Length of irrigation and soil humidity as basis for delivering fumigants through drip lines in Florida spodosols

Bielinski M. Santos, James P. Gilreath, Timothy N. Motis

Abstract


Soil fumigant delivery through microirrigation lines has the potential to replace direct soil injection into planting beds. However, wetting coverage in these spodosols must be improved to increase soilborne pest and weed control. Field trials were carried out to determine the impact of soil humidity on the extent of wetting cross-sectional areas through varying irrigation times. Soil humidity contents were: a) 7% moisture (field capacity), and b) 20% (saturation), along with 2, 4, 6, 8, and 10 h of irrigation. Pressed beds had 70 cm tops. Drip lines had emitters spaced 30 cm apart delivering 0.056 L·min[sup-][ sup1]·m of row at 55 kPa, and two drip lines were buried at 2.5 cm below the surface and 30 cm apart from each other. Water was mixed with a blue marking dye to analyze the water distribution patterns. Beds were opened at the emitters and high-resolution digital pictures were taken for each treatment. Resulting images were adjusted using photographic software and covered areas across the beds were determined. Regression analysis showed significant quadratic equations for both soil moisture situations, with saturated soils obtaining the highest cross section coverage (90 and 94% after 8 and 10 hours). In field ca- pacity beds, the maximum cross section coverage obtained was 82%. Within each soil moisture situation, there were no differences between 8 and 10 h of irrigation.

Keywords


chloropicrin; metham sodium; methyl bromide; 1,3-dichloropropene; sandy soils

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Proc. Fla. State Hort. Soc.     ISSN 0886-7283