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The Plantation of Pongamia Pinnata
Initial Growth Period: In the initial phase of growth, roots grow very rapidly and try to penetrate in soil to suck nutrients from the soil. For this the bags should be filled with good, fertile soil, while preparing the saplings. If the soil is not fertile or if soil is sandy, larger quantity of cow dung and other fertilizers are required. If minerals are present in soil, minerals that neutralize these should be mixed with soil in the pit. Gypsum, quartz or sulfates are used as additives. These soils should be free of weeds and pests. When the seedling is planted, the the upper part of pit is filled completely and tightly with the soil that was dug out. The soil in pit should not sink. This will allow water to accumulate, at the root, which will spoil the roots of seedling.
Maintenance of Soil: While performing weeding, piling the crop row can be done as well. Piling means that the soil around the crop row is lifted up forming a ridge. In this way, the furrow can be irrigated. The soil between two plants should be tilled lightly, for water to percolate in soil. Bending plants are supported by some support to keep them upright. All the weeds that grow naturally in rainy season around the plant should be removed as these consume fertilizers required for Pongamia Pinnata. Weeds affect the growth of Pongamia Pinnata. A lot of pests grow on these weeds, and these pests cause damage to Pongamia Pinnata. The weeds in 600 mm diameter soil are uprooted and the soil is kept soft. Initially for 3 to 4 months, land should be tilled 2 or 3 times after 20 days, to remove weeds. 10 grams of urea should be mixed in the soil, for each plant, one month after plantation. Later, process should be repeated after one and half month. If some pests are observed, then these can be killed by normally available pesticides. 1 to 1.5 gram of Thimate or Phorate per plant is sprayed as a ring, 150 mm away from stem. This prevents growth of termites or red mites.
Shape of Plant: Branches of Pongamia Pinnata that have dried up should be cut and disposed off. Branches that have grown improperly or those leaning down should also be removed. Mulching is the best way to hold water in soil, in case of dry land. Some natural materials can be used to cover the land between the two plants. This can be husk, small branches, stocks of rice and wheat etc. This reduces evaporation of water from the soil. Natural covering is not affected by pests.
Maintainance of Plants: Pruning of Pongamia Pinnata is essential to give tree an umbrella like shape. If tree is not pruned properly, a lot of branches grow from low level. This creates problems in weeding activities. The branches grow in haphazard manner, and the space between two plants is occupied by these. This creates problems for a person to go along the plantation to collect seeds at a later date. Also no inter crop is possible in such soils.
Water Tension: Artificial flowering by water tension is equally important as is pruning and trimming. Normally Pongamia Pinnata can naturally flower only once a year, but with modern techniques tree can be forced to flower twice or thrice a year. To do this watering of the plants is stopped for a period. During this period half the leaves are shed by the tree. Water supply is restarted at this point and tree starts flowering again. When watering is started again, the quantity of water is increased slowly day by day and NPK fertilizers are provided. Normally, flowering takes place after 21 days.
Period of Tension: In this process the application of water tension and releasing water tension is done. Water tension is a technique. Period of tension or period of rest is 35 to 40 days in low quality soil, 45 to 55 days in medium soil and 60 to 70 days in good quality soil. When 35% to 50% leaves are shed by the tree, it is considered that rest period is over.
Releasing the Water Tension: While releasing the tension after rest, half a liter of water, per plant, is sprinkled on the plant. Some NPK fertilizers are added to water. After 7 to 10 days double the quantity is sprinkled. This is repeated once or twice after every 7 to 10 days. New leaves grow on tree, followed by flowers and fruits. Generally this process requires 21 to 25 days. In rainy season, this takes place naturally.
Fertilizers: In case of regular plantation, organic and chemical fertilizers should be provided in proper quantity as per the age of the plant. Soil testing should be done, to find out which type of nutrients are needed. A lot of nutrients are required in the initial phase of plant, which is decided based on soil test. Chemical fertilizers can be applied only if water supply is available. Fertilizers should be provided during certain period in time and during period based on the age of the plant. If applied at wrong time, these fertilizers are wasted. In the initial phase, nutrients are required for the growth of the plant. Growth and bearing of good fruits depend on the nutrients and weather. If fertilizers are provided from time to time, the land becomes more and more fertile. If nutrients are not provided, plants can become sick and can be attacked easily by pests. For one plant, 500 grams to 1 kg of seed cake of Pongamia Pinnata, can be used as fertilizer, when seed cake is available after two to three years of plantation.
Chemical Fertilizers: In case of Chemical Fertilizers, Nitrogen is required in larger quantity for fast and healthy growth of the plant. For an average soil, 10 to 15 kgs of cow dung, 200 to 500 gram of urea, 150 to 200 gram of single super phosphate, 250 to 300 gram of muriate of potash, should be given to each plant. In the first and second year, fertilizer dose should be 46 kgs of Nitrogen, 48 kgs of Phosphorous and 24 kgs of Potash per hectare. As the roots grow longer, fertilizers are applied away from the base of the tree around, as a ring. The rings increase in diameter as the tree grows. The ring should be of 300 mm diameter in first year, 600 mm in second year, 800 mm in third year, 1,000 mm in fourth year. These ring will touch each other, and this area of land will be covered by the tree on the soil.
Organic Fertilizer: Its application is as follows. A small ditch is dug around the plant. The spread of the ditch is three fourth of the crown of the plant and the depth is 30 to 50 mm. Organic Fertilizer is put into the ditch. The ditch is then covered with the soil and compacted.
Pruning: The plant grows vertically, very rapidly. The rising top of the tree should be cut once the tree is 1 meter tall (preferably in nursery itself). When a branch is cut, 4 more branches grow from earlier nodes. These multiply at every pruning action. This will lead to branching of the tree. More the branches, more the production of fruits and seeds. Every year branches grow near the base, and these should be removed and replanted elsewhere. It is very important to cut the branches in time and keep the tree in proper shape. The top of plant should be cut in proper way, so that tree will grow like an umbrella. Care should be taken from the beginning. The branches are pruned every year, so that these multiply.
When Pongamia Pinnata is cultivated as plantation, trees have to be pruned to make the branches grow maximally. Pruning is aimed at increasing the number of productive branches, which means more fruit will be produced. Pruning can be done after the plant is 6 weeks of age. The stem or branch is cut off 20 to 30 cm above the soil surface or from last pruning. At least 2 to 4 leaves are left at the end of the branch cut. New branches will grow on cut stem. Quantity and quality of fruit are influenced by the soil fertility. The type of further pruning is production and maintenance pruning. This is done by cutting off the secondary and tertiary branches, which are already not productive. A good plant has 30 to 40 branches at a height of 600 to 900 mm from the ground.
Thinning of plant is important to reduce competition among plants. Thinning is done by throwing out a plant in a dense surrounding. For instance, plants with 10 meter distance in between 2 plants. After thinning, gap in trees will become 10 meters by 10 meters. The cutting also can be used for grafting. Pruning and thinning should be executed periodically.
Flowering and Pollination: Pollination on Pongamia Pinnata is carried out by insects. Flowering and Pollination takes 90 days to complete fruit formation from flowering up to mature fruit. Fruit production started at the age of 4 to 5 months. Full productivity will occur at 5 years of age with a yield of 1/2 to 1 kg seed per plant per year. Production of flower and seed is influenced by rainfall and nutrient. Shortage of nutrients will reduce the seed production. If only dependant on the rainfall, fruiting occur only once a year, but if irrigation is available, fruiting can be upto three times per year.
Water Management: Water is essential ingredient of all living beings. Water content is different in different parts of the tree. Each tree sucks water from soil, as per its requirements. Plants get the nutrients from soil as water solution. Hence its successful growth depends on water content of soil, or timely watering of the plants. In the initial stages tree is sensitive and hence, water should be provided as per the requirement. Tree requires different quantity of water in different seasons. Growth also depends on temperature in the area and fertility of soil. Average 1 to 2 liters of water should be provided per plant every 5 to 6 days in poorer soils, every 7 to 10 days in medium soils, and every 10 to 12 days in good soils.
Methods of Irrigation: In monsoon the trees bloom and flowering and bearing of fruits can be achieved with rain water. If there is no rain for long time, water should be provided for good yields. After the rainy season, during harvesting, the plant has rest period. For good yield watering should be done once or twice, after the branches start growing. When the fruits are growing, moderate water supply is essential. Otherwise the fruits might crack, and may fall down. Since Pongamia Pinnata is strong and wild variety, Karanj can also grow in jungles, without much of water supply, but yield can be low.
For plantations, it is necessary to erect small boulder check dams, to create small and big water bodies. The size of these ponds depend on the rainfall and slope of the land. This water can be used after the monsoon.
A sprinkler system based on rain gun, can be used for irrigation. sprinkler system can be Stationary or Moving. A Water tank placed in Bullock cart or tractor trailer can be used to supply water. Drip irrigation can enhance the yield. Through this controlled amount of water and fertilizer can be provided all the time. With drip irrigation, 3 crops can be obtained in a year. Water should wet only the area under the tree and rest should be dry. Hence initial requirement of water is very small. If monsoon rain is at regular interval of few days, rain water is sufficient for plantation.