Weed Biology and Control Edited by Vytautas Pilipavičius Weed Biology and Control Edited by Vytautas Pilipavičius D3pZ4i & bhgvld, Den(cid:58)(cid:72)(cid:72)(cid:71)(cid:3)(cid:37)(cid:76)(cid:82)(cid:79)(cid:82)(cid:74)(cid:92)(cid:3)(cid:68)(cid:81)(cid:71)(cid:3)(cid:38)(cid:82)(cid:81)(cid:87)(cid:85)(cid:82)(cid:79)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:40)(cid:71)(cid:76)(cid:87)(cid:72)(cid:71)(cid:3)(cid:69)(cid:92)(cid:3)(cid:57)(cid:92)(cid:87)(cid:68)(cid:88)(cid:87)(cid:68)(cid:86)(cid:3)(cid:51)(cid:76)(cid:79)(cid:76)(cid:83)(cid:68)(cid:89)(cid:76)(cid:254)(cid:76)(cid:88)(cid:86)ixxx & rosea (for softarchive) Stole src from http://avaxho.me/blogs/exLib/ Published by AvE4EvA Copyright © 2015 All chapters are Open Access distributed under the Creative Commons Attribution 3.0 license, which allows users to download, copy and build upon published articles even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. 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Publishing Process Manager Technical Editor AvE4EvA MuViMix Records Cover Designer Published: 11 June, 2015 ISBN-10 953-51-2131-6 ISBN-13 978-953-51-2131-2 C ontents Preface Chapter 1 The Role of Weed and Cover Crops on Soil and Water Conservation in a Tropical Region by Cezar Francisco Araujo-Junior, Bruno Henrique Martins, Vinicius Y ugi Higashi and Carlos Alberto Hamanaka Chapter 2 Weed Control by C hemical and Mechanical Means by Algirdas Jasinskas, Dainius Steponavičius, Povilas Šniauka and Remigijus Zinkevičius Chapter 3 Weed Control by Organic Mulch in Organic Farming System by Rita Pup alienė, Aušra Sinkevičienė, Darija Jodaugienė and Kristina Bajorienė Chapter 4 Weed Control by Soil Tillage and Living Mulch by Kęstutis Romaneckas, Egidijus Šarauskis, Dovilė Avižienytė and Aida Adamavičienė Chapter 5 Current and Potential Use of Phytophagous Mites as Biological Control Agent of Weeds by Carlos Vásquez, Yelitza Colmenárez, José Morales-Sánchez, Neicy Valera, María F. Sandoval and Diego Balza Preface This book is a collection of chapters, concerning the developments within the Weed Biology and Control field of study. The book includes scholarly contributions by various authors pertinent to Agricultural and Biological Sciences. Each contribution comes as a separate chapter complete in itself but directly related to the book's topics and objectives. 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 1. 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 45 % to 95 % depending on the crop, ecological and climatic conditions [1]. 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 [2]. 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 [2]. Herbicides and tillage are the dominant practices in many production systems due to efficiency and facilities for weed control [3]. 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 [4-7] and soil compaction, which affect soil quality [8-11]. Weed management and cover crops also affects micropedological [6], biological [12-13], chemical soil properties [12, 14-17]. 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 [1]. It is known that, weed control and cover crops management has several impact on soil properties and effects soil and water conservation due changes on soil structure in the row and interrow crop. The alternative weed control in a newly developed orchard through three years with mowing in Spring, Summer and Fall and tillage in winter improved soil biological and fertility properties compared to conventional weed control methods (chemical and tillage control) [12]. The authors observed that this alternative weed control method improved microbial biomass carbon, phosphorus-solubilizing microbial activity, mycorrhizal fungal spores numbers and soil organic matter. At Analândia, State of São Paulo, Brazil in a coffee plantation, the constant use of the mechan‐ ical mower between coffee rows caused reduction in the coffee plants yield due to weed infestation. However, at Autumn / Winter seasons, when weed management is performed by herbicide applications, such effect is not observed. [5]. Soil compaction is the main ongoing degradation process and concerns in mechanical weed control. Soils under weed control with rotary shredder may experience detrimental effects, such as increased soil strength, measured by a portable recording penetrometer [8], and soil load bearing capacity [18]. Integrated weed management systems and cover crops used as a green manure can be useful in Tropical region, since it may protect soil against degradation processes, such as compaction and erosion. The integrated weed management systems consists in selection and use of the different weed control based on cost-benefit analysis, taking into account the benefits to the production system and the environment as important strategies in Conservation Agriculture. Conservation Agriculture (CA) involves three basic practices: (i) significant reduction of soil tillage and disturbance, (ii) permanent, or at least semi-permanent, soil protection by using crop residues or selected cover crops, and (iii) diversification of crop rotations and intercropping [19]. CA practices often enhance and utilize soil and crop microenviron‐ ments to inhibit germination, growth, and spread of weeds while minimizing the use of synthetic herbicides. Examples of conservation tillage that may fit into a weed manage‐ ment control/suppression program include reduced tillage, cover crops, crop rotation, variable row spacing, and timing of crop planting [20]. Cover crops and cropping residues used in Conservation Agriculture systems serve as a protection for the soil surface against weather aggressions and water erosion, to maintain soil moisture, to suppress weed growth and to provide shelter and food for the soil biota [21]. Also, under Conservation Agriculture regime, the use of crop rotations or intercropping is consid‐ ered essential, as it offers an option for pest/ weed management that is no longer realized through soil tillage [22].