Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/22/1999
Publication Date: 1/15/2000
Citation: Halvorson, A.D., Black, A.L., Krupinsky, J.M., Merrill, S.D., Wienhold, B.J., Tanaka, D.L. 2000. Spring wheat response to tillage and n fertilization in rotation with sunflower and winter wheat. Agronomy Journal. 92:136-144.
Interpretive Summary: Limited information is available on the production of spring wheat in annual cropping systems without extended fallow periods in the northern Great Plains, particularly using no-till (NT) and minimum-till (MT) production systems. This study evaluated the response of two spring wheat cultivars to three tillage systems [NT, MT, and conventional-till (CT)] and dthree rates of N fertilization ( 34, 67, and 101 kg N ha-1) from 1985 to 1996 in a spring wheat-winter wheat-sunflower rotation. Grain yields were significantly greater with MT and NT than with CT, but response to tillage treatment varied with N rate and year. Nitrogen fertilization generally increased grain yields, but responses varied with tillage treatment and year. The greatest 12-yr average grain yield (1727 kg ha-1)occurred with NT and the highest N rate. Butte86' had a higher yield than Stoa' 6 of the 12 years, with Stoa' equaling Butte86' the other years. Except for three consecutive drought years, spring wheat yields following sunflower i rotation nearly equaled or exceeded reported spring wheat yields produced on fallowed land in south central ND. These results indicate that spring wheat can be grown successfully in rotation following sunflower, except in very dry years, when using MT and NT production systems and adequate N fertilization in the northern Great Plains.
Technical Abstract: Spring wheat is a major crop in the northern Great Plains that is generally grown following a 21-month fallow period. A 12-yr study was conducted to determine the response of two spring wheat cultivars, Butte86' and Stoa', to tillage system [conventional-till (CT), minimum-till (MT), and no-till (NT)] and N fertilizer rate (34, 67, and 101 kg N ha-1) in a dryland spring gwheat-winter wheat-sunflower (Helianthus annuus L.) rotation. Grain yields were greater with MT (1559 kg ha-1) and NT (1540 kg ha-1) than with CT (1431 kg ha-1), but tillage system effects on grain yield varied with N rate and years. Increasing N rate from 34 kg N ha-1 to 101 kg N ha-1 increased grain production from 1388 to 1618 kg ha-1, but yield response to N rate varied among years. The greatest 12-yr average grain yield (1727 kg ha-1) was obtained with NT and application of 101 kg N ha-1. Grain yields were lowest during years when total plant-available water (TPAW) was < 300 mm. In years with >400 mm TPAW, leaf spot disease incidence was lowest with the higher N rates for all tillage treatments. Butte86' out yielded Stoa' 6 out of the 12 years. Spring wheat performed satisfactorily following the deep-rooted, medium water-use sunflower crop in this cropping system with MT and NT and adequate N fertility. Our long-term results indicate that farmers in the northern Great Plains can produce spring wheat following sunflower in annual cropping systems that do not include a fallow period, particularly if NT is used with adequate N fertilization.