RESUMEN
Intercropping legumes with cereals can lead to increased overall yield and optimize the utilization of resources such as water and nutrients, thus enhancing agricultural efficiency. Legumes possess the unique ability to acquire nitrogen (N) through both N2 fixation and from the available N in the soil. However, soil N can diminish the N2 fixation capacity of legumes. It is postulated that in intercropping, legumes uptake N mainly through N2 fixation, leaving more soil N available for cereals. The latter, in turn, has larger root systems, allowing it to explore greater soil volume and absorb more N, mitigating its adverse effects on N2 fixation in legumes. The goal of this study was to evaluate how the supply of N affects the intercropping of faba beans (Vicia faba L.) and peas (Pisum sativum L.) with wheat under varying plant densities and N levels. We measured photosynthetic traits, biomass production, the proportion of N derived from air (%Ndfa) in the shoot of the legumes, the N transferred to the wheat, and the land equivalent ratio (LER). The results revealed a positive correlation between soil N levels and the CO2 assimilation rate (An), chlorophyll content, and N balance index (NBI) in wheat. However, no significant effect was observed in legumes as soil N levels increased. Transpiration (E) increased in wheat intercropped with legumes, while stomatal conductance (gs) increased with N addition in all crops. Water use efficiency (WUE) decreased in faba beans intercropped with wheat as N increased, but it showed no significant change in wheat or peas. The shoot dry matter of wheat increased with the addition of N; however, the two legume species showed no significant changes. N addition reduced the %Ndfa of both legume species, especially in monoculture, with peas being more sensitive than faba beans. The intercropping of wheat alleviated N2 fixation inhibition, especially at high wheat density and increased N transfer to wheat, particularly with peas. The LER was higher in the intercropping treatments, especially under limited N conditions. It is concluded that in the intercropping of wheat with legumes, the N2 fixation inhibition caused by soil N is effectively reduced, as well as there being a significant N transfer from the legume to the wheat, with both process contributing to increase LER.
RESUMEN
The phenotypic diversity and productivity of a diverse alfalfa (M. sativa subspp.) panel of cultivars, landraces and wild relatives with putative drought tolerance were evaluated in two Mediterranean environments (central Chile and Southern Australia). In Chile, 70 accessions were evaluated in rainfed conditions and in Australia 30 accessions under rainfed and irrigated conditions, during three growing seasons. Large phenotypic variation was observed among and within subspecies for NDVI, stem length, intercepted PAR and forage yield. Principal component analysis indicated that the first two principal components (PC) accounted for 84.2% of total variance; fall dormancy, taxa, and breeding status were closely related to the agronomical performance of alfalfa accessions. Forage yield varied largely among accessions across years and locations. A linear relationship was found between annual forage yield and annual water added to the experiments (R2 = 0.60, p < 0.001). The GxE analysis for forage yield allowed the detection of the highest yielding accessions for each of the two mega-environments identified. The accessions CTA002 and CTA003 showed greater forage yield in both Chile and Australia environments. It is concluded that new breeding lines derived from crosses between cultivated alfalfa (M. sativa subsp. sativa) and wild relatives belonging to the primary (M. sativa subsp. falcata) and tertiary (M. arborea) gene pool, achieve outstanding agronomical performance in drought-prone environments.
RESUMEN
Las dermatosis en cobayos es un problema permanente. Muchos productores, incluso médicos veterinarios, atienden el problema como si se tratase únicamente de acarosis. La falta de pruebas de laboratorio y los tratamientos inespecíficos prolongan el problema. Se analizaron las muestras de 26 cobayos de ambos sexos, de todas las edades y tipos zootécnicos; procedentes de pequeñas granjas de la provincia de Huánuco entre los meses de junio a noviembre. Se identificó Trichophyton mentagrophytes en 50% de las muestras, concomitante a acarosis. Este problema se presentó principalmente en la etapa de recría, independientemente se tratase de una explotación en poza o en jaulas. Se recomienda el diagnóstico de laboratorio previo a cualquier tratamiento, el cual deberá considerar el empleo de algún antifúngico; así mismo, implantar medidas de control y profilaxis dentro y fuera de las instalaciones, y el empleo de la medicina alternativa, probando la actividad antifúngica que ofrecen algunas plantas de nuestra región.
The dermatosis is a permanent problema in guinea pigs. Many producers, even veterinarians, manage the problem as an acariasis solely. The lack of diagnosis test and no-specific treatment to extend the problem. We analyzed 26 guinea pigs samples, of both sexes, all the ages and zootechnical types; the samples came from small farms of the Province of Huanuco between June and November. It was identified Trichophyton mentagrophytes in 50% of the samples, concomitant to acarosis. This problem appeared mainly in the fatten stage and any type of operation, pit or cages. It is recommended the diagnosis test previous to any treatment, which will have to consider the use of some anti-fungal; besides to set up controls measures and prophylaxis inside and outside of the facilities, and the use of alternative medicine, testing anti-fungal activity that offer some plants of our region.