Corn (Zea mays L.) grain yields have been related to wide range of management practices. Row spacing and plant population effects have been well documented; however, little research has been conducted on the variability of within‐row plant spacing and its effect on grain yields. Experiments were conducted in 1972–75 at three irrigated locations in Kansas to determine the effect of within‐row variability of plant spacing on corn grain yields. Low variability was obtained by hand planting within machine planted areas which provided a range of variability. Within‐row variability of plant spacing was determined on 3‐m sections of rows by taking individual measurements between adjacent plants and calculating the standard deviation of spacing. Grain yields consistently decreased as variability of spacing increased at two of the three locations. The third location was more variable and in general showed no relationship between variability of spacing and grain yields. A survey of within‐row variability in plant spacing in fields in three Kansas counties indicated that planting precision could increase yields 200 to 1,200 kg/ha without changing planting rates.

Consumptive use of water by alfalfa grown under two phosphorus fertility levels was measured in a 3‐year study at the University of Nebraska Scotts Bluff Station, located in western Nebraska. Soil moisture to a depth of 230 cm was measured with a neutron moisture meter at the start of the growing season, after each cutting, and after the last harvest. Irrigation water was delivered to the benches through an underground pipe and measured before flood irrigation. Alfalfa used 11.4 cm water per metric ton (4.95 in/T) of 88% dry matter hay. Alfalfa used water more efficiently in early May and June than July and August. Average water use per day was 4.1 mm (0.16 in) for the first harvest, 5.6 mm (0.22 in) for the second harvest, and 5.9 mm (0.23 in) for the third harvest. Average evapotranspiration ratios for the 3‐year period were 540 for the first cuttings, 630 for the second cuttings, and 860 for the third cuttings. The average evapotranspiration ratio for the three harvests over the 3‐year period was 680. Two levels of phosphorus applied to the soil did not alter water use nor total yields of hay.