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Assessments of Soil physical properties and estimation of their associated variability are essential for making site-specific decisions on soil and crop management This study examined the spatial variability of soil hydro-physical properties and variance structure at Sector F1 of the Jibia Irrigation project Katsina State, Nigeria. Grid sampling technique was used to obtain one hundred and forty-four (144) soil samples from 206 ha of land using Google earth. The grids were drawn using Google earth software at intervals of 150 m x 150 m. Surface soil samples (0 - 20 cm) were collected at grid intersection points. The collected soil samples were air-dried and passed through a 2mm sieve, and analyzed using standard laboratory procedures for physical parameters. The ArcGIS software package 10.3 was used to model the variance structure of Sand, Silt, Clay, Bulk density, Particle density, Percent total porosity and Organic Matter (OM). Results obtained revealed that the coefficient of variation (CV) ranged from 5.724% in particle density to 109% in clay. The Semivariogram showed that the range of spatial dependence varied from 0.342m for (Dry mean weight diameter) to 9.3m (Organic matter) for all measured soil properties. High Spatial dependency ratios were observed for Bulk density, Sand, Silt and clay contents. Particle density exhibited moderate spatial dependency (Nugget to sill ratio 0.25 – 0.75%). Wet Mean weight diameter and organic matter content have a weak spatial dependency. The results indicated that sandy textured soils dominated the greater part of the study area with low to moderate organic matter content. The soils being sandy-dominated has a high infiltration rate and low ability to retain moisture and nutrients were observed as the major characteristics of the soil of the study area.

Knowledge of the soil hydro-physical properties of any irrigation site is crucial in soil quality assessment and its management. This study was conducted to assess the aforementioned properties in the Jibia Irrigation Dam of Katsina, a Sudano-Sahelian region in Nigeria. After employing the grid soil sampling approach 144 samples were obtained and analyzed, the data obtained were subjected to descriptive statistics, correlation analysis and maps were created using the kriging technique. Findings were used to conclude the higher presence of sandy textured soils (loamy sand to sandy texture), Average Moisture content at Field Capacity (FC) of 0.332 %, Permanent Wilting Point (PWP) of 0.222 % and Available Water (AW) of 0.192 % were observed to be low with high Hydraulic conductivity making the soil require frequent irrigation. Semivariogram analysis showed that moisture content at FC and AW had weak spatial dependence (nugget-sill ratio > 75 %), moisture content at PWP had moderate spatial dependence (nugget-sill ratio, 25 – 75 %) while Saturated Hydraulic Conductivity (Ks) had strong spatial dependence (nugget-sill ratio

El presente trabajo estudia la biología reproductiva de la jibia o calamar gigante, Dosidicus gigas frente a la costa de Chile central capturados en julio-agosto (invierno) y octubre-noviembre (primavera) de 1993. En 254 hembras (93 de invierno y 161 de primavera) se analizó el estado de madurez microscópico, determinándose un predominio de hembras en maduración, y en menor porcentaje a punto de desovar. El índice gonadosomático (IGS) y el índice del peso del complejo oviductual (IPCO) indicaron que las hembras estaban en un proceso de maduración gonádica. En hembras, el IGS y el IPCO muestran diferencias significativas en los valores promedio entre invierno y primavera (p= 0,000 y p= 0,002, respectivamente). Sólo para el IPCO de invierno existió una relación lineal con la longitud dorsal del manto (p=0,009, r²=0,067). En aguas chilenas la presencia de hembras maduras de D. gigas abarcaría gran parte del año, alcanzando los ejemplares de invierno una mayor talla de madurez sexual.The present study examines the reproductive biology of the giant squid, Dosidicus gigas collected off the coast of north-central Chile from july-august (winter) to october-november (spring) of 1993. In 254 females (93 in winter and 161 in spring) the microscopic stage of maturity was analyzed, being determined a prevalence of females in maturation, and in smaller percentage near the spawning. The Gonadosomatic Index (IGS) and the Index of the Weight of the Oviductual Complex (IPCO) indicated females were in process of gonadic maturation. Seasonal significant differences for IGS and IPCO were found between winter and spring (p=0,000 and p=0,002, respectively). Only winter IPCO showed a lineal relationship with the mantle dorsal length (p=0,009, r²=0,067). In Chilean waters mature females of D. gigas were found the major part of the year, but the winter individuals had bigger size of sexual maturity.

Se presentan los resultados de dos cruceros de pesca de investigación de la jibia, Dosidicus gigas (Orbigny 1835) realizados entre julio de 1993 y enero de 1994 en la Zona Económica Exclusiva de Chile comprendida entre los 29º S y 40º S. En cada lance se registró el día, hora, duración del lance, así como el volumen de la captura por lance y máquina potera, para efectuar estimaciones de abundancia relativa. A los ejemplares capturados se les determinó la longitud dorsal del manto (LDM), peso total, peso eviscerado, peso manto, sexo y se les extrajo el tracto digestivo, para un análisis del contenido estomacal. Las jibias sólo fueron capturadas entre los 29º S y los 30º S. En el primer crucero (invierno) se registraron ejemplares grandes (71 a 98 cm LDM) y chicos (< 44 cm LDM) de ambos sexos, mientras que en el segundo crucero (primavera) se capturaron sólo jibias de tamaño intermedio (26 a 60 cm LDM). Las distribuciones de frecuencias de tamaños determinadas en los cruceros muestran dos cohortes de D. gigas en la zona de pesca. La dieta no varió entre las estaciones y estuvo compuesta principalmente por peces pelágicos y demersales, secundariamente cefalópodos y ocasionalmente crustáceos pelágicos, incluyendo también canibalismo. Las relaciones longitud-peso fueron similares en ambos sexos y se corrobora que las jibias registradas en aguas de Chile, alcanzan pesos mayores a la misma longitud que las poblaciones de jibia de México y PerúThe results of two fishing research cruises of the jumbo squid, Dosidicus gigas, between July 1993 and January 1994 in the Chilean economic exclusive zone between 29º S to 40º S, are described. For each trawling, date, hour, trawling duration and volume of squids by catch and jigging machines, were registered to estimate the relative abundance. The squid mantle length, total weight, eviscerated weight, mantle weight, and sexes, were measured in each collected specimen. Then, the digestive tracts were extracted for stomach content analysis. The captures of jumbo squid occurred only from the 29ºS to the 30º S. In the first cruise (winter) specimens of large (71 to 98 cm MDL) and small size (< 44 cm MDL) in both sexes, were collected; while in the second cruise (spring) medium size squids were captured (26 to 60 cm MDL). Size frequency distribution analysis in the both cruises shows two cohorts of D. gigas in the same fishing zone. The diet does not change among seasons and was compound mainly for pelagic and demersal fish and secondarily by cephalopods and occasionally pelagic crustaceans; furthermore, cannibalism may also occurs among squids. Length-weight relationships were similar in both sexes and it corroborates that jumbo squid registered in Chile, reaches bigger weight to the same length that the populations from Mexico and Peru

En el presente trabajo se realizó la caracterización funcional y bioquímica de la carne del manto de jibia (Dosiducus gigas) almacenada a _ 25°C por 6 meses. Se estudiaron la capacidad emulsionante, capacidad de retención de agua y la capacidad de gelificación. Además se buscaron las condiociones óptimas para la separación y diferenciación de las proteínas miofibrilares de las sarcoplasmáticas. Dentro de las propiedades funcionales se encontró que la carne descongelada del manto de jibia es capaz de emulsionar 2.817,4 g aceite/g proteína, de retener 3,64 g agua/g proteína. La capacidad de formar geles fue nula, lo cual se atribuyó al tiempo de almacenamiento. Respecto a la obtención de proteínas miofibrilares de carne del manto de jibia, se concluyó que con dos lavados a baja fuerza iónica (I=0,05), las proteínas sarcoplasmáticas son eliminadas de la matriz proteica. Mediante la realización de PAGE-SDS, de los extractos de carne de manto de jibia obtenidos a dos fuerzas iónicas diferentes (I=0,5 y I=0,05), se logró difrenciar las proteínas miofibrilares de las sarcoplasmáticas. Del estudio realizado se deduce que las proteínas del manto de jibia poseen una buena capacidad de emulsionar y retener agua, por lo que se puede considerar una muy buena materia prima para el desarrollo de productos parea untar. En el caso de productos gelificados, es necesario realizar estudios complementarios en la carne fresca para poder inferir en relación a esta propiedad funcional.Biochemistry and functional characterization of squid mantle meat (Dosidicus gigas). A study for the characterization of frozen giant squid mantle (meat) protein stored at _25°C for 8 month was started. In the present research, the folowing functional properties were investigate: emulsifying, water holding and gel forming capacities. Optimal conditions for the separation and differentiation of miofibrillar and sarcoplasmmatic proteins were also studied. It was found that the unfrozen giant squid mantle meat es capable of emulifying 2.817,4 g of oil/g of protein and holding capacity was 3,64 g of water/g of protein. Related to the gel forming capacity, it was not obtain, probably due to excessive storage of the meat. With regard to miofibrilar protein obtention of the squid mantle meat, it was found that two low ionic strength washings (I=0,05), the sarcoplasmic proteins were practically eliminated from the protein matrix. The differentiation of miofibrilar and sarcoplasmatic proteins was obtained by PAGE-SDS of the squid mantle meat extracted at two differents ionic strength (I=0,05 and I=0,5). This work demonstrates that the giant squid mantle protein has a high emulsifying and water holding capacity, and it can be used, as a raw material, for the improvement of sausage products. About the gelling products, more studies will be necessary with fresh squid mantle meat to conclude about this functional property.

En el presente trabajo se realizó la caracterización funcional y bioquímica de la carne del manto de jibia (Dosiducus gigas) almacenada a _ 25°C por 6 meses. Se estudiaron la capacidad emulsionante, capacidad de retención de agua y la capacidad de gelificación. Además se buscaron las condiociones óptimas para la separación y diferenciación de las proteínas miofibrilares de las sarcoplasmáticas. Dentro de las propiedades funcionales se encontró que la carne descongelada del manto de jibia es capaz de emulsionar 2.817,4 g aceite/g proteína, de retener 3,64 g agua/g proteína. La capacidad de formar geles fue nula, lo cual se atribuyó al tiempo de almacenamiento. Respecto a la obtención de proteínas miofibrilares de carne del manto de jibia, se concluyó que con dos lavados a baja fuerza iónica (I=0,05), las proteínas sarcoplasmáticas son eliminadas de la matriz proteica. Mediante la realización de PAGE-SDS, de los extractos de carne de manto de jibia obtenidos a dos fuerzas iónicas diferentes (I=0,5 y I=0,05), se logró difrenciar las proteínas miofibrilares de las sarcoplasmáticas. Del estudio realizado se deduce que las proteínas del manto de jibia poseen una buena capacidad de emulsionar y retener agua, por lo que se puede considerar una muy buena materia prima para el desarrollo de productos parea untar. En el caso de productos gelificados, es necesario realizar estudios complementarios en la carne fresca para poder inferir en relación a esta propiedad funcional.