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ARS Home » Plains Area » Mandan, North Dakota » Northern Great Plains Research Laboratory » Research » Publications at this Location » Publication #120709
Title: SUNFLOWER ROOT GROWTH AND WATER USE IN COMPARISON WITH OTHER CROPS

Author
item Merrill, Stephen
item Tanaka, Donald
item Krupinsky, Joseph
item Ries, Ronald

Submitted to: Proceedings Sunflower Research Workshop
Publication Type: Proceedings
Publication Acceptance Date: 1/17/2001
Publication Date: 1/17/2001
Citation: N/A

Interpretive Summary: Sunflower is an important oilseed crop in the Northern Great Plains region. Soil scientists have shown that sunflower can extract soil water from deeper soil layers than can such small grain crops as wheat. We observed root growth and soil water use patterns of sunflower to understand its potential for inclusion in diverse cropping systems. Root growth was observed and measured with a minirhizotron-microvideo sytem, in which a miniature video camera is used to magnify images of roots growing up against walls of plastic tubes installed in the field. The average maximum sunflower root growth depths observed with minirhizotrons in our glacial till soil during five years of study ranged from 4.0 to 5.3 feet. In comparison with other crop species, sunflower rooted more deeply than pulse crops (dry bean, pea, soybean), mustards (canola, crambe), and spring wheat, but was less deeply rooted than safflower. Average sunflower water use (soil water depletion plus seasonal precipitation) was greater than al other crops studied. Sunflower is one of the most deeply rooted annual crops commonly grown in the Northern Great Plains, and further research on its belowground growth should be of interest to those studying carbon sequestration potentials.

Technical Abstract: Root growth of sunflower was studied with a minirhizotron-microvideo system in two field studies conducted on Typic and Pachic Haploborolls soils. Root growth was measured for two years in a field study with tillage and rotational treatments. The average median depth (half of total root length above, half below) observed at the time of greatest root growth development twas 0.63 m, and average maximum depth was 1.42 m. Sunflower under no- tillage showed greater median and maximum depths of root growth than did minimal-tillage and conventional-tillage. In a second field study, median and maximum root growth depths of sunflower were found to be greater than those of six other crops, dry bean, dry pea, soybean, canola, crambe, and spring wheat, but depths for safflower rooting were greater than sunflower. The greatest sunflower median depths for 1995, 1996, and 1997 were 0.70, 0.78, and 0.68 m, respectively; greatest maximum depths were 1.61, 1.31, and 1.44 m, respectively. Of the seven crops observed in the second study sunflower had the highest water use during the three year study period. Measurements of water use in 10 crops during a third study confirmed that sunflower was the greatest water user, that safflower was the second greatest, and both crops were shown to deplete from 3 to 10 cm more water than the other crops during the full growing season.