Selection of Grids for Weed Mapping

Abstract

-This study aimed to assess the degree of similarity presented by thematic maps generated by different sampling grids of weed plants in a commercial agricultural area of 7.95 hectares. Monocotyledons and dicotyledons were counted on the 2012/2013 and 2013/2014 harvests, before soybean planting, in the fallow period after wheat harvest, in both years. A regular grid of 10 x 10 m was produced to sample the invasive plants, used as reference, and the counting was done in 1 m² of each sample point, totaling 795 samples in each year, compared to regular grids of 30 and 50 m, generated from the data exclusion of the standard grid. Twenty-two composite soil samples were taken at a depth of 0-20 cm to correlate soil properties with weeds occurrence. For the generation of the thematic maps, the Inverse Distance Weighting (IDW) for interpolation was used; when comparing the maps generated from each grid with the reference map, the kappa coefficient was used to assess the loss of quality of the maps as the number of sample points was reduced. It was observed that the map quality loss was lower in 2013 compared to 2012 when the sampling density of the points was reduced. The 30 x 30 m grids have satisfactorily described the infestation data of the dicotyledons and the 50 x 50 m grids have adequately described the monocotyledon weeds infestation, compared to the standard 10 x 10 m grids.Keywords: precision agriculture, sample grids, weeds. Palavras-chave: agricultura de precisão, grades amostrais, ervas daninhas.

Adoção Da Agricultura De Precisão Na América Do Sul: O Estado Da Arte Em Argentina, Brasil E Colômbia

“…O que segue é uma análise crítica do conteúdo da literatura com o intuito de qualificar a adoção de AP, a partir do entendimento das formas de medi-la, bem como dos desafios desse processo.Evidentemente, predomina a literatura sobre o Brasil, mas, como poderá ser observado adiante, muitos dos desafios são gerais para o uso da tecnologia.A adoção da AP potencialmente aumenta a produtividade e reduz o consumo de insumos, com consequente impacto ambiental positivo. Esse potencial é constantemente reafirmado para diversas culturas e tecnologias utilizadas (DEMATTÊ, 2014), como a calagem do solo a taxa variável(BOTTEGA et al, 2014), o controle de pragas(CAMICIA et al, 2015). Há também estudo estatístico que mostra o potencial de aumento de produtividade e a redução da quantidade de fertilizantes com a adoção de AP na produção de soja em Brasil, Argentina, EUA e continente africano, com ganhos expressivos em todos os casos.…”