Location: Crop Production Systems Research2012 Annual Report
1a. Objectives (from AD-416):
1: Develop sustainable management strategies for cotton, corn, soybeans and other crops grown in the mid-southern United States, and determine the impact of crop rotations, tillage, and herbicide regimes on crop physiology and weed control options. 2: Evaluate the impact of crop management on quality traits of various crops in the system, including cotton (gossypol, boll development, maturity, length, strength, and uniformity) and soybean (fatty acid profiles and protein quality).
1b. Approach (from AD-416):
Conventional corn hybrids and transgenic corn hybrids containing insect and herbicide resistance traits will be compared for variation in physiological components, mycotoxin contamination, insect damage, agronomic performance and economic return. Maturity group IV and V soybean varieties will be grown in both twin-row and single row planting patterns to compare their growth, photosynthesis, and agronomic performance. Glyphosate resistant corn hybrid grown in both twin-row and single row planting patterns will be evaluated for canopy light interception, photosynthesis, weed population densities, and agronomic performance. Conventional and glyphosate-resistant cotton-soybean rotation will be initiated under minimum tillage to assess impact on various soil properties, weed population densities, plant nutrition, cotton physiology, seed composition, crop agronomic performance, and economic return. Barnyardgrass and junglerice populations will be surveyed at various sites within the mid-southern region of the U.S. and characterized for morphological diversity and variation in growth parameters. Weed populations will be monitored throughout the growing season in glyphosate resistant soybeans grown in twin-row pattern to address issues with late season weed control. Different crop management systems for corn, cotton, and soybeans will be utilized on land infested with cogongrass to determine effectiveness and economic viability of various cogongrass control options. Obsolete and modern cotton varieties consisting of both conventional and transgenic types will be grown at two different plant population densities and assessed for variation in dry matter partitioning, canopy light interception, growth analysis, and agronomic performance. Diverse cotton varieties grown under either irrigated or dryland conditions and with 3 different levels of nitrogen fertilization will be assessed for dry matter partitioning, canopy light interception, chlorophyll fluorescence, and agronomic performance. Normal, okra, and super-okra leaf type isolines in the same genetic background will be grown in both twin-row and single row planting patterns and assessed for dry matter partitioning, canopy light interception, growth analysis, and agronomic performance.
3. Progress Report:
The results from the agronomic, physiological, and crop culture studies gave insight to physiological mechanisms leading to lint yield and fiber quality differences among diverse cotton varieties. A uniform population density of 1.5 cotton plants per foot either yielded higher than or the same as 3 plants per foot across all varieties. Variety, nitrogen rate, and irrigation regimes all individually impacted and interacted to affect lint yield, fiber quality, and seed composition. Twin-row cotton yielded the same as single row cotton regardless of the leaf shape in the first year of a study. The second year of an experiment examining the agronomic and economic value of stacked-gene corn hybrids is currently underway with photosynthesis data collection having been completed. The second year of a study examining the growth rates and nutrient uptake of three soybean cultivars of differing maturity is underway with data collection on photosynthesis and dry matter accumulation nearing completion. Twin-row and single-row irrigated corn with varying seeding rates nitrogen fertility rates were compared for yield and yield components during two growing seasons. Yields did not differ between the twin- or single-row treatments.