SynopsisMultiple regression equations, including date of harvest, accumulated rainfall, solar radiation, and temperature as independent variables and forage yields of oats, rye, and wheat as dependent variables, were computed, using data from an 8-year period. The best-fitting equations gave R² values of .96, .91, and .93 for oats, rye, and wheat, respectively. From these equations and long-term weather data, we developed frequency distributions of total yield and yield during the winter months.

SynopsisYield of dry matter was affected very little by applications of phosphate fertilizers when soil temperatures were maintained at 50° F. regardless of available phosphorus in the soil. At 65° and 80° F. soil temperatures, applications of phosphate doubled the yield of dry matter on a low phosphorus soil and had a variable effect on the high phosphorus soil. Phosphorus percentage of the top growth was not affected by soil temperature but was increased considerably by the application of phosphate to the soil.

The interrelations of wheat straw, fertility levels, and three soil temperatures on the growth and nutrient status of winter wheat were investigated. When only N and P were added, the decomposition of straw incorporated with the soil immobilized a portion of the available S and caused a reduction in yield. When S was added with the N and P, the incorporation of straw had no effect on yield. Ratios of total N to total S and protein N to protein S were determined on the wheat tissue. Indications are that a total N/S ratio of these elements can be used as a very good criterion in assessing the S status of plants. A total N/total-S ratio of about 17:1 or less suggests that S is not limiting, while a greater ratio points out that S is limiting the formation of protein. The N-S relation in soil organic matter is also discussed in relation to its abilities and limitations in supplying S for plant growth.

SynopsisSelections were made from 31 wheat breeding lines and cultivars that were phenotypically similar to the original. One to 15 lines were compared with the original and with the bulk of all the selected lines. On the average, the original and bulks gave more consistent performances than the individual selections, suggesting that a cultivar in hard red winter wheat need not consist of a single genotype but of several phenotypically similar lines. Fifteen to 85 lines adequately represented the original.

SynopsisDuring initial tillage of winter wheat stubble, the amount of crop residue retained on the soil surface by a given implement varied with height of stubble, amount of pretillage residue, and spacing between stubble rows. During subsequent tillage, the amount of residue retained on the surface was very slightly affected by height or length of residue, moderately affected by amount of pretillage residue, but strongly influenced by previous method of tillage.

Petrobia latens (Müller) has been known as a minor pest of winter cereals for many years in southern Queensland. In June-September 1963, dry conditions favoured its development over a large area. As a satisfactory chemical providing good kills of brown wheat mite was not known when the pest upsurge occurred, two trials were carried out in seedling wheat crops during August/September, 1963. The only chemicals to show promise in Trial 1 were dimethoate, azinphos-ethyl and Mesurol. An effect was shown on population level for two weeks after treatment and observations indicated that population differences were still present up to five weeks from the time of the applications. Trial 2 results demonstrated that dimethoate at rates as low as 1/4 oz active constituent per ac gave good kills.