ETHAN C. HOLT
Professor, Department of Soil and Crop Sciences
Texas A&M University
THE UTILIZATION of land for hay production or grazing during the early development stages of pecan trees would serve as a source of income during the relatively long initial non-productive period. Grass can be grown successfully during this period, but the extent of the retarding effect on tree development is now well established. Certainly grass competes for moisture and nutrients, and the availability of these influences the competitive effect on the tree. As pecan trees enlarge, increasing amount of shade retards grass growth. The point at which grass production is no longer profitable is not well established.
The above points indicate a need for research to establish both the competitive effect of grass on pecan tree development and production and the effect of shade on grass production and longevity. The interrelationships of plant nutrients, moisture and grass species or variety on these competitive effects require study. Not only light intensity but also light quality may be influenced by pecan trees. Light quality in turn influences the type and amount of grass growth. Only certain types of grass are suitable for use in producing orchards because of possible interference with harvest operations. Species and varieties of grass need to be evaluated.
Research designed to evaluate some of these factors was initiated in 1966, in cooperation with the U. S. Pecan Field Station at Brownwood, Texas, and the Texas A&M Plantation near College Station, Texas. The work in 1966 consists of attempting to establish grasses in orchards of various ages and studying shade patterns, light reduction and light quality in pecan tree shade. No positive results can be reported for the preliminary work in 1966.