ISHS Acta Horticulturae 659: VII International Symposium on Protected Cultivation in Mild Winter Climates: Production, Pest Management and Global Competition
LIQUID EFFLUENT FROM POULTRY WASTE BIOREMEDIATION AS A POTENTIAL NUTRIENT SOURCE FOR HYDROPONIC TOMATO PRODUCTION |
| Authors: | B.E. Liedl, M. Cummins, A. Young, M.L. Williams, J.M. Chatfield |
| Keywords: | Lycopersicon esculentum, fertilizer, soilless culture, ammonium, nitrate, waste recycling |
| Abstract:
Tomatoes are the leading greenhouse vegetable and pressure exists to develop sustainable production systems with alternative nutrient sources. Our research investigated using liquid effluent from anaerobic thermophilic digestion of poultry litter for hydroponic greenhouse tomato production. Fertilizer comparisons were based on N in commercial fertilizer and effluent using a bato bucket system. Effluent plants grew slowly and produced fewer and smaller tomatoes. Tomato plants are sensitive to high ammonia levels and effluent N is predominantly ammonia. Two strategies evaluated the likelihood of ammonia toxicity. First, half of the effluent-grown plants were switched to commercial fertilizer. These plants recovered within one week. Second, the remaining effluent-grown plants were fertilized with an air-sparged, calcium nitrate supplemented effluent (SSE). SSE had approximately 25% of the original ammonia with the balance of N provided by calcium nitrate. SSE plants also recovered, but showed deficiency signs for Mg. Magnesium sulfate was added to SSE equivalent to the commercial rate. The plants recovered with no toxicity or deficiency symptoms. Thus, effluent appears to function as well as a commercial hydroponic fertilizer after balancing N forms (NO3/NH4) and Mg supplementation. Next is growing a crop with SSE and investigating the potential of a biofilter for N conversion. | |
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