Dinámica del fósforo en un agroecosistema conservacionista maíz-ganado de sabanas neotropicales

Abstract

Phosphorus is one of the limiting elements in acid soils, so the incorporation of strategies for its cycling within an agroecosystem is one of the key variables, in order to optimize agricultural production. The dynamics of phosphorus in a maize-livestock agroecosystem were evaluated under the types of forages introduced: Brachiaria dyctioneura (Bd), a grass and Centrosema macrocarpum (Cm), a legume, which in turn served as associated perennial coverages maize grown with direct sowing. The dynamics of this element are contrasted in the savanna of natural vegetation (SN). It determined the availability of this element in the soil (0-15 cm), as well as the total P content in the excreta of the cattle and in the green fraction of the vegetation during the dry season, after the harvest of the corn, when the cattle a grazing is introduced. We analyzed the bromatological quality of livestock and the daily gain of weight in livestock (GDP). Concentrations of total P in the plant biomass varied according to the quality of the pasture forage, being higher in the Cm. This significantly affected (p<0.01) the excreta P and the available P of the soil, which resulted in a higher GDP. In the savanna conditions, P cycling in the subsystems of soil-plant-animal, is more effective when a forage legume is used as Cm, since it favors the incorporation of P through the excreta and by the decomposition of his necromass. Keywords:Forage; relationship soil-plant-excreta; cover; vegetal nutrition. ResumenEl fósforo constituye uno de los elementos limitantes en suelos ácidos, por lo que la incorporación de estrategias para su ciclaje dentro de un agroecosistema es una de las variables claves, a fin de optimizar la producción agropecuaria. Se evaluó, la dinámica del fósforo en un agroecosistema conservacionista maíz-ganado, bajo dos tipos de forrajes introducidos: Brachiaria dyctioneura (Bd), una gramínea y Centrosema macrocarpum (Cm), una leguminosa, que a su vez se desempeñaron como coberturas perennes asociadas al maíz cultivado con siembra directa. Se contrastó la dinámica de este elemento en la sabana de vegetación natural (SN). Se determinó la disponibilidad de este elemento en el suelo (0-15 cm), así como el P total contenido en las heces del ganado y en la fracción verde de la vegetación durante la época seca, después de la cosecha del maíz, cuando el ganado se introduce a pastoreo. Se analizó la calidad bromatológica del forraje y la ganancia diaria de peso en el ganado (GDP). Las concentraciones de P total en la biomasa vegetal varió de acuerdo a la calidad del forraje pastoreado, siendo mayor en la Cm. Ello incidió significativamente (p<0.01) en el P de las excretas y en el P disponible del suelo, lo cual resultó en una mayor GDP. En condiciones de sabana, el ciclaje del P en los subsistemas suelo-planta-animal, es más efectivo cuando se usa una leguminosa forrajera como Cm, ya que favorece la incorporación del P a través de las excretas y por la descomposición de su necromasa. Palabras Clave:Forraje; relación suelo-pl...

Quality of a Cambisol at different times of agricultural use in the region of Los Ríos, Tabasco, Mexico.

“…The highest P contents were observed in Pa in 1984, while the lowest were found in RC and AC of the same year (Table 3). The P value in Pa is consistent with reports on pasture soil by Burst et al (2020) and can be attributed to the application of P mineral fertilizers (Alabi et al, 2019) and to grazing residues (cattle manure and urine) that increase the availability of P in the soil (Ramírez-Iglesias et al, 2017).…”

“…This is confirmed by the varied-aged rocks where the CM of the RR develops, such as Holocene alluvium, Miocene detrital sediments, and Eocene limestones and marls (Salgado-García et al, 2017). The properties that did not show significant differences between the factors of use and establishment year were the following: a) pH, with a prevalence of neutral over moderately acidic (7.3 to 6.1) (SEMARNAT, 2002); acidic pHs in agricultural soils are due to intensive farming and the continuous use of acid-forming inorganic fertilizers (Mulat et al, 2021); b) EC showed low values, characteristic of CM (Salgado-García et al, 2017); this property helps crops assimilate other soil nutrients better (Navarro-García and Navarro-García, 2013); c) N presented low values -especially in RC and AC-, closely related to low to medium OM values, which reduces the mineralization level of N (Alabi et al, 2019); d) P showed high values due to cattle excreta and applied fertilizers (Ramírez-Iglesias et al, 2017); e) BD was higher in Pa, associated with compaction as a result of extensive livestock farming (Xu et al, 2021); and f) AS had a low WMD in RC and Pa, which indicates a structural stability loss, while the increase in AC is related to the OM content; when attached to soil mineral particles, they form clay-metal-humic bonds that increase structural stability (De Freitas et al, 2018).…”

Nutrient dynamics of corn fed to livestock in conservation-based agroecosystems in neotropical savannas

“…VIERA et al (2019) argue that the species and their vegetation composition can have a considerable effect on the accumulation of organic matter (OM) in the soil, favoring decomposition via microbial communities, while this activity is limited in the dry season. RAMÍREZ-IGLESIAS et al (2017a) claim that increased production of GLB can mean an alternative for livestock in the dry season. Despite intensive grazing in pastures, there is still a quantity of green plant material after that process that can be consumed by livestock.…”