by extracting nutrients from deeper layer of soil and depositing them on the surface in the form of organic matter.
At the onset of second year of planting, M. Bracteata dominated the other conventional covers in growth and coverage.
Total biomass is superior to that of Pueraria Phaseoloides and Calopogonium. Caeruleum.
The significant quantities of litter, which decomposes comparatively slowly attributes to longer period of uptake of nutrients.

Mucuna Bracteata