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Iowa State University

Plant Sciences

Andrew W. Lenssen

Dryland

Publication Year

Articles 1 - 3 of 3

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Effects Of Tillage On Microbial Populations Associated To Soil Aggregation In Dryland Spring Wheat System, Andrew W. Lenssen, Thecan Caesar-Tonthat, Anthony J. Caesar, Upendra M. Sainju, John F. Gaskin Jan 2010

Effects Of Tillage On Microbial Populations Associated To Soil Aggregation In Dryland Spring Wheat System, Andrew W. Lenssen, Thecan Caesar-Tonthat, Anthony J. Caesar, Upendra M. Sainju, John F. Gaskin

Andrew W. Lenssen

Tillage may influence the microbial populations involved in soil aggregation.We evaluated the effects of no till (NT) and conventional tillage (CT, tillage depth about 7 cm) continuous spring wheat system on culturable heterotrophic bacterial communities predominant in microaggregates (0.25e0.05 mm) and on soil-aggregating basidiomycete fungi in aggregate-size classes (4.75e2.00, 2.00e0.25, and 0.25e0.05 mm) at 0e20 cm depth of a Williams loam (fine-loamy, mixed, Typic Argiustolls) in dryland Montana, USA. Enzyme-linked immunosorbent assay used to quantify antigenic response to basidiomycete cellwalls,was higher in NT than in CT in 4.75e2.00 mm size class in 2007 and higher in all classes and years …


Long-Term Tillage Frequency Effects On Dryland Soil Physical And Hydraulic Properties, Andrew W. Lenssen, J. D. Jabro, U. M. Sainju, W. B. Stevens, R. G. Evans Jan 2008

Long-Term Tillage Frequency Effects On Dryland Soil Physical And Hydraulic Properties, Andrew W. Lenssen, J. D. Jabro, U. M. Sainju, W. B. Stevens, R. G. Evans

Andrew W. Lenssen

Soil tillage is considered one of most important practices in agricultural production due to its influence on physical, chemical, and biological properties of the soil environment. The effect of a long-term tillage [no-till (NT), spring till (ST), and fall and spring till (FST)] was investigated on soil penetration resistance (PR), bulk density (BD), gravimetric water content (GWC) and saturated hydraulic conductivity (Ks) under dryland conditions. Tillage effects on these physical properties were tested after 22 years on a Dooley sandy loam (fine-loamy, mixed Typic Argiborolls) derived from glacial till parent material. The statistical design used was a randomized complete block …


Farming Systems Research On Crop Diversification, Tillage, And Management Effects On Yield, Pests, And Environmental Quality In A Semi-Arid Environment, Andrew W. Lenssen, U. Sainju, T. Caesar-Tonthat, B. Allen, R. Lartey Jan 2007

Farming Systems Research On Crop Diversification, Tillage, And Management Effects On Yield, Pests, And Environmental Quality In A Semi-Arid Environment, Andrew W. Lenssen, U. Sainju, T. Caesar-Tonthat, B. Allen, R. Lartey

Andrew W. Lenssen

Available water, depleted soil quality, and weed competition are important constraints to crop production in the northern Great Plains. The traditional rotation in the region has been spring wheat with summer fallow, which is used to accrue additional soil moisture for the subsequent wheat crop. Tillage during fallow periods controls weeds, which otherwise would use substantial amounts of water and inorganic nitrogen, decreasing the efficiency of fallow and increasing soil erosion. Chemical fallow and zero tillage systems improve soil water status for subsequent crops (Lenssen et al., 2007a), allowing for increased cropping intensity and improved nutrient cycling (Lenssen et al., …