Experiments were conducted on Zanesville, Elliott, and Muscatine soils to determine the relative efficiency, with respect to corn yields, of broadcast P as compared to banded P. The 16 fertilizer treatments consisted of 4 rates of banded P and 4 rates of broadcast P in factorial combinations. Yields from each of the 3 soils were used to calculate a multiple regression equation for each soil. The equation is of a quadratic form, and it expresses the relation between yield and rates of banded and broadcast P. The regression equations account for 77 to 88% of the variation in yield. The largest yield increases from added P were 1287, 1474, and 873 pounds of corn per acre for the Zanesville, Elliott, and Muscatine soils, respectively. With all the P either banded or broadcast, the relative efficiency of broadcast P ranged from 0.49 to 1.23 for the 3 soils For a given soil, the relative efficiency of broadcast P varied with rate. At 35.2 pounds of P added per acre, higher yields were obtained on Zanesville and Elliott soils if a combination of banded and broadcast application were used than if all the P was added either banded or broadcast. Banding all the P gave higher yields than the other application methods if 17.6 and 8.8 pounds of P per acre were added. Yields from the Muscatine soil were not dependent on whether all the P was drilled, broadcast, or applied by a combination of both methods.

Three experiments were conducted in Illinois to determine the relative efficiency of broadcast versus banded potassium for corn. The pounds of banded K required to obtain a specified corn yield were divided by the pounds of broadcast K required to obtain the same yield. This ratio (banded K/broadcast K) represents the relative efficiency of broadcast K in terms of banded K, with respect to corn yield. Four or 5 rates of broadcast K and 4 rates of banded K, in factorial arrangement, constituted the fertilizer treatments. Multiple regression equations of the quadratic form were calculated to express yield as a function of broadcast and of banded K. The regression equations account for 77, 81, and 62% of the variation in yield for the Cisne, Bluford, and Belknap soils, respectively. The largest yield increases from added K were 83, 33, and 13% for the three soils. Less K was required to obtain a given yield when the K was banded than when broadcast. The relative efficiency of broadcast K, as compared to banded K, ranged from 0.33 to 0.88. In some cases, no rate of broadcast K equaled the yield produced by a given rate of banded K.

No abstract

Corn (Zea mays L.) producers have expressed widespread interest in using low rate foliar sprays of 2‐sec‐butyl‐4,6‐dinitrophenol (dinoseb) as a growth regulator to enhance grain yield. In four experiments conducted at two locations during a 2‐year period, dinoseb was applied as nearly as possible to 3 weeks before tassel emergence to evaluate its effect on yield. Rates of 0, 7.4, 12.4, and 24.7 g dinoseb/ha were used in all experiments, and five adapted commercial hybrids and one two‐ear synthetic were used in the different experiments. Dinoseb applied to four hybrids at one location in 1975 caused a 6 to 8% yield decrease and a 1 to 2% increase in barrenness. An increase in nubbin ears (less than 40 kernels per ear) was also associated with the yield loss. During 1976, yield of the synthetic increased 4% at the 12.4 and 24.7 g/ha dinoseb rates, but a commercial hybrid in the same trials was not affected by treatment. Dinoseb affected the formation of second ears with both increases and decreases in this trait being observed at similar chemical rates. It is concluded that in these experiments corn responded in an unpredictable manner with dinoseb applications to different genotypes in different environments.

Traditional methods of soil cultivation in the Corn Belt of the United States leave the land vulnerable to erosion by wind and water. Studies at Dixon Springs have shown a very marked reduction in soil losses under the “no-till” system, both for continuous maize-growing and for double-cropped wheat and maize, a factor of considerable importance in soil conservation.