Management zones definition using soil chemical and physical attributes in a soybean area

Several equipments and methodologies have been developed to make available precision agriculture, especially considering the high cost of its implantation and sampling. An interesting possibility is to define management zones aim at dividing producing areas in smaller management zones that could be treated differently, serving as a source of recommendation and analysis. Thus, this trial used physical and chemical properties of soil and yield aiming at the generation of management zones in order to identify whether they can be used as recommendation and analysis. Management zones were generated by the Fuzzy C-Means algorithm and their evaluation was performed by calculating the reduction of variance and performing means tests. The division of the area into two management zones was considered appropriate for the present distinct averages of most soil properties and yield. The used methodology allowed the generation of management zones that can serve as source of recommendation and soil analysis; despite the relative efficiency has shown a reduced variance for all attributes in divisions in the three sub-regions, the ANOVA did not show significative differences among the management zones.

Management zones using fuzzy clustering based on spatial-temporal variability of soil and corn yield

Clustering soil and crop data can be used as a basis for the definition of management zones because the data are grouped into clusters based on the similar interaction of these variables. Therefore, the objective of this study was to identify management zones using fuzzy c-means clustering analysis based on the spatial and temporal variability of soil attributes and corn yield. The study site (18 by 250-m in size) was located in Jaboticabal, São Paulo/Brazil. Corn yield was measured in one hundred 4.5 by 10-m cells along four parallel transects (25 observations per transect) over five growing seasons between 2001 and 2010. Soil chemical and physical attributes were measured. SAS procedure MIXED was used to identify which variable(s) most influenced the spatial variability of corn yield over the five study years. Basis saturation (BS) was the variable that better related to corn yield, thus, semivariograms models were fitted for BS and corn yield and then, data values were krigged. Management Zone Analyst software was used to carry out the fuzzy c-means clustering algorithm. The optimum number of management zones can change over time, as well as the degree of agreement between the BS and corn yield management zone maps. Thus, it is very important take into account the temporal variability of crop yield and soil attributes to delineate management zones accurately.

Redundant variables and the quality of management zones

ABSTRACT Precision agriculture (PA) allows farmers to identify and address variations in an agriculture field. Management zones (MZs) make PA more feasible and economical. The most important method for defining MZs is a fuzzy C-means algorithm, but selecting the variable for use as the input layer in the fuzzy process is problematic. BAZZI et al. (2013) used Moran’s bivariate spatial autocorrelation statistic to identify variables that are spatially correlated with yield while employing spatial autocorrelation. BAZZI et al. (2013) proposed that all redundant variables be eliminated and that the remaining variables would be considered appropriate on the MZ generation process. Thus, the objective of this work, a study case, was to test the hypothesis that redundant variables can harm the MZ delineation process. BAZZI This work was conducted in a 19.6-ha commercial field, and 15 MZ designs were generated by a fuzzy C-means algorithm and divided into two to five classes. Each design used a different composition of variables, including copper, silt, clay, and altitude. Some combinations of these variables produced superior MZs. None of the variable combinations produced statistically better performance that the MZ generated with no redundant variables. Thus, the other redundant variables can be discredited. The design with all variables did not provide a greater separation and organization of data among MZ classes and was not recommended.

Propuesta didáctica juegos didácticos en el proceso enseñanza-aprendizaje de las matemáticas en el nivel medio superior [por] Asunción Reyes Hernández

Tesis (Maestría en la Enseñanza de las Ciencias con Especialidad en Matemáticas) U.A.N.L.

De testigo a la asunción del deseo: avatares del tratamiento psicoanalítico en una paciente testigo de Jehová.

Tesis (Maestría en Psicología con orientación en Clínica Psicoanalítica) UANL, 2014.

Relación de méritos del presbítero D. José Ignacio Yáñez y Pérez, bachiller en ambas facultades, cura propio y juez eclesiástico del pueblo de Santa María de la Asunción Tequisquiapan.

UANL

La hija de Nazareth : poema religioso dividido en diez y ocho cantos, desde la Concepción de María Santísima hasta su gloriosa Asunción, con la salutación del Ave María

UANL

Sermón en honra de la gloriosa asunción de María Satísima, predicado el 15 de agosto de 1866 en la Catedral de León

UANL

Sermón predicado en la Iglesia Parroquial de Sta. María de la Asunción de Aguascalientes

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Sumario de las indulgencias que disfruta la Asociación establecida en la Santa Iglesia Catedral Metropolitana de México en favor de las almas de los señores sacerdotes difuntos agregada a la archicofradía llamada De la Asunción de María Santísima en sufragio de las almas del Purgatorio.

UANL

Les variations du taux de change réel influencent-elles l'inégalité des revenus entre zones urbaines et rurales en Algérie?

Rapport de recherche

Capital humain et croissance du revenu - Une étude sur 56 zones métropolitaines aux États-Unis.

Rapport de recherche