Progress of Work and Principal Accomplishments

Objective 1: Development of microirrigation system BMP’s to sustain crop production and minimize water application and water quality degradation.

Dana Porter provided technical assistance in support of a Sustainable Agriculture Research and Education (SARE) grant supported project incorporating vegetable production into rotation with cotton to promote overall farm sustainability. Issues addressed include irrigation scheduling with subsurface drip irrigation systems under cotton and chile production; water quality (salinity) management concerns in these production systems under center pivot and SDI irrigation management; and fertigation requirements for chile under SDI irrigation.

Porter, Dana. West Texas Vegetable Conference, Hereford, TX, January 19, 1999.

"Drip Irrigation for Intensive Vegetable Culture"

Porter, Dana. Graduate Seminar, Plant and Soil Sciences Department, Texas Tech University, April 12, 1999. "Microirrigation for Row Crop Agriculture"

Porter, Dana. Lubbock County Master Gardeners, Lubbock, TX, April 20, 1999.

"Landscape and Garden Irrigation" (including a section on microirrigation methods for landscape and turf irrigation)

Porter, Dana. South Plains Plant Society, Lubbock, TX, June 24, 1999.

"Landscape and Garden Irrigation" (including a dicussion of microirrigation methods and equipment for landscape and turf irrigation).

Porter, Dana. Lynn County Crop Tour, September 15, 1999. Made brief presentations on salinity management and water quality considerations for subsurface drip irrigation.

Objective 2: Carry out field evaluations of BMPs for crop production and water quality degradation control using microirrigation.

Changes in soil water retention, pore size distribution, and saturated hydraulic conductivity due to wastewater application by subsurface drip systems were investigated at three sites in Texas. Undisturbed soil core samples were collected from different locations and depths around drip emitters and from outside the drip fields. Core samples were used to determine hydraulic conductivity and soil water retention. Application of wastewater resulted in an increased soil water retention, a decreased number of pores with large radii, and a decreased saturated hydraulic conductivity. At the three sites, the major influence of wastewater application on soil hydraulic properties occurred at 20 cm below the drip emitter where the average saturated hydraulic conductivity dropped by 30% at site 1 and by 70% at sites 2 and 3. This decrease in hydraulic conductivity was a reflection of the decrease in the number of large pores by 14%, 25%, and 28% at sites 1, 2, and 3, respectively.

Objective 3: Develop an expert system and models for chemical management practices using microirrigation systems.

Objective 4: Assess the economics of BMPs developed for microirrigation systems.

Work Planned

Objective 1:

Jim Bordovsky, Dana Porter and Jaroy Moore are cooperatively planning the installation of several irrigation systems, including SDI systems, at a new research farm (Helms farm) south of the Halfway Research Center. This new farm will be the site of cotton and grain research. The proposed SDI irrigation system will be designed to provide flexibility necessary for SDI irrigation management and optimization.

Jim Bordovsky, Dana Porter, Mike Schubert, TAES Peanut Specialist, and Jaroy Moore are planning to conduct irrigation research at a proposed new peanut research site in Gaines County. This new site is a cooperative effort between the Western Peanut Growers and TAES to address peanut research needs in West Texas. Irrigation management is among the highest priorities for the peanut production research efforts. A center pivot is on site; LEPA modifications and SDI system installations are proposed.

Objective 2:

Bruce Lesikar and Ihab Jnad are evaluating changes in soil hydraulic properties around a subsurface drip emitter dosing wastewater into packed soil bins. A three dimensional array of soil moisture monitoring equipment has been constructed to record soil moisture with time. The soil hydraulic conductivity will be predicted around the drip emitter. A relationship needs to be developed for predicting changes in soil hydraulic properties over time with the addition of wastewater.

Objective 3:

Objective 4: Presentations will be made to industry groups related to production systems and wastewater treatment/reuse.

Publications:

Lesikar, B. 1999. On-Site Wastewater Treatment Systems: Subsurface Drip Distribution. Texas Agricultural Extension Service, Fact Sheet Number L-5237. January, 1999.

Jnad, I, B.J. Lesikar, G.J. Sabbagh, D.L. Reddell, and R.P. Wiedenfeld. 1999. Characteristizing soil hydraulic properties in a subsurface drip drain field. ASAE Paper No. 992253, presented at the ASAE International Meeting, July 18-21, Toronto, Ontario, Canada.

Persyn, R. A., B. J. Lesikar, and I. Jnad. 1999. Evaluating Soil Properties in Subsurface Drip Distribution Systems. Tenth Northwest On-Site Wastewater Treatment Short Course and Equipment Exhibition. September 20-21, 1999. Seattle Washington.