Weed Biology And Control

Chapter 1 The Role of Weed and Cover Crops on Soil and Water Conservation in a Tropical Region Cezar Francisco Araujo-Junior, Bruno Henrique Martins, Vinicius Yugi Higashi and Carlos Alberto Hamanaka Additional information is available at the end of the chapter http://dx.doi.org/10.5772/59952 . Introduction Weed control is one of the most intensive management practices in different production systems in tropical regions and can influence both agricultural productivity and impact the environment. Despite the importance of this issue, studies reporting the action of different methods of weed control on soil physical properties and their effects on the management and conservation of soil and water are scarce, requiring a greater understanding of the adequacy of management systems. Weeds are considered one of the major constraints in crop production and may substantially reduce yields when not controlled properly. Potential yield reductions caused by uncontrolled weeds are estimated at % to % depending on the crop, ecological and climatic conditions [ ]. A key to effectiveness weed management is a holistic approach regarding the scenario considered and must include a combination of tactics and practices in order to successfully and economically reduce the potentially negative impacts inherent to weeds incidence [ ]. There are numerous methods of mechanical control of weeds including mowing, cultivation, hoeing, flaming, mulching, and hand weeding. Chemical control of weeds mainly consists of using pre and post-emergence herbicides and soil fumigants [ ]. Herbicides and tillage are the dominant practices in many production systems due to efficiency and facilities for weed control [ ]. However, these methods may be inadequate for weed control in tropical conditions and may have negative impacts on soil and to the environment most of these impacts are related to hydric erosion [ - ] and soil compaction, which affect soil quality [ - ]. Weed management and cover crops also affects micropedological [ ], biological [ - ], chemical soil properties [ , - ]. © 2015 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited. 2 Weed Biology and Control Given the complexity and limitations inherent to each of these methods, integrated weed management systems is an alternative to traditional methods and can be useful for soil and water conservation in Tropical conditions. One of the goals of the integrated weed manage‐ ment systems is to develop methods that provide better use of resources. In addition, to optimize crop production and growth yield through the concerted use of preventive tactics, scientific knowledge, management skills, monitoring procedures, and efficient use of control practices [ ]. It is known that, wee