Sorghum has become ever more prominent on the global energy scene, with studies in the area becoming extremely important. Agricultural production in the semi-arid region of the Brazilian Northeast is intrinsically dep...Sorghum has become ever more prominent on the global energy scene, with studies in the area becoming extremely important. Agricultural production in the semi-arid region of the Brazilian Northeast is intrinsically dependent on rainfall in the region. However, on both inter- and intra-annual scales, the rainfall regime is quite irregular. The aim of this study was to evaluate the productivity of sorghum grown under a rainfed regime, and the water-use efficiency of crops in the semi-arid region of the northeast of Brazil. The work was carried out in the city of Tabuleiro do Norte in the semi-arid region of the State of Ceará. Mean productivity of the sorghum was 919.42 kg·ha-1, with maximum values being recorded for lot 02 (1032 kg·ha-1), lot 03 (1102 kg·ha-1), lot 04 (2143 kg·ha-1) and lot 12 (1367 kg·ha-1). The greatest value for water-use efficiency, 1.13 m3·kg-1, was found for lot 04, while the smallest value, 4.83 m3·kg-1 was seen in lot 02. It was found that the low productivity of sorghum in a rainfed regime shows that the lack of success in production systems in semi-arid regions is not due to the total amount of rainfall, but rather the spatial and temporal distribution of the rains, as well as the occurrence of hot, dry spells. Furthermore, it can be seen that the best ratio of grain production to water demand shows a strong correlation with the distribution of water throughout the cycle, and not only with the total volume.展开更多
Erosion is the natural process which has the greatest environmental impact, and is the principal trigger for desertification around the globe. The main model used to estimate soil loss by erosion is the Universal Soil...Erosion is the natural process which has the greatest environmental impact, and is the principal trigger for desertification around the globe. The main model used to estimate soil loss by erosion is the Universal Soil Loss Equation (USLE), which unites the major factors that influence erosion into one equation. The soil erodibility factor (K) is the component of this equation that represents soil physics, and is defined as the inherent capacity of the soil to withstand disintegration of its particles and their subsequent transport. The use of geostatistics is seen as an alternative in spatializing this variable from sampled to non-sampled points. The aim of this study therefore, was to determine the soil erodibility factor for an experimental basin in the semi-arid region of Brazil, in addition to generating the soil erodibility map using geostatistics. Disturbed and undisturbed soil samples were collected from 35 points, and laboratory samples were processed to determine the granulometry, permeability and organic matter of the soil, data which are used to determine the K-factor. Kriging was performed to spatialize the study variable, when spherical, exponential and Gaussian semivariograms were tested for generation of the soil erodibility map, these being evaluated by their respective deviations resulting from cross-validation. The mean value of K for the Haplic Luvisol was 0.0328 ton·ha·h/ha·MJ·mm;for the eutrophic Red-Yellow Argisol it was 0.0258 ton·ha·h/ha·MJ·mm;and for the Fluvic Neosol, it was 0.0424 ton·ha·h/ha·MJ·mm. The experimental basin is classified as highly erodible. The semivariogram that presented the best fit for generating the soil erodibility map of the study area was Gaussian.展开更多
文摘Sorghum has become ever more prominent on the global energy scene, with studies in the area becoming extremely important. Agricultural production in the semi-arid region of the Brazilian Northeast is intrinsically dependent on rainfall in the region. However, on both inter- and intra-annual scales, the rainfall regime is quite irregular. The aim of this study was to evaluate the productivity of sorghum grown under a rainfed regime, and the water-use efficiency of crops in the semi-arid region of the northeast of Brazil. The work was carried out in the city of Tabuleiro do Norte in the semi-arid region of the State of Ceará. Mean productivity of the sorghum was 919.42 kg·ha-1, with maximum values being recorded for lot 02 (1032 kg·ha-1), lot 03 (1102 kg·ha-1), lot 04 (2143 kg·ha-1) and lot 12 (1367 kg·ha-1). The greatest value for water-use efficiency, 1.13 m3·kg-1, was found for lot 04, while the smallest value, 4.83 m3·kg-1 was seen in lot 02. It was found that the low productivity of sorghum in a rainfed regime shows that the lack of success in production systems in semi-arid regions is not due to the total amount of rainfall, but rather the spatial and temporal distribution of the rains, as well as the occurrence of hot, dry spells. Furthermore, it can be seen that the best ratio of grain production to water demand shows a strong correlation with the distribution of water throughout the cycle, and not only with the total volume.
基金financial support and the Coordination for the Improvement of Higher Education Personnel(CAPES)Cearense Foundation of Scientific and Technological Support(FUNCAP)National Council for Scientific and Technological Development(CNPq).
文摘Erosion is the natural process which has the greatest environmental impact, and is the principal trigger for desertification around the globe. The main model used to estimate soil loss by erosion is the Universal Soil Loss Equation (USLE), which unites the major factors that influence erosion into one equation. The soil erodibility factor (K) is the component of this equation that represents soil physics, and is defined as the inherent capacity of the soil to withstand disintegration of its particles and their subsequent transport. The use of geostatistics is seen as an alternative in spatializing this variable from sampled to non-sampled points. The aim of this study therefore, was to determine the soil erodibility factor for an experimental basin in the semi-arid region of Brazil, in addition to generating the soil erodibility map using geostatistics. Disturbed and undisturbed soil samples were collected from 35 points, and laboratory samples were processed to determine the granulometry, permeability and organic matter of the soil, data which are used to determine the K-factor. Kriging was performed to spatialize the study variable, when spherical, exponential and Gaussian semivariograms were tested for generation of the soil erodibility map, these being evaluated by their respective deviations resulting from cross-validation. The mean value of K for the Haplic Luvisol was 0.0328 ton·ha·h/ha·MJ·mm;for the eutrophic Red-Yellow Argisol it was 0.0258 ton·ha·h/ha·MJ·mm;and for the Fluvic Neosol, it was 0.0424 ton·ha·h/ha·MJ·mm. The experimental basin is classified as highly erodible. The semivariogram that presented the best fit for generating the soil erodibility map of the study area was Gaussian.
