Johanna Laakso

Sediment from agricultural constructed wetland immobilizes soil phosphorus

Phosphorus (P) losses from agricultural soils impair the quality of receiving surface waters by enhancing eutrophication. This study tested the potential of using sediment from agricultural constructed wetlands (CWs) to immobilize soil P using two soils differing in texture and soil test P (STP). A silty clay soil (SIC) with high STP (24 mg ammonium acetate-extractable P [P] L) and a sandy loam soil (SL) with excessive STP (210 mg P L) were incubated with increasing amounts of clayey CW sediment. The soil-sediment mixtures were studied with the quantity/intensity (Q/I) technique, using chemical extractions, and by exposing the mixtures to simulated rainfall. In both Q/I and simulated rainfall tests, P solubility steadily decreased with increasing sediment proportion in the mixtures. However, in chemical extractions this effect was observed only at high sediment addition rates (10 or 50% [v/v] sediment). At a practically feasible sediment addition rate of 5%, dissolved reactive P (DRP) in percolating water from simulated rainfall decreased by 55% in SIC and by 54% in SL ( < 0.001 in both cases). Particulate P (PP) also showed a decreasing trend with increasing sediment addition rate. Upon prolonged simulated rainfall, the decreasing effect of sediment on DRP and PP declined somewhat. The effects of sediment addition can be attributed partly to increased salt concentrations in the sediment, which have a short-term effect on P mobilization, but mostly to increased concentrations of Al and Fe (hydr)oxides, increasing long-term P sorption capacity. Adding CW sediment at a rate of up to 5% of surface soil volume to soils could provide an alternative to chemical treatment (e.g., with metal salts) for immobilizing P in small, high-risk P leaching areas, such as around drinking troughs in pastures.

Native or borrowed, or both - Is it possible to have many mothers?

Abstract Developments and innovations in the history of a language are customarily explained as either “native” or “contact-induced”. Traditionally, these are considered as mutually exclusive, at least in practice. In the case of two competing explanations, some linguists prefer the “native solution”, while some opt for the explanation which is technically more beautiful or better in accordance with other facts (“pattern explanation”). Accepting both and fitting them together is seldom considered. In this paper, these questions are regarded in the light of some Finnic examples, representing different subsystems of language. Identifying foreign influences can be problematic not only in morphosyntax and phonology but also in the lexicon, as many Finnic word stems have both an IE loan etymology and an “internal” explanation (descriptive words, irregular derivatives). Combining the competing explanations is actually a stronger version of proposing constraints for borrowing: it implies that (at least in some cases) languages only “receive what suits them”. Thus, accepting dual explanations presupposes a “built-in conservativity”. This fits in with the remarkable structural stability in language (despite and behind the constant changes) which is also shown in research on grammaticalization and historical morphology.

Book Review: Systems in contact, systems in motion. The assimilation of Russian verbs in the Baltic Finnic languages of Russia: Stefan M. Pugh (1999) Acta Universitatis Upsaliensis: Studia Uralica Upsaliensia 30. Uppsala ISBN: 91-554-4404-0.pp.150

generated by the process of colonialism, with which English became intrinsically linked. Pennycook illustrates this discursive link through writings by students in Hong Kong regarding their relationships to English, which, he claims (perhaps a little too readily) replay to an extent colonial relations of rejection and unwilling accommodation. Idealistic as the possibility of a counter discourse may be, Pennycook stresses the need to provide alternatives to the cultural constructions arising and persisting through colonial discourses. This marks the importance of the work in terms of developments in critical applied linguistics, in working “towards a critical pedagogy” (Pennycook, 1994) in the ELT field, and also at a wider sociological level of understanding discourses of language and power. While he constantly reinforces the need to uncover the ideological patterns that are revealing of those who reproduce these inequalities, rather than “writing back,” it will be interesting to see how practical developments in the field of “teaching back” will evolve through critical pedagogy.