Wednesday, 15 May 2013

Cover crop establishment in rubber plantation

    Tripura being the hilly state therefore, maximum rubber plantations have been coming up in the hilly areas. As rubber plantation is being taken up in the hilly and sloppy areas so there’s every chance for eroding of top soil due to monsoon rain. Soil erosion therefore, starts right from the field preparation to the initial period of raising rubber seedlings.
   As mentioned in the earlier post on cover crops(  benefit of cover crops), a simple step could of growing cover crops can substantially reduce the soil erosion which not only depletes the top soil but also the valuable soil nutrient for the rubber trees.
    Cover crops not only reduce the soil erosion, it also ensures the followings:-
    1.It enriches the organic matter content of the soil through debris of cover crops.
    2.It reduces the total cost of cultivation by suppressing the growth of weeds.
    3.Cover crops being leguminous fixes atmospheric nitrogen thereby increases the nitrogen content of the soil.
    4.Thus cover crops help in fast growth of the rubber seedlings in the plantation.
    There are various cover crops available in India, of these; followings are some of the cover crops which are widely adopted by the rubber growers of the country.
    Pueraria phaseoloides
    Characteristics of this cover crop are as follows:
    1.It’s fast growing cover crop
    2.It’s twiner-cum-creeper
    3.Once establishes, it effectively covers the ground.
    4.Take over the growth weeds in the plantation
    5.It can be established by both seeds and cuttings.
    Botany of the cover crop:
    1.This cover crop belongs to the family leguminosae
    2.Leaves are trifoliate, broad and pods are cylindrical.
    3.Flowering takes place during January to February
    4.Root system of this cover crop is of shallow type
    Mucuna bracteata   
    Characteristics of this cover crop are as follows:
    1.It’s fast growing legume
    2.It’s deep rooted
    3.This cover is found in the north-eastern region of India
    4.It grows well under shade and drought conditions
    5.It suppresses all weeds of the rubber plantation.
    6.It’s less palatable to cattle
    7.This cover crop retains high amount of moisture in the soil
    8.cuttings of this cover crop can also be used for propagation
    Botany of the cover crop
    1.It’s a member of subfamily fabaceae
    2.flowering of this cover crop takes place during January to February months
    3.Seeds of this cover crop are comparatively big in size
    Calopogonium mucunoides   
     Characteristics of this cover crop are as follows:
    1.It’s twiner-cum-creeper
    2.It’s root system is shallow type
    3.This cover crops establishes very fast
    4.It covers the ground within a short period of time
    Botany of the cover crop:
    1.It’s a member of the subfamily fabaceae
    2.leaves are trifoliate
    3.Flowers are very small and pale blue in color
    Methods of cover crops planting
    Cover crops are generally propagated through seeds. However, cover crops like Pueraria, Mucona and Calopogonium can also be propagated by cuttings.
    Seeds of cover crops are planted in following ways:
    1.Raised seed beds are prepared in between rubber rows.
    2.Seeds are sown in the raised seed beds
    3.Time of field preparation is after the onset pre-monsoon rains.
    Cutting of cover crops (Pueraria and Mucona ) are planted in following ways:
    1.stems of 60 to 100 cm in length, are collected during monsoon season
    2.cuttings are planted in beds
    3.rooted cuttings are transplanted in the field in the pit of 30x30x30cm
    Pre-sowing treatment of seeds
    The thick coverings of the seeds diminishes the over all germination percentage of the seeds sown therefore, to ensure better germination, cover crops seeds are treated before sowing to the field. The followings are the methods of seed treatment for ensuring better seed germination:-  
    1.Acid treatment
    2.Hot water treatment
    3.Abrasion treatment
    Sowing of cover crop seeds
    The pre-treated cover crop seeds are sown in the field on the raised seed bed. Some times, cover crops seeds are also sown after mixing with rock phosphate. The seeds are sown taking after the onset of the pre-monsoon rain. 
    Seed rate for 1(one) ha rubber plantation
    Seed rate of the Pueraria, Mucuna and Calopogonium are in the range of 4 to 5 kg per ha.
    Field management of cover crops
    The followings are taken up as part of the maintenance cover crops once the seed is germinated and young seedling started  establishing:-
    1.weeding is required in the initial stage of growth
    2.preventing the damage from cattle and other livestock
    3.preventing the cover crops to reach in the rubber seedlings
    These are the few aspects on cover crops and some steps in growing of cover crops in the rubber plantation. However, in actual field level practice, there’s some variation and modification from actual practice.
    Grower’s share of experience in cover crops
     Let us see what a rubber grower from south district is to share with respect to the cover crops in his area:
    In his opinion, in Tripura condition, rubber growers prefers mostly to the Mucona as it is said to be very fast in ground coverage compare to the Pueraria. It is also stated that nitrogen fixation in case of Mucona is more compare to the Pueraria.
    Mucona is less palatable to the cattle whereas, Pueraria is preferred by the cattle thereby chances for damage through cattle or other livestock are more in case of the Pueraria.
    Rubber growers also mostly prefer Mucona as it is locally available in the state. Per kilogram rate of Mucona is 300 rupees whereas, pueraria which is sourced through rubber board is within the range of the 300 to 400 rupees.
    However, seed rate of both Mucona and Pueraia is maintained at 5.0 kilograms per ha.
    In local condition, popular seed treatment method is through hot water. Seeds of the cover crop are soaked in the hot water of 50 degree centigrade for 6 hours before sowing to the raised seed bed in the field condition.
    However, local villagers who find it difficult to measure the temperature of the water follow different approach. What they do is; water is heated up to boiling point then the equal quantity of cold water is mixed with that hot water and seed is soaked in the mixed water for 6 hours before sowing to the actual field.
     The time of sowing is said to be best in the month of May and June with the assured the pre-monsoon and monsoon rain that reaches to the state in the month of June in every year.
    Although, some growers might be growing cover crops but percentage of adoption can’t be said as satisfactory as it is evident from the fact that there are lots of new rubber plantation wherein, no cover crops have been grown.
    Looking to the present condition, it could be assumed that awareness level in growing of cover crops is yet to reach to masses.
    Therefore, sensitizing the aspect may be required to bring positive change.
    N: B: For specific package of practices on growing of cover crops, concerned department may be referred.