Chapters authored
Water Productivity Modeling by Remote Sensing in the Semiarid Region of Minas Gerais State, Brazil
This chapter aimed to demonstrate the potential of monitoring water and vegetation parameters by combining weather and satellite measurements in mixed agroecosystems in the semiarid region of the northern Minas Gerais state, Southeast Brazil. Soil moisture indices and water productivity components were quantified with Landsat 8 images under different hydrological conditions along the year 2015. The surface resistance to the water fluxes (rs) performed better than the ratio of actual to the reference evapotranspiration (ETr) to detect soil moisture conditions. The mean pixel values for actual evapotranspiration (ET), biomass production (BIO), and water productivity based on evapotranspiration (WP), for irrigated crops (IC), ranged respectively from 2.5 ± 1.3 to 4.1 ± 1.6 mm d−1; 78 ± 62 to 132 ± 64 kg ha−1 d−1; and from 2.2 ± 0.8 to 3.3 ± 0.9 kg m−3. The corresponding ranges for natural vegetation (NV) were 0.1 ± 0.2 to 1.9 ± 1.3 mm d−1; 1 ± 1 to 44 ± 42 kg ha−1 d−1, and 0.6 ± 0.3 to 1.8 ± 0.8 kg m−3. The incremental values, resulting from the replacement of natural species by agricultural crops, were respectively 2.7 mm d−1 and 83 kg ha d−1. However, this replacement increased water productivity based on evapotranspiration (WP) by 264% during the studied year, what should be considered in land use and climate change studies in the Brazilian semiarid region.
Part of the book: Arid Environments and Sustainability
The Use of MODIS Images to Quantify the Energy Balance in Different Agroecosystems in Brazil
Sugarcane (SC) is expanding over coffee (CO), while both crops have replaced the natural vegetation (NV) in the northeastern side of São Paulo (SP) state, Southeast Brazil. Under these dynamic land-use changes, geosciences are valuable tools for evaluating the large-scale energy and mass exchanges between the vegetation and the lower atmosphere. For quantification of the energy balance components in these mixed agroecosystems, MODIS images were used throughout the Simple Algorithm for Evapotranspiration Retrieving (SAFER) algorithm, during the year 2015 in the main sugarcane- and coffee-growing regions of the state. Regarding, respectively, sugarcane, coffee, and natural vegetation, the fractions of the net radiation (Rn) used as latent heat flux (λE) were 0.68, 0.87, and 0.77, while the corresponding ones for the sensible heat (H) fluxes were 0.27, 0.07, and 0.16. Negative H values were noticed from April to July, because of heat advection raising λE values above Rn, but they were more often in coffee than in sugarcane. It was concluded that sugarcane crop presented lower evapotranspiration rates, when compared with coffee, which could be an advantage under the actual water scarcity scenario. However, sugarcane replacing natural vegetation means environmental warming, while the land use changes promoted by coffee crop represented cooling conditions.
Part of the book: Multi-purposeful Application of Geospatial Data
Water Balance Indices for Tropical Wine Grapes
Over the last few decades, the Brazilian semiarid region has appeared as one of the main tropical wine production areas in the country. The aim of this research was the elaboration and application of water balance indices to upscale them in the wine grape growing regions of the Petrolina and Juazeiro counties in the states of Pernambuco (PE) and Bahia (BA), respectively, simulating different pruning dates along the year. Previous energy balance measurements were used for relating the crop coefficient (Kc) with the accumulated degree-days (DDac). The model was applied to upscale the water balance indices during the growing seasons (GS). It was concluded that if irrigation water is available, the best pruning periods are for GS from May to July because of better natural thermal and moisture conditions. Much care should be taken for pruning done in other periods of the year, with regard to the effect of increasing thermal conditions on wine quality. The classifications and delimitations done, joined with other environmental characteristics, are important for a rational planning of the commercial tropical wine production expansion, mainly in the actual situations of climate and land use changes together with rising water competition along the years in the Brazilian semiarid region.
Part of the book: Grapes and Wines