THE INFLUENCE OF MICROENVIRONMENT MODIFICATIONS ON COMPOSITION IN CORN (ZEA MAYS L.)

FRED TAN, Purdue University

Abstract

Increased plant population densities in corn production is made possible by the use of improved hybrids, better machinery, more effective pesticides and herbicides, and less expensive fertilizers. At high plant populations, environment becomes the limiting factor. It is therefore important to determine which environmental parameters are involved. PION 3306 hybrid corn seed was planted and thinned to final stands of 20,000 plants/acre in 20" and 30" row spacings. Microclimatic parameters were recorded during a six week period around the time of anthesis. Carbohydrate levels were determined from the ear leaves samples during the same period. Data of yield and plant morphology were also collected. Temperature, precipitation and solar radiation during the 1967 growing season were below average. Soil moisture, soil temperature, air temperatures, CO(,2) concentration and air turbulence in the crop canopy were more favorable in the 30" row spacing plots. Mean carbohydrate levels in both 20" and 30" row spacings were similar. For both row spacings, changes in carbohydrate concentration during the day and during the six weeks of sampling were highly significant. During anthesis and early ear formation, the concentration of water soluble carbohydrates increased considerably, while the acid soluble carbohydrate concentration decreased. There are indications that the 30" row spacing was more favorable than the 20" row spacing for dry matter yield during the 1967 growing season. These differences between both row spacings, however, were not statistically significant.

Degree

Ph.D.

Subject Area

Agronomy

COinS