Preparing Coffee for Overhead
Weeds compete with coffee plants for water, light and mineral nutrients. If weeds are allowed to grow during late post-monsoon period, they use the soil moisture which coffee needs in the following dry weather. Free growth of weeds reduces the yield of coffee and plants assume a sickly appearance. In young clearings, weeds are a serious problem particularly during the first three years. The pruned fields where the ground is exposed are also prone to weeds.
Methods of weed control
Typically new clearings are hand-weeded 3 to 4 times and established coffee fields 2 to 3 times a year. During the monsoon season, weeds are slashed back (slash weeding) with the help of a matchete. Clean weeding is generally done during post-monsoon period. It is a labor intensive and time consuming operation in coffee estates.
In new clearings, the field is given a thorough digging (cover digging) to a depth of about 37 to 45 cm towards the end of monsoon. All weeds and vegetative debris are completely turned over and buried in the soil.
In young clearings, coffee at normal spacing covers only a small portion of the soil surface and there is room for prolific weed growth. Inter-planning of green manure crops, cover crops and annual crops such as grain legumes, cassava, beans, pigeon pea, yam, sweet potatoes, vegetables, pineapples help suppress weeds to large extent. Intercropping has been successful in Robusta coffee plantations in Wayanad region of Kerala. In established plantations, scuffling and mulching at the end of monsoon can be effective in controlling weeds.
Chemical Weed Control
Chemical weed control methods (weedicides) are employed where labour is scarce or expensive or when labour has to be diverted to other important cultural operations like manuring and spraying. Weedicides can be classified based on time of application (pre-emergent and post-emergent), mode of action (contact and systemic) etc.
Pre-emergent weedicides are applied before the emergence of weeds to moist soil. These are taken up through the germinating roots of weed seeds and remain in surface layers of the soil long enough to kill the weed seeds. These weedicides have a long residual effect and growth of coffee and cause phytotoxicity. Pre-emergent weedicides (simazine, Atrazine) are not usually advocated in coffee plantations. Post-emergent weedicides
- Farm wastes: Any farm wastes like cherry husk, coffee pulp and other crop residues like straw etc. would form the basic raw etc. would form the basic raw material for compost preparation.
- Animal wastes: cattle shed wastes containing ding and urine, goat droppings, piggery and poultry wastes.
- Green material: Any green plant material (preferably of legumes) like leaves, shade tree lopping, weed biomass etc.
- Compost enrichers: Rock phosphate, bio-fertilizers (Azotobacter, Azospirillum, ‘P’ solubilisers, Trichoderma, VAM) could be used for enriching the compost.
- Decomposition enhancing cultures: Phanerocheate chrysosporium, Trichoderma viride, Aspergillus awamori, Pleurotus sajarcaju, Bacillus, Pesudomonas cultures and yeast cultures.
- Nutrient additives/enhancer: Neem cake, pongamia cake, cow dung slurry, butter milk.
Materials to be Avoided
- Residue from crops sprayed with pesticides or herbicides.
- Materials diseased with rusts and viruses.
- Hard prickles or thorns.
- Persistent perennial weeds. To avoid any chance of these weed spreading, they should be killed by burning or spread in the sun till they dry out completely
- Paratoxic materials like metals, rubber, glass and plastics.
- Large quantities of newspaper and cardboard will greatly slow the rotting process.
Selection of site Composting should be done under shelter of trees to prevent drying of heaps and to preserve moisture. Size of compost heap The compost heaps should essentially have 1.5 to 2 m width and about 1 m height. They can be of any convenient length depending upon the availability of raw materials. Preparation of the materials Although many materials can be used directly, some may need pre-treatment before composting, as given below.
- Material containing high moisture content (e.g. coffee pulp) should be allowed to wither a little.
- Rough and coarse materials such as stalks of paddy should be broken or chopped before use. The best way to break these materials is to spread them over cattle shed. It will also help in collecting the urine and dung properly.
- Dry woody material like cherry/parchment