ISHS Acta Horticulturae 698: VI International Symposium on Chemical and non-Chemical Soil and Substrate Disinfestation - SD2004
EFFECT OF ECOSOIL AND NH4 IN CONTROLLING SOILBORNE PATHOGENS |
| Authors: | Y. Ben-Yephet, L. Tsror, M. Reuven, A. Gips, Z. Bar, A. Einstein, Y. Turjeman, P. Fine |
| Keywords: | Fusarium, Verticillium dahliae, Sclerotium rolfsii, Sclerotinia sclerotiorum, biosolids |
| Abstract:
Ecosoil (alkaline stabilized biosolids) is produced from a mixture of de-watered sludge (125 dry weight basis), cement kiln dust (CKD) and fillers (500 g dry weight basis). The biosolids are pasteurized and stabilized by heating (>60°C for 12 h) and high pH (>12) produced by the hydration of the CaO content of the CKD. Ecosoil is produced by an advanced technology and the product is free of sanitary restrictions. The product simultaneously offers several potential benefits to both growers and the environment, including liming of acid soils, improving soil structure and replenishing plant nutrients. Addition of Ecosoil to soil can increase the soil solution pH and consequently increase converting NH4 to NH3. The fungicidal activity of the combined treatment (Ecosoil + NH4) was studied by testing the following 4 treatments: Ecosoil, ammonium sulfate, Ecosoil plus ammonium sulfate, and control. The materials were incorporated into the soil, which was then irrigated to field capacity. The results of laboratory experiments showed that application of Ecosoil + NH4 to sandy soil reduced counts of Fusarium oxysporum f.sp. dianthi below the detection threshold. The pathogen control efficiency was increased by increasing the Ecosoil dose which increased soil solution pH. Thus, effective control was observed in the pH range of 10-11, with the highest control activity in the pH range of 10.5-11.0. The ammonium sulfate dose that was necessary to achieve effective control decreased as the soil solution pH increased. The effective toxicity was highest 2-4 days after irrigation of the soil. The soil pH gradually declined to the original pH, 8-16 days after irrigation. Other laboratory experiments indicated that the combined application was also effective in controlling other soilborne pathogens such as Verticillium dahliae, Sclerotinia sclerotiorum, and Sclerotium rolfsii. The Ecosoil dose necessary to increase soil pH to 10.5 in clay soil (60% clay) was 4 times as great as that in sandy loam soil (5% clay). | |
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