Abstract:
Pakistan is an agriculture country and wheat is staple food of this region. Wheat is a Rabi crop and sown almost through out the country. Rabi season starts from October and normally ends in April. Water requirement of wheat followed variations in terms of location and time of the season. But due to shortage of water, wheat is normally sown in November and December. The northern half of the country receives good rains during monsoon (July-September), which not only fulfill the water requirement of Kharif season but also provide the better conditions of soil moisture for sowing of Rabi crops. Therefore, the preliminary water demand (for sowing and early stages etc) meets through post monsoon conserved soil moisture. The winter rainfall also proves to be very helpful for wheat crops when it is on flowering stage in most of the rainfed areas. This rainfall fulfils the crop water requirement to some extent not only for flowering but up to maturity stages of wheat crop as well. After this stage hot and dry weather conditions are the pre-requisite for attaining rapid maturity as well as ripening. To workout the water requirement, FAO Modified Penmen Monteith method is employed to estimate reference crop evapotranspiration (ETo). The maps drawn for optimum level have shown that the southern half of the country always requires irrigation while in the northern half at most of the places wheat can be grown with out supplementary irrigation. The areas lies between 33°N to 36°N have moist to humid climate where wheat can be grown successfully under rainfed conditions. Due to more elevated plains, some valleys in northern mountain-ranges also experience dry conditions. For successful growth and effective utilization of water from the soil, the available soil moisture must be at least 50% level which corresponds approximately to half of evapotranspiration of crop level, forming optimum limit.
Page(s):
89-97
DOI:
DOI not available
Published:
Journal: Pakistan Journal of Meterology, Volume: 6, Issue: 11, Year: 2009