Non‐Uniform Infiltration Under Potato Canopies Caused by Interception, Stemflow, and Hilling¹

Abstract

It is generally assumed that infiltration of sprinkler irrigation and rainfall under potato is uniform. However we observed non‐uniform infiltration beneath the hills of sprinkler‐irrigated potatoes (Solanum tuberosum L, var. Russet Burbank) grown on Plainfield loamy sand (Typic Udipsamment; sandy, mixed, mesic). The objective of this field study was to determine the effects of foliage interception and hilling on non‐uniform infiltration, since concentrating water in local zones would increase deep drainage and nitrogen leaching. To do this we traced the rainfall and irrigation infiltration pattern with Rhodamine WT dye and collected the stemflow in stem collars. Throughfall of rainfall, the soil water content, and soil water tension also were measured. From 20 to 46% of the irrigation and from 4 to 23% of the rainfall on the canopy flowed down the stems. Stemflow increased the soil water content around the stems and moved Rhodamine dye deep beneath the soil surface. Deep movement of dye beneath the furrows was caused by runoff from the hills and by leaf drip from the outer foliage. The results obtained suggest that irrigation and fertilizer management could be improved by taking this non‐uniform infiltration pattern into account. Smaller irrigations should improve water use efficiency and minimize nitrate leaching. Further, evaluation of solute movement by soil sampling should consider the spatial variation introduced by the non‐uniform infiltration. Finally, predictive leaching models should account for non‐uniform infiltration.

A comparison of soil-water distribution under ridge and bed cultivated potatoes

“…The shedding of water into the furrows is likely to be exacerbated as the crop emerges and grows (Saffigna et al, 1977;Curwen and Massie, 1984). The canopy of the crop may act rather like an umbrella, again causing water to be shed into the furrows.…”

Furrow Irr Igation and N Management Strategies to Protect Water Quality

“…Broadcast-incorporated N is particularly susceptible to leaching under the furrow (Saffigna et al, 1976). The potential for nitrate leaching is greater with broadcast than banded N (Power et al, 2000).…”

“…1). The sidedressed N was placed nearer the plant row than furrow so that the N would be more available to the corn (Hefner and Tracy, 1995) and less susceptible to leaching if that furrow was irrigated (Benjamin et al, 1994;Saffigna et al, 1976). In both years, the border plots were sidedressed with 90 kg N ha-1 .…”

Surface and Subsurface Solute Transport Properties at Row and Interrow Positions

“…Cultivation of row crops tends to accumulate soil within the plant rows. During rainfall or sprinkler irrigation, the raised microtopography along plant rows can shed water away from the plant rows to interrows and may cause ponding (Saffigna et al, 1976). The ponding in interrows and no-ponding in plant rows can affect infiltration and solute leaching (Saffigna et al, 1976;Ghodrati and Jury, 1990;Bargar et al, 1999).…”

“…During rainfall or sprinkler irrigation, the raised microtopography along plant rows can shed water away from the plant rows to interrows and may cause ponding (Saffigna et al, 1976). The ponding in interrows and no-ponding in plant rows can affect infiltration and solute leaching (Saffigna et al, 1976;Ghodrati and Jury, 1990;Bargar et al, 1999). Some of the solute infiltrating at interrows may spread laterally in the subsurface water to the adjacent plant rows because of lateral hydraulic gradients (Bargar et al, 1999).…”