Sig. Ponzi, the engineer of work, states that these reservoirs have nothing to fear from silt, because the water that reaches them is clear, coming as it does from catchment basins (about three-quarters of a square mile) covered with woods and pastures. Should it, however, be necessary to scour the bottom of the reservoirs, it can be done by allowing the water to issue under a head of 6 feet and if necessary the mud could be previously stirred up. The amount of water available in the reservoirs from the middle of May to the end of June is 5 933 000 cub. feet. This quantity distributed in four times in July and August amounts for each irrigation, lasting 196 hours, to 1 483 250 cub. feet, to which 0.42 cub. feet per second of running water must be added, bringing the total available for each irrigation to 1995 410 cub. ft. The following data refer to the construction and cost of the reservoirs: The price at which the water is sold is valued for all the reservoirs at £2 78 7d per hour, owing to the considerable increase that has taken place in the growing of irrigated forage crops and of tomatoes. This price could even be raised if the water were to be used at times out of the regular succession and for industrial purposes. which allows of all the expense being amortized in only 10 years. TILLAGE AND METHODS OF CULTIVATION 470 Irrigation Experiments in Brandenburg, Germany. AUGSTIN. Ein Acker- No. 14, A detailed description of the experimental installation of irrigation works in 1911, by the Chamber of Agriculture of the Province of Brandenburg in the exploitation of Jüterbog, the Property of Hr. BohnstedtKaltenhausen. The cost and the profit of the installation are given, as well as the excellent results which have been obtained. 471 Field Records relating to Subsoil Water. - Mc GEE, W. G.: U. S. Department of Agriculture, Bureau of Soils, Bulletin 98, pp. 40. Washington, February 1913. In the semi-arid regions of the United States which have been made productive by the adoption of the dry-farming system, large yields of crops are obtained with an apparently totally insufficient moisture supply in the shape of an annual rainfall of 15 inches; and the present bulletin sets forth the result of an enquiry into how far this insufficient rainfall is supplemented by an underground water supply. In South Dakota the soils are derived from the underlying clays and shales, and where the latter are exposed in wells, railway cuttings, etc., they are moist almost to the point of saturation, and the moisture increases uniformly with the distance from the surface, suggesting a subterranean rather than a superficial source of supply. The whole district may be looked upon as an artesian area with a catchment area on the Eastern Slopes of the Rocky Mountains, whence the Dakota sandstone conveys the water to South Dakota, the water gradually leaking into and through the overlying clays and shales. The rate of percolation and seepage cannot be accurately stated pending systematic observation, but it has been provisionally estimated at over 12 inches per annum — sufficient to supplement the 15 inches of rainfall and produce an abundant crop. Another portion of the Region of the Great Plains was studied in South-Western Kansas, and a detailed description of the ground-water condition is given. The conclusion is drawn that the district is underlain by a reservoir of moisture flowing eastward, and derived both from the local rainfall and from catchment on the mountains or higher parts of the plains. The water table occasionally comes to the surface and gives rise to perennial streams and permanent ponds, but though within reach of the surface by capillary movement, it usually lies at an average depth of 30 feet, and may be considerably lowered by excessive use. A provisional estimate was made that 6 to 8 inches of water per annum would rise from the underground supply and be available for plant growth. It would be difficult to overestimate the importance of these results, for the areas where the subterranean movement and supply of water are indicated coincide with those where dry-farming has been most successful, and it may be inferred that there is a close connection between the two phenomena. Moreover, if this be the case, it will also explain why the system yields such far less satisfactory results when applied to other parts of the world where different geological conditions obtain. 472 Experiments in Subsoiling at San Antonio. HASTINGS, S. H. and LETTEER, C. R.: in U. S. Department of Agriculture, Bureau of Plant Industry, Circular 114, pp. 9-14. Washington, February 1913. Experiments were carried on for three years in a semi-arid region of Texas to estimate the value of subsoiling to the crops. In no instance was the difference in yield significant, nor was the moisture content of the soils increased. 473 Dry Farming. - HENDERSON G. S.: in The Agricultural Journal of India, Vol. VIII, Part 1, pp. 41-46. Pusa, January 1913. A general survey of the dry-farming conditions in the semi-arid districts of the United States, with a discussion of how far the system might be applied to similar regions in India. 474 Nitrogen-Enrichment of Soils: Clover as a Manurial Agent. – SHUTT, F. T. Report of the Dominion Chemist. - Appendix to the Report of the Minister of Agriculture, Experimental Farms, Reports for the Year ending March 31, 1912, pp. 139-171 (144-146) + fig. 1. Ottawa, 1912 (1913). This article describes an experiment instituted to determine by direct analysis of the soil the amount of nitrogen that might become part of it through continuous growth of clover, the soil at the outset being a poor one. The plot set apart for this work was, in the early spring of 1902, dug out to a depth of 8 in, and the excavation filled in with a well-mixed, light, sandy loam; the subsoil was sand. At the outset the plot was dressed with superphosphate at the rate of 400 lbs. and muriate of potash at the rate of 200 lbs. per acre; no nitrogen was given, but the soil was watered with a solution of "nitragin"; lime at the rate of 1 ton per acre was worked into the soil in the spring of 1909, as the plot was showing signs of sourness. The first seeding of red clover was made in the early spring of 1902 and a very fair catch obtained; the plot has been in clover continuonsly since that date; the crop was cut as occasion seemed to require throughout the season, the plants not being allowed to go to seed, and the material was allowed to decay on the soil; every second year, the plot was dug over and resown. From time to time, the soil has been sampled and its nitrogen-content determined; the results are tabulated as follows: Nitrogen-Enrichment of Soil due to the Growth of Clover. MANURES AND MANURING, During the 10 years of the investigation, the soil gained, simply from the growth of clover, on an average 50 lbs. of nitrogen per annum, or had doubled its uitrogen-conteut. The value of these data, obtained under conditions considered too unfavourable or disadvantageous for profitable farming, is obvious. The inevitable losses in humus and nitrogen, consequent upon the necessary cultivation of the soil when growing crops other than those which put the land in sod, are also discussed, with a view of emphasizing the necessity for the adoption of a rotation which includes the periodic growth of clovers and grasses. 475 - The Effect of Sulphate of Ammonia on Phosphatic Manures used for Oats. — MITSCHERLICH, E. and SIMMERMACHER, W. Mitteilungen aus dem landw. Institute der Universität Königsberg, Abteilung für Pflanzenbau. Die Landwirtschaftlichen Versuchs stationen, Vols. LXXIX and LXXX, pp. 71-96 + fig. 4. Berlin, 1913. This article describes experiments on the solubility of bicalcic and tricalcic phosphates on the addition of other salts, and especially of ammonium sulphate (I), and pot-culture experiments with oats (II). I. 2 gr. each of bicalcic and of tricalcic phosphate were shaken up for 101⁄2 hours, at a temperature of 30° C., with one litre of distilled water through which a current of carbon dioxide was kept running. The operation was carried out in Mitscherlich's apparatus (Rührapparat). To a certain number of bottles were added at a given time equivalent amounts of various salts, as shown in the following table, which gives the results of the experiments: The amount of phosphorus pentoxide dissolved was only diminished by the action of calcium sulphate; all the other salts increased it, especially ammonium sulphate. It is very probable that this property of increasing the solubility would also be shown, though to a less extent, in manuring experiments, since it has already been found that the application of ammonium salts greatly promotes the assimilation of slightly soluble phosphates. It may therefore be concluded that the use of these salts would increase the yield, when the factor phosphorus pentoxide is present in a relatively minimum proportion. II. In the pot-culture experiments, when the other nutritive principles were present in a soluble condition and in sufficient quantities, the addition of about 16 gr. of soluble salts per 6100 gr. of sand per pot, increased the solubility of the phosphorus pentoxide present in the minimum quantity; the minimum of calcium compensated for by the addition of gypsum was 3 gr. in the case of bicalcic phosphate and I gr. in that of tricalcic phosphate. The addition of only 0.5 gr. of ammonium sulphate brought about a further increase of the crop and a larger assimilation of phosphorus pentoxide. At the same time, the addition of an excess of ammonium sulphate as compared with the amount used in practical agriculture caused injury to the vegetation. On the other hand, the addition of sulphate of ammonia after a treatment with superphosphate and basic slag produced no increase in the utilization of phosphoric acid by the oats; and in a loam soil, susceptible to phosphatic treatment, it did not increase the solubility of the phosphoric acid present, nor indeed hinder the degradation of the soluble phosphoric acid given as a manure. The writers propose, in future experiments, to eliminate the action of nitrogen, as well as the acid chemico-physiological reaction of the salts in question, thereby isolating the solubility phenomena and their effects. 476 The Soluble Silicic Acid in Basic Slag and its Influence upon the Determination of Citric-Soluble Phosphoric Acid. POPP, M. (Ref.), CONTZEN, J., HOFER, H. and MENTZ, H.: in Mitteilung der landwirtschaftlichen Versuchs-Stationen, Vols. LXXIX and LXXX, pp. 229-278. Berlin, 1913. The writers attribute the difficulties in the analysis of basic slag to a want of an accurate knowledge of its chemical composition. They confirm the belief that the precipitation of the so-called "injurious" silicic acid should be attributed to a deficiency in soluble iron. If, on the contrary, there is a large amount of the latter present, the colloidal silicic acid remains in solution in the alkaline liquid. The precipitation of ferrous sulphide, due to the addition of ferric citrate, can be prevented by a weak oxidizing agent. The writers therefore propose the following method to 50 cc. of citric extract should be added 25 cc. of ferric citrate solution, 10 cc. oxygenated water at o. 3%, and 25 cc. of magnesia mixture. The article contains detailed directions, comparisons with other methods, and in conclusion, deals with the analysis of Wolter phosphate. |