Land Preparation and Planting
Land preparation for this year’s planting, if not started yet, can be undertaken. At the time of refilling the planting pits, 12 kg of compost or well-rotten cattle manure and 175g rock phosphate are to be applied in the pits, well-mixed with the top 30cm soil. In newly-cleared forest areas, only rock phosphate need to be added while refilling the pits.
Planting may be carried out during favourable climate. Lateral roots of budded stumps are to be trimmed about 7.5 to 10 cm from the tap root and should in no case be trimmed too close to the tap root, since these lateral roots have an important role in the proper root development and initial growth of the plants in the field.
If polybag plants are used, the top storey of the leaves should be mature at the time of planting. The polybag plants should be watered properly on the previous day of its field planting. When the polybag plants are taken out of the trench, dressing of the roots is necessary, if grown out of the bags. At the planting points, a planting hole bigger than the size of the bag is made. The bottom of the bag is completely cut and then the bag along with the plant is placed into the planting hole. A vertical cut is made at the bottom half of the bag and the space around the bag is gradually filled with soil to fix the soil core firm in the hole. When the hole is thus partially filled, the bag is slit along its full length and carefully removed. The gap around the upper part of the soil core is also to be filled with soil without causing, any damage to the roots. While planting, the scion of the polybag plants should be directed towards the northeast to minimise the adverse effect of direct sunlight on the bud patch.
Cover crops are established and maintained in rubber plantations for smothering weeds, conserving the soil, and improving or maintaining the soil structure and fertility. Leguminous creepers, which are easy to establish are the most desirable ground covers in rubber plantations. Cover crops are to be established in new plantings immediately after clearing the area for planting. Cover crop should not be allowed to grow in a circle of above two meters diameter around the plant base or along the terraces for 3-4 years to prevent competition with the young rubber.
Different legumes are used as cover crops. Pueraria phaseoloides is the popular cover crop in India. The wild legume Mucuna bracteata, which grows fast and covers the field quickly and is not eaten by cattle, can also be used as cover crop. Rooted stem cuttings can be used for its propagation. Cover crop seeds have a very hard seed-coat, which delays or inhibits germination. Certain pre-sowing treatments are therefore warranted to obtain a high rate of germination. Hot water treatment is a common pre-sowing treatment for enhancing the rate of germination. For hot water treatment, hot water (60-80oC) should be poured into a bucket, which contains seeds till all the seeds are submerged and kept as such for 4-5 hours. The pre-treated seeds mixed with equal quantity of rock phosphate can be sown in the fields.
The pre-treated seeds mixed with rock phosphate are sown in rows or in equidistant patches between plant rows. In places, where drought is a limiting factor in the establishment of cover crops, the germinated seeds may be sown in coconut husks filled with soil and the plants with husks should then be planted in the patches in the field. Cattle grazing and cutting away for fodder should be avoided, since it adversely affects the establishment of cover crops. About 3 - 4.5kg of Pueraria phaseoloides is required for 1 ha of plantation.
Manuring Cover Crops
Manuring the newly planted cover crops can be undertaken during this month. Rock phosphate alone or a mixture of rock phosphate and muriate of potash is good for its quick establishment. Application of 150 kg of powdered rock phosphate per ha in two equal instalments, the first, one month after sowing and the second, two months after the first application, and in areas where the soils are deficient in available potassium, application of a mixture of 150 kg of rock phosphate and 50 kg of muriate of potash is recommended. The fertilizers may be broadcast on the strips where the cover crop is planted.
Weeding has to be undertaken in the rubber plantations as the weeds may compete with rubber for light, moisture and plant nutrients and adversely affect the growth of the plants. The weeds so removed may be kept in plant rows. The weeds after drying can be used for mulching the plant base.
Spraying with 1 % Bordeaux mixture may be done on the tender green shoots and on the tender leaves of young rubber, to protect them against diseases like shoot rot, Phytophthora leaf fall etc. Since more leaves are emerging during this time in polybag plants in the nurseries, the disease may occur repeatedly in them. Hence, spraying with copper fungicides before the onset of south west monsoon coupled with repeated spray rounds during bright breaks is necessary. For ensuring proper sticking of the spray on tender foliage, stickers like Tenac, Teepol, Sandovit (@0.5 ml/L) may be added to the spray fluid.
The immature rubber plants may be inspected on sunny days for any incidence of pink disease. White glistening cob-web mycelial growth on the bark surface is the initial stage of the disease. Bordeaux paste or Thiride (10 g in 1 kg wound dressing compound) may be applied 30 cm above and below the affected region. Removal of decayed bark ensures better control.
Patch canker is also noticed during rainy season. The affected region may be scraped to remove all rotting bark. The coagulated rubber pad if any under the bark may be removed. The wound is to be washed with Dithane M 45 / Indofil M-45 @ 10 g/L and after drying, a wound dressing compound like Rubberkote may be applied.
Uprooting and trunk / branch snap occur during rainy seasons. Any wound due to wind may be treated with a fungicide solution and then coated with petroleum wound dressing compounds to keep moisture off. Dry rot disease incidence is noticed where wind damage is more.
If tapping is continued in rainy season using rainguards, the panel may be protected from bark rot disease by washing with Indofil M-45 (Dithane M-45) @ 5g/L or Akomin/Phosjet 2ml /L at weekly intervals.