Planting can still be undertaken if weather is conducive. Rains at periodic interval enhance sprouting of budded stumps and favour better establishment of polybagged plants in field. Before planting, the fertility status of the field can be ascertained by analysis of representative soil samples from the field. Manuring for the initial four years can be based on this soil analysis. Leaf and soil samples can be analysed during the fourth year and fertilizer recommendation for the fifth year can be obtained. From fifth year, it is recommended to analyse the leaf sample every year and soil sample once in three years.
Germination of seeds
In South India, seeds of Hevea normally become available by the end of July. The viability of rubber seeds is short, but the viability can be retained up to one month if they are packed in gunny bags lined with perforated polythene sheets or double gunny bags along with moist charcoal powder. For better germination seeds are sown in germination beds as soon as obtained. The germination beds may be prepared in advance.
Level lands should be selected for raising germination beds. The size and shape of the germination beds can be decided on the basis of the nature of the land available. River sand is the best medium for germination of the seeds. The surface of the germination beds should be raised six inches above the soil surface to avoid waterlogging.
The seeds are sown in a single layer touching one another and pressing firmly into the sand. The seeds are to be sown with its surface just visible above.
The beds may be covered with loosely woven coir mats or plaited-coconut leaves. A high level of moisture is to bemaintained in the bed by evenly sprinkling water early in the morning and later in the evening. Extreme heat or moisture in the germination beds may be avoided. Germination starts within seven days after sowing. Seeds sprouted each day should be picked and planted. Delay in transplanting may cause damage to the tender roots resulting in plants with bent or twisted roots.
Spray 1% Bordeaux mixture on the tender green shoots and on the surface of the tender leaves of young rubber to protect them from diseases like shoot rot and other leaf diseases.
Since the tapping panel is damp during the wet monsoon months, the continuance of tapping during the season, with or without rainguarding, may cause bark rot disease. To protect the panel from bark rot disease, fungicide solutions may be applied as a spray or brushed on tapping cut and just above. Mancozeb (Dithane/Indofil M-45) 0.375 per cent (5g/L of water) or phosphoros acid (Akomin/Phosjet) 0.08 per cent (2ml/L) is effective in controlling bark rot.
Pink disease usually occurs during south west monsoon period, but severe incidence and drying up of the plant/branches are noticed from August to November. Weekly inspection for disease is to be carried out on sunny days, especially on young plants. Initially, white or pink-coloured cobweb mycelial growth on the bark surface may appear with streaks of latex oozing out from the lesions. Rotting, drying up and cracking of the affected bark follow.
In the initial stages of infection, when superficial mycelium only is present, Bordeaux paste may be applied on the infected parts and 30 cm above and below. When the infection advances, the pathogen penetrates into the bark and cracks are formed in the bark and exudation of latex occurs. In such cases, Bordeaux paste may be applied initially and after drying, the affected region may be scraped to remove all the decayed tissues and then the paste is applied again as done earlier.
One kg of powdered copper sulphate is dissolved in 5 L water. In another vessel, 1 kg of fresh quick lime is slaked by sprinkling water and volume of lime solution is made up to 5L by adding water. Bordeaux paste is prepared by pouring the copper sulphate solution in to the lime solution, vigorously stirring the mixture during mixing. Instead of Bordeaux paste, organic sulphur fungicides, Thiride, mixed in petroleum wound dressing compound at the rate of 10g/kg of compound can also be applied on the affected region, to control the disease.
The main stem of young plants may be damaged or broken due to strong wind. If necessary, the plants may be provided adequate support using wooden or bamboo poles.
Manuring the seedling nurseries
Two and a half tonnes of compost or well-rotten cattle manure and 350 kg of powdered-rock phosphate for every effective hectare, i.e. 25 kg compost or well-rotten cattle manure and 3.5 kg of powedered rock-phosphate for 100 sq.m. may be incorporated to the nursery bed as a basal dressing by thorough mixing with the soil. The nursery beds may be leveled and kept ready for planting. If the same beds are used repeatedly, application of rock phosphate has to be made once in three years. If the nursery is opened in a newly-cleared forest area, compost or cattle manure is not necessary during the first year and rock phosphate alone is sufficient.
Manuring may preferably be carried out after ascertaining the specific nutritional requirements of individual nurseries by soil analysis.
For the quick establishment of the newly planted leguminous cover crops in plantations, application of powdered-rock phosphate at the rate of 150 kg per ha. in two equal installments is recommended. The first application can be made one month after sowing the cover crop seed and the second to be made two months after the first application. In areas where the soils are deficient in available potassium, application of a mixture of rock phosphate and muriate of potash in 3:1 proportion at the rate of 200 kg per ha. is recommended.
Cattle grazing and removal of the vines for fodder should also be prevented for ensuring proper growth and ground spread. In plantations where the cover crop is well established, care should be taken to prevent it from competing with young rubber. Cover crop should not be allowed to grow in a circle of about 2 meters diameter around the plants or along the contour terraces.
The growth of weeds is fast during monsoon season. Weeding has to be carried out in the rubber plantations and the weeds so removed may be kept in plant rows. The weeds when dried can be used for mulching the plant base.