Effect of compost particle size on suppression of plant diseases
Lozano, J. ; Blok, W.J. ; Termorshuizen, A.J. - \ 2009
Environmental Engineering Science 26 (2009)3. - ISSN 1092-8758 - p. 601 - 607.
pythium-ultimum - damping-off - soil - mineralization - temperature - turfgrass - pathogens - biowaste - carbon - crops
Predictability of compost-induced suppression of soil-borne plant diseases is poor. Part of the variability in disease suppression could be due to the heterogeneity of a given compost. Therefore, the disease suppressive properties of different wet-sieved fractions of two composts against three soil-borne plant pathogens were studied. The ability of a green waste and a yard waste compost to suppress the soil-borne plant pathogens Fusarium oxysporum f.sp. lini (host: flax), Phytophthora cinnamomi (host: lupin), and Meloidogyne hapla (host: tomato) was determined. The following compost fractions were prepared: 2¿4 mm (40% v/v with peat-based substrate), 1¿2 mm (35 or 45% v/v; comparable number of particles and comparable organic matter content as the 2¿4 mm fraction amendment respectively), and 1¿2 mm (35% v/v) obtained from the 2¿4 mm fraction by a series of dry-sieving, crushing, and wet-sieving. The 2¿4 mm compost fraction of both composts showed significantly higher disease suppression for the three pathosystems, except for P. cinnamomi with one compost, in which there was no effect. For both composts, oxygen uptake rate showed a significant positive correlation with disease suppression of all pathogens except for P. cinnamomi. For the composts studied, substrate quality as expressed by oxygen uptake rate, seems to be of greater importance for disease suppression than compost particle size per se.
Effect of inoculum addition modes and leachate recirculation on anaerobic digestion of solid cattle manure in an accumulation system
El-Mashad, H.M. ; Loon, W.K.P. van; Zeeman, G. ; Bot, G.P.A. ; Lettinga, G. - \ 2006
Biosystems Engineering 95 (2006)2. - ISSN 1537-5110 - p. 245 - 254.
waste - landfill - fermentation - temperature - degradation - biowaste - batch
The effect of both leachate recirculation (at 40 and 50 °C) and the mode of inoculum addition (at 50 °C) on the performance of a non-mixed accumulation (i.e. fed batch) system treating solid cattle wastes was investigated, using laboratory scale reactors at a filling time of 60 days. A relatively high methane production rate (MPR) and low stratification of intermediates occur with leachate recirculation. The leachate recirculation volume flow and methane production rate are smaller at 40 °C than at 50 °C: 0·31 and 0·7 l [CH4] l¿1 [reactor] day¿1, respectively. The increased MPR at higher temperature is at one hand caused by the increase of microbial activity, at the other hand by the lower viscosity causing the increased leachate recirculation volume. Dividing the inoculum in equal doses and distributing them with the feed positively affects the system behaviour as compared to adding the same inoculum amount at the reactor bottom at the start only. Without addition of inoculum a very poor system performance was observed. The average MPR was 0·2, 0·4 and 0·5 l [CH4] l¿1 [reactor] day¿1 for the reactor without inoculum, inoculum addition at the reactor bottom and inoculum addition in different equal doses, respectively.