Pot experiments with Manchu soybeans performed in both fall and spring showed that three effective strains of Rhizobium japonicum (Nos. 9, 18, and 505) produced relatively few, large nodules, the majority of which were located on, or in the immediate vicinity of, the tap root near the surface of the soil. The ineffective strain used (No. 507) produced many small nodules that were scattered over the entire root system. The ineffective strain produced a greater number, volume, and weight of nodules on each plant than the effective strains. The relative effectiveness of the strains used was determined by comparing the dry weight and nitrogen content of plants grown from inoculated seed with that of plants grown from uninoculated seed.

1 Cultures of Ephestia kühniella were reared at 30° C. and 23° C. These were mainly related stocks, and the emergence of adults from the two types of culture overlapped sufficiently to enable the high temperature moths to be paired with those reared at the lower temperature. 2 The effect of temperature on the longevity and the number of eggs laid was determined by placing alternate females (from both types of cultures) at 23° C. and 30° C. immediately after pairing. The percentage of eggs hatching was also determined. 3 Males reared at 30° C. were impotent when young, i. e., aged two days or less, but a small percentage of them (5 per cent.) attained potency as they aged. 4 Females reared at 30° C. and aged two days or less gave as high a percentage of successful pairings with males reared at 23° C. as did females reared at 23° C., irrespective of the temperature at which the eggs were laid. 5 Older females reared at 30° C. gave no successful pairings with males reared at 23° C. when the eggs were laid at 30° C., but gave a moderate percentage (64 per cent.) of successful pairings when the eggs were laid at 23° C. The conclusion drawn was that a temperature of 30° C. had a sterilizing effect on the females. 6 When young females reared at 30° C. were paired with males reared at 23° C. a smaller percentage of eggs hatched when these were laid at 30° C. than when they were laid at 23° C. This indicated that potent sperm may be weakened by exposure to the higher temperature. The possibility that the effect observed was due at least in part to a higher degree of abortion of the fertilized eggs when these were laid at 30° C. could not be excluded. 7 The number of eggs laid was greater and the longevity was less in females reared at 30° C. which received potent sperm than in those receiving impotent sperm. 8 The longevity of females, whether they were impregnated with potent or impotent sperm, was determined by the temperature at which they were kept after emergence, and not by the temperature at which they were reared. 9 Among females reared at 30° C. and receiving potent sperm the number of eggs was independent of the temperature at which they were laid. 10 Among females receiving impotent sperm the number of eggs laid was directly proportional to the longevity, which itself depended on the temperature at which the females were kept after pairing.

Summary and ConclusionSamples of soil were collected from definite types of soil. They were obtained from thirty-six different locations. From each location, the samples came either from definite horizons of the soil, or from definite distances from the exposed surface downward. Magnesium ammonium phosphate was the only inorganic material added to the soil in making plaques for determining the presence of organisms capable of producing macroscopic colonies. Employing this method, the numbers of colonies appearing on the surface of the plaques were counted. This gave a comparison of the population of a certain group of organisms inhabiting the soils. The identity of these was not determined. It is concluded that organisms capable of producing macroscopic colonies permeate the various horizons of the soil and are found in the unweathered material which may be fifteen feet below the exposed surface of the soil.

The response of pastures to fertilizer and lime treatments as measured by grazing has been compared with the response as measured (a) by clipping permanent plats and (b) clipping by the "difference-method", i. e., obtaining the difference between the yields of temporarily inclosed areas and corresponding grazed areas. Although the yields obtained by clipping permanent plats have shown a progressive decrease in relation to the yields obtained by grazing, there has been a high correlation in any one year between the yields from clipping and the yields from grazing. A method is suggested whereby the clipped yields can be expressed in terms of grazing units. The response to fertilizer and lime treatments determined by the "difference-method" of clipping was a good measure of the response obtained by grazing. The ratio between the weight of oven-dry forage obtained by this method and total digestible nutrients calculated from grazing was 1:0.61.

Calcium and phosphorus, and in some cases total nitrogen and "excess base", were determined on samples of pasture herbage and of pure species of Kentucky bluegrass, white clover, poverty grass, and broomsedge collected during the period of 1931 to 1936. The samples were obtained from variously fertilized and limed plats on two different soils. The herbage from the unproductive soil at Morgantown was only 60% as high in phosphorus as the herbage from the untreated plats of the fertile soil at Moorefield. Liberal fertilization increased the phosphorus content of the herbage to about the same level on the two areas. The percentage increases, however, were 29 at Moorefield and 101 at Morgantown. The calcium content of a mixed herbage is apparently determined largely by the botanical composition of the pasture, which in turn is related to the lime and fertilizer treatments. White clover and some of the common weeds are much higher in percentage of calcium than are the grasses. When grown in association on a number of untreated and of variously treated plats, white clover was found to average 88% as high in phosphorus as bluegrass, but 248% higher in calcium. Phosphorus fertilization increased the phosphorus content of white clover an average of 10% as compared with an average of 40% for Kentucky bluegrass. Broomsedge contained 68 to 86% as much phosphorus and 54 to 76% as much calcium as Kentucky bluegrass. The percentage increase in phosphorus from the use of phosphate fertilizers was approximately the same for broomsedge as for bluegrass. The use of lime on the acid Morgantown plats increased the percentage of calcium in broomsedge by an average of 19 as compared to an average of 36 for bluegrass. Poverty grass averaged less than 70% as high in phosphorus as bluegrass on the untreated plats, but approximately 85% on plats receiving a high amount of phosphorus fertilizer. The percentage increase in the phosphorus content of poverty grass from phosphate fertilizers was approximately twice as high as that for bluegrass. Poverty grass was 49 tO 70% as high in calcium as bluegrass and the average increase in the calcium content of poverty grass from liming was 25% as compared to 36% for bluegrass. The "excess base" content of white clover was 195% higher than of Kentucky bluegrass, whereas broomsedge and poverty grass averaged only 67 and 62% as high as bluegrass, respectively. Broomsedge and poverty grass averaged 76 and 74% as high in nitrogen, respectively, as did bluegrass. It is concluded from a consideration of the data obtained with both the mixed herbage and the individual species that the herbage from many West Virginia pastures is likely to be insufficient to meet the phosphorus requirements of the grazing animal, but probably contains, in general, a sufficient amount of calcium. The minimum and average percentages of calcium and phosphorus for Kentucky bluegrass and white clover obtained in this study are compared with the values obtained by other investigators, and the phosphorus content of bluegrass discussed in relation to Macy's theory. The data indicate that the minimum percentage of phosphorus for bluegrass in the vegetative stage of growth is approximately 0.16% and the critical percentage approximately 0.30%.

A number of weeds common to Florida were analyzed for watersoluble and total nitrogen. Also, the rate of nitrification was determined on these crops in both the green and dry stage, using Norfolk fine sand for cultures. The results may be summarized as follows: Boerhaavia, coffeeweed, careless weed, and crab grass contain a comparatively high percentage of water-soluble and total nitrogen, and appear suitable for cover crop purposes where a rapidly nitrifying material is required. Wire grass, pepper grass, sandburr, Spanish needle, and ragweed are low in total and water-soluble nitrogen and slow to yield available nitrates. The water-soluble nitrogen content appears to be the most important factor involved in the nitrification of green and dried plants followed by total nitrogen and degree of hydration or moisture in the order named. The nitrification of plants containing above 1.7% nitrogen and 1.7% water-soluble nitrogen is only slightly affected by driving, while plants containing less than 0.5% water-soluble nitrogen show a decrease in nitrification upon drying, even where the total nitrogen content is above 1.7%. If the water-soluble nitrogen is 0.5% or above, favorable nitrate accumulation occurs, even though the total nitrogen is less than 1.7%. Plants containing above 1.7% total nitrogen but less than 0.33% water-soluble nitrogen have a slow accumulation of nitrate nitrogen in the soil.

Greenhouse experiments were carried out on two acid Iowa soils, Marshall and Grundy silt loams, to determine the value of fine limestone applied in the row with certain legume seed. Small amounts of fine limestone applied in the row with sweet clover seed on Marshall silt loam caused a depression in the early growth of the plants when grown in deep greenhouse pots. There was no depression in the case of alfalfa nor with sweet clover on Grundy silt loam. Limestone applied in the row appeared not to be depressive to the formation of nodules. The death rate of seedlings caused by pythiaceous fungi was decreased 3.4% for the alfalfa, 3.7% for the sweet clover, and 8.2% for the red clover by applying fine limestone with the seed at the time of planting. As determined by the direct microscopic ratio method fine limestone, when applied in the row with legume seed on Marshall silt loam, stimulated the growth of micro-organisms. The average number of micro-organisms counted for samples taken 0 to 4 cm deep in the row was 93.7 million per gram of soil. This was 46.8 million more than was found in the check soils. As indicated by pH determinations, penetration of limestone when applied in the row was evident in soils receiving water from below only.

The approximate numbers of Rh. meliloti, Rh. trifolii and ammonia-oxidizing organisms in variously treated soils on the Agronomy farm of the Iowa Agricultural Experiment Station were determined at several different periods. The logarithms of the numbers of Rh. meliloti and Rh. trifolii in the soils studied had a highly significant correlation. The logarithms of numbers of Rh. meliloti and nitrite-forming organisms in the variously treated soils cropped to the 3-year rotation of corn, oats, and clover were highly significantly correlated. In similarly treated soils cropped to a 5-year rotation of corn, oats, red clover, winter wheat, and alfalfa, a highly significant correlation between these organisms was also noted. The correlation between the logarithms of numbers of these organisms in soils cropped only to corn and oats was much lower, being just significant. The correlations between the actual numbers of organisms showed a similar trend to those found between the logarithms of numbers. The presence of legumes in a crop rotation seems to promote a more stable flora of the organisms investigated. The ammonia-oxidizing organisms and the legume bacteria studied showed similar responses to fertilizer treatments. Greater fluctuations were observed, however, in the numbers of legume bacteria. The ammonia-oxidizing organisms reached their maximum numbers in the spring or early summer. The alfalfa and red clover bacteria showed no consistent seasonal fluctuations.

SummaryA check on the value of the rapid soil tests on Maryland soils was determined by comparing the results with those obtained by recognized quantitative methods. A brief description of the procedure used is given. The results were compared on the following tests: organic matter, calcium, magnesium, potassium, manganese, phosphorus and nitrate nitrogen. The data are given in tabular form by soil types for each province. Although there were considerable variations in the results for specific soils between the two tests, the following conclusions seemed justified. The short tests for organic matter gave consistently lower values. The results of the two methods for calcium were similar for the Piedmont soils. The rapid tests showed slightly more available calcium in the Limestone soils, and slightly less in the Coastal Plains, Mountain, and Appalachian Plateau, and Bottomland and Terrace soils. In the magnesium tests, the short method did not remove all the available magnesium. This test did indicate the small and excessive amounts of this ion. The quick tests for potassium gave slightly lower results for the Coastal Plain, Piedmont, Mountain soils and Bottomland soils, and higher values for the Limestone soils. The results for manganese by the rapid test compared very favorably with those found in exchangeable form, especially in the higher and lower amounts. Practically the same amount of available phosphorus was obtained by the two procedures. The short method gave slightly higher values for nitrate nitrogen. The average of all the soils in the state showed a good agreement between the two methods.