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Protective cultivation

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Protective Cultivation- A Key for Sustainable Production in North Western Himalayas

By Navin C Shahi

Introduction: Major hilly areas in country are located in Himalayas, extending in 2500 km and 250 to 400 km width. Himalayas can be classified in 3 major categories, (1) Western Himalayas, (2) Central Himalayas and (3) North Eastern Himalayas. The specific environment and natural resources when coupled with appropriate technology provide a 'niche' for growing of vegetables, spices and condiments, medicinal herbs and ornamentals in hilly areas. These regions in India demand sustainable development. It was observed that in Kashmir valley maximum temperature inside the greenhouse was 10 to 20 0C higher than open field and 1.94 to 6.54 0C differences in minimum temperature. Average outside soil temperature at the depth of 5 and 10 cm were 11.25 and 11.11 whereas in the greenhouse were 15.03 and 14.14, respectively. However, the Ladakh region has conventional design for polyhouse locally known as 'Ladakhi Polyhouse' which increases the temperature upto 20 0C higher than the ambient outside-temperature.

Production Systems: Hills and mountainous areas are broadly classified as :

 1. Central Plateau Hilly Regions

2. Western Plateau Hilly Regions

3. Southern Plateau Hilly Regions

4. East Coast Hill Regions

5. West Coast Hill Regions

6. Gujarat Hill Regions

Jammu and Kashmir:

 1. Low altitude sub tropical zone.

2. Mid to high altitude intermediate zone

3. Mid to high altitude temperate zone

4. Cold arid zone

 Protective Structures:

 Net houses: These are used to reduce adverse effect of scorching sun and rains in vegetables, ornamentals and herbs.

Plastic low tunnels: These are used to raise early nurseries of vegetables and flowering annuals.

Green houses: These are framed structure covered with a transparent material in which crops could be grown under controlled environment. The environmental conditions refer to light, temperature, air composition and nature of root medium.

Glasshouse: Glass is used as a Glazing material in the green house. Glass houses are fitted with the help of wooden or metal frame. The glass houses are constructed in all shapes and sizes and is quite effective for winter cultivation but due to increase in day temperature in summer, it becomes unfit for cultivation during summer. High initial cost, difficulty in construction and frequent damage of glass panels by strong winds have limited its use in both the regions. Number of glass houses have been erected in the Kashmir region but very few were observed in Ladakh region. The variation in temperature between outside and inside conditions is 20 to 25º C

Gable Type: A number of wooden structures, constructed gable type, uneven span type and even span type structures are used in Kashmir valley and are covered with 200 micron ultra violent stabilized polythene. Generally wooden structure fabricated gable type greenhouses are predominant in the valley with an average size of 40 sq. m (4 x 10m).

Gothic Type: Big size polyhouse is generally made of gothic type in Kashmir valley because the use of heavy iron structure which can sustain heavy snow load. The slope of the top layer is 300 and its side walls and central height is 1 m and 3.7 m respectively. Generally gothic type greenhouses are an average size of 120 sq. m. (6 m x 20 m). 

Walk in Tunnel: It is most popular type greenhouse which is small semi spherical structure frame made of materials like wood or plastic, iron , G.I. pipes and covered with polyethylene or fiber reinforced plastics. Maximum number of walk in tunnel type green houses have been installed in Kashmir valley and Ladakh region. Department of Horticulture is providing these types of green houses to the farmers on subsidized rates. The various sizes of tunnel type green houses that were being utilized by the farmers and installed by different development departments are 40 sq. m (4 m x 10 m), 80 sq. m (5 m x 16 m) and 54 sq. m ( 9 m x 6 m).

Ladakhi Polyhouse: The most common green house in the Ladakh region is the Ladakhi polyhouse and is constructed by three side mud brick wall in place of polyethylene sheets which not only cuts down the installation cost but also reduces the adverse effects of strong winds and increases temperature retention in the green house. The polyhouse has three sides made of sun dried mud bricks. The back wall is 7 ft in height, while front has no wall. The average length of the poly house is 32 ft. with a width of 16 ft. The polythene is supported on wooden poles and side walls. 

Trench: This is a very simple, cheap and common green house structure especially for the Ladakh region of the state and, thus, has unlimited potential in the region. The various sizes of the trenches are (9 x 3 x 0.9 m) and (10 x 4 x 1 m) respectively.  In this pit type of structure, wooden poles are used to hold UV stabilized polyethylene film. The polyethylene is also covered by an additional polyethylene film or woolen or cotton sheet during night to reduce heat loss in extreme winter.

FRP Greenhouse: The glazing material used in the green house is fiber reinforced polyester. The normal dimensions of the green house are (30 x 9 m) with an centre height of 3.04 m and a side height of 1.82 m.  The initial cost required for fabrication of the greenhouse is high but the comparative life of the green house is much more than other.

Double layered Polycarbonate Greenhouse: The glazing material used in the green house is double layer polycarbonate. The normal dimensions of the green house is 16.8 x 9.1 m with a center height of 3.3 m and a side height of 1.8 m. The variation in temperature between outside and inside conditions is 20º C.

Polyench Greenhouse: This type of green house combines the trench and green house technology for achieving more temperature inside green house during peak winter. The glazing material utilized in the green house is polyethylene, FRP, double layer and triple layer polycarbonate. The normal recommended dimensions of the green house are (18 m x 4.5 m x 0.8 m).

Solar Polyhouse Drier: Field Research Laboratory (DRDO), Leh has designed and developed a low cost non-conventional zero energy based solar polyhouse drier for scientific and hygienic dehydration of surplus fruits and vegetables like apricot, apple, cauliflower, cabbage, tomato, etc. when there is a glut in the market and to facilitate its availability during the snow bound winter. The drier works on the principle of greenhouse effect where it traps the solar radiation and maintains the temperature inside between 55-69o C. Provision has also been made for removal of hot and moist air from the chamber. It reduces drying period by 40 - 50 % as compared to sun drying.  

Functional design:

 Light transmission: The green house should have adequate transmission of visible portion of sunlight depending upon crop requirement.

Crops: Tomato, capsicum and cucumber could be grown during off season in Northern plains.

Size: Size may be upto 1000 sq. mt growing area or as small as 20 sq. mt for hardening of tissue culture.

Environmental control: It depends on location of green house. The initial and operating cost become high for some structures. Cooling is generally avoided in this region.

Frame: It could be constructed with wood, aluminium, steel bamboo, bricks, stone, concrete, etc.

Glazing material: UV stabilized LDPE, PVC, EVA acrylic, fibre glass and polycarbonate are being used nowadays.

Structural designs: It must provide adequate safety from wind and snow. Life span of green houses is 25 years, tolerance against atleast 130 km/hr wind speed, temperature extremes, etc.    

Protective cultivation in temperate- dry areas: Protective cultivation and farming in trenches or poly houses has emerged as an important technique in Ladhak region. Poly houses are made of local wood and polythene sheets. These are used for increasing growth period. Mulching is also an important area in view of high transpiration and low availability of moisture. Black alkathene mulch proved superior and increased cabbage yield.

 Hi- Tech Protective Cultivation:

Hardening units for tissue cultured plants: Hardening of tissue culture raised plants is very crucial for successful field transfer. The commercially multiplied tissue culture plantlets of ornamentals, fruits, species and vegetables are hardened in green house undercongenial environmental conditions before planting them in open fields.

Transgenic green houses: Development of transgenic plants having industrial, economic, pharmaceuticals, nutritional and environmental importance is need for sustainable production in near future. The transgenic need is to be introduced with cautions in hills and mountain region.

Hydroponics: It allows growing if plants in nutrient solutions with or without use of an artificial medium. High economic value crops are grown in hydroponic systems.

Aeroponics: It is the modified form of hydroponics wherein nutrient mist is provided periodically at plant roots. This technology may have applications in Himalayas.

 Green house technology: Green house is the framed or inflated structures cover with transient material large enough to grow crops under partially or fully controlled environmental conditions to get optimum growth and productivity.

 Advantages of green house:

 1. Crops can be grown all through the year

2. Higher yield

3. Quality produce

4. Plant moisture requirement optimized

5. Good control on pests and diseases

6. Less requirement of intercultivation practices

Points to be considered for planning of green house construction:

 1. Site selection - size and future expansion

2. Water supply - source - well, tank, pipeline, river, etc.

3. Fencing - type, gate, cattle trap, etc.

4. Greenhouse - design, plant layout and working drawing

5. Plant system - soil, pot, bags, platform or soil less media

6. Irrigation - drip, sprinkler and ridge- furrow

7. Ventilation - natural, forced and openings

8. Environmental factors - tempeture, RH, carbon dioxide

 Construction of cost effective green house:

 Fabrication of structure: In order to reduce the cost of construction, use of mild steel and galvanized iron pipes is found to be desirable. These are less expensive than Aluminium angle. The size of greenhouse could vary from 100 to 500 sq. mt.

Covering/Cladding the frame: 200 micron (800 gauge) UV stabilized LDPE film is used for covering the frame. These films give service life of 2 to 3 years.

 Management of cost effective green houses:

Tempeture: It affects the germination, flowering, pollination, fruit set, quality of product and seed production. Generally, temperature requirement range is 20°C to 30°C during day time and 15°C to 18°C during night time.

Light: The performance of crop is influenced by three aspects of light namely intensity, quality and duration. Greenhouse shading material of 20 to 90% shade value can be used.

Humidity: The acceptable range of humidity is between 50-80%. During summer, humidity can be maintainted by fan-pad and humidifier.

Ventilation: Ventilation can either be natural or forced. However, fan ventilation is essential to have control over air temperature, humidity and carbon dioxide level.

Irrigation/ Nutrition: The water requirement for soil based substrates is at the rate of  20l/ of bench and 0.3 to 0.35litres per 16.5cm diameter pot. The nutrient requirement of a crop is generally high inside the cover due to high density planting in comparison with conventional method under open conditions.

Pest and Diseases: Normally the incidence of pest and diseases in greenhouses is less as the structure is covered either with 40 to 60% mesh or completely covered with cladding material.

 General recommendation for management of cost effective greenhouse in hot and dry climate:

 1. The uncontrolled polyhouses may be used for nursery management, propagation of some horticultural crops and raising of seedbed nursery.

2. The semi controlled type polyhouse with fan-pad system can effectively work in this region. It is possible to maintain the desired level of temperature of relative humidity inside polyhouse.

 Practical considerations during construction of greenhouse:

 1. The structural frame should not have any shape edges as otherwise it would damage the cladding material.

2. Film must be stretched and secured to the frame tightly by use of nuts and bolts to ensure that no sagging of film occurs.

3. M.S. pipes used in the structure need to be regularly painted atleast once in two years to avoid rusting of the frame work.


 1. There is a lack of trained human resource so the suitable courses/ trainings must be initiated in selected institutions in country to meet immediately requirements.

2. Selective import of technology should continue for adoption of greenhouse cultivation.

3. Strengthening of research of various types of greenhouses for different production systems in different regions should be done.

4. Greenhouse projects are capital intensive, therefore adequate insurance cover both the facility and plant material should be made available.

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Please note that this is the opinion of the author and is Not Certified by ICAR or any of its authorised agents.