No abstract

Efecto de tipos de inóculos de tres especies fúngicas en la micorrización controlada de plántulas de Pinus radiata SUMMARYIn the present study different types of inoculum: sporal (SI), solid micelial (SMI), and liquid micelial (LMI) of ectomycorrhizal fungi were evaluated on the controlled mycorrhization of Pinus radiata seedlings growing under experimental nursery conditions. The fungal species were Rhizopogon luteolus, Suillus bellinii and Suillus luteus collected from Pinus radiata plantations in the province of Bíobío, in the VIIIth Region of Chile. The fungal species were cultivated on the solid medium MMN (modified Melin-Norkrans), pH 5.8, and incubated for 30 days to produce the sources of micelial inoculum under liquid (LMI) and solid (SMI) conditions. To obtain the SI the carpophores collected in field were cleaned (previous identification in the laboratory) and then crushed in blender (1000 rpm) containing desionized water. The different types of inoculum were kept in glass bottles, at 4° C in darkness, until their use. The results indicated that the effect of the type of inoculum changed according to the fungal species studied. The best results after eleven months for the plant mycorrhization were observed when SMI and LMI obtained from R. luteolus and LMI from S. luteus were used. The species S. bellinii did not present differences in the mycorrhization reached by the plants with the different types of inoculum. Among three species of ectomycorrhizal fungi studied, R. luteolus showed the biggest effects on the growth of the P. radiata seedlings in nursery.

There are few studies about the impact of sewage sludge on the biological properties in Alfisols of the Chilean Coastal Range drylands. Hence, the objective of this study was to evaluate its effect on the microbial respiration and enzymatic activities of a degraded Alfisol located in the Bío Bío Region (Chile) that was cropped with yellow serradela (Ornithopus compressus L.). Sludge was added to the soil at rates of 15, 30, and 60 t ha -1 ; he following treatments were defined: L15-P = 15 t ha -1 sludge + O. compressus; L30-P = 30 t ha -1 sludge + O. compressus; L60-P = 60 t ha -1 sludge + O. compressus; L15 = 15 t ha -1 sludge; L30 = 30 t ha -1 sludge; L60 = 60 t ha -1 sludge; CP = non-amended soil, cropped; and C = non-amended soil, no crop. Soil microorganism activity was evaluated by respirometry. Hydrolytic enzyme activity representative of soil C, N, and P cycles was determined. Crop phytomass development was also evaluated. The amount of C-CO2 produced by soil microorganisms was directly proportional to the dose of amended sludge (p ≤ 0.05). Similarly, greater β-glucosidase, urease, and acid phosphatase were more active at 60 t sludge ha -1 . However, both respiratory and enzymatic activities were greater (p ≤ 0.05) in treatments with sludge-amended soil cropped with O. compressus. This greater activity was notorious when the legumes achieved greater phytomass development, thus highlighting the root's stimulating effect on soil biological activity.