Tree Nutrition Research Articles

REVIEWS

An Introduction to Pollen Analysis. By G. Erdtman. The Cytoplasm of the Plant Cell. By Alexandre Guilliermond. Trans, by L. R. Atkinson Wild Flowers in Britain. By Geoffrey Grigson. Problems in Tree Nutrition. By M. C. Rayner and W. Neilson‐Jones.

Problems in Tree Nutrition

ONE of the most difficult problems, either in botany as a pure science, or in forestry as applied biology, has always been, and still is, to assess the relationships which exist between the root of a tree and its environment in the soil. The reason for this lies, of course, in the fundamental difficulty of observing the root under natural conditions without, at the same time, destroying its environment, or at least changing this in some radical manner. A secondary source of difficulty is also to be found in the need for a specialist's knowledge in making accurate observation of the micro-flora and -fauna of the soil, which form so important a part of the natural environment of the root. The consequence of this is to be seen in the relative neglect in general works on plant ecology of that part of plant associations which occurs below the ground, notwithstanding its admitted very great importance. The book under notice is concerned with the study of a special aspect of this relatively neglected subterranean field. Its topical interest lies herein, and especially in view of the wide interest aroused in the effect of composting on soil fertility—that is, on the value of the soil for root development—by Sir Albert Howard and others during recent years. The book consists of a collection of papers which have appeared at various times since 1934. They are here brought together with little or no alteration or editing and, with a short but excellent introduction, form the chapters of the book. A list of references, a glossary and an index are appended, and there is also a large number of plates illustrating the various papers. Problems in Tree Nutrition An Account of Researches concerned primarily with the Mycorrhizal Habit in relation to Forestry and with some Biological Aspects of Soil Fertility. By M. C. Rayner and W. Neilson-Jones. Pp. 184 + 27 plates. (London: Faber and Faber, Ltd., 1944.) 12s. 6d. net.

Mycorhizas of Filbert and Walnut Trees in Oregon Orchards

Walnut and filbert trees in orchards of Oregon show the development of mycorhizas in sufficient abundance to justify a survey to determine the types involved and their prevalence. In 1934, studies of roots of filbert and walnut trees in orchards of the Willamette Valley in Oregon were begun by SCHUSTER and STEPHENSON. The investigation included determination of the distribution of the roots within each soil horizon. In some soils roots were restricted to very limited depths; and apparently typical root absorptive regions (root-hair zones) were inadequate for satisfactory plant development, as the quantity of roots recovered from the soil was very small compared with that found for some other fruit trees. FRANK (2) proposed as early as i885, and also subsequently, that both endotrophic and ectotrophic forms of mycorhizas were capable of modifying root absorptive regions to the advantage of the host plants. Later, HATCH (4) and MITCHELL, FINN, and ROSENDAHL (7) showed that ectotrophic mycorhizas are capable of aiding in the nutrition of specific forest trees in definite soil types. The influence of an endophytic fungus on the germination of orchid seed has been shown (5) to be related to the nutrition of the developing embryo. Other cases of assumed benefit or detriment from ectotrophic or endotrophic mycorhizas have largely remained unproved. METHODS.-In determining the prevalence of mycorhizas, several hundred root samples were taken at random from nine filbert and twelve walnut orchards, representative of most of the soil types on which these trees are grown in the Willamette Valley. Since, according to SCHUSTER and STEPHENSON (io), the greatest concentration of roots occurs generally in the first or second foot, samples were collected for the most part from the upper 2 feet of soil, with sufficient material from lower depths to establish the presence or absence of mycorhizas. The roots were washed free of loose soil in a large-mesh sieve and stored in water for several hours to loosen adhering soil particles. They were then inclosed by fine-mesh wire screenand washed thoroughly with a strong stream of tap water. The desired parts were removed from the washed material with forceps and scissors and kept submerged in water or in killing and fixing solution at all times. In preparation for histological study, the material was fixed in weak chromacetic fixative for 48 hours (i) or for 24 hours (9), then dehydrated in dioxan and imbedded in paraffin in the usual way and cut 8-iO /i thick. Preparation for staining was according to GALIGHER (3) and the staining was in Delafield's haematoxylin. Results

Scientific and Industrial Research in New Zealand

AN admirable survey of the work carried out under the Council of Scientific and Industrial Research, New Zealand, during 1927-38 has been issued by the Department as Bulletin No. 69. It includes accounts of work carried out by the Dairy Research Institute, the Plant Research Bureau and the Wheat Research Institute, as well as of the activities of the Department in soil survey, fruit research, animal research, tobacco research and the work of the research associations. The work of the Dairy Research Institute on the cause and control of openness in cheese is described in some detail, as well as further work on discoloration in cheese, and on cheese manufacture. Reference is made to the work of the Plant Diseases Division on chemical sprays and the spray certification system which has been introduced, as well as on virus diseases of tobacco, tomato and of potato, and the importance of the methods introduced for the control of smut of barley. The contribution of the Wheat Research Institute to the improvement of the technique of wheat growing and harvesting, the growing of varieties most suitable for special districts, and cheapening the cost of production is emphasized, as well as the selection and distribution of a new wheat, Cross 7, which yields as well as standard varieties, and has by itself a baking quality equal to that of the old varieties plus the proportion of Canadian wheat formerly used. Fruit research has covered manurial experiments on fruit tree nutrition, boron as a cure for internal cork of apples, orchard sprays, wrappers for fruit; and the soil survey studies have included reference to the physiological diseases of plants. An important discovery ha the field of animal research relates to the wasting diseases caused by deficiencies in the diet of cobalt, to which the bush sickness in the North Island, Morton mains disease in the South Island, and Glenhope ailment in Nelson are due.

Government explores public phosphate lands in Florida

Infestations of Essigella californica following the installation of post-thinning fertilizer trials in Pinus radiata plantations provided an opportunity to examine the impact of repeated defoliation over a period of 8 years (1997–2005). Replicated treatments (n = 4) of nil fertilizer (control), N (300 kg ha−1) as urea, P (80 kg ha−1) and S (45 kg ha−1) as superphosphates were applied immediately after thinning at three sites and this was followed by a second application of NPS fertilizers 6 years later with N applied at 300 kg ha−1 as urea and ammonium sulphate and P at 80 or 120 kg ha−1. Defoliation of untreated P. radiata gradually increased to 50% over a period of 8 years. Basal area growth was negatively correlated with average defoliation for two consecutive post-fertilizer periods of 6 and 2 years. Growth responses to fertilizer varied considerably between sites but the largest improvement in growth was due to NPS fertilizer, this increased basal area by 30–80%. Application of N fertilizer raised total N levels in foliage and increased defoliation with a commensurate loss in growth under conditions of deficiencies of S or P. Repeated infestations gradually increased the percentage of trees with severe defoliation (>80% loss of foliage) indicating that nutrient-deficient trees have a reduced capacity for foliage recovery between episodes of peak infestation. In contrast, treatment with N fertilizer in combination with S- and P-corrected deficiencies of these nutrients, raised levels of total N in foliage and reduced defoliation to approximately 20%. Basal area growth responses to NPS fertilizers reflected improved nutrition as well as reduced insect damage. The reduction in defoliation under conditions of balanced tree nutrition was most likely due to enhanced needle retention following correction of P deficiency as well as greater availability of nutrients enabling a more vigorous recovery of P. radiata after an episode of E. californica activity. Treatment with fertilizer therefore reduced the long-term impact of aphid damage and improved growth of P. radiata.

NUTRITIONAL STUDIES ON LOBLOLLY PINE

The investigation herein reported was undertaken as part of a cooperative project on the biology of forest trees at Duke University. It represents an attempt to add a contribution to knowledge of the mineral nutrition of certain forest trees, in the hope that ultimately it may be possible to correlate the findings with studies of soil composition and with the local distribution of these tree species. Loblolly pine (Pinus taeda L.) was selected as a species that is relatively cosmopolitan, and yellow poplar (Liriodendron tulipifera L. ) as a species that is relatively specific in environmental requirements. The present paper is a preliminary report on loblolly pine only. For the purposes of this investigation, sand cultures were regarded as the most desirable method. Of the extensive work with sand cultures by many investigators within the past few years, little has been concerned with woody plants, and very little with forest trees. Mitchell 's (4) experiments on Scotch pine and white pine in the Black Eock Forest represent the most fruitful work of the kind that has been done with forest trees.