Apple, coconut, date palm, arecanut, black pepper, cocoa, coffee, tea and rubber are amongst the major plantation crops grown in many regions of the world. There are many other fruit crops and spices which are important in specific regions. Plantation crops are usually high price crops. Many of the plantation crops are developed in favourable environments so that irrigation may not be a major limiting factor in their production at the global level. However, most plantation crops respond well to irrigation during periods of water scarcity at specific growth periods.
Coffee: Coffee crops are normally of two species, namely, Coffee Arabica and Coffee robusta. Only Coffee Arabica is irrigated on a significant scale. Coffee Robusta commands a much lower price in the world market and is usually grown in hotter and wetter areas. Coffee Arabica provides the highly aromatic variety, forming the bulk of the commercial blends of coffee, which is usually grown in moderately high altitudes. Mean monthly minimum temperature for coffee plantations is 10°C. .
Coffee varieties have a vigorously developed root system and can withstand soil moisture stress to a great extent. Properly controlled irrigations, however, increase the yield and bean quality of Coffee Arabica. Limited soil moisture availability controls flowering and hence better period of Picking. Continuous replacement of soil moisture through irrigation is not advisable in the monsoon regions. Amongst the surface methods of water application, furrow irrigation (usually contour furrows) is preferred. Both sprinkler and drip irrigation are suitable. Drip irrigation is preferred in. regions with limited water availability.
Tea: Tea (Thea sinensis) is one of the important crops of India and Sri Lanka which together produces over half of the world production. It is also grown in many regions of the tropics and sub-tropics under cool and high altitude conditions.
The major root system of tea plant is in the top 70 cm of the soil. Irrigation is highly desirable in regions with prolonged drought periods. Sprinkler and drip methods of water application are suitable in tea plantations. Furrow irrigation, particularly contour furrows is also suitable.
Cocoa: Cocoa (Theobroma cocoa) is a tree crop grown in wet, tropical lands around the world. The climatic requirements are high humidity and comparatively high temperature. Cocoa is a shallow rooted plant with most of its active roots spread in the top 60 cm of the soil. The crop is sensitive to soil moisture stress. Soil moisture stress below 60% of the field capacity moisture level affects the plant growth. Furrow irrigation is the most commonly used surface irrigation method. Drip irrigation is suitable and will result in substantial savings in water.
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