Soil temperature, soil moisture, weed control, and tomato (Lycopersicon esculentum) response to mulching

Shredded newspaper (2.5, 7.6, 12.7, and 17.8 cm depth), chopped newspaper (2.5 and 7.6 cm), wheat straw (15.2 cm), black plastic, and plastic landscape fabric were evaluated during 1993 and 1994 in West Virginia for their effect on soil temperature, soil moisture, weed control, and yield in tomato. Shredded newspaper and wheat straw applied at 0, 2, 4, or 6 weeks after transplanting (WAT) and napropamide (2.1 kg ai/ha) plus metribuzin (0.28 kg ai/ha) applied at transplanting were evaluated during 1992 and 1993 in North Carolina for effect on weed control and tomato yield. Results from West Virginia indicated that shredded (7.6 cm) and chopped (7.6 cm) newspaper conserved moisture similar to higher application rates of the shredded material. Higher newspaper mulching rates reduced soil temperature compared to black plastic and bare ground. Chopped newspaper controlled weeds more consistently than other treatments. At least 7.6 cm of chopped newspaper mulch was required to control weeds at least 90%. Wheat straw was not as effective in controlling weeds as 7.6 cm or greater of newspaper mulch. Chopped newspaper provided higher tomato yields than shredded newspaper applied at the same rates. Mulches applied at 0, 2, or 4 WAT resulted in weed control similar to the chemical treatment. In North Carolina, mulches applied 2 or 4 WAT resulted in tomato yields similar to the chemical treatment. Shredded and chopped newspaper have potential as a mulching material but may vary in effect in different environments and vegetable crops.