Antecedentes y Objetivos: La fijación biológica del nitrógeno (FBN) en leguminosas nativas de México ha sido poco estudiada; particularmente en especies del género Lupinus no se tiene información al respecto. En este sentido, el objetivo de esta investigación fue cuantificar la acumulación de biomasa y nitrógeno (N) en tres lupinos silvestres del estado de Jalisco, México (Lupinus exaltatus, L. rotundiflorus y L. mexicanus), así como evaluar la FBN en términos de cantidad de N fijado (kg ha-1) y proporción de N derivado de la atmósfera (% Ndda).Métodos: Las especies en estudio al igual que la cebada, una especie conocida como no fijadora de N y usada de referencia, fueron cultivadas en suelos agrícolas de Zapopan, Jalisco, en el periodo otoño-invierno de 2015-2016. Durante el crecimiento de las especies en estudio se realizaron muestreos destructivos a los 93, 108 y 122 días después de la siembra (Dds). En cada muestreo se cuantificó el número de nódulos por planta, contenido de materia seca (Ms) y % de N. Con estos valores se estimó mediante el método de la diferencia de N, la proporción de N derivado de la atmósfera (% Ndda) y cantidad de N fijado (kg ha-1).Resultados clave: A los 93, 108 y 122 Dds, L. exaltatus fijó 87.4, 86.9 y 187 kg de N ha-1, lo cual fue equivalente a 71.0, 70.9 y 83.8% de Ndda, respectivamente. Las especies L. rotundiflorus y L. mexicanus solamente mostraron valores significativos de N fijado hasta los 122 Dds.Conclusiones: Bajo las condiciones de este estudio se puede concluir que L. exaltatus se caracterizó por ser la especie más eficiente en la fijación de N atmosférico, debido a una favorable simbiosis entre las raíces y las bacterias nativas del suelo fijadoras de N atmosférico.

In the state of Jalisco, corn and tequila agave are the most important agricultural crops. The soils to cultivate these species are characterized by low content of organic matter and nitrogen. The amendments applied to the soil provide an important source of energy and nutrients for microorganisms; promotes the diversity of nitrogen-f ixing bacteria and nitrifying bacteria, which increases nitrogen availability in the soil. The aim of this study was to evaluate the use of two species of wild legumes: Lupinus exaltatus and Lupinus rotundiflorus as green manure (AV), and its effect on soil microbial biomass. An aerobic incubation experiment (14 days) was carried out on soil samples with green manure and without green manure (control). Under laboratory conditions, the microbial activity of soil was monitored through the response in basal respiration and the concentration of C and N in the microbial biomass. The CO2 production and C and N content in the microbial biomass showed significant differences (P < 0.05) due to the effect of green manure. The residues of Lupinus are considered better quality than the residues of Zea mays due to its nitrogen content and low C: N ratio. The response of microorganisms presented a positive primer effect with the input of AV. Therefore, we conclude that the input of L. exaltatus and L. rotundiflorus as a green manure to the soil increases the biological activity of the soil and promotes the enrichment of C and N of the microbial biomass.

The potential of Lupinus exaltatus, L. mexicanus, and L. rotundiflorus foliage as green manure in terms of total dry matter production and nitrogen (N) content was evaluated. This study was conducted from November 2015 to March 2016 in Zapopan Jalisco, México. The experiment was established in a randomized 3×7 block factorial design. Whole plants, leaves and stems were collected at different periods after sowing and analyzed for N and dry matter content. At the start of the experimental period, a slow growth was observed, based on dry matter production; however, at 93 days after sowing, both biomass and total N increased in the aerial part. The lowest and highest N content was found in L. rotundiflorus (1.2 to 4.0%).The highest dry matter and N accumulated in whole plants were found in L. exaltatus at 169 days after sowing with 21,605 and 410.6 kg ha-1, respectively.

The use of organic fertilizers contributes to the improvement of the fertility of agricultural soils. The objective was to evaluate three doses of organic fertilizer incorporated into the soil (10, 20 and 30 t.ha-1) and a control, in corn production. The management of the crop was conventional, after the preparation of the soil with agricultural machinery, the doses of compost were incorporated. Planting was manual with a density of 66,500 plants.ha-1. A completely randomized design and three replicates per treatment were used. Data were analyzed with analysis of variance, tests of means, correlation analysis, and economic evaluation. The results indicated that the incorporation of organic fertilizer to the soil benefited the height of the plant and ear, leaf area, stem diameter, number and yield of ears.ha-1. A direct and positive relationship was found between the dose of amendment incorporated into the soil and the production of ears in the milky-dough state. The application of 30 t.ha-1 of organic fertilizer showed the best results for the indicated agronomic variables and presented the best economic benefits.

The effects of genotype and harvest date on lupin (Lupinus angustifolius) forage yield and quality were evaluated in Zapopan Jalisco, Mexico. Cultivars Haags Blaue, Boregine, Borlu, Probor, Sonate, and Boruta were grown during the 2013-2014 cool season and harvested twice, in January (early harvest) and February (late harvest). Fresh and dry matter (FM, DM) yield, crude protein(CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), minerals, and total alkaloids were measured at each harvest. FM yields varied from 9.1 to 12.2 t ha -1 and from 23.4 t ha -1 to 35.3 t ha -1 at the first and late harvests, respectively. DM yields from early harvest plants varied from 1.2 to 1.7 t ha -1 ; those from the second harvest (late harvest date) varied from 3.4 to 6.8 t ha -1 . The highest CP content for both (early and late harvests) was identified in the Probor cultivar, at 226 and 187 g/kg, respectively. At early harvest, ADF values varied from 291.2 in Sonate to 392.3 g/kg in Borlu; at late harvest, ADF values varied from 417.2 in Sonate to 488.3 g/kg in Borlu. Harvest date and varieties did not influence alkaloid and mineral content.