Author
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Merrill, Stephen |
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Tanaka, Donald |
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Hanson, Jonathan |
Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only Publication Acceptance Date: 7/15/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Cultivation of crop types alternative to wheat and small grains in dryland rotations serves to abate pest depredations and stabilize farm income. Study of root growth of will reveal potentials for water and nutrient use. Root length growth of 7 crops in spring wheat - winter wheat - alternative crop rotation under no-till management and spring wheat on fallow, all on Haploborolls soils, was measured during a 3 year period. Two types of minirhizotrons - standard and pressurized-wall - were read with a micro- video camera. Average maximum rooting depths fell into agronomic and botanic family groups: oilseeds safflower (Carthamus tinctoris), 1.64 m, and sunflower (Helianthus anuus L.), 1.45 m; spring wheat (Triticum aestivum L.), 1.31 m; mustard family crops crambe (Crambe abysinnica), 1.17 m, and canola (Brassica rapa), 1.13 m; and legumes dry bean (Phaseolus vulgaris L.), 1.00 m, soybean (Glycine max L. Merr.), 0.99 m, and dry pea (Pisum sativum L.), 0.99 m. Ratios of median total root length depth to maximum depth had a median value of 0.57, and ranged from 0.91 m for safflower to 0.46 m for dry bean. Six out of 8 crops showed greatest rooting depth in relatively wet 1995, which is attributed to higher subsoil water content. Greatest total root length (TRL) growth in 5 of the crops (safflower, crambe, canola, soybean and dry bean) occurred in 1997 under significantly below average precipitation. These results are interpreted as a fine root growth response to soil water deficit. |