Elsevier

Field Crops Research

Volume 118, Issue 3, 10 September 2010, Pages 259-263
Field Crops Research

Critical precipitation period for dryland maize production

https://doi.org/10.1016/j.fcr.2010.06.004Get rights and content

Abstract

Grain yields for dryland maize (Zea mays L.) production in the semi-arid Great Plains of the United States can be unpredictable because of the erratic nature of growing season precipitation. Because of the high input costs for maize production, farmers need to have a tool that will help them assess the risk associated with dryland maize production. The objectives of this work were to determine the critical period for precipitation during the maize growing season and to develop a relationship between critical period precipitation and maize yield to use as a tool to quantify expected yield variability associated with dryland maize production in this region. Maize yield data were collected at Akron, CO from two dryland cropping systems experiments (1984–2009) in which maize was grown in a 3-year winter wheat (Triticum aestivum L.)–maize–fallow rotation. Yields were correlated with weekly precipitation amounts from planting to harvest in search of the period of time in which yield was most influenced by precipitation. Soil water contents at planting were measured either by gravimetric sampling or by neutron attenuation. Yields were found to be most closely correlated with precipitation occurring during the 6-week period between 16 July and 26 August. The data separated into two linear relationships defined by whether the sum of available soil water at planting and May precipitation was less than or greater than 250 mm. These two linear relationships between precipitation during this critical period and yield were used with long-term precipitation records to determine the probability of obtaining a maize yield of at least 2500 kg ha−1 (generally considered to be a break-even yield) at three locations across the central Great Plains precipitation gradient. This analysis quantified the production risk associated with the highly variable corn yields that result from erratic summer precipitation in this region.

Introduction

Maize has been increasingly used as a component of winter wheat-based dryland cropping systems in the central Great Plains (Farahani et al., 1998, Anderson et al., 1999, Nielsen et al., 2005, Bowman et al., 1999, Peterson and Westfall, 2004, Norwood and Currie, 1998, Lyon et al., 2003). For example, in Colorado the fraction of dryland hectares planted to maize has risen from 0.6% in 1984 to about 12% in 2001, and thereafter remained relatively constant between 10 and 15% of planted dryland hectares (USDA-NASS Quick Stats-Crops, available at http://www.nass.usda.gov/QuickStats, verified 5/21/2010). The primary production system for dryland maize in Colorado is wheat–maize–fallow. But dryland maize yield can be greatly reduced by water stress that occurs during the reproductive stages of tasseling, silking, and pollination when the number of ovules that will be fertilized is being determined (Shaw, 1976, Robins and Domingo, 1953, Denmead and Shaw, 1960, Claassen and Shaw, 1970). Soil water depletion to the wilting point for 2 days during tasseling or pollination was reported by Robins and Domingo (1953) to decrease maize yield by 22%, while a 6–8-day period of such soil moisture stress could cause a yield reduction of 50%. Water stress at tasseling and silking reduces viability of maize pollen, delays silk emergence past pollen shed, and results in desiccation of silks, while subsequent water stress can induce embryo abortion or reduce the potential size of kernels (Waldren, 1983, Hall, 2001). Westgate (1994) provided a comprehensive review of literature describing the effects of water stress on the physiology of the maize plant in reproductive development that ultimately results in decreased seed yield.

In a more recent study, Nielsen et al. (2009) showed that maize yields in northeastern Colorado increased as soil water content at planting increased, but that the relationship between these two quantities was greatly influenced by the precipitation that fell from 15 July to 25 August (approximately 10 days prior to tasseling through the middle of grain filling). The yield response to available soil water at planting increased dramatically as the amount of precipitation during this critical phase of development increased.

Because the effects of water stress during the critical reproductive developmental stage can be so extremely devastating to maize yield, the highly variable growing season precipitation in the semi-arid Great Plains of the United States can result in highly variable maize yields. Therefore, the objectives of this analysis were to (1) determine the critical period for precipitation during the maize growing season, (2) develop a relationship between critical period precipitation and maize yield to use as a tool to quantify expected yield variability associated with dryland maize production in this region, and (3) determine the probability of achieving a dryland maize yield of 2500 kg ha−1(generally considered to be a break-even yield).

Section snippets

Materials and methods

Two dryland cropping systems experiments were conducted from 1984 to 2008 at the USDA-ARS Central Great Plains Research Station (40°09′N, 103°09′W, 1383 m elevation) located near Akron, CO. Experiment 1 (years 1984–1992) was a nitrogen fertility rate experiment with four replications in a randomized complete block design conducted on a Platner loam (fine, smectitic, mesic Aridic Paleustoll). Experiment 2 (years 1993–2009) was a cropping systems experiment with three replications in a randomized

Precipitation

Growing season precipitation (7 May to 30 September) varied widely from 135 mm (2002) to 418 mm (1996), averaging 272 mm (Table 1). The distribution of average precipitation indicates a maximum of about 20 mm per week during two periods: 28 May to 10 June and 30 July to 12 August. The greatest weekly precipitation amount recorded (77 mm) occurred 7 May to 13 May 1995 and 2003. Almost 20% of the weeks of record shown in Table 1 received no precipitation. This data set provided a wide range of

Discussion

The variability in maize yield (0–5808 kg ha−1) seen over the 23 years of this study was similar to that reported at other central Great Plains locations for shorter term studies [878–6711 kg ha−1 by Peterson et al. (1999) over 13 years in northeastern Colorado; 0–7276 kg ha−1 by Schlegel et al. (2007) over 12 years in western Kansas; 1500–5800 kg ha−1 by Lyon et al. (2003) over 2 years in western Nebraska]. Those studies all reported generalized conclusions about the effects of water availability on

Conclusions

This long-term study determined that dryland maize yields are highly correlated with precipitation falling between 16 July and 26 August, verifying the findings of many shorter term studies with controlled water stress that the critical time for water stress effects on maize yield is from just prior to tasseling through the middle of grain filling. Precipitation during this 6-week period is highly variable in the central Great Plains resulting in maize yields which are highly variable. The

Acknowledgement

The authors express their appreciation to Tawney Bleak for assistance with data analysis.

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