H.—34.

The soils on the main fiats are grey-flecked clays with a marked crumbly structure. Raupo and other swamp vegetation is said to have been the main cover in the past, though certain areas supported Kahikatea and mixed bush. On lower areas close to the foothills the topsoils are fertile peaty loams and peaty clays ; deep peaty loam soils cover only small areas and in the foothill re-entrants. Drainage is the chief soil problem on these flats. Because of the heavy texture the soils are difficult to drain, and during wet weather, they poach badly with even moderate stocking, many farmers being forced to shift their stock on to neighbouring hill lands during the winter. These clay meadow soils are the complement of the podsolized soils of the adjacent hills and should be used in conjunction with them, for each tends to grow grass when the other is not producing. Soil Conservation. Attention has been paid to the problem of soil conservation on the hill lands and the results of some of the work has been published by one of the writers (N. H. Taylor) in the New Zealand Journal of Science and Technology. It is necessary to build a stable grass soil on the hills in order to protect them from deterioration. An example from the hills near Whangarei shows this clearly. Part of the clay hillside with a 22° slope was covered with good paspalum and part with poor danthonia pasture which was frequently burned. Beneath the paspalum had been built a layer of brown humus 2 in. to 3 in. thick, whereas beneath the sparse danthonia cover the profile was similar to that of a treated forest soil. With a poor pasture cover the general process of deterioration in North Auckland appears to be first the removal of topsoil by sheet erosion, followed by shallow slipping induced by wider fluctuations in soil moisture, and finally destruction of the slipped ground by channelling. FOREST LITTERS. By N. H. Taylor and J. K. Dixon. Farmers have long been able to estimate the quality of the soil by the forest trees growing upon it. For example, such trees as puriri and kohekohe are regarded as signs of good land, whereas kauri trees indicate land of definitely poorer quality. During the course of the North Auckland soil survey this correlation of forest trees with stage of soil leaching, even where the underlying rock is the same, has been very apparent and has been one of the problems studied. Three main types of forest floor are recognized. Under dicotylous trees (such as puriri, kohekohe, and taraire) a loose litter of dead leaves directly overlies the mineral soil. Under podocarps and related trees (such as rimu, totara, and miro) the litter does not decompose so rapidly and the intermediate stage of decomposition is shown by the powdery humus layer which separates the layer of fresh litter from the mineral soil below. Under kauri (a conifer) this intermediate layer is much thicker and resembles a greasy peat. Analyses of the forest-floor samples, although incomplete, show the litter of dicotylous trees to contain more lime and potash than does the litter of the kauri. The alkalinity of the litter ash (i.e., the excess of basic over acidic constituents) agrees with the field evidence in placing the trees in the following order : puriri, taraire, rimu, kauri. The puriri produces the most fertile soils from a given parent material, and the kauri the least fertile. PUMICE SOILS OF THE GISBORNE DISTRICT. By L. I. Grange. In December, 1937, the writer made an examination of the pumice soils of East Cape Peninsula in order to provide basal soil data for the experiments on anaemia in sheep that are being carried out in that district. The map in Bulletin No. 32 of the Department of Science and Industrial Research shows the Taupo pumice extending east as far as Matawai, but the present survey disclosed the fact that this ash shower does not extend into the Gisborne district—it probably does not reach much beyond Lake Waikaremoana. The ash that covers the Gisborne district is the product of an eruption, from Lake Taupo, which immediately preceded the eruption of the Taupo pumice. It is given the name Gisborne Shower, a typical section of which is :— 7 in. black sandy silt. 8 in. grey-brown gravelly sand. 7 in. creamy-grey gravelly sand. This means it is a light-textured soil with a gravel layer in its subsoil. The shower extends from the Taupo pumice boundaries north to a few miles, beyond Matawai, to within a short distance of Gisborne, and to the Mangaheia Valley, ten miles west of Tolaga Bay. The area covered by the Gisborne Shower covers almost all the local farms on which bush sickness has been reported. Analyses made by Mr. K. J. McNaught, of the Department of Agriculture, show that the soils are low in total cobalt content, but are higher in this element than those derived from Taupo pumice. The soils are low in phosphate and are distinctly acid.

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