Growers frequently are concerned about the response of corn (Zea 1968). The optimum planting date in the Corn Belt mays L.) to planting date. Early planting of corn is recommended because full-season hybrids utilize the entire growing season, achieve typically occurs between 20 April and 10 May (Benson, physiological maturity before a killing frost, and start to dry, thereby 1990). While some studies show an advantage for plantincreasing profit through reduced drying costs. The objective was to ing before 20 April, other areas in the northern Corn evaluate the influence of planting date and hybrid maturity on corn Belt may yield well when planted around 20 May (Cargrain yield and harvest moisture in Wisconsin. Two or three corn ter, 1984). hybrids ranging in relative maturity from 80 to 115 d were planted Several researchers have described planting date efbetween 19 April and 22 June at six locations in Wisconsin from 1991fects on corn (Alessi and Power, 1975;Benson, 1990; to 1994. In southern Wisconsin locations, the optimum planting date Johnson and Mulvaney, 1980;Imholte and Carter, 1987; for grain yield of full-and shorter-season hybrids ranged between 1 Nafziger, 1994;Swanson and Wilhelm, 1996). Our objecand 7 May, and was still at 95% of optimum between 9 and 18 May.Abbreviations: MN RM, Minnesota relative maturity [rating]. Published in Agron.

Determining the proper time to harvest corn (Zea mays L.) for whole plant silage is difficult for growers. The objective of this study was to determine the relationship between kernel milk‐line position and whole plant yield, quality, and dry matter (DM) content. Our goal was to develop a means to predict the optimum stage for harvesting corn for silage. Four early maturity (85 d) hybrids were evaluated for yield, forage quality, and DM content at five stages of kernel maturity, including: soft dough (SD) (dents first visible); early dent (ED) (dents visible on 95% of kernels); 1/2 milkline (1/2 ML) (milkline positioned half‐way between the tip and base of the kernel); 3/4 milkline (3/4 ML) (milkline positioned 3/4 of the way from tip to base); and no milkline (No ML) (milkline no longer present in kernel) over 3 yr (1988–1990) in north central Wisconsin. Whole plants, stover, and ears were harvested before killing frosts, except in 1989 when plants were frozen shortly after 1/2 ML. Whole plant DM content was within the optimum range for silage harvest (30 to 40%) when corn plants were between the 1/2 and 3/4 ML stages. Maximum whole plant yield was reached by 1/2 ML, while grain yield reached maximum levels by 3/4 ML. Whole plant neutral detergent fiber (NDF) and acid detergent fiber (ADF) decreased an average of 7.6 and 4.4 percentage units from SD to 1/2 ML and then increased at the No ML stage. Whole plant in vitro dry matter disappearance (IVDMD) was greatest between ED and 3/4 ML. Whole plant and stover crude protein (CP) concentration declined at each successive harvest stage from SD to No ML. Early season hybrids can be harvested for silage between 1/2 and 3/4 ML for maximum whole plant yield and optimum quality and DM content. Kernel milkline position was a good indicator of optimum harvest stage for this range of kernel maturities. Research Question In the North Central states, a high proportion of corn (Zea mays L.) harvested for silage is planted in the extreme northern part of the region, where adapted hybrids range from 70 to 90 d relative maturity (RM). When growing corn intended for silage use, critical factors which influence optimum harvest timing include whole plant dry matter (DM) content, total yield, and nutritional quality. Determining the proper maturity to harvest corn for whole plant silage is difficult for growers. The objective of this study was to determine the relationship between kernel milkline position and whole plant yield, quality, and dry matter content. Our goal was to develop a means to predict the optimum stage for harvesting corn silage. Literature Summary Estimates of whole plant DM content in corn frequently are based on grain maturity. Researchers in Minnesota demonstrated that kernel milk‐line position was a reliable and useful visual indicator of grain maturity and whole plant DM content. Several investigations have evaluated corn whole plant DM accumulation and nutritive value at various stages of crop maturity. Maximum whole plant yield is generally reported to occur...

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Recent introductions of new disease resistant, higher yielding winter wheat (Triticum aestivum L.) cultivars and plant growth regulators (PGRs) to reduce lodging, coupled with a growing awareness of high wheat yields in Europe, has resulted in an increased interest in and the development of Intensive Cereal Management (ICM) systems in the USA. Increases in fertility levels and seeding rates, practices used in ICM systems, may significantly increase lodging in winter wheat. The objective of this study was to evaluate the effects of the PGR ethephon [(2‐chloroethyl) phosphonic acid] on grain yield, lodging, plant height, test weight, and moisture percentage of seven winter wheat cultivars grown in various environments. Averaged across environments and cultivars, ethephon reduced lodging and plant height, and increased grain yield an average of 0.28 Mg ha−1, of 6.4%. Average environment × PGR and cultivar × PGR interactions were nonsignificant for grain yield, plant height, lodging, and test weight, but orthogonal contrasts showed variable responses to ethephon between environments and cultivars. Lodging and grain yield were negatively correlated, while lodging and plant height were positively correlated. With the exception of the cultivar Caldwell, grain yields were not increased by PGR applications when there was no lodging.

Forage cutting management recommendations emphasize early and frequent harvests to maximize forage nutrient yields. This study was conducted to determine forage yield, quality, and persistence of five modern red clover (Trifolium pratense L.) cultivars harvested at different frequencies and stages of maturity throughout the growing season. Red clover plots were established at Arlington, Marshfield, Spooner, and Ashland, WI, in 1989 and at Marshfield, WI, in 1990. During the establishment year, forage was removed once or twice when red clover plants reached 20% bloom. Five cultivars were harvested for 2 yr after the seeding year under five harvest management systems (HMS): A = 3 summer cuts at bud stage + late fall cut; B = 3 summer cuts at bud stage; C = 2 summer cuts at 20% bloom + late fall cut; D = 2 summer cuts at 40% bloom + late fall cut; E = 2 summer cuts at 40% bloom. Cutting red clover twice at 20% bloom and once in late fall (HMS C) produced maximum seasonal forage yield during both harvest years at all locations. In the northern Wisconsin locations, HMS D and E yielded the same as HMS C, while southern locations favored the earlier, more frequent cutting schedules (HMS A, B, and C). Fall harvest of red clover before the second winter did not significantly reduce forage yield in the third year. When comparing forages cut at bud stage, 20% bloom, or 40% bloom, maximum red clover yield is attained by 20% bloom. Forage quality of spring growth forage was lower than subsequent summer harvests as measured by crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF). Forages cut at bud stage had the highest concentration of CP and lowest concentration of NDF and ADF, and forage quality declined with increasing maturity. Persistence of red clover was not greatly affected by HMS, but where differences occurred, plant stands and fourth year yields were highest for management systems C, D, and E where plots were cut less frequently or at later growth stages. Current red clover cultivars should be harvested three times (2 summer cuts + 1 late fall cut) during the year when plants are between bud stage and 20% bloom stage for optimum forage yield, quality, and persistence. Research Question Red clover cultivars developed during the 1970s and 1980s are higher yielding, more disease resistant and persistent than those developed prior to 1970. Forage cutting recommendations emphasize early and frequent harvests to maximize forage nutrient yields. This study was conducted to determine forage yield, quality, and persistence of five modern red clover cultivars harvested at different frequencies and stages of maturity throughout the growing season. Literature Summary Red clover has been characterized as a biennial or short‐lived perennial that is harvested two or three times per season. Under hay harvesting systems, red clover typically produces its greatest forage yield in the year after establishment. When three cuttings are made in the second year of growth, third year yields will be lower compa...