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Full-Text Articles in Systems Biology

Sheep Grazing Effect On Dryland Soil Carbon And Nitrogen In The Wheat-Fallow System, Andrew W. Lenssen, Upendra M. Sainju, Hayes B. Goosey, Erin Snyder, Patrick G. Hatfield Jan 2011

Sheep Grazing Effect On Dryland Soil Carbon And Nitrogen In The Wheat-Fallow System, Andrew W. Lenssen, Upendra M. Sainju, Hayes B. Goosey, Erin Snyder, Patrick G. Hatfield

Andrew W. Lenssen

Weed control by sheep grazing during fallow periods in the dryland wheat-fallow system may influence soil C and N levels. The effects of fallow management for weed control and soil water conservation [sheep grazing (grazing), herbicide application (chemical), and tillage (mechanical)] and cropping sequence [continuous spring wheat (CSW), spring wheat-fallow (SW-F), and winter wheatfallow (WW-F)] on wheat biomass (stems + leaves) yield and soil organic C (SOC) and total N (STN) at the 0-120 cm depth was evaluated from 2004 to 2008 in western Montana. Annualized wheat biomass yield was greater in CSW than in SW-F and WW-F from 2004 …


Evaluation Of Winter Cereals For Pasture In Montana, Andrew W. Lenssen, A. N. Hafla, S. D. Cash, L. M. M. Surber, J. A. Paterson, A. L. Todd, M. S. Huffman Jan 2008

Evaluation Of Winter Cereals For Pasture In Montana, Andrew W. Lenssen, A. N. Hafla, S. D. Cash, L. M. M. Surber, J. A. Paterson, A. L. Todd, M. S. Huffman

Andrew W. Lenssen

In the southern Great Plains, it is common to graze winter wheat pastures prior to grain harvest to take advantage of economic returns from the grain crop and value added to livestock. In Montana, a similar management practice could provide complementary pasture for livestock in the late spring to relieve pressure on cool season native rangelands. A two year study was conducted to evaluate the forage yield and quality of winter cereals, when grazed at three growth stages, vegetative (V), boot stage (B), and at heading (H), prior to hay and grain harvest. Western white faced ewes were used to …


Sheep Grazing Wheat Summer Fallow And The Impact On Soil Nitrogen, Moisture, And Crop Yield, Andrew W. Lenssen, E. E. Snyder, H. B. Goosey, P. G. Hatfield Jan 2007

Sheep Grazing Wheat Summer Fallow And The Impact On Soil Nitrogen, Moisture, And Crop Yield, Andrew W. Lenssen, E. E. Snyder, H. B. Goosey, P. G. Hatfield

Andrew W. Lenssen

In typical dryland farming areas of Montana, annual precipitation is not sufficient for annual harvest of small grains. Summer fallow in alternate years, is a common method of conserving soil moisture to produce a crop in the following season. Current methods of fallow management are primarily mechanical tillage and spraying with herbicides. Although these methods are effective, they are expensive, making fallow management the highest variable cost associated with dryland grain production. The objectives of this study were to compare the impact of grazing small grains stubble with sheep, as a fallow management tactic, against traditional management practices of chemical …


Incorporating Targeted Grazing Into Farming Systems, Andrew W. Lenssen, Patrick Hatfield, Hayes Goosey, Sue Blodgett Jan 2006

Incorporating Targeted Grazing Into Farming Systems, Andrew W. Lenssen, Patrick Hatfield, Hayes Goosey, Sue Blodgett

Andrew W. Lenssen

When incorporating targeted grazing into farming systems, livestock producers and farm operators need assurance that the benefits from their activities are worth their investments. This chapter will focus on how integrating grazing, particularly with sheep and goats, into farming systems can offer those benefits. The concepts are not new. Cropping systems were once integrated with livestock production: Livestock gained forage value from crop aftermath, crops were grown to sustain livestock, and livestock were used as implements to produce crops. Today, few cropping systems include livestock. Sheep and goats are traditionally produced on rangelands or pasture forages and supplemented during winter …


Induced Lsoflavonoids In Diverse Populations Of Astragalus Cicer, Andrew W. Lenssen, Susan S. Martin, Charley E. Townsend Jan 1994

Induced Lsoflavonoids In Diverse Populations Of Astragalus Cicer, Andrew W. Lenssen, Susan S. Martin, Charley E. Townsend

Andrew W. Lenssen

lsoflavonoids were induced in mature leaves of the legume Asbagalus cicer L. by spores of the fungus Bipoaris zeicola. The five major elicited compounds included two isoflavans (mucronulatol and astraciceran), two isoflavones (cajanin and acicerone), and a pterocarpan (maackiain). Only occasional traces of these compounds were detected in controls. Among 41 populations originating in Europe or Russia, mean total elicited isoflavonoid content differed 12-fold. Mucronulatol was the predominant compound elicited, comprising 20-70% of total isoflavonoids. Significant interpopulational differences existed for each isoflavonoid, but no geographic patterns of total or relative proportions of the five compounds were discernible.