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ARS Home » Pacific West Area » Maricopa, Arizona » U.S. Arid Land Agricultural Research Center » Water Management and Conservation Research » Research » Publications at this Location » Publication #309446
Title: Fertigation uniformity under sprinkler irrigation: evaluation and analysis

Author
item ZERIHUN, D - University Of Arizona
item SANCHEZ, C - University Of Arizona
item SUBRAMANIAN, J - University Of Arizona
item BADARUDDIN, M - University Of Arizona
item Bronson, Kevin

Submitted to: Journal of Irrigation and Drainage Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2017
Publication Date: 2/6/2017
Citation: Zerihun, D., Sanchez, C.A., Subramanian, J., Badaruddin, M., Bronson, K.F. 2017. Fertigation uniformity under sprinkler irrigation: evaluation and analysis. Journal of Irrigation and Drainage Engineering. 6:1-13.

Interpretive Summary: Fertigation is widely practiced in the Western US as a cost effective and convenient method of applying soluble fertilizers to irrigated croplands. Together with efficiency, uniformity is an important issue in fertigation practice. Fertigation uniformity is defined here as a parameter that combines irrigation and fertilizer application uniformity measures. This paper presents a framework for the evaluation and analyses of fertilizer application uniformity under solid-set sprinkler irrigation systems. Fertilizer application rate as a function of irrigation depth and fertilizer concentration is described in this paper. The conditions for attaining acceptably high fertilizer application rate uniformity are detailed, and the practical implications for fertigation system design and management is also discussed.

Technical Abstract: n modern farming systems, fertigation is widely practiced as a cost effective and convenient method for applying soluble fertilizers to crops. Along with efficiency and adequacy, uniformity is an important fertigation performance evaluation criterion. Fertigation uniformity is defined here as a composite parameter consisting of irrigation and fertilizer application uniformity indicators. The field and computational procedures for sprinkler irrigation uniformity evaluation have been the subject of various studies. The objective of the study reported in this paper, however, is the development of an analytical framework for the evaluation and analyses of test-plot scale fertilizer application uniformity under solid-set sprinkler irrigation systems. Irrigation uniformity indices are adapted for use in fertilizer application uniformity evaluation. Fertilizer application rate, given as a function of irrigation depth and fertilizer concentration, is identified as the appropriate variable to express fertilizer application uniformity indices. Pertinent mathematical properties of the uniformity indices along with their practical fertigation management implications are outlined. Carefully designed hypothetical fertigation scenarios were analyzed to examine the significance of the interactive effects, of the local spatial trends of depth and concentration data, on the uniformity of the resultant test-plot scale fertilizer application rate data. The results of the study show that the spatial overlap patterns between depth and concentration data sets are the main determinants of test-plot scale fertilizer application rate uniformity. The study also shows that often the uniformity levels of irrigation and fertilizer concentration data sets cannot be uniquely related to the uniformity of the resultant application rate data. However, some practically useful qualitative relationships between the uniformity of irrigation depth, solute concentration, and application rate data sets are enumerated. Application of the approach presented here in the evaluation and analysis of fertigation uniformity data sets, measured under sprinkler irrigated conditions, is highlighted.