A water deficiency in some areas of the state, a growing population, with added irrigated acreage will increase the use and re-use of agricultural waters and tend to pollute and degrade them to the point of becoming a serious problem.

The determination of sulfur and its compounds in rayon is described. These sulfur compounds are sulfides, sulfites, xanthates, and sulfates. The methods for the determina tion of these compounds and elemental sulfur were first applied to standard solutions of these compounds. After it was established that these methods yielded accurate results, they were applied to the determinations in rayon. Apart from these determinations, the sums of some and of all compounds were determined. These determined sums proved to be in good agreement with those calculated from the determinations of the individual amounts, so that it is assumed that all methods yield accurate results when applied to the determinations of the S-compounds in rayon.

The soil moisture stream is characterized, even in the simplest cases, by a heterogeneous velocity pattern that affects the movement of dissolved solutes. The solutes are carried by the moving stream at diverse rates, causing a spreading action whose amount depends upon the detailed pattern of the flow. The amount of dispersion (σd) in unidirectional flow is proportional to the square root of the linear displacement of fluid. The proportionality constant is a characteristic of the flow system and can be determined experimentally. The amount of dispersion obtained for a given amount of linear displacement is theoretically independent of the velocity of flow. Experiments supporting this conclusion are cited. The experiments with ion exchange resin described herein indicate that the free ions are translocated in accordance with Scheidegger's probability theory. One concludes that the movement of dissolved solutes in the soil moisture stream cannot be determined adequately from the average fluid velocity unless the hydrodynamic dispersion effect is taken into account.

SynopsisThe inheritance of awn barbing was studied using F₂ and F₃ populations of two barley crosses. A single dominant factor governed the expression of semi-smooth awns in one cross, while two dominant linked genes determined the segregation of rough and smooth awn types in the second cross. A recombination value of 26% was calculated for the linked genes operative in the second cross.

The solubility product of iron phosphate was determined by both dissolution and precipitation methods in dilute salt solutions. Solution pH values slightly below the determined isoelectric pH of 2.75 for iron phosphate were employed to get determinable amounts of iron in the solution. The pKₛₚ value was calculated from the ionic activities of Fe³⁺ and H₂PO₄⁻ in the equilibrium solution by the following equation, pKₛₚ = pFe³⁺ + pH₂PO₄⁻ + 2pOH⁻ which was found to coordinate the data most satisfactorily. The pKₛₚ value of iron phosphate increased with a 1000-fold decrease of the solid-to-solution ratio from 33.6 to 35.1. It increased from 33.0 to 33.2 over a 50-fold decrease of the concentration of the precipitation reagents. A medial value of 33.5 was approached by the two procedures; however, for low iron phosphate-solution ratios, such as those commonly employed for soil extraction, the applicable pKₛₚ value agrees with the most dilute solid-solution value of 35 or more. Similarly for aluminum phosphate, the applicable pKₛₚ value extends as high as 32 for dilute suspensions. The variation in apparent solubility product with amount of solid per unit volume of solution is negligible compared to the magnitude of the pKₛₚ which is the reciprocal of a billion trillion trillion. The calculations from solubility products show that aluminum phosphate and iron phosphate should precipitate and accumulate even in neutral soils, as observed experimentally.

A major problem in cauliflower is the occurence of buttoned plants in which vegetative growth was checked shortly after planting out. This results in too early formation of small curds of poor quality ('premature heading').It was found that this could be prevented by transplanting small plants. All factors favouring growth of the young plants in the seed-bed promoted buttoning.Spring crops should be sown late in the autumn and planted out early, whilst early quick-growing varieties should be sown later than late varieties. Plants should be kept cool and dry.Young plants for summer crops should be grown at rather high densities in the seed-bed. Through severe competition plants thus remained small and therefore less prone to buttoning after transplanting. Experiments on breeding showed that cauliflower could be inbred for several generations without any deleterious effect. Seed-setting after selfing was normal and the crop therefore should be considered as self-fertilizing. This was confirmed by field experiments.For selection after July plants must be propagated vegetatively. A method of obtaining cuttings from shoots developing on the stem base and roots was described.Male-sterile plants were found at a rate of 0.05 %. It was determined by a single recessive factor.Earliness was positively correlated with leaf number (r 0.9017).Firmness of the curd was related to its structure and was determined by recessive genes. Plants with poor curds yielded more seed than plants with firm curds.

The quantitative determination of clay minerals by X-ray diffraction procedures was investigated using MgO as an internal standard. The determination of intensity constants for the 001 diffraction lines of samples of illitic, kaolinitic, and montmorillonitic types of clay was made with reference to the 1.48 Å MgO diffraction line. These constants were calculated using the integrated intensity of the specified diffraction lines, the known weights of clay and MgO in each sample, and the calculated value for the intensity of the MgO line. For kaolinitic and illitic types of clay the constants were evaluated with less than 2% average deviation, whereas for the montmorillonitic types the average deviations varied from 2 to 5%, depending upon the clay sample used. The values of the constants vary quite markedly from one species of clay mineral to another within each general clay type and, therefore, constants must be determined for each of the various clay species when they occur in a sample to be investigated. From the intensity constants for the 001 diffraction lines of each clay specie present in a mixture and the integrated intensity of the respective lines, the percentage composition of known synthetic mixtures of two and three components was determined with an average deviation of 1.87% from the actual composition. It was found that clay constituents appearing in quantities less than 10% by weight gave considerably larger deviations, and in the case of such small quantities of illitic types, the diffraction line often could not be differentiated from the background radiation.

SynopsisA comparison was made between heritability percentages calculated by two regression methods, the conventional, and the standard unit or correlation. Their comparative reliability was determined by comparing predicted and actual gains in hypothetical selection experiments for date of heading in oat crosses. In an F₃-F₄, selection experiment, the mean actual and predicted gain in days was 2.8 and 1.5 respectively when conventional heritabilities were used. With the standard unit method, the predicted and actual gains were both 0.9 standard deviation units. In an F₂-F₄ comparison, both methods showed satisfactory agreement between actual and predicted gains.

A laboratory investigation was undertaken in which the movement of nitrate nitrogen through columns of coarse-textured soil materials was studied. Eight soil materials from the Coastal Plain region of North Carolina were used, and the movement of added nitrates as a function of the porosity of these soils and the quantity of water added to the columns was determined. A multiple regression equation was developed which permitted an estimate of the mean nitrate movement from a knowledge of the value of these two variables.

A major problem in cauliflower is the occurence of buttoned plants in which vegetative growth was checked shortly after planting out. This results in too early formation of small curds of poor quality ('premature heading').It was found that this could be prevented by transplanting small plants. All factors favouring growth of the young plants in the seed-bed promoted buttoning.Spring crops should be sown late in the autumn and planted out early, whilst early quick-growing varieties should be sown later than late varieties. Plants should be kept cool and dry.Young plants for summer crops should be grown at rather high densities in the seed-bed. Through severe competition plants thus remained small and therefore less prone to buttoning after transplanting. Experiments on breeding showed that cauliflower could be inbred for several generations without any deleterious effect. Seed-setting after selfing was normal and the crop therefore should be considered as self-fertilizing. This was confirmed by field experiments.For selection after July plants must be propagated vegetatively. A method of obtaining cuttings from shoots developing on the stem base and roots was described.Male-sterile plants were found at a rate of 0.05 %. It was determined by a single recessive factor.Earliness was positively correlated with leaf number (r 0.9017).Firmness of the curd was related to its structure and was determined by recessive genes. Plants with poor curds yielded more seed than plants with firm curds.