FERTIGATION DISTRIBUTION WITH LOW PRESSURE MULTIGATE IRRIGATION SYSTEMS IN A SUGARCANE AGROECOSYSTEM

Abstract

In the state of Veracruz, Mexico, low sugarcane yields are reported despite the high use of inputs. This results in economic losses and environmental pollution. A fertigation system designed at the Colegio de Postgraduados (COLPOS) Campus Veracruz was established to determine the uniformity and stability of fertilizer distribution in the sugarcane crop. This study was carried out in a sugarcane plot with a farmer participant. Three levels of valve openings at the injector inlet (1/3, 2/3, and 3/3) were tested to determine the homogeneity of fertigation at the outlet of the gates and the stability of the system over time. Samples of water-fertilizer mixture were taken at the outlet of the gates. They were analyzed in the laboratory with a UV-visible spectrophotometer at 202 nm for nitrogen. It was found that the 1/3 and 3/3 valve position openings caused instability in the system. For the 2/3 opening with p = 0.359, no statistical difference (α= 0.05) was found during the time of emptying the container of the water-fertilizer mixture. Therefore, the fertigation system proved to be stable with a valve opening close to 2/3. Using the valve openings, the flow rate of water-fertilizer entering the system is uniformly mixed at the outlets of the multi-gate pipeline that pours into the crop furrows (p = 0.474 and α = 0.05). It can be concluded that in fertilization using a low-pressure irrigation system, nitrogen fertilizer is uniformly distributed when a Venturi type injector is used in a sugarcane agroecosystem with a valve opening close to 2/3.