• Soil Health: Nitrogen Cycle and Management in Agricultural Soils

  Silvertooth, Jeffrey C.; University of Arizona (College of Agriculture, Life & Environmental Sciences, University of Arizona (Tucson, AZ), 2025-11-11)

  This article, published in the Vegetable IPM Newsletter (Vol. 16, No. 23), explains the nitrogen cycle and the biological processes that transform nitrogen into plant-available forms. It highlights the importance of the mineralization–immobilization transformation (MIT) cycle in maintaining soil fertility, supporting crop productivity, and managing nitrogen efficiently in agricultural systems.
• Performance Curves for Slightly Sloping Basins

  Fangmeier, Delmar Dean; Patnaik, Rabindranath (The University of Arizona., 1994)

  The comprehensive, mathematical model SRFR in its zero-inertia form, is utilized here for simulation of flow in slightly-sloping basins using various flow and basin parameters. These parameters are combined in dimensionless form for plotting performance curves pertaining to field slopes ranging from 0 to 0.02%. These show the distribution uniformity (DU) resulting from a particular set of input variables. DU is an important and useful tool for describing the performance of slightly-sloping basins. The DU was found to increase with flow rate and application time but decrease with the increase in infiltration rate, length of run and roughness coefficient. Increase in slope does not affect DU for the highK*, but for low K* can yield DU either increasing or decreasing, based on the downstream conditions of the basin. For medium K* and where a downstream stagnant pool of water is absent, increase in slope increases DU.
• Arizona Agricultural Enterprise Budgets: Pinal County’s 2025 Field Crops’ Production Budgets

  Quintero, José H.; Mukherjee, Avik (College of Agriculture, Life & Environmental Sciences, University of Arizona (Tucson, AZ), 2025-10)

  This report estimates the typical economic costs and returns for growing major crops, including alfalfa, barley, corn silage, cotton, sorghum grain, sorghum silage, durum wheat, and winter wheat in Pinal County, Arizona. The Arizona Agricultural Enterprise Budgets are estimated based on a representative farm and its related cropping operations in a determined location; numbers are reported on a per-unit basis.
• EPA’s Mitigation Menu to Protect Endangered Species

  Fournier, A.; Brown, A.; Ellsworth, P. C.; Rohner, J.; University of Arizona; Arizona Cotton Growers Association (College of Agriculture, Life & Environmental Sciences, University of Arizona (Tucson, AZ), 2025-11)

  The Environmental Protection Agency (EPA) must ensure that the use of a pesticide will not jeopardize federally listed threatened or endangered species, nor damage their critical habitats. For certain pesticides where runoff or soil erosion may pose threats to listed species, EPA may require users to ensure that protections are in place that will limit the potential for pesticide exposure. This is done through a system of “mitigation points” or “credits” that are obtained by users through adopting mitigation practices or documenting existing conditions that reduce risks of runoff and erosion. If points are needed to apply a pesticide, this requirement will be listed on the pesticide label and/or on an Endangered Species Bulletin. Arizona has many common field conditions, including a low to very low potential for runoff, that should make it easy for most growers in most situations to comply with mitigation requirements. This piece outlines situations where fields may be completely exempt from point requirements and identifies the most common conditions and practices in Arizona agriculture that can earn mitigation relief points. A link is provided to EPA’s Mitigation Menu website where definitions and additional mitigation practices are listed.
• Endangered Species Protection Bulletins Part 2: Understanding Pesticide Use Limitation Areas

  Fournier, A.; Brown, A.; Ellsworth, P. C.; Weber, J.; Murray, M.; Rondon, S.; Jima, T.; University of Arizona; Utah State University; Oregon State University (College of Agriculture, Life & Environmental Sciences, University of Arizona (Tucson, AZ), 2025-11)

  The Environmental Protection Agency (EPA) must ensure that the use of a pesticide will not jeopardize federally listed threatened or endangered species, nor damage their critical habitats. When required on a pesticide label, online Endangered Species Bulletins provide geographic-specific protections for listed species while allowing full labeled use of the pesticide in other areas. They are obtained through EPA’s Bulletins Live! Two, an interactive web-based app. An increasing number of pesticide products, though not all, require users to view and download Endangered Species Bulletins prior to making an application. Part 2 in this series explains the nuances of Pesticide Use Limitation Areas (PULAs) on Bulletins Live! Two using an example of a grower with fields both within and outside of a PULA. It clarifies differences in how to print a bulletin when a PULA is present or absent in the map view. it also highlights the main elements presented in an Endangered Species Bulletin.

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