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Soil oxygenation effects on growth, yield and nutrition of organic greenhouse tomato crops

Dorais, M., Pepin, S.
Acta horticulturae 2011 no.915 pp. 91-99
Solanum lycopersicum var. lycopersicum, biological activity in soil, carbon dioxide, crops, fruit quality, fruit yield, greenhouses, growth and development, hypoxia, iron, irrigation water, loam soils, long term effects, magnesium, mineral content, nutrition, organic soils, oxygen, plant growth, soil depth, soil nutrients, soil water, tomatoes, water uptake
Soil oxygen deficiency (hypoxia) reduces respiration, mineral uptake and water movement in roots, and may thus have a negative impact on plant growth and productivity. The supply of air or oxygen to the rhizosphere usually improves crop performance under anoxic/hypoxic soil conditions. However, little is known about the effect of O2 enrichment of the irrigation water or soil on organic greenhouse crops. The objective of this study was to determine the effect of soil oxygenation on soil biological activity, plant growth and development, yield and fruit quality. Seedlings of Lycopersicon esculentum (‘Macarena’ grafted on ‘Beaufort’) were transplanted into a loamy soil and grown in a greenhouse from February to October (oxygenated vs. control plots; four complete blocks). In 2008, O2 enrichment was provided by the irrigation water using pure O2 gas and venturi injectors (mean water O2 ~16 ppm), whereas in 2009 pure O2 was released from a network of small perforated (0.5 mm diameter holes) tubes installed at 25-cm depth into the soil (mean soil O2 ~25%). Soil surface CO2 flux was measured three times/year to determine biological activity. Growth parameters, yield and fruit quality were measured weekly. Soil and leaf mineral content were determined monthly. There was no difference in marketable yield between O2-enriched and control plots in 2008 but increased production (~2 kg m-2, P=0.108) under soil O2 enrichment in 2009. Soil CO2 fluxes were also higher in O2-enriched plots but on three sampling dates only. In general, no significant differences were observed in plant growth parameters or fruit quality. Leaf Mg and Fe levels and several soil nutrients (NO3, NH4, P and K) were significantly higher in O2-enriched plots. Long-term effects of soil O2 enrichment should be examined in different types of organically cultivated soils to conclude on any significant beneficial effect on soil biological activity and crop productivity.