Monday, November 13, 2006

Cover Crops as Killed Mulches, an Alternative in Sustainable Agriculture in Semi-Arid New Mexico.

Shiella Merriman-parr, E.M. Silva, and Constance Falk. New Mexico State Univ, Msc 3q Po Box 30003, Las Cruces, NM 88003

Cover crops used as killed mulch have been shown to decrease evapotranspiration, in addition to acting as a barrier against weeds, and providing a habitat for beneficial insects.  Using cover crops could be especially beneficial in semi-arid New Mexico where water use is an ever decreasing commodity.  In this study, six annual cover crop varieties were evaluated in killed-mulch cropping systems in order to measure the potential decrease in water use on chile pepper fields during the growing season.  Additionally, the effect of the killed mulch on weed and insect populations was determined.  Six cover crop cultivars were planted into 101.6 cm beds in a split-plot design, with crop cold-hardiness as the whole plot factor and cover crop variety as the sub-plot factor.  Each replication consists of three beds (60.39cm2), with a total of three replications per cultivars. Three cold-sensitive cultivars crops were planted in September 2005 and three cold-tolerant cultivars crops were planted October 2005, with bare ground as the control.   Irrigation for each treatment was accomplished through subsurface irrigation and was quantified using water meters.  Chile peppers (Capsicum annuum, cv. ‘AZ-20') were transplanted into each bed during April 2006.  Data regarding irrigation scheduling, weed densities, insect populations, and vegetable crop yield were taken from the center row of each sub-plot.  Irrigation schedules were established with soil moisture measurements at 20cm and 30cm depth using Frequency Domain Reflectrometry (Diviner 2000®).  Weed densities were evaluated every two weeks using a quadrat.  Insect populations were monitored weekly by pit-fall traps and sticky traps.  Both the cold-sensitive and cold-tolerant cover crops, the grass varieties established faster, at a greater density, and with less water applied than the legume cover crop varieties.  This illustrates a greater potential benefit of grass cover crops as part of a killed mulch system for water conservation purposes.

Handout (.ppt format, 9606.0 kb)