Resumo

DE LA CASA, A et al. La cobertura del cultivo como indicador de la productividad de maíz en un lote con siembra variable. Agriscientia [online]. 2017, vol.34, n.1, pp.1-14. ISSN 1668-298X.

Yield variability within field can be monitored by various remote sensing technologies. The objective of this study was to determine the crop cover (CC) of corn (Zea mays L.) from NDVI data obtained from digital photographs, looking for productivity differences between sectors in an irrigated field of 45 ha located south of Córdoba city, Argentina, during 2013-2014. In this field six sampling sectors were set and digital photos were taken periodically in them with a modified camera to produce NDVI data. The CC estimation was conducted using different thresholds to NDVI values to discriminate between pixels with vegetation and soil. A different behavior of CC was observed in the six sectors whatever the threshold that was used, and these differences were more pronounced during the reproductive stage. The contrast of local NDVI values with those of AQUA-MODIS showed very consistent linear relationships and allowed to distinguish different productive sectors between the north and the south of the field. Soil water content accused significant differences (P<0.01) between the north and south sectors during R1 and R4 stages, which concurrent with the decrease in CC and the lower density of planting, could explain the lower production in the northern sectors of the field.

Palavras-chave : Precision agriculture; NDVI; Biomass; Soil water.

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