UP to half or more of the total P in soils may be present in organic forms [ I , IS]. Considerable importance, therefore, attaches to methods for determining the total organic P.A comprehensive review of organic P and its estimation in soils has recently been given by Black and Goring [I]. Two main types of method can be used. In one, the organic P is measured as the increase in inorganic P extracted by a suitable acid solution after the soil organic matter has been destroyed by ignition or by treatment with an oxidizing agent such as H,O,. The other main type depends on alkaline extraction of the organic P after acid pretreatment of the soil to remove bases. The organic P is then estimated by difference between the total and inorganic P in the extracts; both these estimations are done colorimetrically, the inorganic P being determined directly in the extracts and the total P after treatment to destroy the organic matter. Thus, although the two types of method represent a different approach, they both involve oxidation of organic matter; in the first case this is done by treating the soil before extraction whereas in the second it is done in the extracts.Apart from the disadvantage that the values are obtained by difference, organic P estimations are subject to many uncertainties [I]. The main requirements in ignition-acid extraction methods are to ensure complete release and recovery of the organic P and avoid changes in the solubility of the inorganic P during the ignition. In alkaline extraction procedures, the main roblem is to arrive at a combination of acid extraction of the organic P without bringing about hydrolysis. In view of these conflicting requirements, it is not surprising that a wide variety of procedures has been used and that different workers have obtained contradictory results [I].The present results were obtained during a study of the distribution of phosphorus in a series of soil profiles from long-term field experiment areas. The total organic P was determined in the first place by a slight modification of the very simple and rapid Ignition-0.2 N H,SO, extraction method used by Mattson, Williams, and Barkoff [IO]. T o check the results, the organic P content of the topsoils was determined by the hot ammonia extraction method of Pearson [II]. The results showed large discrepancies between the two methods which made it necessary to test the validity of the estimations. T o this end, the effects of varying the experimental conditions in the two methods have been pretreatment and alka F me extracting agent which ensures complete I Present address : Soil Bureau, Wellington, New Zealand.

A 5-year prospective, quasi-experimental investigation demonstrated that grade-level teams in 9 Title 1 schools using an inquiry-focused protocol to solve instructional problems significantly increased achievement. Teachers applying the inquiry protocol shifted attribution of improved student performance to their teaching rather than external causes. This shift was achieved by focusing on an academic problem long enough to develop an instructional solution. Seeing causal connections fosters acquisition of key teaching skills and knowledge, such as identifying student needs, formulating instructional plans, and using evidence to refine instruction. These outcomes are more likely when teams are teaching similar content, led by a trained peer-facilitator, using an inquiryfocused protocol, and have stable settings in which to engage in continuous improvement.

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The authors conducted a quasi-experimental investigation of effects on achievement by grade-level teams focused on improving learning. For 2 years (Phase 1), principals-only training was provided. During the final 3 years (Phase 2), school-based training was provided for principals and teacher leaders on stabilizing team settings and using explicit protocols for grade-level meetings. Phase 1 produced no differences in achievement between experimental and comparable schools. During Phase 2, experimental group scores improved at a faster rate than at comparable schools and exhibited greater achievement growth over 3 years on state-mandated tests and an achievement index. Stable school-based settings, distributed leadership, and explicit protocols are key to effective teacher teams. The long-term sustainability of teacher teams depends on coherent and aligned district policies and practices. S chool-based teacher collaboration, inquiry, and learning are a focus of many efforts to improve student learning. Such efforts are variously described as professional learning teams or communities, and their central goals include deprivatizing teaching through school-based collaboration and reflective dialogue to improve classroom instruction and student learning. In spite of their intuitive appeal and compelling logic, and the approbation of many educators, the limited evidence base is reason for pause. Scarce resources and urgent needs in public schools make funding learning teams and communities a fraught choice for districts because they require culture changes

Pastures from 27 sites (19 farms). mainly in the Hawke's Bay district. were sampled during an outbreak of grass tetany in beef breeding cows. Pastures were generally ryegrass-dominant. with little clover at grazing height, and were mainly closely grazed. Chemical analyses gave the following results (mean value and range of values, (1.42-3.63).The magnesium levels fall within the range where occurrence of hypomagnesaemic tetany may be considered a possibility. and the over-all results suggest that the deficiency of magnesium in the animal is induced by a high-protein-vlow-energy intake. Possible contributory factors in the pasture are high potassium, low calcium. and low sodium. Since no fertiliser nitrogen or potassium was used. the high level of these elements is attributed mainly to luxury consumption from highfertility patches resulting from the return of animal excreta.

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