Irrigation Scheduling Advantages And Disadvantages

Irrigation scheduling is a decision mechanism aimed at applying water to the irrigated area. The aim for irrigation scheduling is to achieve an optimum supply of water for productivity, with soil water content at field capacity (Kirda, 2002). To achieve an appropriate irrigation schedule requires sophisticated methods, however, less sophisticated methods like the soil water balance method, sometimes known as the profit and loss is used and give good results.

Improper irrigation scheduling has a negative effect on the productivity of an irrigation enterprise. Poor scheduling can lead to under irrigation which reduces yield due to reduced evapotranspiration (ET). On the other hand over irrigation have similar consequences as it increases pumping

This scheduling method is basically a soil water balance method referred to as a give and take in the Swaziland industry. Climatic data is obtained from the company's satellite weather station in Simunye for RSSC while for the smallholder schemes the data is form the national weather stations. Cathula, Manzana, Bambanani Malibeni and Ntamakuphila irrigation schemes use climatic data from Mhlume weather station. This is the same weather station RSSC could have used if there did not have a fully fledged satellite weather station in-house. Crop coefficients are estimated for all growing stages of the cane and used to calculate ET after Penman Monteith has been used to compute reference evapotranspiration (Eto). The RSSC has the agronomy section that computes these parameters and the SSA technical team is responsible for computing the parameters for the farmers in the project. The daily ET is sent to the farmers using short message system of cellular phones for the farmers to know how much water is to be applied for that day. The profit and loss is based on total available water (TAW) of 60 mm for small scale farmers and 40 mm for RSSC with both institutions using the 120 mm as the (WHC). The daily ET is noted and deducted from the TAW and effective rainfall is added to the

The pin-peg is incorporated with all growing dates and pins to be used to track the water balance. Agronomic activities such as soil sampling, fertilizer, weedcide and hoeing are also included in the pin-peg to track such activities together with the