No-till corn yields and water balance in the mid-Atlantic coastal plain
2002
Roygard, J.K.F. | Alley, M.M. | Khosla, R.
Water is the main limiting factor to rainfed corn (Zea mays L.) yield in the mid-Atlantic coastal plain. This study was conducted to determine the water balance, yields, and efficiency of water use (EWU) of no-till rainfed corn grown on three soils of varying water-holding capacity, a Wickham sandy loam (fine-loamy, mixed, thermic, Typic Hapludults) and two Bojac soils, a sandy loam and a loamy sand (coarse-loamy, mixed, thermic, Typic Hapludults). Soil water balance was determined from climate data and weekly measurements of soil moisture from time domain reflectometry (TDR) probes. Water balance components of water stress, crop coefficients, and evapotranspiration were determined for vegetative, tasseling, and grain-fill growth stages in 1998 and 1999. Yields were determined by overlaying georeferenced yield maps, order-1 soil survey maps, and locations of TDR probes. The EWU concept was defined as yield divided by [precipitation + (initial soil water content - final water content)], clarifying it from water use efficiency measurements that are calculated similarly but do not include drainage. Yields in 1998 (4833-12200 kg ha(-1)) were higher than 1999 yields (2245-8240 kg ha(-1)) due to higher growing season precipitation in 1998 (400 mm) than 1999 (220 mm). Drainage was determined in 1998, ranging from 65 to 105 mm. Minimizing drainage losses has potential for increasing the EWU and yields. This study establishes baseline water balance data for the mid-Atlantic coastal plain that can be used to parameterize computer models for investigating the effect of management practices on EWU and yields.
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