Reducing DCPA Losses in Furrow Irrigation by Herbicide Banding and Straw Mulching

Abstract

There are concerns about residues of DCPA (dimethyl 2,3,5,6‐tetrachloro‐1,4‐benzenedicarboxylate) and its two acid metabolites in surface runoff from furrow‐irrigated croplands. We studied the effects of mulching irrigation furrows with wheat (Triticum aestivum L.) straw on DCPA movement in runoff solution, with sediment, and in the soil profile. The study site had a Nyssa silt loam (coarse‐silty, mixed, mesic Xerollic Haplodurid) with a 3% slope. The field was planted to onion (Allium cepa L.) and was furrow‐irrigated 17 times. Prior to mulching, DCPA was either broadcast at 10 kg a.i. ha−1 or banded at 3.4 kg a.i. ha−1 on the top of beds between furrows. DCPA (parent plus metabolites) was measured in the runoff sediment of the first 6 irrigations, and in the runoff solution of the 1st, 3rd, and the 5th irrigation. Regardless of herbicide application method, mulching reduced DCPA losses in sediment of all irrigations and in the runoff solution of the fifth irrigation. Averaged across the 6 irrigations and the 2 herbicide application methods, mulching reduced DCPA transfer in sediment by about 90%. Straw mulch effects on DCPA losses were primarily through reductions in soil loss and runoff volume, whereas DCPA concentration was not affected in runoff solution and was increased in runoff sediment of some irrigations. Mulching increased infiltration of broadcast DCPA but tended to decrease infiltration of banded DCPA. Also, compared with broadcast DCPA, banding the herbicide reduced DCPA losses in sediment of some irrigations. We concluded that the combination of straw mulching and banding DCPA reduces herbicide transfer in surface runoff and movement into thesoil profile.

Soil moisture variation and water consumption of spring wheat and their effects on crop yield under drip irrigation

“…Thus, information is needed about optimal soil water contents, crop water requirements and water use of drip-irrigated crops. A number of studies have been done for furrow-irrigated crops (Smith and Freney 1998;Shock et al 1998;Yin et al 2000) but very few for drip-irrigated dense crops (Shock et al 2005). The major crop in north and northwest China is wheat, which is a dense crop.…”

Research, Extension, and Good Farming Practices Improve Water Quality and Productivity

“…DCPA metabolites, however, were found in shallow aquifers underlying parts of the intensively farmed areas of Malheur County, Oregon (Bruch 1986;Parsons and Witt 1988). Due to concerns about residues of DCPA and its metabolites in surface water and sediment runoff from furrow-irrigated crop land, as well as through deep percolation through the soil profile, MES conducted intensive studies to trace the fate of DCPA and DCPA metabolites' with both banding and broadcast DCPA application techniques (Shock et al 1998e).…”

Effects of vegetative mulches on growth of indigenous crops in the Kingdom of Tonga

“…Shock et al . () reported that 0.9 t straw/ha applied to irrigation furrows substantially reduced soil erosion by 95%, run‐off by 43%, N losses by at least 50% and 15‐fold for P losses in sediment.…”