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A comparison of some effects of blast furnace slag and of limestone on an acid soil Texte intégral
1930
Crane, F.H.
Blast furnace slag and limestone were compared in greenhouse and laboratory tests. On the gross ton basis 100-mesh limestone was somewhat superior to 100-mesh slag in its effects on red clover growth and soil reaction with the soil used, but on the basis of CaCO3 equivalent, as determined by titration using phenolphthalein as indicator, the two materials had nearly the same effectiveness. The CaCO3 equivalent of these materials, as computed from their contents of total calcium and magnesium, was a less satisfactory measure of their relative effectiveness, as shown by clover yields and effects on soil reaction, than was the CaCO3 equivalent obtained by titration. Four-ton applications of granulated slag gave results approximately equal to those from 1 ton of 100-mesh slag.
Afficher plus [+] Moins [-]Inter-annual correlation for protein content and weight per unit volume in wheat Texte intégral
1930
Treloar, A.E. | Harris, J.A.
The possibility of the prediction of the quality (protein content, weight per unit volume, quality index, etc.) of the wheat crop of the individual districts of a large geographic area must depend on the existence of significant correlations between these variables in different years. Statistical analysis of the data for average weight per hectolitre, protein content, and quality index of the Roumanian wheats tabled by Zaharia for the nine year period 1900 to 1908 shows average values of +0.3653 for weight per unit volume, +0.4652 for protein content, and +0.5447 for quality index. The inter-annual correlations for rainfall are low, averaging only +0.1767 for May and +0.0869 for June. It is significant to note that, while these correlations represent interrelationships covering a range of nine crop years, the magnitudes of the correlations are not greatly affected by the period of separation of the two variables. With inter-annual coefficients of the magnitude of those determined herein, the prediction of future quality of wheat crops should be possible within a reasonable degree of accuracy. While this paper is based on Roumanian data, the primary consideration is that of the principle involved. There can be no reasonable doubt that similar results will be found for districts of other geographic areas. The magnitude of the correlation will depend upon the extent of differentiation of the districts in soil and climatic conditions.
Afficher plus [+] Moins [-]Sap extraction on sorghum and the localization of juice and sugars in internodes of the plant Texte intégral
1930
Janssen, G. | McClelland, C.K. | Metzger, W.H.
1. The percentage juice and the total sugars of juice extracted from sorghum plants in the process of crushing for syrup manufacture were determined on plants given the following treatments: (a) Cut without stripping leaves at time of crushing; (b) cut with stripping leaves at time of crushing; (c) stripped, cut, and left to lie in a pile for various intervals before crushing; and (d) unstripped and left lie in piles before crushing. 2. It is clearly shown that there is a proper time for harvesting sorghum in order to obtain high percentage of juice and of total sugar (Fig. 5). The highest total sugar was obtained from October 1 and October 4 cuttings; less from the September 25 cutting and later dates in October. 3. There is some difference in the value of internodes from different parts of the sorghum stalks, the central having the highest, the lower ones an intermediate, and the uppermost the least value (Fig. 2 and Table 1). 4. Heavy pressure during the processes of crushing the sorghum stalks usually gave the higher amounts of sugar and juice (Table 3). 5. By repeating the crushings three times and by increasing the pressure of the rollers in each case, the respective crushings yielded total sugars in ratio of 2.71:2.4:1.26, or in percentage, approximately 43:40:17. 6. Stripping of leaves from the plant three to four days previous to cutting and crushing caused a slight depression in amounts of total sugars obtained on various dates (Table 2). 7. Allowing the stalks to remain in piles several days after cutting increased the sugar content of the juice probably due to two reasons, namely, evaporation, thereby making the sap more concentrated; and hydrolyses of starch and dextrins to sugars. 8. Allowing leaves to remain on stalks in each instance reduced the percentage of juice and the total amount of sugars (Table 2).
Afficher plus [+] Moins [-]Lime-magnesia ratios in dolomitic limestones as influencing solution and soil reactions Texte intégral
1930
MacIntire, W.H. | Shaw, W.M.
A study was made to determine the influence that calcium-magnesium ratios exert upon the behavior of dolomites toward carbonated water. The higher proportions of calcium the greater were the alkalinities of the extracts and the more quickly were equilibria obtained in initial carbonated water suspensions. The Ca:Mg ratios determined the proportions in which the two elements are initially and progressively available for absorption in the soil system. When subjected to repeated treatments with carbonated water, the dolomites at first disintegrated through the dissolving out of CaCO3 and CaCO3-MgCO3; but after the removal of the CaCO3 excess, the dolomite residues yielded solutions in a constant Ca:Mg ratio of 1:1. Additions of CaCO3 and MgCO3 to dolomite suspensions in carbonated water were found to be reciprocally repressive upon solubility and mutually protective to the solid-phase dolomite. It is pointed out that the Ca:Mg ratio of a solid dolomite, or that of its carbonated-water solution, is not an index to the proportions of calcium and magnesium that are to be found in the soil solution after the dolomite has become a part of the soil system. The addition of economic amounts of dolomite resulted in percolates that contained less calcium and more magnesium than did those from the untreated soil. It was shown that acids engendered in a soil-dolomite medium will combine preferentially with magnesium to enhance the magnesium outgo from fallow soil, or to enrich the contents of growing plants. It was pointed out that dolomites exert a protective action upon the hydrolysis of both native calcium and native potassium, the latter function being in common with that of high-calcic limestone. It was also pointed out that periodic outgo of calcium and magnesium from a dolomite addition differs from that derived from its calcined oxides. The correlation of solubility and acid-reaction studies with lysimeter findings apparently justifies the conclusion that, under humid conditions, additions of dolomitic limestone cannot produce a toxic condition from an accumulation of magnesium per se, since the outgo of added magnesium exceeds that of added calcium.
Afficher plus [+] Moins [-]Root reserves of alfalfa with special reference to time of cutting and yield Texte intégral
1930
Willard, C.J.
1. Any extensive reduction of root reserves of alfalfa as measured by total weight of roots per acre consistently resulted in a reduction in yield and vigor of growth. Severe winterkilling from heaving followed extreme reduction in reserves, but the loss in vigor occurred without this. 2. Up to the first cutting for hay, young alfalfa gained in root reserves regularly and consistently, both in the fall of the seeding year and in late April, May, and early June of the next year. 3. Under Columbus conditions, alfalfa did not in four years show a gain in root reserves in August when the second cutting was allowed to stand from full bloom to seed stage. During the same period in June, gains took place in some years and not in others. This failure to store root reserves after full bloom was associated with yellowed and diseased leaves and does not indicate that gains during this stage would not take place in a region where the leaves remained healthy. 4. The loss in root reserves in recovery after cutting, as an average of 35 observations, was 177 pounds per acre. This was accompanied by an average loss in percentage of nitrogen (on an air-dry basis) of 0.17. 5. Recovery after cutting was almost uniformly accompanied by a decrease in the percentage of dry matter in the green roots, averaging 4.9% in 23 comparisons. 6. At Columbus the most uniformly important period of root storage is in October, when the last cutting of the season has been taken off early enough so that a considerable top growth has been produced by October 1. 7. The most favorable condition for storage of root reserves seems to be the combination of a large amount of healthy leaf area and drier weather than normal. 8. While Grimm and other variegated varieties of alfalfa are more winterhardy than common alfalfas under all cutting treatments, there is no evidence that this difference is due to or associated with differences in the amount of root reserves stored. 9. The effect of cutting on different dates at Columbus is determined nearly as much by the activities of the potato leafhopper as by root reserves, but at present the former are to a large extent unpredictable.
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