Colorado State University

About: Colorado State University is a education organization based out in Fort Collins, Colorado, United States. It is known for research contribution in the topics: Population & Laser. The organization has 31430 authors who have published 69040 publications receiving 2724463 citations. The organization is also known as: CSU & Colorado Agricultural College.

Use of ammonium bicarbonate DTPA soil test to evaluate elemental availability and toxicity

Abstract: The literature published on the use of the Soltanpour and Schwab Ammonium Bicarbonate‐DTPA (AB‐DTPA) soil test shows that it can be used to determine availability and toxicity indices for many elements. It has been shown to be an effective test for measuring the availability indices of P, K, Zn, Fe, Mn, Mo, Pb, Ni, Cd and Se. Theoretically, it can also be used to determine the availability indices for S, Cu and As. The AB‐DTPA test can predict toxicity of B as well as the standard hot water rest, although within the non‐toxic range of B, it is not as effective as the hot water test. The hot water test alone predicts B availability well, but the AB‐DTPA B test result requires inclusion of soil water pH, organic matter and clay contents in a regression equation for predicting B availability. This test is not suitable for determination of exchangeable plus soluble Ca and Mg (high levels), as these precipitate as carbonates during extraction. The AB‐DTPA test procedure with analysis by an inductively...

Generalized model for NOx and N2O emissions from soils

Abstract: We describe a submodel to simulate NOx and N2O emissions from soils and present comparisons of simulated NOx and N2O fluxes from the DAYCENT ecosystem model with observations from different soils. The N gas flux submodel assumes that nitrification and denitrification both contribute to N2O and NOx emissions but that NOx emissions are due mainly to nitrification. N2O emissions from nitrification are calculated as a function of modeled soil NH4+ concentration, water-filled pore space (WFPS), temperature, pH, and texture. N2O emissions from denitrification are a function of soil NO3− concentration, WFPS, heterotrophic respiration, and texture. NOx emissions are calculated by multiplying total N2O emissions by a NOx:N2O equation which is calculated as a function of soil parameters (bulk density, field capacity, and WFPS) that influence gas diffusivity. The NOx submodel also simulates NOx emission pulses initiated by rain events onto dry soils. The DAYCENT model was tested by comparing observed and simulated parameters in grassland soils across a range of soil textures and fertility levels. Simulated values of soil temperature, WFPS (during the non-winter months), and NOx gas flux agreed reasonably well with measured values (r2 = 0.79, 0.64, and 0.43, respectively). Winter season WFPS was poorly simulated (r2 = 0.27). Although the correlation between simulated and observed N2O flux was poor on a daily basis (r2 = 0.02), DAYCENT was able to reproduce soil textural and treatment differences and the observed seasonal patterns of gas flux emissions with r2 values of 0.26 and 0.27, for monthly and NOr flux rates, respectively.

Toward greater understanding of market orientation and the resource-based view

Abstract: Connor's commentary offers a series of thoughtful comments on the ideas presented in Hult, Ketchen, and Slater (2005). We focus on two of his contentions in our response. First, we argue that the theory underlying our study—the resource-based view—is not tautological. This is because resources and performance are not directly related. Instead, realizing the potential value of resources depends on those resources being exploited through a firm's strategic actions. Second, we disagree with Connor's contention that market-oriented and customer-led firms lie along a continuum. We propose a richer conceptualization centered on a two-by-two matrix that contains market-oriented firms, customer-led firms, and two additional types. Copyright © 2007 John Wiley & Sons, Ltd.