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Nitrogen Form, Aluminum, And Their Interaction Effects On Growth, Nitrogen Absorption And Chemical Composition Of Annual Ryegrass (Lolium Multiflorum Lam.)., Jose Ramon Binns
Nitrogen Form, Aluminum, And Their Interaction Effects On Growth, Nitrogen Absorption And Chemical Composition Of Annual Ryegrass (Lolium Multiflorum Lam.)., Jose Ramon Binns
LSU Historical Dissertations and Theses
Annual ryegrass (Lolium multiflorum Lam.) is frequently grown on acid soils with potentially toxic levels of aluminum (Al). Interaction effects of nitrogen (N) form and Al on growth and nutrient relationships in ryegrass require further definition for environmental, biological, and economic reasons. Nutrient solution and soil experiments were conducted in growth chambers to determine interactive effects of ammonium: nitrate (NH$\sb4$:NO$\sb3$) ratios and Al on growth, N absorption, nutrient composition, cation influx rate, and N use efficiency. In nutrient solution studies, highest dry weights of shoots were obtained when the two N forms were present in equal proportions, while highest dry …
Field Evaluation Of The Movement Of Agricultural Chemical Contaminants In Alluvial Soils With A Shallow Water Table., Orlino Agustin Mercado
Field Evaluation Of The Movement Of Agricultural Chemical Contaminants In Alluvial Soils With A Shallow Water Table., Orlino Agustin Mercado
LSU Historical Dissertations and Theses
The movement of agricultural chemical contaminants in alluvial soils with a shallow water table in a warm, humid environment was evaluated in this study. Bromide, a non-adsorbent tracer, was used to assess the pathways of water and solute in the soil profile. The movement and fate of three commonly used herbicides: Trifluralin, Metolachlor, and Metribuzin were determined. The data gathered from the herbicide study were used to compare with the results of simulation to validate the pesticide component of the GLEAMS model. The study was conducted at the Ben Hur Research Farm of the Louisiana Agricultural Experiment Station. Five relatively …
Pedogenic Development Of Soils At High Altitude In Burundi., Salvator Kaburungu
Pedogenic Development Of Soils At High Altitude In Burundi., Salvator Kaburungu
LSU Historical Dissertations and Theses
To evaluate the effects of long-term cultivation and pasture on deforested soils at high altitude in Burundi, comparisons of morphological, physical, chemical and mineralogical properties of soils under natural forest with their counterparts under cultivation and pasture were performed. A typical soil under natural forest classifies as fine, oxidic, isomesic, Typic Haplorthods. Cultivated soils classify as fine, oxidic, isothermic Humic Hapludoxs. Pastured soils classify as fine, oxidic, isothermic, allic Humic Hapludoxs. When the sombric horizon is prominent, they classify as Sombriudoxs. We proposed a Spodic subgroup for the Hapludoxs. The studied area was highly weathered prior to faulting and uplifting …
Predicting The Movement And Retention Of Pesticides In Soils: Physical And Chemical Nonequilibrium Modeling Approaches., Liwang Ma
LSU Historical Dissertations and Theses
Atrazine retention and transport in a highly aggregated Sharkey clay soil were investigated through kinetic batch experiments, miscible displacement (column transport), and mathematical modeling. Batch results indicated that atrazine retention was kinetic and adsorption-desorption was hysteretic. Adsorption and desorption isotherms were well described using the Freundlich equation (S = KC$\sp{\rm N}).$ Fitted Freundlich K was a function of reaction time and initial atrazine input concentrations, whereas fitted N was only affected by reaction time. Desorption hysteresis was quantified by the maximum difference between adsorption and desorption isotherms, and showed a linear increase with reaction time. Atrazine adsorption kinetics was successfully …
Factors Contributing To Resistance In Rice To The Rice Water Weevil, Lissorhoptrus Oryzophilus Kuschel., Francois Kouame N'Guessan
Factors Contributing To Resistance In Rice To The Rice Water Weevil, Lissorhoptrus Oryzophilus Kuschel., Francois Kouame N'Guessan
LSU Historical Dissertations and Theses
Studies were conducted in the field and greenhouse to identify sources of rice water weevil (Lissorhoptrus oryzophilus Kuschel) resistance in rice, Oryza sativa L., and determine the mechanisms of resistance. Rice lines of various sources, including breeding lines, somaclone lines and world collection lines, were evaluated. Tolerance was investigated using replicated insecticide treated and untreated plots in a split-plot design, and antibiosis and/or antixenosis were assessed using caged insect-infested plants in randomized block designs. Resistance predictors included rice water weevil larval populations, larval root pruning damage, plant height and grain yield. Anther culture lines 95-2836 and 95-3527, Louisiana breeding lines …
Cultural Tactics For Control Of The Rice Water Weevil, Lissorhoptrus Oryzophilus Kuschel., Reginald Alexander Thompson
Cultural Tactics For Control Of The Rice Water Weevil, Lissorhoptrus Oryzophilus Kuschel., Reginald Alexander Thompson
LSU Historical Dissertations and Theses
A series of field studies were conducted from 1990 to 1992, designed specifically to identify cultural tactics that may be used to control the rice water weevil, Lissorhoptrus oryzophilus Kuschel, on rice (Oryza sativa L.). The objectives of the studies were: to examine the effects of plant density on rice water weevil oviposition, to compare carbofuran and drainage as rice water weevil control tactics and to examine the impact of 1-3 days delay in reflooding after drainage on rice yields, and to assess the impact of planting date on rice water weevil larval damage. The results of the plant density …