An experiment was conducted to evaluate the individual and combined effects of treatment with the phosphate solubilizing fungus Mortierella sp. and the arbuscular mycorrhizal fungus Rhizoglomus fasciculatum on the plant growth and phosphate uptake on plantlets of avocado (Persea americana Mill. cv. ‘Hass’) grown in a nursery. A completely randomized test design was used. Treatments consisted of individual and combined inoculations with R. fasciculatum and Mortierella sp. at two concentrations (106 and 108 CFU·mL−1), and the results were compared with an uninoculated control. The plant height, shoot dry mass, and shoot phosphate uptake were significantly higher in plants inoculated with both of the fungi than with either fungus individually, or in the uninoculated control plants. The colonization of fine roots with both fungi decreased when they were co-inoculated by comparison with when they were individually inoculated, which suggests that these fungi compete for root space. Despite this competition, the dual inoculation showed that the fungi had additive effects on plant performance. Thus, shoot phosphate levels in plantlets inoculated with mycorrhizae was significantly higher when Mortierella sp. was co-inoculated at both concentrations, compared with the single inoculations and the uninoculated control plants (mycorrhiza free).

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The amount of leaf litter produced by avocado trees cv. Hass is an important potential source of mineral resources, and quantifying its production and nature is crucial to understanding the cycling of nutrients. The main objective of this study was to quantify the production of leaf litter and fallen flowers and small fruits in avocado orchards at eight locations in three producing areas in the Department of Antioquia (west, southwest, and north). The highest leaf litter production occurred in southwest Antioquia, at Jardin (7.6 t ha-1 year-1); the east locations had similar leaf fall (4.03-3.4 t ha-1 year-1). The dry matter produced in the north was very similar in both locations. The dry matter was 2.8 t ha-1 year-1. Higher leaf litter was recorded in all locations during the driest periods. Approximately 80% of the fallen fruits had diameters less than 1 cm. The highest flower production and fall occurred in southwest Antioquia, followed by the northern region.

The objective of this study was to evaluate the effect of a fungal inoculation on the litter decomposition in three plantations of avocado (Persea americana) cv. Hass in Colombia at different altitudes (Támesis 1340 m, Jericó 1900 m, and Entrerríos 2420 m). These processes are key in the proper functioning of soil biogeochemical cycles. The litter was either uninoculated or inoculated with the fungus Mortierella sp., then transferred into litter bags and finally deposited in the field sites where remained for 430 days. Residual dry matter (RDM) and nutrient content was monitored overtime. Five regression models of litter decomposition were employed: single, double, and triple exponential models and two continuous models. Although, all models properly fitted the data variation, the double exponential was the most effective based on regression parameters (mean square error and Akaike index). In all three sites the rate of decomposition was higher when the litter was inoculated with the fungus. Thus, the RDM was significantly lower when the litter was inoculated with Mortierella sp. At day 430, the uninoculated RDM in Tamesis, Jerico, and Entrerrios was 0.48, 0.47, and 0.50, respectively; while the inoculated RDM was 0.47, 0.44, and 0.46, respectively. The rate of decomposition followed the decreasing sequence: Jericó > Támesis > Entrerríos. The nutrient release pattern was: K > Ca > Mg > N > P > Cu > Mn > Zn > Fe. While K was rapidly released, Ca, Mg, and N were slowly released; P, Cu, Mn, Zn, and Fe were immobilized during the decomposition process. However, fungal inoculation on the litter significantly reduced the magnitude of nutrient accumulation for P, Mg, S, Mn, and Zn. This effect was variable overtime and among sites. Litter N and P contents and the N:P ratio were good indicators of the decaying process.

The objective of this research was to evaluate genotypes of iron- and zinc-enriched common beans during breeding in producers’ farms. Yield, disease reaction, and commercial grain characteristics were evaluated to achieve this objective. In three locations of Antioquia (Rionegro, Jardín, and Betulia), seven bush beans and eight climbing bean genotypes were planted. A randomized complete block design with four replications was used in each location. There were significant differences between the bush and climbing bean genotypes that were evaluated. The highest yields, in all locations, were for the biofortified bean NUA 45 and the control variety Uribe Rosado, followed by the CAL 96 and AFR 612 genotypes. For the climbing beans, the highest yields were found in the G2333 genotypes, being this treatment equal to the MAC 27, a bean that is adapted to mid-climate and altitudes. The MAC 27 material is presented as a promising variety because of its high yields and tolerance to diseases, mainly anthracnose.