Decision Support Systems for Weed Management

Editors: Guillermo R. Chantre, José L. González-Andújar.Weed management Decision Support Systems (DSS) are increasingly important computer-based tools for modern agriculture. Nowadays, extensive agriculture has become highly dependent on external inputs and both economic costs, as well the negative environmental impact of agricultural activities, demands knowledge-based technology for the optimization and protection of non-renewable resources. In this context, weed management strategies should aim to maximize economic profit by preserving and enhancing agricultural systems. Although previous contributions focusing on weed biology and weed management provide valuable insight on many aspects of weed species ecology and practical guides for weed control, no attempts have been made to highlight the forthcoming importance of DSS in weed management. This book is a first attempt to integrate 'concepts and practice' providing a novel guide to the state-of-art of DSS and the future prospects which hopefully would be of interest to higher-level students, academics and professionals in related areas

Sorption, desorption and leaching potential of sulfonylurea herbicides in Argentinean soils

The sulfonylurea (SUs) herbicides are used to control broadleaf weeds and some grasses in a variety of crops. They have become popular because of their low application rates, low mammalian toxicity and an outstanding herbicidal activity. Sorption is a major process influencing the fate of pesticides in soil. The objective of this study was to characterize sorption–desorption of four sulfonylurea herbicides: metsulfuron-methyl (methyl 2-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)carbamoylsulfamoyl)] benzoate), sulfometuron-methyl (methyl 2-[(4,6-dimethylpyrimidin-2-yl)carbamoylsulfamoyl]benzoate), rimsulfuron (1-(4,6- dimethoxypyrimidin-2-yl)-3-(3-ethylsulfonyl-2-pyridylsulfonyl)urea) and nicosulfuron (2-[(4,6-dimethoxypyrimidin-2-yl) carbamoylsulfamoyl]-N,N-dimethylnicotinamide) from different soil horizons of different landscape positions. Sorption was studied in the laboratory by batch equilibration method. Sorption coefficients (Kd-SE) showed that rimsulfuron (Kd-SE D 1.18 to 2.08 L kg -1) and nicosulfuron (Kd-SE D 0.02 to 0.47 L kg -1) were more highly sorbed than metsulfuron-methyl (Kd-SE D 0.00 to 0.05 L kg -1) and sulfometuron-methyl (Kd-SE D 0.00 to 0.05 L kg -1). Sorption coefficients (Kd-SE) were correlated with pH and organic carbon content. All four herbicides exhibited desorption hysteresis where the desorption coefficients (Kd-D) > Kd-SE. To estimate the leaching potential, Koc and ground-water ubiquity score (GUS) were used to calculate the half-life (t1/2) required to be classified as “leacher” or “nonleacher”. According to the results, rimsulfuron and nicosulfuron herbicides would be classified as leachers, but factors such as landscape position, soil depth and the rate of decomposition in surface and subsurface soils could change the classification. In contrast, these factors do not affect classification of sulfometuron-methyl and metsulfuron-methyl; they would rank as leachers.Fil: Azcarate, Mariela Pamela. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Montoya, Jorgelina Ceferina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Koskinen, William C. Department of Agriculture. Agricultural Research Service. Soil and Water Management Research Unit; Estados Unido

Adsorption and transport of imazapyr through intact soil columns taken from two soils under two tillage systems

The objective of this work was to study the sorption and transport of imazapyr (IMZ) in two soils with different physical–chemical properties, subject to long-term conventional tillage (CT) and no-tillage (NT) systems. Sorption was carried out using batch equilibrium method and high performance liquid chromatography analytical routines. Displacement experiments through intact soil cores were done using IMZ as reactive solute and bromide (Br) as non-reactive solute. Equilibrium (CDEeq) and non-equilibrium (CDEnon-eq) transport models (CXTFIT 2.1) were employed to describe the breakthrough curves (BTCs). IMZ was only sorbed by NT soils with Kd values ranging from 0.22 to 1.1 L kg−1 . Clay content, pH and CEC values were the main factors affecting the sorption of IMZ. Miscible displacement studies showed that almost all the soil water was mobile and transport was related to physical equilibrium conditions. Some evidence of sorption non-equilibrium was seen in column experiments with IMZ; retardation factors were close to one, demonstrating the low sorption and the high potential to leach of this compound.Fil: Porfiri, Carolina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Montoya, Jorgelina Ceferina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; ArgentinaFil: Koskinen, William C. Department of Agriculture. Agricultural Research Service. Soil and Water Management Research Unit; Estados UnidosFil: Azcarate, Mariela Pamela. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; Argentin