Developing a Sustainable Groundwater Management System from Decreased Nitrogen Use

Project Number:

96D-04

Project Duration:

36 Months

Dates:

May 1, 1996 to April 30, 1999

Institution of Principle Investigator while on this project:

New Mexico State University

Investigators (most current known information)

Ball, Shane (PI)

Extension Agronomy Specialist, Cooperative Extension Service, New Mexico State University, Drawer 3AE, Las Cruces NM 88003-0031

TEL: +1-575-646-7999, FAX: +1-575-646-8085, Email: shball@nmsu.edu

Sammis, Theodore

Professor, Department of Agronomy and Horticulture, New Mexico State University, Las Cruces NM 88003

TEL: +1-575-646-2104, FAX: +1-575-646-6041, Email: tsammis@nmsu.edu

Proposal Abstract

Increased concern over potential contamination of groundwater from nitrogen fertilizers has generated a need for better tools to assess regulations concerning chemical use. Groundwater contamination caused by nitrate-nitrogen (NO3--N) leaching through soils is becoming a serious problem in the irrigated Mesilla Valley of southern New Mexico. The greatest groundwater contamination probably results from large amounts of nitrogen fertilizer being applied to shallow-rooted, high-value vegetable crops (i.e., onion, lettuce, and chile). However, limited information is available pertaining to the extent and management of NO₃--N leaching to groundwater. We must know the amount of nitrogen leaching to the ground water and the irrigation efficiency in order to improve current management practices. Therefore, our objectives are:

to demonstrate to farmers that by using chloride as a tracer, they can determine the irrigation and nitrogen use efficiency of their management system,
to demonstrate to farmers that this information can be used to increase profitability by decreasing nitrogen inputs, and
to develop a case study describing the factors that determine farmers' adoption or non-adoption of this natural resources innovation.

A technique using chloride in irrigation water as a tracer has been used to monitor NO₃--N loading below the root zone and irrigation efficiency. The diffusion of the chloride technique to monitor the nitrogen loading to the groundwater and the irrigation efficiency of water applied to farmers' fields was investigated.

Five farmers were chosen as innovative farmers who would transfer the technology to others. Although farmers have stated that this agricultural innovation may be useful, none have used it to monitor their management systems. Farmers rejected the adoption of the technology because they felt the costs outweighed the benefits. Although nitrogen loading to the groundwater may be a problem, they did not think it was their responsibility to change management practices unless their profits would increase or expenses decrease. Consequently, the diffusion process of this technology failed.

Outcome

Presentation

Al-Jamal, M.S., S.T. Ball and T.W. Sammis. 1998. "Developing a sustainable groundwater management system by decreasing nitrogen inputs." Presented, Annual ASAE Meetings.