Author details

Ozoemena Ani<sup>1</sup> \*, Ogbonnaya Onu<sup>1</sup> , Gideon Okoro<sup>1</sup> and Michael Uguru<sup>2</sup>

\*Address all correspondence to: ozoemena.ani@unn.edu.ng

1 Department of Agricultural and Bioresources Engineering, University of Nigeria, Nsukka, Enugu State, Nigeria

2 Department of Crop Science, University of Nigeria, Nsukka, Enugu State, Nigeria

## References


[7] Webb M, Conroy C. The Socio-economics of weed control on smallholder farms in Uganda. Brighton Crop Protection Conference Weeds: Brit Crop Protection Council; 1995. pp. 157-162

iii. Some weed species have developed resistance to some chemical herbicides and biological

iv. Classical method of biological weed control has been the most popular and widely adopted and practiced; it involves the introduction and release of agents in form of exotic

v. Inundative method of biological weed control involves the releases of predators, use of bioherbicides and other integrated pest management which usually are not as widely

vi. Biological weed control is presently widely adopted in the USA, Canada, Australia, South

vii. The biological approach to weed control holds great prospects for sustainable, environmentally friendly and economically viable control of exotic weeds and should be

1 Department of Agricultural and Bioresources Engineering, University of Nigeria, Nsukka,

[1] Culliney TW. Benefits of classical biological control for managing invasive plants. Critical

[2] Gerber E, Schaffner U, Gassmann A, Hinz H, Seier M, Müller-Schärer H. Prospects for biological control of Ambrosia artemisiifolia in Europe: Learning from the past. Weed

[3] Carruthers RI. Biological control of invasive species, a personal perspective. Conservation

[5] McFadyen REC. Biological control of weeds. Annual Review of Entomology. 1998;43:369-393 [6] Louda SM, Masters RA. Biological control of weeds in Great Plains rangelands. Great

[4] Cai X, Gu M. Bioherbicides in organic horticulture. Horticulturae. 2016;2:3

2 Department of Crop Science, University of Nigeria, Nsukka, Enugu State, Nigeria

, Gideon Okoro<sup>1</sup> and Michael Uguru<sup>2</sup>

explored further through research, development and legislation.

control readily comes as a viable alternative

\*, Ogbonnaya Onu<sup>1</sup>

Reviews in Plant Sciences. 2005;24:131-150

Research. 2011;51:559-573

Plains Research. 1993:215-247

Biology. 2004;18:54-57

\*Address all correspondence to: ozoemena.ani@unn.edu.ng

used as the classical method.

Africa and New Zealand.

12 Biological Approaches for Controlling Weeds

Author details

Ozoemena Ani<sup>1</sup>

Enugu State, Nigeria

References

insects, mites or pathogens to give permanent control


[22] Clewley GD, Eschen R, Shaw RH, Wright DJ. The effectiveness of classical biological control of invasive plants. Journal of Applied Ecology. 2012;49:1287-1295

[39] Duke SO. Weed science directions in the USA: What has been achieved and where the

Overview of Biological Methods of Weed Control http://dx.doi.org/10.5772/intechopen.76219 15

[40] Reznik SY. Classical biocontrol of weeds in crop rotation: A story of failure and prospects for success. In: Proceedings of the IX International Symposium on Biological Control of

[41] Chippendale JF. The biological control of Noogoora burr (Xanthium occidentale) in Queensland: An economic perspective. In: Proceedings of the VIII International Symposium on

[42] Marsden JS, Martin GE, Parham DJ, Risdill-Smith TJ, Johnston BG. Skeleton Weed Control. Returns on Australian Agricultural Research. Canberra: CSIRO Division of Entomol-

[43] Pemberton RW. Predictable risk to native plants in weed biological control. Oecologia.

[44] Suckling DM. Benefits from biological control of weeds in New Zealand range from negligible to massive: A retrospective analysis. Biological Control. 2013;66:27-32

[45] Sheppard AW, Hill R, DeClerck-Floate RA, McClay A, Olckers T, Quimby PC, et al. A global review of riskbenefit-cost analysis for the introduction of classical biological control agents against weeds: A crisis in the making? Biocontrol News Info. 2003;24:91-108

[46] Funasaki GY, Lai P-Y, Nakahara LM, Beardsley JW, Ota AK. A review of biological control introductions in Hawaii: 1890 to 1985. In: Proceedings of the Hawaiian Entomological

[47] Paynter Q, Fowler SV, Hayes L, Hill RL. Factors affecting the cost of weed biocontrol

[48] Morris M, Wood A, Den Breeÿen A. Plant pathogens and biological control of weeds in South Africa: A review of projects and progress during the last decade. African Entomol-

[49] Vurro M, Evans H. Opportunities and constraints for the biological control of weeds in Europe. In: Proceedings of the XII International Symposium Biological Control Weeds;

[50] Olckers T. Targeting emerging weeds for biological control in South Africa: The benefits of halting the spread of alien plants at an early stage of their invasion: Working for water.

[51] Moran V, Hoffmann J. The fourteen international symposia on biological control of weeds, 1969–2014: Delegates, demographics and inferences from the debate on non-target effects.

[52] Winston RL, Schwarzländer M, Hinz HL, Day MD, Cock MJW, Julien MH. Biological Control of Weeds: A World Catalogue of Agents and their Target Weeds. 5th ed. Morgan-

town, West Virginia: Forest Health Technology Enterprise Team; 2014

programs in New Zealand. Biological Control. 2015;80:119-127

Wallingford: CAB International; 2008. pp. 455-462

South African Journal of Science. 2004;100:64-68

Biological Control of Weeds; Melbourne, Australia: DSIR/CSIRO; 1995. pp. 185-192

Weeds: University of Capetown Rondebosch, South Africa; 1996. p. 503-506

USA is going. Plant Protection Quarterly. 1997;12:2-6

ogy; 1980. pp. 84-93

2000;125:489-494

Society. 1988;28:105-160

ogy Memoir. 1999;1:129-137

Biological Control. 2015;87:23-31


[39] Duke SO. Weed science directions in the USA: What has been achieved and where the USA is going. Plant Protection Quarterly. 1997;12:2-6

[22] Clewley GD, Eschen R, Shaw RH, Wright DJ. The effectiveness of classical biological

[23] Keane RM, Crawley MJ. Exotic plant invasions and the enemy release hypothesis. Trends

[24] McEvoy PB. Insect-plant interactions on a planet of weeds. Entomologia Experimentalis et

[25] Hoddle MS. Restoring balance: Using exotic species to control invasive exotic species.

[26] McEvoy P, Cox C, Coombs E. Successful biological control of ragwort, Senecio jacobaea,

[27] Hierro JL, Callaway RM. Allelopathy and exotic plant invasion. Plant and Soil. 2003;256:29-39

[28] Zedler JB, Kercher S. Causes and consequences of invasive plants in wetlands: Opportunities, opportunists, and outcomes. Critical Reviews in Plant Sciences. 2004;23:431-452

[29] Harper DB. Fungal degradation of aromatic nitriles. Enzymology of CN cleavage by

[30] Goeden RD. Biological control of weeds. Introduced Parasites and Predators of Arthropods Pests and Weeds: A World Review. USDA Agriculture Handbook. 1978. pp.

[31] Harley KLS, Forno IW. Biological Control of Weeds: A Handbook for Practitioners and

[32] Andres LA, Davis CJ, Harris P, Wapshere AJ. Biological Control of Weeds 1976. pp. 481-499

[33] Batra SW. Insects and fungi associated with Carduus thistles (Compositae): The adminis-

[34] Wapshere AJ, Delfosse ES, Cullen JM. Recent Developments in Biological Control of

[35] McFadyen REC. Successes in biological control of weeds. In: Spencer NR, editor. Proceedings of the X International Symposium on Biological Control of Weeds; Montana State

[36] Chaboudez P, Sheppard AW. Are particular weeds more amenable to biological control? A reanalysis of mode of reproduction and life history. In: Proceedings of the Eighth

[37] Dennill G, Donnelly D. Biological control of Acacia longifolia and related weed species (Fabaceae) in South Africa. Agriculture, Ecosystems & Environment. Melbourne and

[38] Mack RN. Predicting the identity and fate of plant invaders: Emergent and emerging

Weeds. Canberra, ACT, Australia: CSIRO Division of Entomology; 1989. p. 8

control of invasive plants. Journal of Applied Ecology. 2012;49:1287-1295

by introduced insects in Oregon. Ecological Applications. 1991;1:430-442

Fusarium solani. Biochemical Journal. 1977;167:685-692

University, Bozeman, Montana, USA. 2000. pp. 3-14

approaches. Biological Conservation. 1996;78:107-121

Sidney: Inkata Press; 1991;37:115-135

International Symposium on Biological Control. 1995. pp. 95-102

in Ecology & Evolution. 2002;17:164-170

Conservation Biology. 2004;18:38-49

Applicata. 2002;104:165-179

14 Biological Approaches for Controlling Weeds

Students. Inkata Press; 1992

357-14

tration; 1981


[53] Nowierski RM. Some basic aspects of biological weed control1. Great Plains Agricultural Council Leafy Spurge. 1984. pp. 23-26

**Chapter 3**

**Provisional chapter**

**The Effect of Tillage on the Weed Control: An Adaptive**

The tillage systems and performance of the operations have an important impact on the weed control. The primary goal for the tillage is to establish the best possible conditions for the crop establishment and growth under the given conditions as soil texture, moisture and so on. In addition, the tillage system also strongly influences the weed pressure and conditions for weed control. As tillage requires a substantial amount of fuel, and

the tillage operations due to the local conditions in the field. A big challenge is how to sense the local conditions and information that are needed to optimize the tillage system for local treatment and intensity. This chapter focuses on how to optimize the tillage operations in a local adaptive approach aiming at the best possible weed control.

This chapter describes how the tillage operations contribute to the weed control. It is important to understand that the weed pressure, both perennials and annual germinating species, depends on the common conditions controlled by the cropping system, involving the crop rotation, the soil fertility, nutrient strategy, tillage, and direct control methods as weed harrowing and hoeing. The different actions that contribute to weed control can be considered like filters that favor some plant traits and filter out others. The challenge then is to design the growing system like a system of filters such that all weed species are controlled such that they do not grow unrestrained [1, 2]. By all means, diversity is important in the growing system. As a part of this, it is important that the crop rotation includes different crops, seeded in both

from the soil, there is a big motivation in optimizing

**The Effect of Tillage on the Weed Control: An Adaptive** 

© 2016 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 reproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. 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 reproduction in any medium, provided the original work is properly cited.

DOI: 10.5772/intechopen.76704

**Approach**

**Approach**

Martin Heide Jorgensen

Martin Heide Jorgensen

**Abstract**

**1. Introduction**

Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.76704

affects the leak of nitrogen and CO<sup>2</sup>

**Keywords:** tillage, weed control, adaptive, soil fertility


#### **The Effect of Tillage on the Weed Control: An Adaptive Approach The Effect of Tillage on the Weed Control: An Adaptive Approach**

DOI: 10.5772/intechopen.76704

Martin Heide Jorgensen Martin Heide Jorgensen

[53] Nowierski RM. Some basic aspects of biological weed control1. Great Plains Agricultural

[54] Palmer W, Heard T, Sheppard A. A review of Australian classical biological control of weeds programs and research activities over the past 12 years. Biological Control. 2010;52:

[55] Morin L, Reid AM, Sims-Chilton N, Buckley Y, Dhileepan K, Hastwell GT, et al. Review of approaches to evaluate the effectiveness of weed biological control agents. Biological Con-

[56] Hoffmann J. Biological Control ofWeeds: TheWay Forward, a South African Perspective. 1995 [57] Cullen JM. Predicting Effectiveness: Fact and Fantasy. In: Delfosse ES, Scott RR, editors. Proc. 8th. Int Symp Biol Control Weeds. Melbourne: CSIRO; 1995. pp. 103-109

[58] Gassmann A. Classical biological control of weeds with insects: A case for emphasizing agent demography. In: Proceedings of the IX International Symposium on Biological Control of Weeds: University of Cape Town Rondebosch, South Africa; 1996. pp. 171-175 [59] TIA. Biological control of weeds. Agricultural Research Information Bulletin. Weed Bio-

logical Control Pamphlet. Tasmanian Institute of Agriculture TIA; 2008

Council Leafy Spurge. 1984. pp. 23-26

271-287

trol. 2009;51:1-15

16 Biological Approaches for Controlling Weeds

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.76704

#### **Abstract**

The tillage systems and performance of the operations have an important impact on the weed control. The primary goal for the tillage is to establish the best possible conditions for the crop establishment and growth under the given conditions as soil texture, moisture and so on. In addition, the tillage system also strongly influences the weed pressure and conditions for weed control. As tillage requires a substantial amount of fuel, and affects the leak of nitrogen and CO<sup>2</sup> from the soil, there is a big motivation in optimizing the tillage operations due to the local conditions in the field. A big challenge is how to sense the local conditions and information that are needed to optimize the tillage system for local treatment and intensity. This chapter focuses on how to optimize the tillage operations in a local adaptive approach aiming at the best possible weed control.

**Keywords:** tillage, weed control, adaptive, soil fertility

#### **1. Introduction**

This chapter describes how the tillage operations contribute to the weed control. It is important to understand that the weed pressure, both perennials and annual germinating species, depends on the common conditions controlled by the cropping system, involving the crop rotation, the soil fertility, nutrient strategy, tillage, and direct control methods as weed harrowing and hoeing. The different actions that contribute to weed control can be considered like filters that favor some plant traits and filter out others. The challenge then is to design the growing system like a system of filters such that all weed species are controlled such that they do not grow unrestrained [1, 2]. By all means, diversity is important in the growing system. As a part of this, it is important that the crop rotation includes different crops, seeded in both

© 2016 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 reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. 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 reproduction in any medium, provided the original work is properly cited.

spring and autumn. It is important to have in mind that fast-germinating and established crops are highly competitive and contribute substantially to weed control [3]. Another specific element is the benefit of cutting perennial forage grass in the rotation three times or more per year to control quack grass and other root-emerging weeds. With respect to the direct control methods, it is important that the crop rotation allows for space to perform dedicated quack grass control after harvest. The presence of row crops allows one to perform the control by hoeing during the growing season. This potentially gives a good weed control but can also cause substantial problems if the operation fails.

capacity of the upper soil layer is controlled by the microbes and the content of organic matter. This is maintained by the incorporation of fresh organic matter with smooth tillage operations. At the same time, at stable conditions, the planning and performance of the primary tillage must ensure that no increase in the occurrence of the root-emerging weeds occurs. To control root-emerging weeds, the plant must be covered in the soil layer the deeper the better. Normally a depth of approx. 20 cm is recommended. This conflicts with the preferred conditions for the turnover of plant residuals and is supported by the presence of a smooth mix into the soil having access to the oxygen from the air and soil moisture getting into contact with the soil fungal and fauna that catalyze the process. Jacobs et al. [8] test has shown that the best conditions for the turnover of plant residuals are placements in the upper soil layer—0–5 cm. In practical the working depth of approx. 20 cm for the primary tillage is used. The experience is that this gives a good balanced result, just that the operator must be aware, that the working depth must be as shallow as possible. Deeper working depth increases the effect due to weed control but reduces the access to oxygen. Tillage operations may not be overdone in intensity as the operations are highly energy consuming. Also, that the tillage is not only positive. Unnecessary tillage damages the soil structure, this both due to the workability in the seed bed preparation, and the porosity. The challenge for the tillage operations is to support

The Effect of Tillage on the Weed Control: An Adaptive Approach

http://dx.doi.org/10.5772/intechopen.76704

19

If it occurs from the monitoring of the fields, that it is necessary to apply a dedicated treatment to reduce the occurrence of root emerging weeds this can be done in more ways. One obvious method is to increase the working depth for the primary tillage operation, and to make sure, that all the residuals are effectively covered deeply under the soil layer. Another more dedicated method is to make space in the crop rotation; this allows for a series of operations in the period after harvest. Here there are in principal two different methods: "drying" and "starving". Convenient conditions allow additionally to cultivate just prior to a period with

In Scandinavian countries, as in many other countries, the primary implements used for the primary tillage has been the moldboard plow and the stubble cultivator. Often, the stubble cultivator is used for a shallow operation immediately after harvest to stop the growth and cut the roots of weed plants and to catalyze the contact from the microbiological life to the residues. Hereafter, the strategy is different and highly dependent on the crop rotation and local conditions. If there is a need for a dedicated treatment to reduce the occurrence of perennial weeds, it is generally after harvest that a series of repeated stubble cultivations can be performed [4]. Danish tests show that repeated stubble cultivations in the autumn can reduce the density of perennial weeds up to 90%. Similar results can be seen in a test in Norway and Germany [9, 10]. Under wet conditions in Norway, it has been observed that the best results are obtained by applying the treatment in spring prior to moldboard plowing and seeding. By this method, the time for seeding becomes too late and too costly in yield reduction. In the autumn, as the temperatures are getting lower, the plowing operation is performed. Here, the growth is stopped, and the turnover of the residuals are continued, now integrated into

the dynamics of the growing system, not the operation itself.

temperatures below 0°C.

**2.1. The type of operation**

the soil and sowed in some depth.

The tillage operations are, in general, divided to be part of the primary tillage or the preparation of the seedbed. The primary tillage is aimed to obtain a good turnover of the plant residuals and to maintain a healthy soil structure. In this multi-oriented context, the demands for the tillage operations can be different if it is related to optimizing the soil fertility or the weed control. An example here is the performance of the moldboard plowing. Aiming for an effective control of perennial weeds demands that the plants are cowered deep in the soil or that they are dried out in a starvation strategy. Whereas the requirements related to the soil fertility can with good conditions be fulfilled by more superficial treatments. In fact, an unnecessary intensive tillage strategy will cause harm to the soil fertility [4, 5]. Therefore, in the operative planning, it is very important to be aware of the actual field conditions for the specific year, and thereby also the infield variations.

The performance of the operations for seedbed preparation and seeding also affect the weed germination and the weed control. The goal of this operation is to do the final leveling of the soil surface and to establish the right structure for the soil aggregates to form the best possible conditions for the seeds to germinate and establish growth. If the time schedule allows, it can be beneficial to perform a weed harrowing prior to the seeding to reduce the density of the first generation of germinating weeds. In the seeding operation, it is off course important to establish the best possible conditions for the seed. A quick and fast germination and establishment of the crop is important to optimize the competitiveness against the weed. In addition, a uniform seeding depth is important for the subsequent weed control, in a way that this enables room for weed harrowing prior to the crop seeds that break through the soil surface [6, 7]. A uniform seeding depth causes a uniform germination and propagation of the crop plants, and thereby the best possible conditions for the following weed control by weed harrowing or hoeing.

All this together makes good sense to involve the principles of precision agriculture, also to support the effectiveness of the contribution to the weed control. This can be site-specific primary tillage, site-specific seedbed preparation, fixed tracking and controlled traffic, implement control in general, and row control of the hoeing process.
