Chemical Aids in Forest Fire Control

Progress in development of chemical aids in suppressing andretarding forest fires and in drying vegetation to facilitatecontrolled burning is reviewed briefly. The main part of thepaper describes exploratory trials in 1958–61, using arange of fire-retardant compounds for control of grass and heathfires. All chemicals tested were markedly superior to plainwater in checking fire spread. Ammonium phosphate solution,and ‘viscous water’ prepared using sodium alginate,were the most promising retardants tested, the latter beingthe more effective on heavier fuels such as heather and gorse.The costs and mechanics of use are discussed. Subject to operationaltrials, it is concluded that these chemicals could be of practicalvalue in checking the front and hottest parts of vegetationfires. Recent trials suggest that herbicides, of those testednotably Paraquat, may be used to desiccate grass vegetationto permit safe and rapid controlled burning during summer months.     

LOSSES IN THE CONSERVATION OF HEAVILY-WILTED HERBAGE SEALED IN POLYTHENE FILM IN LINED TRENCH SILOS

A conservation experiment is described in which the losses in ensiling heavily-wilted herbage, of approximately 50% dry matter, in lined trench silos, with and without a polyethylene film seal, are compared. The composition and digestibility of the silages produced in the sealed silos were comparable with those of the original herbage. The content of organic acids in the sealed silos was low, suggesting that fermentation was suppressed by the partially gas-tight seal. In the unsealed silos there was considerable spoilage, 70% of the material being inedible. In the 2 sealed silos losses of dry matter were 8·2 and 5·2% and losses of SE 11·5 and 7·8%, respectively. The losses recorded are compared with those usually encountered in lined trench silos.     

THE TESTING OF GRASS VARIETIES IN SWARDS WITH CLOVER: THE EFFECT OF GRASS SEED-RATE ON COMPARISONS OF GROSS YIELD

Three experiments were carried out to examine the influence of grass seed-rate upon the amount of clover growing with different varieties of perennial ryegrass. The bred varieties S23 and S24 were compared with Irish ryegrass. A larger quantity of clover grew with Irish ryegrass than with bred varieties at any given seed-rate. If the varieties were to be compared in terms of herbage of similar clover content, then Irish ryegrass sown at 20 lb/ac had to be compared with S23 or S24 sown at about a quarter of that rate. Reducing the seed-rate of the bred varieties from 20 to 5 lb/ac had only a small effect upon yield of ryegrass, and this was offset by an increase in yield of clover. Since weed grasses also took advantage of low grass seed-rate, it is concluded that other factors in the management of variety trials must be so controlled as to produce a satisfactory clover content without too drastic a reduction in the seed-rate of any variety. The relationship between grass seed-rate and yield of clover varied markedly with the availability of moisture.     

III. Buchbesprechungen

Ohne Zusammenfassung     

The genetic system for reaction of field beans (Phaseolus vulgaris L.) to infection by three physiologic races of Colletotrichum lindemuthianum

Genetic resistance to race alpha of C. lindemuthianum in the nine varieties of beans studied can be accounted for by dominant alleles at either of two loci, which are unlinked and which behave as duplicate factor loci in the classical sense. A similar system of loci governs reaction to races beta and gamma, with evidence favoring multiple allelism and dominance of alleles conferring susceptibility in certain instances in the case of beta. In addition, for reaction to races beta and gamma, there are distinct systems of complementary factors, again with multiple allelism at the beta loci. Finally, there is genetic linkage between genes of the duplicate factor set governing reaction to gamma and genes of the duplicate factor set, and complementary factor set conditioning reaction to beta. The genes that are members of the set(s) pertaining to any one race alone are independent of each other in a linkage sense.Paper based on work conducted by the senior author in partial fulfilment of requirements for the Doctor of Philosophy degree at Michigan State University and supported by the Rockefeller Foundation.Formerly Rockefeller Foundation Student in Crop Science, now Director, Instituto Nacional de Investigaciones Agricolas, Veracruz, Mexico; Professor of Crop Science, Michigan State University; and Research Pathologist, Crops Research Division, Agricultural Research Service, USDA.     

THE NUTRITIVE VALUE AND AGRONOMIC ASPECTS OF SOME FODDERS IN NORTHERN NIGERIA

Digestibility data are presented on the following; Andropogon gayanus hay and bush foggage, Arachis hypogoea (groundnut) haulms, Glycine max (soya-bean) hay. Sorghum vulgare (sorghum) leaves and hay, Stizolobium sp. (velvet bean) hay, Vigna sinensis (cowpea) hay and haulms, and S. vnlgare/Stizolobium sp. mixture. The results are discussed from the agronomic aspect.     

Einflu? von Jahrringbreite und Alter auf den mikroskopischen Bua von Trauben- und Stieleichenholz

Ohne ZusammenfassungÜberarbeiteter Teil einer Ingenieur-Abschlußarbeit an der Staatlichen Ingenieurschule für Holztechnik in Rosenheim des letztgenannten Verfassers.     

ANTHILLS AND TERMITE MOUNDS IN PASTURES

The distinctive vegetation of some anthills in chalk grasslands is shown diagrammatically, and some differences between the soils of anthills and those of the surrounding grasslands are discussed. The termite mounds of the tropics also have soils differing from those of the grasslands in which they are built; some harvester termites destroy areas of pasture: and the large mounds of fungus-eating termites hinder mechanical cultivation. Temperate and tropical pastures benefit from control of ants and termites.     

Einfluss Weicher Röntgenstrahlen und Mechanischer Effekte auf das Keimen von Kartoffeln

Zusammenfassung Um eine schonende Keimhemmung bei Kartoffeln der SorteBona zu erzielen, wurden Versuche mit sehr weichen R?ntgenstrahlen von 12 keV Energie durchgeführt. Sogar mit einer Bestrahlungsdosis von 10.000 bis 15.000 r wird — bei der hier angewandten weichen R?ntgenstrahlung — eine über 22 Wochen andauernde Keimhemmung erreicht ohne Verschlechterung des ?usseren Ansehens und Geschmacks. Der Schwund der Knollen wurde einzeln bis 5.000 r gemessen und mit anwachsender Dosis bis zu 15.000 r eine starke Verminderung des Schwundes erzielt. Au?erdem wurde nachgewiesen, da? durch langstündiges, vorsichtiges Rollen in der beschriebenen Versuchsanordung ebenfalls eine Keimhemmung zu erreichen ist. Es wird versucht, diese Erscheinung biologisch und rechnerisch zu deuten. Aus praktischen Gründen w?re es wünschenswert, den neuen, erw?hnten Effekt weiter zu untersuchen.

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Summary In order to bring about sparing sprout inhibition of theBona variety of potatoes experiments were undertaken with very weak X-rays of an energy of 12 keV. A radiation dose of only 10.000 to 15.000 r (with the weak X-radiation employed in this instance) was sufficient to inhibit sprouting for over 22 weeks without adversely affecting the appearance and flavour. The tuber shrinkage was individually measured up to 5.000 r and a marked reduction of shrinkage obtained with an increasing dose up to 15.000 r. It was also shown that sprouting may be inhibited by protracted, careful rolling in the described order of experiments. An attempt is made to explain this phenomenon biologically and analytically. From practical considerations it would be desirable to make a further study of the novel effect referred to.

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Résumé Pour réaliser de fa?on délicate une inhibition de la germination des pommes de terre de la variétéBona, nous avons effectué des essais de traitement par les rayons X très mous d'une énergie de 12 keV. Même l'irradition à une dose de 10.000 à 15.000 r sufit déjà — dans le cas des rayons très mous utilisés dans ces essais — pour inhiber la germination pendant 22 semaines au moins sans nuire à l'aspect ni au go?t des tubercules. La perte de poids des tubercules fut mesurée isolément jusqu'à 5000 r. Les doses croissantes jusqu'à 15.000 r réduisaient fortement la perte de poids. Il a également été constaté que dans les conditions de l'essai, un roulement très lent et doux des tubercules permet aussi de retarder la germination. Nous avons tenté d'expliquer ce phénomène au point de vue biologique et statistique. Pour des raisons pratiques, il serait désirable que l'étude de cet effet nouvellement observé soit approfondie.