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dc.contributor.author Martino, Daniel L. en_US
dc.date.accessioned 2009-12-03T19:17:41Z
dc.date.available 2009-12-03T19:17:41Z
dc.date.issued 1991-08-01-01:09T00:00:00Z en_US
dc.identifier ocm72800851 en_US
dc.identifier.uri http://hdl.handle.net/1993/3639
dc.description.abstract The trend toward reduced or zero tillage systems may bring about changes in the physical environment for crop roots. A study was conducted on three Manitoba soils (Marquette heavy clay, Fortier silty clay loam, and Souris loamy sand) with the objectives of: a) assessing the effects of contrasting tillage systems on various soil physical properties; and b) relating these effects to wheat or barley response. The zero (ZT) and conventional (CT) tillage treatments had been established between 3 and 10 years prior to the initiation of the study. Penetrometer resistance, bulk density, soil moisture, pore size distribution and oxygen diffusion rate were measured at various depths and times during two growing seasons. The effects of the tillage systems were generally low, particularly in the poorly structured Souris loamy sand. Penetration resistance in the top 10 cm of soil tended to be higher under ZT than CT. ZT also tended to produce a higher proportion of macropores (>100 um in diameter) near the soil surface, suggesting a better preservation of biopores under this system. The aeration status of the roots may have been impaired at the beginning of the growing seasons at the finer-textured soils, but there was no evidence of a negative effect of aeration on the final root density profiles of wheat. The cone index varied markedly in time, and was related to changes in the soil water content. The proportion of roots penetrating the soil was negatively related to the resistance to cone penetration. The relationship obtained suggested that no roots penetrated the soil when the cone index was over 2 MPa. However, in most situations, roots were able to grow in soil with high mechanical impedance, probably by making use of spatial and temporal heterogeneity in the soil structure. en_US
dc.format.extent x, 108 leaves : en_US
dc.format.extent 4598635 bytes
dc.format.mimetype application/pdf
dc.language en en_US
dc.language.iso en_US
dc.rights The reproduction of this thesis has been made available by authority of the copyright owner solely for the purpose of private study and research, and may only be reproduced and copied as permitted by copyright laws or with express written authorization from the copyright owner. en_US
dc.title Soil physical properties and root density under zero and conventional tillage in three Manitoba soils en_US
dc.degree.discipline Soil Science en_US
dc.degree.level Master of Science (M.Sc.) en_US


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