Deterioration of Potentially Biodegradable Alternatives to Black Plastic Mulch in Three Tomato Production Regions

Four potentially biodegradable mulch products (BioAgri, BioTelo, WeedGuardPlus, and SB-PLA-10) were evaluated during 2010 in three contrasting regions of the United States (Knoxville, TN; Lubbock, TX; and Mount Vernon, WA) and compared with black plastic mulch and a no-mulch control for durability, need control, and impact on tomato yield in high tunnel and open field production systems. WeedGuardPlus, BioTelo, and BioAgri had the greatest number of rips, tears, and holes (RTH) and percent visually observed deterioration (PVD) at all three sites (P <= 0.05), and values were greater in the open field than high tunnels, likely as a result of high winds and greater solar radiation and rainfall. SB-PLA-10 showed essentially no deterioration at all three sites and was equivalent to black plastic in both high tunnels and the open field. Weed growth at the sites did not differ in high tunnels as compared with the open field (P > 0.05). Weed growth at Knoxville and Mount Vernon was greatest under SB-PLA-10 (P <= 0.02), likely as a result of the white, translucent nature of this test product. Tomato yield was greater in the high tunnels than open field at all three sites (P <= 0.03), except for total fruit weight at Knoxville (P <= 0.53). Total number of tomato fruit and total fruit weight were lowest for bare ground at both Knoxville (150 x 10(4) fruit/ha and 29 t.ha(-1); P <= 0.04) and Mount Vernon (44 x 10(4) fruit/ha and 11 t.ha(-1); P <= 0.008). At Knoxville, the other mulch treatments were statistically equivalent, whereas at Mount Vernon, BioAgri had among the highest yields (66 x 10(4) fruit/ha and 16 t.ha(-1)). There were no differences in tomato yield resulting from mulch type at Lubbock.