|Aase, J - ARS (RETIRED)|
Submitted to: ASAE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: July 28, 2004
Publication Date: September 1, 2004
Citation: Bjorneberg, D.L., Aase, J.K. 2004. Conservation tillage effects on sediment and phosphorus losses from a furrow irrigated field. Proceedings of ASAE Annual International Meeting, August 1-4, 2004, Ottawa, Ontario, Canada. p. 1-10. Interpretive Summary: A three year field study was conducted to measure the effects of conservation tillage on runoff, soil erosion and phosphorus loss from a furrow irrigated field. Residue from the previous spring wheat crop was incorporated by three different tillage treatments (1. disk in the spring, 2. disk in the fall and spring, and 3. disk and chisel plow in the fall and disk again in the spring). Dry beans were also seeded without any tillage and without removing any wheat straw. As expected, direct seeding increased residue in the irrigation furrows, which tended to reduce runoff volume and soil loss but increased the amount of soluble P lost with runoff. Direct seeded dry bean plots also had 40 to 50% lower yields the last two years of this study. The three tilled treatments had similar crop yields, residue amounts and phosphorus losses. Based on results from this study, direct seeding dry beans into spring wheat residue is not recommended when straw is not removed from a furrow irrigated field.
Technical Abstract: Dry beans are often grown after alfalfa in southern Idaho, which conventionally involves four or more tillage operations before planting. The objective of this three year study (1998-2000) was to determine the effects of conservation tillage on runoff, soil erosion and phosphorus loss from dry beans following small grain under furrow irrigation. Tillage treatments were direct seed, spring disk, fall disk and fall chisel plow. Polyacrylamide (PAM) was applied to half of the furrows during the last two years of the study. Direct seeding increased residue in furrows, which tended to reduce runoff volume and soil loss but increased soluble P loss. Applying PAM significantly reduced soil loss for only 4 of 11 irrigations, but significantly decreased total annual soil loss 63% in 2000. Direct seeding did not significantly reduce dry bean stand, but weed competition and other factors reduced bean yields from direct seed by 39% and 47% the last two years of this study. The three tilled treatments had similar crop yields, residue amounts and phosphorus losses.