Soil erosion is a major environmental problem in many parts of the world and represents a serious problem for sustainable agriculture and the environment, with direct and indirect impacts on soil quality and fertility. This study aimed to use the Water Erosion Prediction Project (WEPP) model to estimate rill erosion and determine soil physical and hydraulic properties, which are essential to investigate its performance. To this end, an experiment was carried out in the Exu Creek watershed, in Serra Talhada, semi -arid region of Pernambuco State (Brazil), under increasing flow rates: T1: 5.87 L min-1; T2: 12.10 L min-1; T3: 20.33 L min1; and T4: 27.57 L min-1. Liquid and solid discharges were sampled for determination and characterization of hydraulic parameters in preformed rill flows. Reynolds numbers between 2,019 and 6,929 and Froude numbers below 1 found in this study attest to occurrence of erosive rills. Soil losses due to rill erosion increased as flow rates increased. Rill erodibility was 0.0011 kg N-1 s-1, and critical shear stress (tc) was 1.91 Pa, collapsing rill sidewalls and increasing local uplift, wet perimeter, and rill hydraulic radius.
Sorghum is a plant of tropical origin, of short days and with high photosynthetic rates, requiring a warm climate in order to express its production potential. The objective is to evaluate the agroclimatic aptitude of the cultivation of sorghum that allows to visualize or identify its productive potential in the state of Pernambuco. The pluviometric data were acquired from the Northeast Development Superintendence and the Pernambuco water and climate agency, the temperature data were from the National Institute of Meteorology and estimated by the estima_T software between the period 1960-2019. In the region of the high sertão and sertão there is moderate fitness due to excess water. In the agreste region full fitness was obtained with prolonged rainy season. In the Zona da Mata and Litoral regions, fitness is unrestricted. The study was carried out using information from the rainy season and without the aid of irrigation, that is, taking into account the rainfed planting.
Through sustainable agriculture it is possible to explore the coffee culture in consortium with native forests in more rugged reliefs, as coffee is a permanent crop in addition to the climatic conditions offered by the swamps that favor its development. Given the above, the present work proposes, based on the acidity results, to quantify the need for correctives in the soil to obtain a better nutritional use offered by agroforestry cultivation of organic coffee in the shade with favorable results to increase productivity and, consequently, the farmer's profit. The research was carried out at the Várzea da Onça farm, in the Yaguara Ecological Complex, located in the municipality of Taquaritinga do Norte, Borborema plateau, in the Agreste Pernambuco mesoregion. Altitude, it is necessary to adopt appropriate management techniques that guarantee production, soil conservation and biodiversity, proposing soil correction to guarantee the ideal nutritional conditions for coffee growth. For this purpose, soil samples were collected in the Top (T), Hillside (E) and Pedimento (P) ranges at depths of 0-20, 20-40 and 40-60 cm when planting shaded coffee and soil samples from Native Forest (MN) preserved and legally protected from the Brejo de Taquaritinga. Active, exchangeable and potential acidity were analyzed, as well as the sum of bases, the potential and effective cation exchange capacity, base saturation and aluminum saturation. The results obtained were subjected to analysis of variance and the means were tested at 5% by the Tukey test. A potential of the system was found with low to very low natural fertility, with a strongly acidic reaction. Thus, adequate soil management and correction techniques are necessary for the crop to absorb all the nutrients made available by the organic matter present on the surface, concluding that all slopes require liming, the slope of Hillside and Mata Nativa they also need plastering for the culture to develop properly.
Intense soil preparation and disturbance in crops, over time, reduces the quantity and quality of soil organic matter. Given this context, this work aimed to determine soil carbon stocks and labile fractions under agroforestry system (AFS) and toposequences in an altitude marsh, Taquaritinga do Norte, Pernambuco, Brazil. The study was carried out at the Yaguara farm, and the areas studied were native forest with 4.57 ha and coffee plantation in shade with native forest with 25.59 ha. Soil samples were collected in four trenches measuring 1.5 x 1.5 x 0.60 m, with a distance of 50 meters. Soils were collected at depths of 0–20, 20–40 and 40-60 cm, followed by chemical, physical and density analyzes to determine soil carbon stocks and labile fractions. The area with shaded coffee showed higher values of soil carbon stocks at depths of 0-20 cm and 20-40 cm. At a depth of 40-60 cm, the AFS top toposequence showed the highest carbon stock with 11.73 Mg ha-1, followed by the area with native vegetation with 10.6 Mg ha-1, slope with 9.23 Mg ha-1 and pediment with 7.00 Mg ha-1. It was found that the top toposequence with shaded coffee exhibited a greater stock of labile carbon at depth 0-20 cm with a value of 1.06 Mg ha-1, followed by the bedding areas (SAF) with 0.88 Mg ha-1, native forest with 0.79 Mg ha-1 and slope with 0.67 g kg-1. However, the area of native vegetation showed the highest value of labile carbon at a depth of 40-60 cm. It was concluded that the area with shaded coffee in the top toposequence showed great capacity to increase total carbon stocks and labile carbon stocks of soil organic matter.
Assessing technologies based on sediment yield in watersheds is increasingly important to determine the delivery rate. This work aimed to determine values of sediment delivery of the hydrographic basin of the river Jacu in the semiarid of Pernambuco and its relations with the soil and vegetation. Therefore, it was calculated the rates of interrill and rill erosion by yield testing under shrub and uncovered Inceptisols conditions, and it was carried out direct measurement campaigns of suspended sediment and bedload, by means of US DH -48 e US BLH -84, respectively. The sediment yield obtained in Jacu stream was considered low. The soil loss due to interril erosion under uncovered conditions equal to 8.43 t ha -1 was considered high, as well as the same way for the values of rill erosion with erodibility equal to 0.0021142 kg N -1 s -1 and critical shear stress equal to 2.34 Pa. The mean value of sediment delivery ratio of Jacu watershed was equal to 0.165 and ranged from 0.29 in the year 2008 to 0.026 in 2010. This variation is associated with the natural variability of semiarid environment, indicating the necessity of assessment in a large period of years to improve the knowledge about the sediment delivery ratio of Jacu semiarid watershed.
Dinâmica populacional de monotagma densiflorum (KOERN.) K. Schum. (CANTAN), familia Marantaceae em floresta manejada de terra firme na região de Moju-PA Population dynamics of monotagma densiflorum (KOERN.) K. Schum. (CANTAN), familia Marantaceae in forest managed from firm land in Moju-PA region
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