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Wholesale prices for 1940-1941 forcing season Полный текст
1940
Wholesale prices for 1940-1941 forcing season
1940
Wholesale prices for 1940-1941 forcing season Полный текст
1940
Growing barley for malt and feed Полный текст
1940
Harlan, Harry V. (Harry Vaughn) | Wiebe, G. A. (Gustav A)
Protein and vitamin supplements for growing and fattening pigs
1940
Willman, John Peter | Morrison, F. B. (Frank Barron)
House plants
1940
Wingert, J. B.
"Growing plants indoors serves at least three purposes. It satisfies a common desire to have growing plants the year around. It provides an interesting and challenging hobby for those who attempt to grow an extensive collection of pot plants -- House plants also can play a definite part in interior decoration when varieties are carefully chosen, well grown and properly placed. Regardless of purpose, there are relatively few homes that do not include at least one house plant. House plants vary widely in their ability to thrive under certain house conditions. One objective of this bulletin is to point out the strengths and weaknesses of various indoor plants so that the homemaker may select varieties which are suited to growing conditions in the house. Light, temperature, humidity and frequently the type of fuel used for cooking or heating will influence the degree of success with which potted plants can be grown." p. [397].
Показать больше [+] Меньше [-]Studies on the basic characteristics of South African merino wool. II. Specific gravity Полный текст
1940
1. The specific gravity of 54 samples of South African Merino wool from various wool-growing areas was determined. Significant differences occurred among these samples. 2. The mean value was 1.3052 at 25°C., water at 4°C. with a standard deviation of ±0.0035 and a coefficient of variability of ± 0.27 per cent. 3. A series of samples presumed to have been selected for differences in specific gravity were analysed. The results were inconclusive. 4. No correlation between the specific gravity and the fibre fineness of the samples was obtained. 5. The influence of variations in specific gravity on the determination of fibre fineness by the weight-length method is discussed.
Показать больше [+] Меньше [-]The nitrogen, organic carbon, and pH of some southeastern coastal plain soils as influenced by green-manure crops
1940
Lewis, R.D. | Hunter, J.H.
The total nitrogen, organic carbon, and pH of Greenville, Norfolk, and Tifton sandy loam soils under various systems of green-manuring are reported. These systems include the growing of summer and winter green-manure crops in different cropping systems and with varying crop management for soil improvement. The soils used in the experiments are typical of the soils of the same types in the southeastern coastal plain. The total nitrogen is increased and the organic carbon either increased or maintained under all systems in the experiments. In no case were these constituents raised to levels that correspond to the levels reported for fertile soils in latitudes farther north. In the Greenville soils nitrogen was conserved at the expense of organic carbon with a resulting narrow carbon-nitrogen ratio of about 6.0, under all systems of management. In the Norfolk soil more accumulation of carbon than of nitrogen was obtained under most of the systems with the result that the carbon-nitrogen ratio was broadened to around 10.0. The Tifton soil is intermediate in this respect showing a carbon-nitrogen ratio of about 8.0. The pH is generally lowered by the use of green manures on all the soils. Satisfactory yields of cotton and corn were produced with the following approximate levels of organic carbon and total nitrogen where green manures and commercial fertilizer were applied: 0.44% carbon and .044% nitrogen for the Norfolk soil; 0.34% carbon and 0.058% nitrogen for the Greenville soil; and 0.40% carbon and 0.050% nitrogen for the Tifton soil. More than one green-manure crop in succession results in higher nitrogen and carbon than one crop per year, but the added gain is not sufficient to justify the loss incurred by tying up the land for the time required. The most economical system for using green manure seems to be one in which the most important cash crop follows the green-manure crop.
Показать больше [+] Меньше [-]"Milorganite" as a source of minor nutrient elements for plants
1940
Rehling, C.J. | Truog, E.
The availabilities of the minor nutrient elements in and their influence on plant growth were studied by growing corn, tomatoes, and sunflowers in nutrient solutions, some of which were supplied with carbonated water extract of Milorganite as the only source of boron, copper, manganese, molybdenum, and zinc. The tomato and sunflower plants were analyzed for each of these elements, except molybdenum, and corn for each except boron and molybdenum. obtained may be summarized as follows: Corn made very little growth and exhibited typical deficiency symptoms in solution cultures from which either manganese or zinc was omitted, while a fairly large but abnormal growth resulted where copper was omitted. The addition of Milorganite extract to some of these cultures during the last 2 weeks of the 7-week growth period resulted in the resumption of normal growth in each instance. Milorganite extract increased the yield in all cases except in controls which were already supplied with all nutrients. Increases in the amounts of copper, manganese, and zinc absorbed by the plants were noticed wherever the extract was supplied. Tomato and sunflower plants made good growth in every culture where Milorganite extract served as the only source of one or more of the minor elements. Inferior growth, exhibiting deficiency symptoms, was generally observed in the series of duplicate cultures which did not receive the extract or other sources of these elements. In all cultures that received it, except controls, Milorganite extract significantly increased the dry weights of the plants and the contents of boron, copper, manganese, and zinc. The results of the investigation show clearly that Milorganite when used as a fertilizer or as a constituent of mixed fertilizer may serve as a source of the minor nutrient elements for plant growth.
Показать больше [+] Меньше [-]Relation of boron to heart rot in the sugar beet
1940
Sugar beet seedlings were grown in quartz sand cultures with and without borax. Symptoms of boron deficiency were carefully observed and studies were made regarding the recovery of beets afflicted with heart rot. Field-grown mother beets showing heart rot symptoms were, divided into halves and planted in quartz sand cultures, with and without borax applied at various times during the subsequent growth period. Observations were made on the types of leaves produced by these mother beets. Soil and leachate tests were made to determine the extent of absorption of boron by sugar beets and the state of solubility of the boron remaining in the soil. This was done to throw some light on the possibility of boron accumulation in the soil. From the results of these experiments the following observations were made: 1. Seedlings grown in jars receiving no borax developed characteristic deficiency symptoms as follows: a. Blackening of tips of heart leaves, followed by death of growing portion of crown. b. Shortened, twisted petioles associated with crinkled condition of heart leaves and some of outer leaves. c. Abnormally dark green and thicker leaves, accompanied by more rapid wilting under drought conditions. d. Pimpled condition of petioles in early stages, followed by breakdown in form of cross and linear checking. e. Yellowing and eventual death of outer leaves, following the death of heart leaves. f. Stunted, second growth leaves following death of first leaves. g. Breakdown of heart of beet root. h. Darkened layer under skin of root and development of surface cankers in advanced stages. i. Restricted fibrous root system. 2. The available boron content of the quartz sand and the seed was adequate to prevent the appearance of deficiency symptoms for a period of two months after the seedlings were transplanted. 3. Yields of roots were increased as much as 80% by an application of 11.9 mg of borax per 5 kg of sand in divided applications. 4. Seedlings in advanced stages of heart rot definitely recovered upon the application of 4.9 mg of borax per pot. 5. Halves of field-grown mother beets planted in quartz sand cultures without borax produced stunted leaves with marked symptoms of boron starvation, whereas the corresponding halves which received like treatment but with borax added at the rate of 2 mg per 1-gallon pot, produced a more abundant leaf growth free of deficiency symptoms. 6. Soil tests for available boron showed that a crop of sugar beets produced in pot cultures removes an appreciable quantity of boron from the soil. 7. By determining the quantity of B(2)O(3) in leachates from pot cultures it was found that it was relatively easy to remove added borax from soils by leaching with distilled water even a year after the borax was applied.
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