Water is an important determinant in the growth of plants or crops. The phenomenon which explains the conversion of water and carbon dioxide into food using the light energy from sun is Photosynthesis.
Irrigation, a bail-out from erratic or little rainfall, is an artificial or man-made system of water application to farmland to meet crops demand. It not only makes the survival of the crops possible even under harsh condition but also makes early planting a realistic plan for diligent farmers. Irrigation helps in both the pre-planting and post planting stage of cultivation, softening the soil for easy tillage and increasing plant productivity and crop yield.
Irrigation can be Surface, Subsurface or Overhead. Surface Irrigation involves passing water across the surface of the plot to wet the farmland and also moisturize the soil. This method can cool the soil in the very extreme weather conditions, but may result in flooding without proper control. Sub-surface irrigation, which is effective for all dry lands, involves the channeling of small quantities of water at frequent intervals below the soil surface, in a uniform manner. With improvement in the system design and maintenance protocols, perhaps the only demerit of Sub-surface irrigation is the setup and maintenance cost. However, any irrigation system capable of revitalizing the wastelands of Sahara is a worthwhile investment.
Overhead irrigation systems promise an even distribution and controllable supply to crops, a higher soil penetration because it mimics the drops and showers of rainfall. Overlap is inevitable when this kind of design is employed in windy area and condition.
Apart from managerial, financial, pecuniary and economic constraints, there exists a number of factors to consider when choosing a design for your farmland. Among others, examples include topography of the farmland, soil structure and texture, type of crop, prevailing weather and climatic condition of the area.
The topography is the landslide, i.e. the degree of sloppiness. The shape and feature of the land surface should be considered when choosing a design. While surface irrigation can work for a flat-levelled ground, it will result in catastrophic flooding and altering of the soil structure through erosion when applied to a sloppy farmland. The kind of soil on the farmland must also be considered. Among others, the permeability of the soil, it’s texture, water-retention capacity and topsoil weight also determine the choice of irrigation design.
To answer the question of whether the irrigation is a supplement or complement for the natural supply of rainfall to the crops, the prevailing weather and climatic condition of the area should be ascertained. For every plant or crop variety is different water demand. A palm tree, for instance, could withstand severe atmosphere than vegetable plants. Annual crops tend to be more demanding than perennial crops as the latter can draw moisture from deep below through their roots.
Conclusively, it is always better that the farm managers or owners to employ the service of a professional to oversee the planning, design and maintenance of a suitable design.