A M Ajith Fernando 
Kohombe Estate. Kakkapalliya 

A MULCH ROLLER 
FOR 
THE MANAGEMENT 
OF COVER-CROPS 

A legumirious cover-crop is particularly 
important on rubber and coconut estates. It 
helps conserve moisture in the soil below the 
surface mulch; it contributes the nitrogen 
equivalent of several hundreds of kilograms of 
urea each year to the soil, and helps control 
other obnoxious weeds by shading them out of 
existence. It protects the soil from erosion and 
shades it from the severe heat of the tropical 
sun, and provides organic matter which is an 
essential component in the structure of the soil. 

But cover-crops also need to be kept under 
control - throughout the year - if they are not to 
become weeds themselves. An over-grown 
cover-crop results in several inconveniences to 
the coconut grower; it results in great difficulty 1 

to collect fallen and plucked nuts; it provides a 
medium for the breeding of serpents and 
causes great difficulty to the pickers who 
harvest the coconuts as it impedes their 
movement between trees, a task already made 
difficult by having to balance a heavy pole all 
the while. 

Of the one mjllion acres of coconut 
plantation in Sri Lanka, some 70-80% are 
owned by small-holders with very limited 
income and on which production costs need to 
be kept as low as possible. These 
small-holders cannot afford to purchase (or 
even rent) tractors and related machinery to 
control surface cover-crops which might 
otherwise grow rampant all over their lands. 
Most of them permit the surface cover-crops to 
be over-grazed by cattle, and goats as a cheap 
method of weed-control, but by so doing they 
also deny themselves the great advantages to 
be derived from the retention of cover-crops. 

Some progressive planters use the (twin) 
animal-drawn buffalo or bullock harrow 
equipped with eight discs in two gangs of four 
each which can be angled to promote more 
aggressive action of the discs against the soil 
and surface vegetation. Such animal-drawn 
disc harrows were earlier imported from Britain, 
and more recently have been manufactured 
locally, using imported discs. These disc 
harrows, while performing an excellent job 
when used correctly, are still somewhat 
expensive at about Rs. 20,000 each, so have 
been used only on 'estate' sized holdings. 

The observation above 'when used correctly' 
is important for if the harrow is used when soil 
conditions are very dry, or if the discs are 
incorrectly angled, the cover crops are 
damaged irretrievably and soil left exposed to 
the ravages of the sun. Further, when next it 
rains, the weed-seeds usually get a 'head-start' 
on the covers and sobn the estate is inundated 
with destructive weeds. 

Yet other estates have used herbicides to 
control weeds and usually succeed in 
destroying their cover--crops too. 

A low-cost alternative for -regulating 
cover-crops and controlling other weeds is 
therefore a very much needed tool on small 
coconut properties. 

Construct ion of the chopping roller 

1. The roller consists of a tree trunk, one 
meter long and about 50 cm (2') in 
diameter. The wood must be in good 
condition so that it does not split or break 
up. Make six saw cuts along the length of 

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the tree trunk, about 6 cm (2') deep, 
spaced equally around the circumference 
of the trunk (Fig. 1a). 

2. The knives are made strips of hardened 
steel, eg. leaf springs of a motor car. They 
should be about 1 m long and about 12-14 
cm (about 5") broad (Fig. 1b). 

3. T i e axle is made of two 40 cm (15") 
lengths of steel shafts, 2 cm (less than 1") 
ir. diameter. 

4. Hammer one steel knife into each of the 
slots in the trunk. The knives should be 
fastened by two metal hoops at either end 
cf the trunk. 

Drill holes about 20 cm (8") deep in the 
ends of the trunk. The holes should be 
slightly smaller than the diameter of the 
axle. Drive the steel shaft into each hole 
with a heavy hammer (Fig. 1c). 

5. Wooden blocks should be inserted into the 
axle as bearings. The roller can now be 
fitted to the frame* with flat steel bars. 

A local blacksmith can turn out the required 
steel bars. A small wooden platform can be 
mounted on the chassis and a seat for the 
operator could be fixed on the platform, at a 
point directly above the roller, so that the 
weight of the operator would keep the roller 
steady and firm. As necessary, additional 
weight can be kept on the platform for firmer 
chopping (Fig. 2 a; completed roller'and 2 b;J 

details of bearing and support system). 

Use of the chopping roller 

The roller can be drawn by a pair of draught 
animals. It can be easily constructed by a 
village blacksmith using local materials at a 
cost of about Rs 5,000/-. A mapr advantage is 
that it can be maintained and repaired by the 
village blacksmith. Performance-wise, it 
comfortably 'manages' abou* 120 coconut 
squares (about 2 acres) each day without 
excessive exhaustion for either the animals or 
the operator. 

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