Significant Reduction In Grain Yield Research Articles

Leaf Removal to Simulate Grazing of Corn by Lambs1

AbstractMost of the corn grown in the United States is harvested for grain or silage. Only a small percent is grazed. In corn growing areas where lambs are available, corn might provide some limited grazing without affecting yield. Field experiments (Aridic calciustoll soils) were conducted during 1978–1980 to simulate the grazing of corn by lambs. The lower 2, 4, 6, 8, and 10 leaves were removed at 90 to 100% silking and at 2‐week intervals for 6 weeks thereafter. Removing the bottom 10 leaves either at 90 to 100% silking or 2 weeks afterward caused a significant reduction in grain yield, 1,000‐kernel weight and number of kernels per ha. No significant yield losses were measured with less severe defoliation or defoliation at later stages of maturity.The data showed that 890 kgha of oven‐dried forage could be removed during the first 4 weeks after 90 to 100% silking or 1,284 kg/ha after 4 weeks from silking without significant yield reductions. At the later stages, protein and P content are below the level required for proper lamb growth.These studies indicate that yield losses can be minimized by restricting leaf removal during and after pollination. However, before this can become an acceptable practice, additional investigations are needed to study the effects that lambs might have on ears, stalks, and soil compaction.

EFFECT OF CEREAL APHID INFESTATION ON GRAIN YIELD AND PERCENTAGE PROTEIN OF BARLEY, WHEAT, AND OATS IN SOUTHWESTERN QUEBEC

AbstractNatural infestations of cereal aphids caused significant reductions in grain yield in field plots of early and late cultivars of barley, wheat, and oats in southwestern Quebec. Severely reduced grain yields resulted when caged plants of wheat and late cultivars of barley and oats were artificially infested, but early cultivars of barley and oats were less affected. The percentage protein of grain was significantly reduced in all crops, but wheat and late oats were most affected.

Über die Wirkung von Pydanon auf Halmlänge und Ertrag von Winterweizen und Winterroggen

Influence of Pydanon upon Stalk Length and Grain Yield of Winter Rye and Winter Wheat..In pot experiments with three varieties of winter rye a considerable reduction of stalk length was obtained by the growth regulator Pydanon without a significant reduction of grain yield. The necessary amount of active substance however was rather high and the period of time for optimal application was limited. Winter wheat did not respond to Pydanon.

Effect of Fertility Treatments on the Growth, Chemical Composition and Yield of No‐Tillage Corn on Orchardgrass Sod1

AbstractMany data are available on the relative efficiencies of various fertility treatments for corn (Zea mays L.) when grown by the conventional methods of clean tillage. Few data are available, however, on the relative efficiencies of sources and rates of N, P, and K on the growth, chemical composition, and yield of corn grown with the notillage system.An experiment was conducted at Blacksburg, Virginia, on Groseclose silt loam (Typic, Hapludults; clayey, mixed, mesic) to determine the effects of 168 and 280 kg N/ha, 0 and 100 kg P/ha from partially and fully acidulated rock phosphate, 25 kg P/ha from fully acidulated rock phosphate, and 140 kg K/ha from KCI and K2~SO4 on the growth, chemical composition of leaves and yield of notillage corn on a chemically killed orchardgrass sod.Growth was significantly slower with the higher rate of N, but significantly increased with increased rates of applied P. Plant growth rate was unaffected by sources of K. Leaf concentrations of N and K were unaffected by rates of N and sources of K, respectively, but the P and K concentrations were significantly increased with the higher P rates. Leaf Mn concentration was higher with the higher rate of N than with the lower rate. The Ca, Mg and Mo concentrations in the leaf increased with P fertilization, but the Zn concentration decreased with P fertilization.Corn yields were significantly higher with concentrated superphosphate than with partially acidulated rock phosphate applied at the same rate of P. The higher rate of N resulted in a significant reduction in grain yield of 552 kg/ha. There was no response to S in the K2SO4.