Horticultural and Economic Performance of An Organic No-till Tomato System

In the most current (2008) U.S. Dept. of Agriculture statistics on organic agriculture, land under certified organic production increased to 4.8 million acres, with 98,525 acres in organic vegetable crops. Weed management and soil quality enhancement remain as top organic producer research needs. The objective of this experiment was (1) to compare the effects of an organic no-tillage system using a roller/crimper and two cover crop combinations (hairy vetch/rye and winter wheat/Austrian winter pea) with a tilled organic system on organic tomato weed management and yield; and (2) to compare the economic performance of the organic no-tillage system to the tilled organic system. Plots were laid out in a randomized complete block design of three treatments with three replications at a certified organic site on an Iowa State University research farm. The treatments: 1) organic tilled, with tillage used before and after commercial crop planting; 2) organic no-tillage cover crop combination of winter wheat and Austrian winter pea; and 3) organic no-tillage cover crop combination of rye and hairy vetch were established in each crop section. ‘Roma’ tomato seeds were planted in organic-compliant media in April each year and transported to the field in early June. Results included excellent weed management in the organic no-till system. Broadleaf weeds were managed by the wheat/winter pea mulch early in the season compared to tilled treatment plots, but lost this advantage at the mid-sampling date when the mulch degraded at a higher rate than the rye/hairy vetch mulch. Total harvested fruit weight was equivalent among treatments, averaging 19.2 tons/acre in 2006 and 28.4 tons/acre in 2007 across all treatments. Tomato quality was high in all treatments, with an average of 84% and 87% of harvested tomatoes reaching the highest grade, in 2006 and 2007, respectively. Total production costs for 2006 ranged from $11,601 to $11,666/acre, with cover crop seed, interest, and machinery labor costs varying by system. Total costs for 2007 ranged from $12,149 to $12,214/acre. The stability of production costs and constant sale prices for tomatoes resulted in returns to management differences derived from yield differences only. Numerically, the tillage treatment incurred the highest yields for both 2006 and 2007, with returns of $14,986/acre and $22,466/acre, respectively. Among the no-tillage treatments, the vetch-rye cover crop produced the higher yields, with returns equaling $11,922/acre in 2006 and $21,679/acre in 2007. Overall, the organic no-till tomato system demonstrated great promise for organic vegetable production.