Drought Avoidance Assessment for Summer Annual Crops Using Long‐Term Weather Data

Abstract

during the cropping season when water supply is likely to be more abundant. This approach has been an effec-Seasonal rainfall is a key factor determining yield of nonirrigated, tive tool for crops grown in monsoonal climates where summer crops. In temperate regions, however, systematic analyses of they are sown near the beginning of the wet season and long-term weather data have not been used for directing breeding programs or for crop management options. We evaluated long-term mature before the dry season (Monteith and Virmani, weather data (36-98 yr) for 16 sites in four geographical regions in 1991). Similarly, soybean [Glycine max (L.) Merr.] prothe USA to assess the potential for drought avoidance. For each day duction in the southern portion of the Mississippi Delta of year when the probability (P ) of having a minimum temperaturehas shifted to early sowing dates combined with early Ͻ0؇C was less than 0.05, water deficit was estimated as the difference maturing cultivars to avoid droughts, which frequently between the 7-d running sums of rainfall and potential evaporation.occur in August (Bowers, 1995;Heatherly, 1999). For comparative purposes across locations, a 7-d water deficit Ͼ50 mm Despite the recognition that matching crop phenology was defined as a drought. For the Midsouth, there were approximately with seasonal water supply is an effective means of 62 d at both the beginning and end of the growing season with P Յ avoiding drought, tools for evaluating weather patterns 0.20 of drought. In the Southeast, there were approximately 48 d and for the potential of avoiding drought are not widely 121 d at the beginning and end of the growing season, respectively, with P Յ 0.20 of drought. For the Midwest, P of drought was Յ0.20 used. Several of the most common meteorological meththroughout the growing season for three of the four sites, and it was ods for assessing drought have limited utility for evaluatconcluded that a 50-mm water deficit was not likely to be a production ing the potential for a given crop production system to constraint on the deep soils of the Midwest. For the Northern Great avoid drought in a particular region. For example, the Plains, P of drought was Ͼ0.20 for more than half of the region's Palmer Drought Index (Palmer, 1965) uses a soil water growing season. This meteorological approach for assessing drought balance approach to evaluate drought severity, which may provide insights for drought avoidance in breeding and crop manis normalized for the departure from climatological agement.norms. Thus, a Palmer Drought Index of Ϫ4 for an arid region and for a very humid region would both indicate extreme droughts, but because this index is normalized 1566

Evaluation of the SMOS-Derived Soil Water Deficit Index as Agricultural Drought Index in Northeast of Brazil

“…In line with the results from some previous studies [26,28,36,67,75,76], it was found that the atmospheric conditions over NEB influences the upper soil water balance dynamic. This characteristic is reflected by a moderate coupling strength between the AWD and SWDIS from June 2010 to December 2013 in the entire NEB (Figures 2 and 3).…”

“…The concept of the Atmospheric Water Deficit (AWD) was proposed by Purcell et al [28]. AWD is a suitable tool to identify the drought dynamics related to soil water storage [26,67].…”

Physiological Traits Contributing to Differential Canopy Wilting in Soybean under Drought

“…Vapor pressure defi cit was calculated for each corresponding ambient air temperature using methods described by Purcell et al (2003) and Allen et al (1998). First, CTD was analyzed using ANOVA, similar to the model discussed for conductance.…”

Temporal and Spatial Comparison of Agricultural Drought Indices from Moderate Resolution Satellite Soil Moisture Data over Northwest Spain

“…In this study, weekly comparisons were made because one week is the time interval commonly used by farmers for irrigation schedules [15]. Therefore, weekly maps of the drought indices (SWDI Rawls , SWDI CYL , SMADI, SMDI and SWetDI) were estimated over the agricultural areas of the Castilla y León region.…”

“…To improve this issue, a self-calibrating PDSI (sc-PDSI) was proposed [14]. The Atmospheric Water Deficit (AWD) is also a meteorological index that uses the simple water balance between evapotranspiration (ET) and precipitation [15,16]. passive and active microwave satellite sensors from 1978 to 2015 [43].…”