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Reduced Input SystemsSome farmers are looking for alternatives to purchased inputs due to their cost, their toxicity, or a commitment to organic production ideals. The WICST project has focused on the use of cover crops to help in weed suppression and nitrogen fixation (see cover crop section), mechanical weed control techniques and expanded rotations as methods to reduce input use. In one set of trials we have set up a comparison between our three-phase organic grain rotations, a modification we call our chemlite that does use some chemicals, and the two-phase no-till corn and soybean standard. Results from our mechanical weed control studies indicate: With a good crop rotation and aggressive mechanical weed control (generally 2 rotary hoeings and 2 cultivations) producers could avoid using herbicides a majority of the time. However, there are some years when cultural and mechanical weed control cannot prevent significant weed problems. In these cases, use of post-emergence herbicides can offer a reliable weed control back-up plan that reduces the risks of low-input production. In order to measure the economic costs of exclusive reliance on mechanical weed control, we superimposed post-emergence spraying on subplots within CS3 corn and soybeans for four years at both locations. In four of the 16 crop situations, returns to post-emergence herbicide was high (>$35/a), in four situations returns were modest (>$5/a but < $35/a) and in half of the cases, returns were low (<$5/a) or negative. The higher prices for organic crops can however offset yield losses due to weeds. Over the past few years certified organic premiums have been $5-10/bu for soybeans and $1-1.50/bu for corn, as well as for wheat. Modifications to the low-purchased-input cash grain system (CS3)We initially envisioned CS3 as a low-input system, relying on no synthetic fertilizers, but using post-emergence herbicides to prevent major crop losses when cultural and mechanical weed control failed. As we gained experience with this system, we decided to try several modifications on satellite plots. The “chem-lite” option: In this system, we lowered the barrier to herbicide use, using a post-emergence herbicide as soon as it appeared that it would be profitable to do so. We also applied sidedress nitrogen if a soil test indicated it would increase economic returns. For example, if cover crops performed poorly the year before, or if the early growing season conditions were slowing nitrogen release from the cover crops, we applied sidedress nitrogen based on results from the pre-sidedress test. We ran the comparison between CS3 and the chem-lite modification from 1995 to 1999 at Arlington. Corn yields averaged 19 bu/a higher in the chem-lite system (1% significance), soybean yields were four bushels better (10% significance) and wheat yields were similar. In the case of both corn and soybeans, yield variability was reduced due to the addition of modest levels of inputs. In the case of the cool spring of 1996, nitrogen additions to the chem-lite corn resulted in far better yields than CS3 corn (150 vs. 74 bu/a), and due to abundant rain in the spring of 1999, post emergence herbicide in the chem-lite system resulted in better soybean yields than we were able to achieve with mechanical weed control (50 vs. 32 bu/a). The chem-lite system produced sufficiently more grain than CS3 to pay for the additional inputs. In fact, the net return to labor, management, and capital for a 1000 acre chem-lite Farm was $14,000 more than for the same size CS3 Farm ($34,092/yr. versus $20,043/yr.). Sensitivity analyses showed that fertilizer N prices would have to increase nearly 6-fold to reduce the chem-lite return to the level of the CS3 Farm. For an organic system to match the net returns of the chem-lite system would require price increases of 6% across the board. Actual certified organic premiums in SE Wisconsin have been much higher and range from 25 to 50% for corn and wheat to 200% for soybeans. The organic option: We note that organic premiums for some crops can make the agronomic risks of organic production more tolerable today than they were in 1989. Starting in 1999 we decided to run CS3 as a completely organic system; we will report results in the future. |
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