Thirteen field trials were conducted to test the effects of rates of N and K fertilizers and seeding dates differing by 2 weeks upon yield, percentage plump kernels, and protein content of malting barley. N fertilizer increased average grain yields on early‐seeded plots by 253, 410, and 534 kg/ha for 22.4, 44.8, and 67.2 kg N/ha, respectively. On late‐seeded plots, same rates of N increased average yields by 264, 303, and 389 kg/ha, respectively. Late seeding reduced average grain yields by 295 kg/ha. Rates of 14 and 28 kg K/ha increased average grain yields by 42 and 48 kg/ha, respectively, on early‐seeded plots and by 71 and 81 kg/ha, respectively on late‐seeded plots. N did not affect average percentage of plump kernels but 14 and 28 kg K/ha increased percentage plump barley by 1.3 and 1.7 percentage units on early‐seeded plots and by 1.8 and 2.7 percentage units on late‐seeded plots, respectively. Late seeding reduced the percentage of plump kernels by 9.8 percntage units. The average protein content of grain was 12.8, 13.1, 13.2, and 13.5% on early‐seeded plots and was 13.4, 13.6, 13.9, and 14.2%percent on late‐seeded plots for O, 22.4, 44.8, and 67.2 kg N/ha, respectively. Late seeding increased the average protein content by 0.7 percentage units. K reduced the average protein content by 0.1 percentage unit on both early and late‐seeded plots.

It is generally recognized that appropriate plant density and appropriate fertilizer application to deficient soil are necessary for optimum yield of crops. These variables also affect the quality of some crops. There is limited research data on the effects of these variables on yield and quality factors of oil and confectionery cultivars of sunflower (Helianthus annuus L.) grown in North Dakota. The objectives of this research were to determine the effects of three rates of nitrogen fertilizer, two rates of phosphorus fertilizer, and three plant densities upon seed yield, head size, oil concentration of oil cultivars, and seed size of confectionery cultivars. Nitrogen fertilizer increased seed yield, head size, oil yield from oil‐type cultivars, and percentage of large size seeds from confectionery cultivars. However, N reduced oil concentration of oil‐type seeds and percentage of medium size seeds of confectionery cultivars. Yield response to nitrogen was obtained at all locations because soil tests for nitrate‐N to a 61 cm soil depth were less than 60 kg/ha at planting time. Phosporus fertilizer failed to increase seed yields in 10 of 12 trials and had little effect on size of confectionery seeds and oil concentration of oil‐type seeds. Lack of response to phosphorus cannot be explained by soil test data. Increasing plant density increased seed yield, yield of oil from oil‐type sunflower, and percentage of medium‐size seeds from confectionery cultivars. Increasing plant density reduced head size and percentage of large‐size seeds of confectionery cultivars. Percentage of small sized confectionery seeds was increased by increasing plant density and decreased by increasing rate of nitrogen fertilizer. Results of this study show that nitrogen and plant density have a relatively large effect on seed yield and a smaller effect on oil concentration and seed size.

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Laboratory phases of a study to evaluate the effectiveness of various long‐time management practices in maintaining fertility of Fargo clay are reported. Soil samples which had been taken at the beginning of the trial in 1913 and those taken in 1952 and 1953 were used for chemical analyses. Physical measurements were made on samples taken from 1954 to 1956. Analyses included total N, organic C, pH, cation‐exchange capacity, exchangeable cations, extractable and organic P, nitrification capacity, aggregation and aggregate stability by wet‐sieving, porosity, density, and hydraulic conductivity. Soil organic C and N declined 27% in check plots and 20% in residue or manure plots. Phosphorus‐treated plots suffered slightly greater loss than similar plots without P. Lime had no effect. C/N ratio did not change. Nitrification capacity correlated with total N content. Extractable P declined appreciably in check plots, less in residue and manure plots, and increased in P‐treated plots. Organic P losses were similar to those of organic carbon. In all plots, CEC declined slightly. pH increased slightly in nonlimed plots and moderately in limed plots. Physical measurements did not reveal any important differences in structural properties of Fargo clay that could be related to past management practices.