Flow rate sprinkler development for the site specific irrigation

Author(s)

Robson André Armindo

• Document type: Doctoral Thesis
• Press: Piracicaba. , ilustrações.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2009-09-03

Examining board members

Tarlei Arriel Botrel; Durval Dourado Neto; Edson Eiji Matsura; Fernando Campos Mendonça; Joaquim Paulo da Silva

• Advisor: Tarlei Arriel Botrel
• Field of knowledge: Agronomical Sciences - Agricultural Engineering
• Indexed in: Banco de Dados Bibliográficos da USP-DEDALUS; Biblioteca Digital de Teses e Dissertações - USP
• Location: Universidade de São Paulo. Biblioteca Central da Escola Superior de Agricultura Luiz de Queiroz; t631.7 94988; A729d

Abstract

Due to depletion of hydric resources which are nearing limits, water use in agriculture requires more efficient to maintain current levels of yield in the expansion of irrigated areas. The efficiency of irrigation systems as for water use can be increased adjusting the amount of water applied to the specific conditions of soil and crop, which vary in the field. It is evident the need for equipment capable of applying different irrigation levels in order to supply the water requirement of the soil taking into account the spatial and temporal variability. So, this work aims to develop and evaluate a flow rate sprinkler to be used in center pivots or linear moving irrigation systems with the potential for utilization in scheduling irrigation. Two prototypes were developed. Their calibrations and discharge coefficient adjustments were carried out in a laboratory. To predict flow rate, it was established a successful model that represents flow rate sprinklers operation. The calibration of the flow rate sprinkler prototype I showed good statistical results, however questionable technical results. As for the calibration process of flow rate sprinkler prototype II showed satisfactory statistical and technical results. This prototype was chosen to be implemented in field-testing and to be automated. In field tests, it was determined radial distribution profiles for the second prototype, following recommendations of ASABE technical standard. Sprinkler radius of throw was determined by different flow rates tested and two types of rotating deflectors: four and six jets. The automation of the prototype was obtained through driving a step motor using the communication of parallel door of a microcomputer which was controlled by a software program developed for this purpose. Results were considered satisfactory and provided technical feasibility to build a flow rate sprinkler to be used in precision irrigation. (AU)