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Clonal Poplars |
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| INTRODUCTION |
| Poplar is a fast growing tree which is considered to be one of the best species for agro-forestry. Some of the selected clones of polar are being grown successfully in the states of Punjab, Haryana, Uttar Pradesh and Uttaranchal of India, which are harvestable within 6 to 8 years of short rotation. The growers are advised to buy healthy and high quality saplings of poplar from reliable nurseries only to ensure high returns and better productivity. It is deciduous in nature hence winter crops can be grown with poplars further it adds tremendous amount of leaf litter to the soil. |
| USES OF WOOD |
| Wood of polar is suitable for manufacturing match splints, plywood, ply-board, packing cases, sports goods, artificial limbs, furniture, paper pulp, light constructional timber, pencils and wood wool etc. Due to its multiple uses, demand of poplar wood is increasing day by day. |
| SELECTION OF SITE |
| Well drained, fertile and rich soils in organic matter, loamy to sandy loam in texture are most suitable for better growth of poplars. Well before planting poplar trees, it is desirable to have assured source of irrigation to ensure higher survival and better growth. |
| SUITABLE CLONES |
| A number of good quality and high yielding clones of Populus Deltoides variety namely G-3, G-48, Udai, WSL-22, WSL-32, WSL-39, S7C8 and S7C15 etc. are most acceptable among growers. |
| SUITABLE TIME OF PLANTING |
| The most appropriate time for planting of Poplars is mid December to end of February, because polar is dormant and leafless during that period. |
| PLANTING DISTANCE/ SPACING |
| Each poplar tree needs approximately 20-25 square meter space for its optimum growth. Spacing, generally adopted by the growers for raising Poplars under Agro-forestry system in block plantations are:
5 x 4 meter 5 x 5 meter 7 x 3 meter 6 x 4 meter 8 x 3 meter
Thus, 160- 200 trees can be planted in an acre. Plant to plant distance is kept as 3 meter apart for single line or field boundary plantations. |
| LAY OUT AND PREPARATION OF SITE & PITS |
| With deep ploughing get the fields free from weeds and apply phosphatic and potassic fertilizers as basal dose as per the recommendations of soil testing report. Dig irrigation channels 45 cm. wide and 30 cm. deep in north to south direction based on pre determined spacing. It will result wider spacing in the east to west direction ultimately ensuring better sunlight to the trees as well as intercrops. Pits should be dug 90 cm. to 100 cm. (approx. 3 feet) deep with the help of screw auger or boki in these channels at the time of planting poplars. It is desirable to prepare the pits well in advance before carrying the saplings from the nursery for planting. |
| PREVENTIVE MEASURES AND PLANTING TECHNIQUE |
| The poplar saplings should be kept immersed in running fresh water for about 48 hours before planting. At the time of treatment of preventive measures before planting in the field unwanted, broken and damaged roots may be trimmed with secateurs or saw. For protection against termites lower one meter of the poplar transplant should be dipped in 0.25 percent Lindane or Chloropyriphos 20% EC Emulsion (250 ml. per 100 liter of water) for about 10 minutes. Similarly, to avoid fungal infection, dip the saplings in 0.25 percent solution of Emissan-6 (250 gm. per 100 liter of water) for about 20 minutes. Afterwards lower down the saplings in upright position in one meter deep pits prepared in advance with the help of auger or boki and fill up the pits with pulverized surface soil mixed with 100 gm. Single Super Phosphate, 2-4 kg. well decomposed Farm Yard Manure and an anti termite insecticide with chloropyriphos as an active ingredient. Light compaction of soil and adequate irrigation immediately after plantation enhances the chances of survival of the plants. It will ensure root’s contact with the soil and elimination of air pockets in the pits which can otherwise be starting point for fungal attack. The pits may be kept unfilled up to 4-6 inches lower than the ground level in saucer shape till the set of monsoon season, to ensure maximum advantage of irrigation water to each plant. At the time of on set of monsoon, refill more soil into the pits by keeping the saplings straight. Care should be taken that stem or roots of the saplings are not damaged while compaction of the soil around the plant. |
| IRRIGATION |
Regular, adequate and timely irrigation is essential for proper growth of poplars. The frequency and extent of irrigation depends upon various factors like amount of rainfall, type of soil, age of trees and climatic conditions etc. Ensure adequate irrigation during first two years of plantation through irrigation channels and afterwards apply flood irrigation in the fields.
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| AGE OF TREES |
SUMMER SEASON |
RAINY SEASON |
WINTER SEASON |
| 1-2 YEARS |
7-10 DAYS INTERVAL |
AS PER NEED |
10-15 DAYS INTERVAL |
| 3-8 YEARS |
10-15 DAYS INTERVAL |
AS PER NEED |
15-20 DAYS INTERVAL |
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| LEADER TRAINING AND PRUNING |
Initially, lower one third portion of the stem should be kept clean by removing emerging buds to ensure good growth of the leading shoot and avoiding obstruction to agricultural crops. Leader training is an important operation during the first two years. Co-leaders are to be removed so that a clean and straight leader is there.
Pruning should always be done during the months of December to February in winters when the poplars are dormant and leafless. Pruning should always be judicious. In second and third year, lower one third and in fourth and fifth year lower one half of the stem should be pruned with the help of a sharp pruning saw. It is better to apply Bordeaux paste after pruning at the cut ends. |
| INTER-CROPPING |
| In initial two years, it is desirable to grow following rabi and kharif crops as inter crops in block plantations of poplar e.g. ladyfinger, spinach, barley, coriander, strawberry, oats, berseem, mustard, radish, carrot, potato, chilly, brinjal, tomato, sweet potato, peas, cauliflower, cabbage, ginger, turmeric, wheat and sugarcane etc. After two years, any shade tolerant crop like turmeric and ginger or Rabi crops e. g. wheat and fodder crops etc. can be grown. |
| FERTILIZER APPLICATION |
It is better to apply Nitrogenous, Phosphatic and Potassic fertilizers as basal doses and top dressing as per the recommendations of soil testing report.
Generally, a basal dose of 2-4 Kg. fully decomposed FYM and 100 gm single super phosphate per plant should be mixed up with pulverized surface soil for filling up the pits at the time of planting poplars.
If soil samples are not tested, then a well decomposed FYM @ 10 tones per acre twice in a year, DAP @ 50 kg. per acre twice in a year and Potash @50 kg per acre once in a year should be applied while preparing the field for inter-cultivation of Rabi and Kharif crops.
Nitrogenous fertilizers should be applied in three equal doses with the difference of about one month during growing season (June-September) for obtaining a good tree growth. |
| AGE OF TREES |
FIRST DOSE |
SECOND DOSE |
THIRD DOSE |
| 2 YEARS
(50 kg. per acre) |
First fortnight of June @ 75 gm per tree i.e. approx. 15 kg per acre |
First fortnight of July @ 75 gm per tree i.e. approx. 15 kg per acre |
First fortnight of August @ 75 gm per tree i.e. approx. 15 kg per acre |
| 3-4 YEARS
(100 kg. per acre) |
First fortnight of June @ 150 gm per tree i.e. approx. 30 kg per acre |
First fortnight of July @ 150 gm per tree i.e. approx. 30 kg per acre |
First fortnight of August @ 150 gm per tree i.e. approx. 30 kg per acre |
| 5-8 YEARS
(150 kg. per acre) |
First fortnight of June @ 250 gm per tree i.e. approx. 50 kg per acre |
First fortnight of July @ 250 gm per tree i.e. approx. 50 kg per acre |
First fortnight of August @ 250 gm per tree i.e. approx. 50 kg per acre |
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Fertilizers should be applied to the whole field and not close to the stem of the trees as these can result in girdling of young saplings and can even kill them. Apply fertilizers when the field is free of weeds. Application of fertilizer must be followed by light irrigation.
Most of the soils are deficit in zinc and application of zinc sulphate @ 10 Kg per acre in such soils makes up the deficiency. In case of acute deficiencies in young plants, 2-3 sprays of zinc and lime (5 Kg zinc sulphate and 2.5 Kg hydrated lime in 100 litre of water) should be done. Symptoms of micro-nutrient deficiency include intra-veinal yellowing of leaves, small and shriveled leaves and poor tree growth. |
| PRECAUTIONS TO BE TAKEN AT THE TIME OF PLANTING |
(1) Poplar does not perform well on the lands having hard ‘Kankar’ pan in sub soils, , water logged areas, hard clays, dry sandy and drought susceptible soils, saline and alkaline ( pH > 8.5 ).
(2) Poplars have heavy crown thus it needs pruning. Therefore, plant to plant distance less than 3 meter apart may adversely affect the growth of the trees.
(3) Your assurance of high returns and better productivity from the trees depend upon purity, high quality, healthiness and site specific adoptability of the clones to be planted there. Therefore, buy decease resistant and healthy clonal plants from reliable nurseries only. It will be in the own interest of the grower to visit and verify the nursery and planting stock well before buying the saplings.
(4) Always plant healthy and freshly uprooted saplings. Saplings uprooted days before, may suffer from dehydration which may result in causalities later on.
(5) over healthy and very tall saplings in the nursery is not a parameter of better growth of poplars in the field in any way.
(6) Initially 3-5 meter tall saplings are more suitable for planting than very thick and big plants. Similarly, saplings less than 3 meter in height should be avoided for planting as these may remain suppressed in growth.
(7) one year old Entire Trans Plants (ETPs) without any co-leader or branches and with naked root (without any ball of earth) are better for planting and in growth in comparison to two year old coppice shoot saplings.
(8) The time gap between uprooting of saplings from nursery and planting out in the field should be minimized to avoid dehydration. This may ensure better survival.
(9) Proper care should be taken while carrying the saplings from nursery, during loading, unloading and transporting so that plants should be protected from scratches and the main stem does not break or damaged. During long distance carriages care should also be taken that the roots are kept moist and protected from excessive sun or wind.
(10) Do not mix up Choloropyriphos and Emisan-6 while treating the saplings. Treatments of anti-termites and to avoid fugal infection are to be done separately.
(11) In case poplars are to be planted along with crop of wheat, ensure preparation of irrigation channels at 5-6 meter (according to the spacing adopted) distance while sowing wheat. Plant the poplars in between the channels only. It will ensure timely irrigation to poplars as and when required without harming the crop of wheat.
(12) Use of weedicides in poplars as well as in intercrops is restricted.
(13) FYM should not be used if it is not fully decomposed otherwise it may attract termites.
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| CARE TO BE TAKEN AFTER PLANTING |
(1) Regular weeding should be done to keep insects and pest attacks under check.
(2) Fertilizers should be applied from second year onwards in the beginning of March. The fertilizer should not be applied too close to the stem. Apply light irrigation after the application of fertilizers.
(3) Poplars are extremely sensitive to fire. As such waste and trash of crops should not be burnt in the poplar fields or in the adjoining fields.
(4) The trees can be damaged by intense sunlight and high temperatures therefore, proper irrigation must be ensured to prevent this. It is desirable to apply white wash of lime and Copper oxidize all around the stem of the tree up to 1.37 meter above from the ground level.
(5) Attack of termites is common comparatively in dry and less irrigated areas. To prevent this soils should be treated with Choloropyriphos as and when necessary and arrange frequent irrigations.
(6) Proper care should be taken during field operations so that trees are not damaged by tractor/ farm implements.
(7) First year causalities should be beaten up with tall, sturdy and healthy ETPs during next planting season of January-February in the following year. After that no beating up should be done as the new saplings are not able to catch up with rest of the trees.
(8) Unless or until it is necessary do not make mounds near the collar region of the trees as roots may develop from that portion of the stem resulting loss of valuable wood. If it is necessary to make mounds to protect the trees from wind damage then collar region of the trees should be treated with Emissan-6 solution to avoid fungus attack.
(9) Paddy/ Rice should not be grown as intercrop with Poplars at all.
(10) Poplars respond well with cultivation of inter crops. Thus, those intercrops which are complimentary in nature with poplars can be grown successfully.
(11) Poplar does not survive in the land under stagnant water or water logged conditions. Therefore, take care of proper drainage.
(12) Coppice crop of poplars is not recommended due to its poor coppicing, lesser height and more taper in stems than the normal.
(13) Address the Zinc deficiency in the fields of poplars by applying 10 kg. of Zinc Sulphate per acre every year.
(14) Excessive and poor pruning is more harmful than no pruning. Pruning should therefore, be done carefully and systematically.
(15) Where there is an insect/pest or pathogens attack, seek proper technical guidance to adopt and follow appropriate remedial and plant protection measures.
(16) To get maximum weight of poplar wood harvest the trees in winter only because it has maximum weight then due to dormancy.
(17) Protect plants from animals. By rubbing their horns or body against the tree they peel off the bark thereby hampering its growth.
(18)Some times bark bursts are there in poplars and water oozes out through the wounds resulting in cankers. Avoid injury and high water table sites. Clean the wounds and apply Bordeaux paste or Emisan-6.
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