Seed rot, seedling diseases, and seed treatment; Root and stalk diseases; Foliage diseases: Fungal leaf spots and blights; Foliage diseases: Rusts, downy mildews, and Sooty moulds; Inflorescence and grain diseases; Bacterial and virus diseases; Parasitic flowering plants; Diseases due to other causes.

Wheat and oat straw, soybean and sweetclover hay, corn and sorghum stalks, bromegrass and sweetclover stems were extracted with hot and cold water, using 1 part of residue to 15 parts of water. One-half of the water extract of each residue was autoclaved for 1 hour at 20 pounds steam pressure. In addition, wheat straw was extracted with ethanol and the extract was separated into strong and weak acids, neutral, basic, and water-soluble compounds. The ethanol-soluble compounds were tested for their effect on wheat, whereas the hot and cold water extracts of residues were tested for their effect on germination and growth of wheat, sorghum, and corn seeds. All the residues contained water-soluble substances that inhibited the germination and growth of sorghum, corn, and wheat. The cold water extracted more toxic materials than did the hot water. Autoclaving increased the toxic effect of the water extract of residues on root growth. The toxic effect on germination and shoot growth was decreased for most residues by autoclaving of aqueous extract. Ethanol-soluble substances of wheat straw inhibited the germination and growth of wheat seeds. The ethanol extract of wheat straw, separated into strong acid, water-soluble, neutral, weak acid, and basic compounds, showed decreasing toxicity in the order listed.

A nonporous wax surface crust technique was devised to study seedling emergence of wheat, grain sorghum, and guar. Emergence through crusts with wax penetration numbers ranging from 15 to 80 was evaluated using crust thicknesses of ¼, ½, and 1 inch. Seedling emergence of wheat, grain sorghum, and guar was affected by hardness and by thickness of crusts. A curvilinear relationship existed between seedling emergence and crust hardness. No emergence occurred in any of the 3 plant species when the wax penetration number was 27.0 or less. There was no difference between species in this critical wax penetration number. As crust thickness increased, higher wax penetration, i.e., softer waxes, were required before any seedling emergence occurred.

SynopsisResults of greenhouse experiments indicated that competition between alfalfa and sorghum for moisture and for potassium was not great enough to seriously limit their use as companion crops.

SynopsisClear plastic soil covers increased Houston Black clay early season soil temperatures 10° F. at the 3-inch depth and accelerated plant development sufficiently to hasten maturity and increase grain yield. Grain sorghum yields per acre varied from 62.6 cwt. on bare plots to 73.5 cwt. with a clear plastic cover. Water-use efficiency varied from 315 pounds on bare plots to 428 with clear plastic.

Greenhouse and field studies with foliage sprays of 3 per cent ferrous sulfate solutions provided excellent correction of iron deficiencies in grain sorghum. Greatly increased yields also followed treatment in severely chlorotic areas. Although effective, the large amounts of ferrous or ferric sulfate required for soil applications proved economically impractical.

Field experiments designed to measure the response of corn and grain sorghum to starter fertilizer containing P in Nebraska have shown both negative and positive responses to the starter. Positive responses have been associated with low soil P levels and negative responses with high soil P. These experiments also have shown that corn and sorghum are quite efficient in utilization of soil P, making optimum yields without fertilization possible with these crops on soils of substantially lower soil P supply than is possible with small grains. Excessive vegetative growth and water use with accentuated drouth damage accounted for yield decreases due to starter P in some experiments in dry years. In other cases, it appeared that a hastened physiological development due to applied P may have left the plant in the most critical stage of the reproductive cycle when dessicating weather conditions occurred, with resulting damage that was not apparent in later or earlier corn. In still other cases, there was evidence in plant appearance of a disturbed utilization of trace element(s) where starter P was applied, which is the subject of later papers in this series.

Fifteen Hereford heifers fed solely on restricted quantities of sorghum grain were bled at intervals during the 24-hr period before and after parturition. Blood samples were analysed for glucose, inorganic phosphate, haemoglobin and packed cell volume. Calcium, magnesium, total protein, albumin and globulin were determined on serum. There was a moderate decrease in blood glucose levels prior to parturition and a significant rise to peak values at or about parturition. Blood inorganic phosphate levels showed a significant decline. No significant changes were evident in blood haemoglobin, packed cell volume, serum calcium and magnesium levels. Total protein and globulin levels in serum decreased significantly when compared with the values obtained some weeks before and after parturition. The diurnal variations in blood glucose, haemoglobin and packed cell volume were determined on three steers bled at 2-hr intervals throughout a 24-hr period. Two of these steers were fed solely on restricted amounts of sorghum grain; the other received a restricted amount of lucerne chaff. No regular pattern of diurnal variation was evident, although blood glucose levels tended to rise after feeding. The magnitude of changes due to the time of day at which calving took place was considered insufficient to affect conclusions with regard to changes in blood constituents associated with parturition.