A brief history of development of the 1985 Hargreaves equation and its comparison to evapotranspiration ~ET! predicted by the Food and Agricultural Organization of the United Nations ~FAO! Penman-Monteith method are described to provide background and information helpful in selecting an appropriate reference ET equation under various data situations. Early efforts in irrigation water requiremen...

mates of the temporal and spatial root water uptake patterns are needed. Quantification of root water exAlthough solutions of multidimensional transient water flow can traction rates also contributes to an improved underbe obtained by numerical modeling, their application may be limited in part as root water uptake is generally considered to be one-dimenstanding of chemical fluxes in the vadose...

Tile systems drain water applied to agricultural fields as irrigation and precipitation but also may intercept regional groundwater flow. Identification and characterization of the potential sources of tile water is essential for informed management of salinity and contaminants. Factors influencing tile discharge including depth of water applied, evapotranspiration, water storage, drain blockag...

A study was conducted to compare three measurements of determining water status of grapevines (Vitis vinifera L.) in the field. Predawn leaf water potential (ΨPD), midday leaf water potential (Ψl), and midday stem water potential (Ψstem) were measured on ‘Chardonnay’ and ‘Cabernet Sauvignon’ grapevines grown in Napa Valley, California late in the 1999 growing season. Both cultivars had been irr...