Selecting Optimum Planting Dates and Plant Populations for Dryland Corn in Kansas

Abstract

Corn (Zea mays L.) production practices have to be evaluated periodically to ensure that producers are fully using improvements in hybrids. A 2‐yr study was conducted to assess corn yield response to plant population, planting dates, and hybrid maturity. The study was conducted at three sites during the 1994 and 1996 growing seasons. A 102 and a 113 d relative maturity corn hybrid were established at plant populations of 14 000, 20 000, and 26 000 plants/acre. Planting dates in early April, May, and June were also used. At two locations, delaying planting from April to May decreased yields slightly. At the third location, yields increased 27 bu/acre as planting was delayed until early May. Delaying planting at this location resulted in ear development occurring after a period of severe drought, which reduced yields with the April planting. At all three locations, delaying planting until early June reduced yields as a result of ear development under higher temperatures and grain fill occurring under cooler temperatures. Increasing population from 14 000 to 20 000 plants/acre resulted in a yield increase of 14 bu/acre across all six environments. Grain yields increased an additional 4 bu/acre when plant population was increased to 26 000 plants/acre. When planted in April or May, the full season hybrid produced higher yields than the earlier maturing hybrid. Corn producers in north central and northeast Kansas can increase corn yields by using planting dates in April and a population of approximately 26 000 plants/acre. Research Question Corn production practices have to be evaluated periodically to determine whether management changes are needed to fully utilize improvements in water and nutrient use efficiency as well as shade, drought, cold, and pest tolerance. Increased tolerance to shade and drought stress should enable producers to increase plant populations, resulting in higher yields in the more productive years without the risk of yield loss during a drought year. Greater cold tolerance and seedling vigor should allow earlier planting dates, thus enabling producers to take advantage of fuller season hybrids. The objectives of this study were to evaluate the effects that plant population, planting date, and hybrid maturity have on corn yield. Literature Summary Studies conducted in 1966 and 1967 in Kansas indicated that dryland corn yields increased as plant population increased until reaching a maximum at approximately 20 000 plants/acre and then declined as plant population continued to increase. However, recent studies have reported that the corn yield response to plant population was quadratic with yields reaching a plateau rather than declining at higher plant populations. Corn producers in northeast Kansas may plant earlier to increase the growing season length or to move harvest earlier in the year to distribute labor. Approximately 260 heat units can be accumulated during April in northeast Kansas, yet little data exist to quantify the effects that these additional heat units have on corn yields. As...

Effect of Planter Speed and Seed Firmers on Corn Stand Establishment

“…At this same location, higher yields were obtained with higher seeding rates, with the 67,500 seeds/ha (27,330 seeds/acre) seeding rate producing yields that were approximately 630 kg/ha (10 bu/acre) higher than yields attained at a seeding rate of 58,100 seeds/ha (23,500 seeds/acre). This response of 67 kg (2.6 bu) per 1000 plants is similar to that reported by Staggenborg et al (1999) at this location. (0.10) ns [a] Corn yields declined as planter speed increased at Cornbelt in 2001 ( fig.…”

“…Planter speed and seeding rates affected yields through the impact that each had on plant density at Cornbelt in 2001. It is obvious that increasing seeding rate will result in increased plant densities, which has already been shown to increase yields within the plant densities established in this study (Staggenborg et al, 1999). The less obvious impact on final plant density is that of planter speed.…”

“…The impact that planter speed has on plant density complicates yield evaluations of planter speed studies as plant densities can influence corn yields. Staggenborg et al (1999) reported an overall response of approximately 94.2 kg/ha (1.5 bu/acre) increase in corn yields for every 2470 plants/ha (1000 plants/acre) increase in plant density from 34,600 to 64,250 plants/ha (14,000 to 26,000 plants/acre). However, the response was quadratic, meaning that smaller yield increases occurred at the upper end of the range in plant densities.…”

“…Nielsen reported that effects of planter speed might have been confounded by plant density. Staggenborg et al (1999) reported a 2.0−kg/ha (2.3−bu/acre) increase in corn yields for 2470−plants/ha (1000−plants/acre) increase in plant density for northeast Kansas. Nielsen (1995) also did not account for the influence of multiples or misses on corn yields, whereas Nafziger (1996) reported that multiple plants can increase yields approximately 6% whereas misses can decrease yields by as much as 7%.…”

Espaçamentos e densidades de milho com diferentes ciclos no oeste de Santa Catarina, Brazil

“…Em assim sendo, a tendência tem sido em direção a um estreitamento entre fileiras e aumento da população de plantas. No Meio Oeste Americano, a recomendação tem variado de 62000 plantas ha -1 a 75000 plantas ha -1 (STAGGENBORG et al, 1999;COX, 1996;WESTGATE et al, 1997) para a obtenção de maiores produtividades, semelhantes àquelas observadas no sul do Brasil (SILVA et al, 1999;ALMEIDA et al, 2000), porém, diferentes daquelas ainda recomendadas para Santa Catarina. Em se tratando de espaçamento entre fileiras, ARGENTA et al (2001) ao analisarem dois experimentos realizados no RS, observaram clara evidência num dos experimentos, de que os incrementos na produtividade em fileiras mais estreitas estavam mais associados a híbridos de ciclo superprecoce e baixa estatura.…”