IRRIGATION:This is the artificial application of water to the soil or land in order to eliminate soil water handicap or insufficient rainfall to soil production.
IMPORTANCE:(i) It enables crops to mature or increase their yield.
(ii) Provision of optimum environment for plant production.
(iii) It modifies both plants and soil climate.
(iv) To cool the soil and the atmosphere thereby making them conducive for growing crops.
(v) Softens tillage pans.
IRRIGATION SYSTEM: Irrigation system is divided into two :
(a) Surface Irrigation
(b) Subsurface Irrigation
EVALUATING LAND FOR IRRIGATION.
(i) The soil must be able and retain good quality water, i.e good water holding capacity.
(ii) Topography should be suitable for irrigation or of such a nature that the land can be levelled without exposing subsoil of undesirable characteristics.
(iii) Soil profile should be premeable so that drainage will not be impeded.
DRAINAGE SYSTEM
Drainage in the removal of excess water or lowering the ground water table to prevent water logging. The excess water may originate from direct Irrigation applications from slippage, reservoirs, canals and ditches or it may come into the area through Subsurface flows from other areas, where there is excess precipitation or Irrigation.
IMPORTANCE OF DRAINAGE
(i) It facilitates early Ploughing and planting.
(ii) Lengthens the crop growing season
(iii) provide more available soil moisture and plant nutrients by increasing the depth of the root zone.
(iv) Helps in soil aeration
(v) Decreases soil erosion and gullying by enhancing water infiltration into the soil.
METHOD OF DRAINAGE
(i) Surface and
(ii) Subsurface drainage.
Surface drainage :is the removal of excess water from the surface of the land using constructed open ditches, field drains, land grading and lateral ditches.
Subsurface drainage :is the use of topograpy undulating or soil vary and the field contains isolated wet spots.
PLANNING A DRAINAGE
(i) Survey of the general geology of the area
(ii) Measurement of depth to water table over the area at frequent intervals throughout the year.
(iii) Finding the direction of flow of ground water.
(iv) Estimate of the quantities of water that must be removed and the rate of removal
(v) surveys of the general topograpy of the area.
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