Water-extractable anions in soils and plants are major forms of essential nonmetal nutrients (N, P, S, and Cl) and important for understanding the soil's current nutrient supply conditions and the plant's recent nutrient uptake status. We investigated the compositions of major inorganic anions (nitrate, orthophosphates, chloride, and sulfate) in both soil and plant water extracts obtained from 19 farmlands (5 monocots, 4 tree dicots, and 10 non-tree dicots). We observed that, although there were several important general properties of soil and plant anions, the anionic compositions were mostly inherent characteristics of each soil and varied largely depending on the plant species. A multivariate factor analysis revealed that the anionic compositions of each soil solution were well characterized by their responses to increments of electrical conductivity. In addition, the leaf anion compositions of each plant tended to share similar characteristics within the same plant types (monocots, tree dicots, and non-tree dicots).

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While electrical conductivity (EC) and sodium adsorption ratio are commonly used to assess soil salinity, for detecting salinity responses during a growing season, those indicators appear to be insensitive when the soils are already high in salinity. We found that the EC and chloride concentrations in soil extracts from salt-affected greenhouses did not show a significant difference in response to different fertilizations of tomato (with a high N demand and a low susceptibility to salinity) and lettuce (the opposite) over the growing season. The fields had been treated with chemical fertilizers or chemical fertilizers plus manure composts combined with food wastes to investigate salinity enhancement by the amendments. On the other hand, the regression lines between EC and chloride concentration could show differential responses in both soil and plant extracts to the doses and salinities of fertilizers. Therefore, using the relationships between EC and associated ions can provide a better insight into the salinity susceptibilities of soils and plants.

Chloroform fumigation and extraction (CFE) has been a widely accepted method for quantifying overall size of soil microbial community, which is a key indicator to assess the quality and health of a given soil. However, the standard procedure of CFE requires careful operations to generate enough CHCl 3 vapors and flush them into soil pores. We suggest a new simple alternative for facilitating gaseous diffusion of CHCl 3 molecules under ambient air pressure conditions. The microbial C values by the new approach, examined for several farmland, forest, and grassland soils, coincided well with those obtained by the standard CFE. The cell lysis and extraction coefficient was also close to that of standard CFE and much higher than that evaluated for a liquid-based CHCl 3 cell lysis.