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A new selective medium for Fusarium species has been developed using Czapek‐Dox agar (CZ) containing the fungicides iprodione (3 mg/1) and dicloran (2 mg/1). This new medium (CZID) is selective against numerous species of Alternaria, Epicoccum, Penicillium and mucoraceous fungi. CZID was compared with CZ using samples of barley, malt, sorghum, bean and pea. Fusarium species produced large and easily recognizable colonies on CZID while isolates of Alternaria, Epicoccum and Rhizopus were significantly restricted on CZID compared with their growth on CZ. The use of CZID thus facilitates the isolation and subculturing of Fusarium species.

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Soil organic matter (OM) is a key attribute of soil quality. It affects, directly or indirectly, many physical, chemical and biological properties that control soil productivity and resistance to degradation. Changes in the quantity of soil OM and the equilibrium level of soil OM depend on the interaction of five factors: climate, landscape, texture, inputs and disturbance. Some of these factors, called soil OM capacity factors, can be managed, whereas others cannot. As OM enters and resides in soil, it is subjected to processes that alter its composition and quantity. Fundamental soil processes such as humification, aggregation, translocation, erosion, leaching and mineralization are driven by the capacity factors. These capacity factors and soil processes, in turn, largely dictate the management system imposed on a soil. Understanding how soil OM capacity factors and fundamental soil processes interact with management over time allows the comparison of management systems that affect soil OM levels. We propose a ranking of general benchmark management systems for the purpose of identifying how a particular system might influence OM levels relative to a new or different system.

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