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The addition of organic and inorganic amendments can improve soil structure and reduce soil compaction. In this context, this study aimed to evaluate whether the application of amendments reduces penetration resistance (PR) in the short term and describe the spatial variability of PR in the surface horizon of an Aquic Argiudoll under no-tillage in northeast Argentina. Four treatments, consisting of surface applications of 7.5 Mg ha-1 poultry litter (PL), 3.0 Mg ha-1 gypsum (G), the combination of PL+G, and untreated control (T), were arranged in a complete randomized block design with three replications. Two more treatments were added to the experiment 12 months later, consisting of PL reapplications on half of the surface of the PL+G and PL treatments (PL+G+PL and PL+PL, respectively) in a split-plot design with three replications in 4×20-m plots. PR was determined in the field with an Eijkelkamp penetrologger following a 2-m long transect perpendicular to the sowing direction at 10 different spots separated 0.2 m from each other. The spatial variability was quantified for each treatment using semivariograms. The highest PR was observed in the T treatment (1.96 MPa) and the lowest PR in PL+G+PL (0.21 MPa). All treatments showed a high spatial dependence (94.9 to 99.9%). Treatments with PL reapplication (PL+PL and PL+G+PL) showed profiles with lower PR and more homogeneous kriging maps. PL reapplication on PL treatments showed no effects on PR values. However, PL reapplication on the PL+G treatment led to positive effects in all PR ranges. Thus, the PL+G+PL treatment, which had the highest PR values, showed a decrease in PR from 54.17 to 6.65% with the reapplication 12 months later. The addition of organic and inorganic amendments reduced specific compacted soil areas on the surface horizon of an Aquic Argiudoll under no-tillage. [ABSTRACT FROM AUTHOR]

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Pasture recovery by the re-composition of soil fertility has low operational costs, although studies are required to compare it to application systems at variable rates within planning and development of a region. Research evaluates economically the recovery of soil fertility of a degraded pasture in two production systems: the conventional system (CS) and precision agriculture (PA), by simulation, with estimate of costs and respective rentability coupled to recovery practices in Selvíria MS Brazil. A bioeconomic simulation was employed and costs were classified according to the methodology of the Institute of Agricultural Economy of São Paulo. CS and PA recovery showed 5.41% and 6.42% gain respectively, with cost price @-1 of R$205.96 and R$203.54 for CS and PA, respectively. Due to valorization of @ during the last year, both systems revealed a feasible economic return according to the estimates given. When regions cultivated with PA and CS are compared, probably more reliable results are obtained coupled to better perspectives in larger areas. [ABSTRACT FROM AUTHOR]

The objective of this study was to generate information through the analysis of variability and given structure of spatial dependence as well as the linear correlation of physical and chemical attributes of the soil, in order to assist in the planning of agricultural activities in six cities in the province of El Oro, Ecuador. The soil sample collections were carried out every two kilometers in the form of a grid with small changes in the field with a Dutch-type auger and GPS for georeferencing, with a depth of 0-0.20 m, thus totaling 368 points in the sample grid. Chemical and physical attributes of six municipalities in the province of El Oro were evaluated: Huaquillas, Machala, Chilla, Atahualpa, Portovelo and Las Lajas. The sampling was carried out in each city, but not between them. Distances between cities were 20,000 km to 180,000 km. Each soil attribute was subjected to an initial descriptive analysis, geostatistics and simple linear correlation matrix. Only pH and sand showed a high variation coefficient (22.02% and 25.42%) and all other attributes showed very high variation. Most of the semivariograms were adjusted to the spherical model. The longest range was indicated by magnesium (41,500 m) and the shortest by copper (7,740 m). The Mg pair versus sum of bases was the highest linear correlation among all the analyzed attributes. The pH stood out with a greater linear correlation between the other chemical attributes of the soil and its specific management zones. In view of the great taxonomic variation of the soil, climatic types, cultures used and management adopted, a specific analysis in each city is recommended for better agricultural recommendations. [ABSTRACT FROM AUTHOR]

The adoption of the cattle feedlot system allows greater control of costs, however, the survey of spending must be well planned. This study aimed to analyze and evaluate the economic feasibility of producing a feedlot beef cattle in Auriflama/SP. Input costs have integrated 85.14%, however obtained profitability index 68.55% and positive net present value from the 4th year. Considering the analysis studied the livestock had to be a profitable and viable activity. [ABSTRACT FROM AUTHOR]