Presentation on theme: " The cereal cyst nematode Heterodera avenae Wollenweber 1924 (NEMATODA: HETERODERIDAE) is widespread in most cereal- growing regions of the world, including."— Presentation transcript:
The cereal cyst nematode Heterodera avenae Wollenweber 1924 (NEMATODA: HETERODERIDAE) is widespread in most cereal- growing regions of the world, including the uplands of the Castilian plateau (Central Spain). It can reduce yields of winter wheat and barley as much as 50% in infested soils, with the additional difficulty of a restricted use of pesticides in these – due to economic, ecological, or social factors - low-input agricultural systems. The use of passive solar heating in a moist soil mulched with a plastic sheeting, has been proved as an effective method for the control of pathogens in agricultural areas with hot weather periods, in greenhouses or in soil containers, and with a parallel increase in the health, growth, yield, and quality of crops (Stapleton, 2000). Improving the efficacy of the process is possible by combining solarization with a low dose of pesticide treatment or with the simultaneous addition of residual organic matter: crop residues, animal manure, agro-industrial by-products, compost or green manure (Gamliel et al. 2000). More commonly used in horticultural crops, their practice could be introduced into other extensive crops such as cereals, potatoes or sugar beet, if it was properly managed. In some instances, wetting the soil with the simultaneous incorporation of raw materials and, thereafter, passing a roller could create a soil crust that is enough to maintain the soil under anaerobic conditions and to retain temporally the gases produced during the organic matter decomposition. Javier López-Robles*, Casilda Olalla, Carlos Rad, Yolanda Arribas, Milagros Navarro, Juana Isabel López-Fernández and Salvador González-Carcedo. Author for correspondence: Use of different manures and organic wastes in the suppression of the cereal cyst nematode Heterodera avenae by biofumigationIntroduction Material and Methods Results and Discussion Conclusions Soil. The biofumigation experiments have been carried out in the laboratory using a Xerochrept calcareous clay loam soil affected by H. avenae. The main soil properties were: pH 8.51, organic matter content 3.43%, total N 2.4‰ and total P 0.489‰. The biofumigation experience was conducted by incubating, in sealed zip plastic bags, mixtures of 500 g soil, previously saturated with water, and 0, 5, 10 and 20 g of the different organic amendments over a period of thirty days at 30 ºC in a randomised block design with four replicates. The organic residues added were: crop residues of strawberry plants (S), sewage sludge compost (SS), compost of urban solid wastes (US), dehydrated pig slurry (P), spent mushroom compost of Pleurotus spp. (PM), sheep manure (SM), poultry litter (CH), and mixtures of sewage sludge compost and lime (SS+C), in which 0.2, 0.4 and 0.6 g of lime were added to 5, 10 and 20 g of sewage sludge, respectively, as the necessary amount to reach a pH of 12 in the final mixture. All of the treatments were done by quadruplicate. The populations of the pathogen H. avenae in each plastic bag were estimated in the mixtures with (Pf) and without incubation (Pi). Cysts were extracted from 100 g of soil using a flotation technique (Fenwick 1940), thereafter crushed in a homogeniser (Eijkelkamp) and the eggs counted. The final result was expressed as No. eggs 100 g -1 of dry soil. Fenwick, D.W., Methods for the recovery and counting cysts of Heterodera schachtii from soil. Journal of Helminthology 18: Gamliel, A., Austerweil, M. and Kritzman, G., Non chemical approach to soilborne pest management – organic amendments. Crop Protection 19: Stapleton, J.J., Soil solarization in various agricultural productions systems. Crop Protection 19: References The use of organic residues with high contents of N could be applied to biofumigation processes with a positive reduction of soil-borne pathogens. The anaerobic organic matter degradation involves the generation of biocidal compounds that could exert a biofumigant effect. Among them, the volatile ammonia could be the main biocide agent. Future research of the group is directed to determine the changes in soil microbial properties and the evolution of soil solution composition during and after the biofumigation process. Aknowledgments Aknowledgments: This work has been supported by the collaboration agreement between the Instituto Tecnológico Agrario de Castilla y León (ITACYL) and the University of Burgos. The aim of this work The aim of this work was to test the ability of different animal manures and agro-industrial by-products to suppress the pathogenic nematode H. avenae in an infested soil in a simulated laboratory experience. Figure 1. Percentage of reduction of the population of H. avenae after biofumigation with different organic amendments. All the treatments significantly reduced the pathogen population as compared with the control with a range between 20 and 85% of the initial populations. The most efficient treatment was the mixture of sewage sludge compost and lime at all doses (SC), and the dehydrated pig slurry (P) at the highest dose (Figure 1). For the rest of the organic residues, the response was closely related to their N content; the lowest efficacy was obtained with the residue of strawberry crops and the high positive responses were obtained with N-rich residues, such as sewage sludge compost and animal manures generated in pig, sheep or poultry production. This positive effect was magnified by the addition of lime, which could increase the volatilization of ammonia after the mineralization of organic residues. Only with dehydrated pig slurry (P), sheep manure (SM) and the mixtures of sewage sludge and lime (SC) was it possible to detect significant differences with the dose of added residue. The absence of a proportional response could suggest that in most of the cases the lowest dose was enough to obtain an important suppression of the pathogen H. avenae in this infested soil. Research Group in Composting. University of Burgos. Faculty of Sciences. Misael Bañuelos Sq Burgos. Castile (Spain).