Ladino clover was grown in the greenhouse in 11 different soils for periods ranging from 271 to 391 days. From four to six crops were harvested from each of the different soils studied and the amount of potassium removed by the tops and roots of each crop was determined. The exchangeable potassium content of the soil was determined at the start and at the time of each crop harvest. The amount of nonexchangeable potassium released was calculated by subtracting the decrease in the exchangeable potassium content of the soil from the total amount of potassium removed by the crop. Upon continuous cropping the exchangeable potassium content of the different soils decreased very rapidly at first, then more gradually until a certain level was reached, when the potassium-supplying power of the soil was determined largely by the rate at which the nonexchangeable potassium was converted into the exchangeable form. The dry weights and the potassium content of the plants of the successive crops were closely associated with the amount of exchangeable potassium in the soil. The potassium content of the plants decreased upon continuous cropping. Symptoms of potassium deficiency appeared on the clover leaves when the potassium content of the plants fell below 0.8% on the oven-dry basis. Of the 11 different soils studied, Honeoye silt loam, Chenango gravelly silt loam, and Ontario loam released large amounts of nonexchangeable potassium; whereas Mardin silt loam, Gloucester loam, and Honeoye gravelly silt loam released only small amounts of nonexchangeable potassium upon continuous cropping. These findings are related to crop responses to potassium under field conditions. The relative significance of the exchangeable and the nonexchangeable forms of potassium in determining the potassium supplying power of soils is discussed in light of the results obtained in this study.

Four perennial tropical legumes - Calopogonium mucenoides (calopo), Centrosema pubescens (centro), Pueraria phaseoloides (puero) and Stylosanthes guianensis (stylo) - after 18 months' growth were ploughed under in July at South Johnstone, on the wet tropical coast of Queensland, and soil nitrate nitrogen values were determined in four layers to a depth of 24 inches over the ensuing seven months.

Protein, phosphoric acid, and lime were determined in 336 samples of 64 important species of grasses grown on a Victoria clay loam at San Antonio, Texas, collected on six dates covering a period of over a year. Crude fiber, nitrogen-free extract, water, and ash were determined in 222 of the samples. Considerable differences in chemical composition were found among the various species of grasses. These differences were found not only among different genera but also among different species of the same genus. Percentages of protein and phosphoric acid were generally relatively high in Cynodon and Paspalum species and relatively low in Andropogon, Hilaria, and Eragrostis species. Advancing maturity greatly decreased the percentages of protein and phosphoric acid inall species, so that many were deficient for beef cattle in phosphoric acid and protein. The relative decreases differed considerably with differences in genera and species. The relative decrease due to maturity was least in short grasses commonly found in the subhumid section of the state and greatest in tall grasses ordinarily found in the humid section. Species of grasses of importance to the native pastures of the humid section of the state averaged lower in protein and phosphoric acid and a much larger proportion of the samples were deficient in these constituents than is the case in species of importance to the ranges of the subhumid section. Species ordinarily found on improved pastures of the humid section may be as good as or better than those of the subhumid section.

"Each year the Iowa Farmer has a multitude of corn hybrids from which he can choose seed for planting. Some are well established strains of proven worth while others are new and relatively untried. It is impossible to determine, from the appearance of the seed in the bag, the desirability of any particular hybrid. The real test of its value is determined by planting it along with other hybrids to check its field performance. The Iowa Corn Yield test attempts to provide comparable performance records on a number of hybrids. It is believed that the information presented in this bulletin should afford a reliable comparison of the relative performance of various hybrids when grown in different parts of the state. Data are presented on each entry for yield, stand moisture, root and stalk lodging, ear height, dropped ears and damaged corn. A performance score has been used in evaluating the relative agronomic value of the various hybrids tested."--Page [473].

The results of experimental work at locations throughout the Great Plains and at two locations in the Columbia River Basin show that, except for the one location where lack of available nitrogen was a controlling factor, moisture storage and yields of crops were about the same under three conditions of tillage and disposition of organic residues, namely, leaving all the residues on the surface, leaving a portion of the residues on the surface, and completely burying the residues by plowing. Cultural practices that leave part of the crop residues on the surface are in general use over much of the area because they are adapted to low-cost, extensive-type farming. Maintaining additional quantities of residues on the surface for greater erosion control is desirable if the protection afforded compensates for certain accompanying disadvantages, such as mechanical difficulties and the greater effort necessary to control grassy weeds. Present indications are that the amount of effort that should be expended in keeping residues on the surface will be determined by the need for erosion control with especial regard to the long-time effects of erosion and the relative cost of tillage rather than by the expectation of materially influencing current yields.

Grasses and associations of legumes and grasses were grown in sand cultures. Excretion was determined by observing whether the associated nonlegume benefited during growth and by nitrogen analyses of the plants in some of the experiments. The effect of a number of differences in experimental procedures and growth conditions upon nitrogen excretion was tried, including different plant associations, variations in potassium supply, planting method and day length, different sources of legume organisms, addition of a commercial vitamin B1 preparation, addition of sterile and unsterile soil, and a variety of carefully controlled conditions including abrupt changes in day length and temperature during the state of rapid growth. Grasses benefited six times in 157 associations with legumes, 114 of which were combinations of hairy vetch and Balbo rye. The evidence for excretion in two of the six cases is inconclusive. The gain by the nonlegume did not exceed 2.5 mgm of nitrogen per container in the other four instances, whereas approximately 40 mgm of nitrogen were fixed per container. Excretion, at most, was infrequent and of insignificant amounts. Addition of soil to some of the sand cultures did not result in transfer of fixed nitrogen to the nonlegume until a late growth stage in the legume.

Although certain effects of calcium and potassium on kernel development and yield of large-seeded type peanuts have been determined, the effects of these elements on peanuts of smaller seed size have not been thoroughly investigated. To compare the behavior of four varieties which differed widely in type and seed size to the addition of calcium and potassium, field investigations were undertaken on soils low in these elements. The soils selected represented those commonly encountered in the southern Coastal Plain area of North Carolina. They were somewhat lower in fertility and calcium levels than those characteristic of the older peanut area of this state. The four varieties selected were Virginia Bunch, North Carolina Runner, Spanish 2B, and White Spanish. Four fertilization variables were superimposed on each variety, viz., no treatment, gypsum, gypsum plus potash, and limestone plus potash. The effects of these treatments upon each variety were determined by measuring yield, true shelling percentage, and percentage of the ovarian cavities filled. The most striking feature of the results was the pronounced difference that the four varieties exhibited in their requirements for calcium. Virginia Bunch was found to have by far the highest calcium requirement of any of the varieties used. At one location, for example, yield of this variety was increased nearly six fold by the application of gypsum, that of North Carolina Runner nearly two fold, whereas those of Spanish 2B and White Spanish were not appreciably affected. The effect of calcium on the quality of fruit of each of the varieties at the same location is shown by the following increase in percentage cavities filled which were obtained by the use of gypsum: Virginia Bunch, 35.5; North Carolina Runner, 24.8; Spanish 2B, 19.0; and White Spanish, 4.6. The increases in yield from added potash were small in comparison with those obtained by the use of gypsum. There was little difference in varietal response to potash additions, although North Carolina Runner tended to respond somewhat less than the other varieties. Potassium had no beneficial effect on kernel development and its addition resulted in increased yields through its effect on plant size. This behavior is in marked contrast to that of calcium, in which yields were increased through the beneficial effects of this element on kernel development. The oil content of large and medium kernels was affected comparatively little by fertilization or by variety. In general, however, the kernels from fruit of a high shelling percentage were somewhat higher in oil than those from fruit of lower quality. The yield of oil per acre is essentially a function of pounds of plump kernels produced. When all the results of this study are considered, it is evident that peanut breeding and soil fertility programs are virtually inseparable. Recognition of differences in fertilizer practice and soil characteristics, particularly with respect to calcium, are essential for research in peanut breeding. Furthermore, problems in peanut nutrition cannot be attacked so successfully when differences in varietal behavior are disregarded.

The data obtained from this investigation indicate that irrespective of the light intensity or the time of year during which the experiments were conducted, root temperatures as low as 12 degrees C and as high as 37 degrees C restricted production of dry weight of Dunfield and Manchu soybean plants. In four of the five experiments, root temperature as low as 17 degrees C prevented maximum plant development. Root temperatures from about 22 degrees to about 27 degrees C appear to be most favorable for maximum dry weight production of top and roots when soybean plants are grown under a wide variety of aerial environmental conditions in the greenhouse. A rather close relationship was found between the top:root ratios throughout the temperature treatments, when the experiments are considered individually. However, when the experiments are considered collectively, it was found that the magnitude of the ratios apparently was determined largely by the light intensity of the photoperiod. The low top:root ratios were obtained under high light intensity conditions and the high ratios were obtained under low light intensity conditions. In general, the height of the soybean plants increased with increasing root temperature from 2 degrees to about 17 degrees C, remained uniform from about 17 degrees to about 27 degrees C, and decreased rapidly at 37 degrees C.

The solubility of several phosphates and of 34 soils of low basicity in 0.2 N nitric acid, 0.75 N hydrochloric acid, 0.002 N sulfuric acid, and 0.52 N acetic acid in 10% sodium acetate was determined. Pure calcium phosphates were completely soluble in all extractants. Rock phosphates were almost completely soluble in 0.75 N hydrochloric acid and 0.2 N nitric acid, less soluble in 0.002 N sulfuric acid, and practically insoluble in 0.52 N acetic acid. Apatite was not completely soluble in the different extractants; the solubility was influenced by the strength of the acid and the period of extraction. The differences between acetic acid and the other solvents were probably due to the presence of calcium fluophosphates. The quantity of phosphoric acid dissolved from the soils by 0.52 N acetic acid was from 20% to 40% of the dissolved by the mineral acid extractants. Fixation of dissolved phosphoric acid from the acetic acid was about the same as from water, but was less from the other solvents. The amount of phosphoric acid removed by corn from 34 soils was related to the phosphoric acid dissolved by the solvent. The correlation coefficients for the relation between the phosphoric acid removed by the crops and the phosphoric acid dissolved by the solvents were much larger for the mineral acids. Chemical methods determine the easily soluble phosphates but do not determine the availability of the soil phosphates. Any interpretation of the chemical data secured in terms of availability should be aided by agronomic data.

In an experiment designed to measure the yield of alfalfa hay when cut at various times of day, it was found that no marked increases occurred from morning until night, nor were large decreases found from evening until the next morning. At about one-half bloom, a growth of about 100 to 200 pounds dry matter per acre per day was found. The average fluctuation in yield of 10% between night and morning reported by Curtis was in no way approximated. In almost continuously sunny weather, there was a small but rather consistent increase in the percentage of sugars and starch in the hay as the day proceeded. The highest percentage of these carbohydrates was found on the brightest and hottest day. When samples of hay were dried in unheated circulated air, over a period of 3 days, there was a considerable loss of sugars as compared with rapidly dried samples. Whether this sugar was lost as carbon dioxide in respiration, or used in the synthesis of other materials, is not known. Certain data from Henson (3) suggest the former. When hay was dried much more slowly over a period of about 3 weeks in a "mow drier", the losses of sugar were still more pronounced. Ordinary field-cured hay was far higher in sugars than the hay dried slowly in the mow. Precisely how much difference in actual feeding value will result from such differences in sugar content remains to be determined. The feeding trials now in progress may give some idea of the influence of slow mow drying, in deep mows, upon the feeding value of the hay.