PACKAGE OF PRACTICES FOR MULBERRY CULTIVATION AS TREE PLANTATION FOR RAINFED SERICULTURE

PK. Das, SB. Magadum and DS. Chandrasekhar
Dr.P.K.Das is Scientist-D at Regional Sericultural Research Station (RSRS), Central Sericultural Research & Training Institute, Central Silk Board (CSB), Government of India Chamarajanagar, Karnataka, India. He has put up a service in Central Silk Board, for more than 28 years. He worked for more than 20 years at Central Sericultural Research & Training Institute (CSR&TI) Mysore in Agronomy laboratory and developed a number of technologies for cost effective mulberry cultivation. Among his interests are recycling technologies of sericultural wastes, compost and vermicompost, Azotobacter and VA-mycorrhiza as biofertilizers and developing Integrated Nutrient Management for mulberry cultivation. He was selected as the best scientist of moriculture of CSR&TI, Mysore in the year 2005. At RSRS Chamarajanagar he is developing technologies for rainfed mulberry. He has more than 100 research publications in national and international journals and guided four Ph.D students in Applied Botany under the university of Mysore. He has also visited Japan under Japan International Co-operation Agency (JICA) project of Central Silk Board during the year 2000. Dr. Das can be contacted at pkd3@rediffmail.com

Dr. S.B. Magadum is Scientist-D with CSR&TI, Mysore, India. He has more than 35 year’s research experience. A veteran silkworm physiologist, he has published more than 140 research publications in national and international journals. Dr. Magadum can be contacted at sbmagadum@rediffmail.com  

Dr. D.S.Chandrashekar is Scientist –D and in charge of RSRS, Chamrajanagar. He is an expert of mulberry pathology. He has more than 33 year’s research experience. He is currently supervising 6 Ph.D students and have more than 100 research publications in national and international journals. Dr. Chandrasekhar can be contacted at rsrschnagar@rediffmail.com  

What is tree mulberry?

The mulberry plants which are allowed to grow tall with a crown height of 5 - 6 feet from the ground level having stem girth of 4 -5 inches or more is called tree mulberry. They are specially raised with the help of well grown saplings of 8 - 10 months old with any of the varieties recommended for rain fed areas like S-13 (for red loamy soil) or S-34 (black cotton soil) which are tolerant to draught or soil moisture stress conditions. Usually the plantation is raised as block plantation with a spacing of 6 feet x 6 feet or 8 feet x 8 feet as plant to plant and row to row distance. The plants are usually pruned once in a year during monsoon (July - August) at a height of 5 - 6 feet from the ground level and allowed to grow with maximum of 8 - 10 shoots at crown. The leaf is harvested 3-4 times in a year by leaf picking method under rain fed or semi-arid conditions depending upon the monsoon.

Fig-1: Two years old mulberry tree plantation

Concept of tree plantation:

Combining trees and field crops in arable lands is called as "agro-forestry". The objective of agro-forestry is to improve the productivity and sustainability of land management system through introduction of woody perennials in herbaceous crop husbandry. Selection of tree species to be used in agro forestry must be based on cultural and economic as well as environmental and biological factors. Thus growing mulberry as tree in highly eroded flat to gentle sloppy land unfit for growing arable crops, arable lands with soil fertility problems, degraded sloppy land can serve as one of the best means of agro-forestry.

Who can grow tree mulberry?

Mulberry is a perennial plant with reasonably drought tolerance capacity. It can be cultivated as a trained tree by maintaining specific spacing between trees and crown height. This type of mulberry plantation is highly suitable for farmers of semi-arid / rain fed areas in plain land, hilly regions or in denuded lands unsuitable for agriculture. This form of cultivation is already been practiced in temperate and hilly regions. Of late, the concept of tree cultivation has also spread into the plains as a sustainable crop under severe water stress condition in waste and denuded lands. With the recommended packages, it is now possible to get about 6 - 8 MT of mulberry leaf yield per hectare per year through 3 - 4 harvests. It is also possible to take up appropriate inter crops in the tree mulberry plantation to reap higher economic benefits. Considering the above, mulberry can be cultivated under rain fed conditions with different systems of cultivation. These include;

(a) Bush system of mulberry cultivation: under protective irrigation.

(b) Low-height tree type mulberry cultivation: Suitable in hilly regions.

(c) Tree mulberry cultivation: Best suited to overcome acute water stress conditions.

Package of practices for mulberry tree plantation:

Development of mulberry tree saplings:

The mulberry saplings are developed in the nursery. A flat land nearer to water source is preferred as nursery site. Well drained land with loamy soil is ideal for nursery. The land must be ploughed or dug 30‑40 cm deep and allowed for weathering in sun for 2 - 3 weeks. Land is again ploughed two or three times to bring the soil to fine tilth. Root stocks, pebbles and weeds are removed at the time of ploughing and the land is leveled. The land is divided into a number of small beds to prepare the nursery. The size of each bed is decided keeping working convenience in to mind. A bed size of 3.0 m (L) x 1.2 m (B) accommodates 100 cuttings (row to row 30 cm and cutting to cutting in a row 10 cm distance) to raise 8-10 months old saplings. Each bed on all sides is separated by a bund of 25 to 30 cm width and height and provided with irrigation channel of 25 to 30 cm width and 15 to 20 cm depth. Each bed should be manured and mixed thoroughly with 5 pans of FYM / sericulture compost / vermicompost. In the case of clayey or black cotton soil, additional 5 pans of sand per bed should be mixed with soil uniformly. In the case of red loamy or sandy loam soils, there is a possibility of termite infestation. As a preventive measure, 0.1 % Chloropyriphos (5 ml per litre of water) can be sprayed to drench the soil of nursery beds (2-3 litres per bed). Regular care and irrigation should be provided for good growth.                

 Fig-2: Mulberry nursery under preparation

Transplantation of saplings from the nursery

For tree plantation, the saplings are transplanted from the nursery after 8-10 months of maturation. The matured saplings are removed from the nursery by deep digging and without damaging the roots. It is advisable to irrigate the nursery beds thoroughly at least 2-3 days before uprooting to facilitate easy and complete removal of saplings with roots intact. The uprooted saplings are immediately planted in the main field after removal of leaf, top clipping and dipping the roots of the plants in 0.2 % solution of Diethane -M 45 to avoid fungal root disease.

Fig-3: Appropriate mulberry cuttings for nursery to grow as saplings

Plantation of saplings in the main field & establishment care:

A flat / sloppy land with red loamy / black cotton soil or denuded land not suitable for other agricultural crops can be selected for raising tree mulberry as block plantation. Plantation can be taken only during rainy season preferably in July - September or depending upon the onset of monsoon. The land should be thoroughly ploughed by tractor / bullock plough depending upon the soil condition after receiving one or two pre monsoon shower and weeds should be removed.

Fig- 4: One year old mulberry saplings ready for transplantation as tree plantation.

Once the land is made ready, farmyard manure / sericulture compost can be applied @ 10 MT/ ha and mixed with the soil. It is highly necessary to follow soil moisture conservation practice by raising wide bunds all along the four boundaries of the plantation to avoid runoff and allow rain water percolation in the planted area during monsoon. Before plantation, pits of the size of 35 cm (L) x 35 cm (B) x 35 cm (D) are dug at 8 feet apart from each other considering plant to plant and row to row distance as 8 feet x 8 feet. Each pit is then planted with one transplanted matured sapling exactly in the centre of the pit. To determine the centre of the pits and to keep the rows straight to avoid zigzag plantation, two ropes are used length and breadth wise and the intersecting point of the two ropes is considered as the centre of each pit. The pits are then filled with soil and pressed properly for better anchorage with the ground. Once the plantation is over, all the planted saplings are pruned uniformly at 5 feet height (crown height) from the ground level within 2-3 weeks and allowed to grow for 8-10 months as establishment period or even a year without harvesting leaf / disturbing the plants. However, weeding should be done as and when required during the establishment period to facilitate better growth. After 4 -5 months of plantation, the first weeding is done manually or by using power tiller to avoid damage and chemical nitrogen fertilizer only @ 50 kg per hectare is applied to boost the growth of plants. The required fertilizer in the form of urea / ammonium sulphate is applied near each plant by making basin and irrigation is followed. If required gap filling can be made with properly grown sapling. Plants should be given life saving irrigation as and when required in non rainy period for better establishment. Further, the whole planted area can be divided in to small blocks of 15 - 20 plants in each having wide bunds all along the four sides to allow in-situ soil moisture conservation during rainy season. During the establishment period, the plants may attain a height of 10 -15 feet from the ground level with three to four branches if properly maintained.

Fig-5: Mulberry tree plantation under progress in main field.

Pruning and package to be followed from the second year:

Once the plantation is established properly, the plants are pruned uniformly at the same crown height (5 feet) where the plants were pruned earlier during the time of plantation. This should invariably be followed only during rainy season (July - September) to facilitate the vigorous growth of shoots from the second year onwards. Farmyard manure @ 10 MT per hectare per year is applied within a week of pruning and the weeding is followed with the help of tractor / power tiller / country plough to mix the manure with soil and to save the manual lobour days. Immediately after this basins around the plants are cleaned to apply fertilizers and allowing rain water percolation near the plants. Depending upon rainfall, chemical fertilizer NPK is applied @ 150:60:60 kg per hectare per year in two equal splits in the form of ammonium sulphate for alkaline soils or urea for acidic soils in early and later part of rainy season. Green manuring with sunhemp or dhaincha for the improvement of soil fertility and water holding capacity or intercropping with short duration crops (Groundnut, Cowpea, Horsegram , Ragi etc) for augmenting income can also be done from the second year onwards. If the plantation is inoculated with VA-mycorrhiza followed by green manuring, reduced dose of FYM & NPK fertilizer can be applied @ 10 MT and 50:25:25 kg per hectare per year respectively. Leaf can be harvested by individual leaf picking after every three months depending upon the rainfall and soil moisture condition. Thus it is possible to harvest 3 - 4 crops annually ranging from 7 - 8 MT of leaf per hectare per year.

Fig-6: Pruned mulberry saplings after one year of plantation.