Keywords

12.1 Introduction

Weeds are any plants that are objectionable or interfere with the activity or welfare of humans. They are competitive in nature, persistent, and pernicious; hence they are one of the major limiting factors to an efficient crop production. Weeds are undesirable and considered as pests like insects and diseases. High weed densities reduce the yield and quality through competition with crop plants for space, light, moisture, and plant nutrients as well as also exhaust the soil (Herren 2011). Although the weed management practices have developed more influential over time, weeds still exist in cropping systems. Weed control was conventionally accomplished by mechanical means (hoe, plow, hand weeding). The establishment of herbicides provided an alternative control method. However, the extensive use of herbicides has led to pervasive herbicide resistance in weeds. The recent observation made by the International Survey of Herbicide Resistant Weeds, USA has placed the number of herbicide-resistant weeds to a total of 217 species (129 dicots and 88 monocots).

There is an old adage that “One Year’s Seeding – Seven Years’ Weeding.” The importance of this adage has increased with the advent of herbicide resistance in weeds and is much anticipated that the herbicide-resistant weeds produce seeds which will germinate and produce the plants that are also herbicide-resistant (Shrestha 2004). Incidentally, we keep eliminating the susceptible weed plants, the densities of the resistant weed plants will increase, and they modify the volume and diversity of the weed seed bank and thus demand for a modification in our present weed management policies. As a value of operational issues, the ethnic state of the soil declines and weeds thrive; numerous species are difficult to eliminate. While herbicide-resistant weeds are not a big problem to the farmers who do not rely on chemical weed control (Farkas 2006), however, it is correspondingly important for all the growers to understand weed seed banks because it is the most important source of weed plants in agricultural fields. Most of the weeds start their life cycle from a single seed in the soil, and if the weeds escape control strategies, they will grow and produce thousands of seeds, and ultimately these weed seeds are returned to the soil seed bank and become the source of future weed populations (Zimdahl 2013). For instance, Amaranthus spinosus produces 2,35,000 seeds from a single plant, while other weeds like Eleusine indica 50,000–1,35,000, Chenopodium album 72,000, Striga asiatica 90,000, and Orobanche cernua 1,00,000 seeds per plant.

12.2 Weed Seed Bank

The term “seed bank” denotes to the place where the weed seeds accumulate and remain until germination. It is the reserve of viable weed seeds existing on the soil surface and spread in the soil profile. In other words, the seed bank is the resting place of weed seeds and forms an important element of the life cycle of weeds. The seed bank is an indicator of past and present weed populations. Thus, the seed bank comprises of massive numbers of new seeds recently shed by a weed plant and older seeds that have continued in the soil for several years.

Agricultural soils can contain thousands of weed seeds per square meter of which many seeds die within a few years or are removed from the seed bank by other processes (Mahesh and Robert 2007). Nevertheless, some weed seeds remain viable for decades and produce new plants as well as new seeds. Viable seeds in the soil reserve are the first guess of actual weed infestation (Dvořák and Smutný 2003). It has been assessed that about 1–9% of the viable seeds produced in a given year develop into seedlings and the rest remain viable or will germinate in subsequent years depending on the depth of their burial (Swanton et al. 2000). Seeds are dispersed both horizontally and vertically in the soil profile. The greatest seed reserves were in the surface layer (0–5 cm) of the soil (Janicka 2006), and the majority (about 95%) of the seeds entering the seed bank are from annual weeds. The seed densities in agricultural soils have been reported from near 0 to as much as one million seeds per square meter. Although seed banks and the resulting weed populations are composed of many species, a few dominant species generally comprise 70–90% of the total seed bank (Gselman and Kramberger 2004). These dominant species are the primary pests because they are resistant to control measures and are adapted to the cropping system (Buhler et al. 2001). Thus, the understanding of the factors impacting on the dynamics of weed seed banks can help us for the development of integrated weed management (IWM) programs.

12.3 Purpose and Characteristics of Weed Seed Bank

Weed seeds are a vital constituent of the weed life cycle as they are the beginning of future populations and are mainly important in annual and perennial weed species (Taraxacum officinale, Sorghum halepense, Saccharum spontaneum, etc.) which reproduce by seed only. The perennial weed species usually depend on the seeds to commence the new colonies some distance away from the mother plant, while the colony expansion near the mother plant is the result of vegetative reproduction. Thus, the weed seed bank is the viable reservoir in the upper part of the soil profile, which determines the composition of weed flora in the concrete region (Caetano et al. 2001). Species composition and density are influenced by farming practices and vary from field to field and among areas within fields.

Weed seed banks serve many purposes viz. enhances the survival of a weed species throughout time by buffering against harsh environmental conditions, tolerating high and low temperatures, dry and humid environments and variation in the oxygen supply or highly effective control methods as well as allow them to germinate over a period of many years. The significant fact in the success of weed survival is their persistence capability. This ability is a significance of a great number of seeds produced, long-term viability, continuous germination, and phenotypic and genetic plasticity. Thus, this potential decelerates the genetic shift of a weed population exposed to severe selection pressures by confirming that all the seedlings that germinate in any 1 year are not all from similar genetic backgrounds. Thus, the above considerations clearly give attention toward the existence of aerial seed banks which is most common in all the arable lands. Aerial seed banks are the seeds remain on the mother plant for erstwhile after maturity and allowing them for different dispersal mechanisms.

Some of these mechanisms consist of weed seeds dispersal by clinging to the fur of animals (Arctium minus, Xanthium strumarium, Lappa minor, Torilis arvensis, Bidens frondosa, etc.), or depending on passage through the digestive tract as in the case for many fruit-bearing weeds, or agitation of the mother plant as seeds are blown away from its point of origin by wind (Kochia scoparia, Carthamus oxycantha, Salsola kali, Amaranthus graecizans). Other weeds have a variety of mechanisms for short- and long-distance dissemination of seeds mainly blown by wind. Thus, the aerial seed banks are of greater significance in pastures or orchards than in agricultural fields. Weed seed banks are typically categorized by their prolonged existence and are determined by how long an individual seed may exist within it in a viable state. The structure of seed bank is unpredictable, which contains a fewer species to a large number of species with different growth habits, and is classified as temporary or persistent, when modifying the regeneration of the vegetation during different times of the year. Temporary or transient seed banks are composed of seeds of those species (Avena fatua, Alopecurus myosuroides, Galium aparine, Kochia scoparia, Lapsana communis, Matricaria perforata, Taraxacum officinale, etc.) having short life, which do not show any type of dormancy and are dispersed in time for short periods during the year (Grillas et al. 2004). The rate of decrease of these temporary seed banks is around 80%. Persistent seed banks are composed of seeds of those species whose seeds are generally buried into the soil and have more than 1 year of age and seed reserves remain in the soil year after year. Chenopodium album, Sinapis arvensis, Aethusa cynapium, Papaver rhoeas, Viola arvensis, and Amaranthus retroflexus are examples of persistent soil seed banks. Thus, the success of a seed bank relies on the seed population ready to germinate, when replacement is necessary and environmental conditions are favorable.

12.4 Persistence of Weed Seeds in the Seed Bank

The viability and longevity of seeds represent a major mechanism of survival of the weed species, and it in the soil varies among species, characteristics of the seeds (intrinsic dormancy), burial depth, climatic conditions (e.g., light, temperature, moisture), and biological processes (e.g., predation, allelopathy, microbial decay, aging, and senescence). The longevity of weed seeds mainly depends on variable dormancy of the seeds, presence of the seeds at various depths of soils experiencing different edaphic conditions, and variable viability of the seeds.

Although, the researches on weed seed banks have shown that agricultural weed seeds of some species have variable and long dormancy and remain dormant and viable for several years together. It is considered that grassy weeds, in general, remain dormant and viable for 10 years, whereas, broad-leaved weeds for 50 years. Despite the fact that most of the weed seeds will either germinate or die shortly after being dispersed from the parent plant (Table 12.1, 12.2, and 12.3). In a field study conducted, wild oat seeds were incorporated into the top four inches of a wheat-fallow field and approximately 80 percent of them died during the first winter.

Table 12.1 Number of years required for 99% reduction in seed number in the seedbank of nine common agricultural weeds (Davis et al. 2005)
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Table 12.2 Life span of some weed seeds in soils (Kurth 1975)
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Table 12.3 Seed density, seed production, and maximum longevity for some of the noxious weeds
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An experiment on the longevity of different weeds seeds was done by Freitas (1990) which were buried and placed to germinate in different times of the year. The result showed that the weed species like Amaranthus retroflexus, Ambrosia eliator, Lepidium virginucu, Plantago major, Portulaca oleracea and Rumex crispus originated their seedlings after 40 years of burial. Broadleaf weed seeds tend to last longer in the soil than grassy weed seed since they usually have tougher seed coats. In most cases, the majority of seeds only exist in the soil for a few years due to germination, decomposition, predator feeding, or other factors. However, with the large number of seeds produced, a small percentage may remain viable for long-term survival.

12.5 Seed Dormancy

The seed dormancy is another characteristic that affects the seed bank reservoir. Seed dormancy could be considered as a block to the completion of germination of an intact viable seed under favorable conditions, but earlier reviews concluded that it is one of the least understood phenomena in the field of seed biology (Hilhorst 1995; Bewley 1997; Finch-Savage and Leubner-Merzger 2006).

Dormancy prevents germination of the weed seeds during the condition that would otherwise be ideal for germination. The seeds of various weed species behave in different ways regarding germination, and there are several internal and external factors which prevent germination. Baskin and Baskin (2004) suggested internationally acceptable hierarchical system of classification for seed dormancy. The modified system includes three (hierarchical layers – class, level, and type); thus, a class may contain levels and types, and a level may contain only types. The system includes five classes of dormancy: physiological dormancy (PD), morphological dormancy (MD), morph physiological dormancy (MPD), physical dormancy (PY), and combinational dormancy (PY + PD). This modified system of classification helps us in thorough understanding of different types of dormancy and ways to overcome these dormancy types for better germination. Among the internal factors, the presence of a seed coat is important, which is a barrier to the penetration of water and oxygen, presence of a biochemical inhibitor in the seed, and immature embryo. Among the external factors, the most common are soil water content and temperature (Fernández-Quintanilla and Saavedra 1991).

Carmona (1992) used the term innate dormancy (primary) and induced dormancy (secondary) to characterize the development of the dormancy in the mother plant and after the dissemination in space, respectively. Most weed seeds are dormant at the time of maturity which is referred to as primary dormancy. However, seeds can set in and out of a dormant state because of environmental conditions and the process is referred as secondary dormancy; hence, regulates seasonal germination in weed seeds (Baskin and Baskin 1998). The secondary seed dormancy averts germination at a time of the year when the life cycle of a plant could not be completed, and this ensures that summer annual species germinate primarily in the spring and winter annual weeds germinate primarily in the fall. This process is regulated by seasonal changes in soil temperatures. Most of the summer annual weeds viz. Amaranthus retroflexus, Chenopodium album, Digitaria sp. and others can germinate in the spring because the cold of winter will break the dormancy and allow the seed to germinate in the spring. While on the other hand, winter annual weeds such as Ailanthus altissima, Capsellabursa pastoris, etc. require the heat of summer to break their dormancy and thus, germinate in the early fall and form a rosette before winter (Gulden and Shirtliffe 2009). The inability of the seeds to germinate due to an environmental restriction, like water deficit, low temperature, and poor aeration, is termed as enforced dormancy.

The dormancy represents a main mechanism of species preservation in the seed bank, distributing the germination through the year. It can guarantee the species survival in the form of seeds, under adverse conditions, even when the population of plants is completely eliminated (Carmona 1992). However, some seed physiologists do not consider the induced dormancy as an actual dormancy since the seed does not germinate because of the absence of environmental conditions and characteristics of the seed and since the seed does not need break dormancy but responds only to favorable conditions for germination. This situation is more conveniently referred as a case of dormant seeds.

The studies on population dynamics have the objective to determine their size throughout time and factors that influence their size (Saavedra 1994). In agroecosystems, where the soil is disturbed frequently, the soil seed bank acts to stabilize and ensure species survival (Roberts 1981). The dynamics of a seed bank involves a series of events of and of seeds from the bank, in relation to time (Simpson et al. 1989). The input is determined by the seed “rain.” This way of dispersion includes passive forms, mechanical ejection of seeds, fire, wind, water, and animals. This way of dispersion includes passive forms, mechanical ejection of seeds, fire, wind, water and animals; and thus, results from physiological answer of plants to environmental factors, which induces the germination, seed burial or redispersion of the seeds, and predation of the seeds.

12.6 Topographical Tetrazolium Test

The tetrazolium test is a measure of seed viability and also provides quick estimation of seed viability. Tetrazolium testing originated in Germany during the early 1940s. George Lakon and colleagues discovered that embryonic tissues had to be alive and respiring in order for the seed to germinate normally. The early experiments used toxic chemicals such as selenium and tellurium to indicate viability, which limited their usefulness in seed testing. In 1942, Lakon developed a method using less-toxic tetrazolium as the viability indicator (source: Tetrazolium Testing Handbook, Contribution No. 29, Revised 2009).

12.7 Fate of Seeds in the Seed Bank

The weed seeds under continuous dynamism indicate the loss and replenishment of the seed reservoir through various means. The potential ways through which weed seeds may be distributed into the field depict that few weed seeds can germinate, emerge, grow, and produce more seeds; a large proportion of them will germinate and die (also known as fatal germination), or decay in the soil, or fall to physical damage by implements, pathogens, or fungi; predation by rodents, insects, birds, or mammals; or an unfavorable environment for growth; and thus, the losses/withdrawals of weed seeds occur in the soil.

Weed seeds have many fortunes for their distribution into the field (Fig. 12.1). Many weed seeds will remain dormant in the soil and not germinate under any set of the favorable environmental conditions. This state of dormancy is not permanent, and weed seeds can change from a state of dormant to nondormant, wherever they can germinate over a wide range of environmental conditions. When inputs of weed seeds exceed losses, the seed bank becomes larger and results in the potential for a large weed population. Successful weed management programs focus on reducing the seed bank by reducing inputs and/or increasing losses so they exceed inputs.

Fig. 12.1
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Seed bank cycle (Anil Shrestha 2004)

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Weed seeds can spread on the soil surface after shedding and become the part of the soil seed bank through several avenues. The main source of weed seeds in the seedbank is from local matured weeds that set seed. Agricultural weed seeds can also be dispersed in a field by wind, water, animals, vehicle, and human activities. The dissemination of weed seeds depends on the dispersal process and the weed species (Fig. 12.2). Understanding the importance of these dispersal mechanisms is vital in the development of preventive weed management strategies.

Ball (1992) stated that there are two primary agricultural practices, land preparation and crop rotation, which create the impact on weed seed banks. Land preparation is done with the aim to control weeds, break soil surface hardness, and increase aeration so as to provide an optimum condition favorable for growth and development of crop as well as weed seeds. Thus, after attaining the favorable condition, weed seed germination is stimulated because light, alternated temperature, water, and nitrate ions break the weed seed dormancy (Cavers and Benoit 1989). The weed seeds dispersal in the soil profile is influenced by the kind of land preparation and the management at same depth favoring a uniform supply of the seeds in the soil profile and thus resulting in the lower seed populations at deeper layer of the soil (Dessaint et al. 1990). The stimulus of land preparation types over the seed bank was studied by Clements et al. (1996), and he observed that >70% of the weed seeds were present in the layer of 0–5 cm where no mechanical method was used, while the weed seeds were distributed up to 30 cm in the case of plowed fields (Yenish et al. 1992). Some of the weed species may exhibit higher intensity of emergence in zero tillage than in the conventional tillage (Fig. 12.2).

Fig. 12.2
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Agricultural weed seeds travelling over a range of distances depending on the method of transport and the weed species (Mohler 2001)

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Carmona (1992) quantified that zero and minimum tillage tends to diminish the quantity of weed seeds at the soil surface shed by plants because of initiation in the germination or loss of viability of the weed seeds. The existence of weed seeds at upper soil layer and recurrent cultivation are the main factors which reduce the seed bank rapidly. This condition can simplify seed predation by exposure of seeds to variations in temperature and humidity and/or by breaking the seed dormancy. Nevertheless, the speed of soil seed bank depletion depends on the seed production of the weed species (Yenish et al. 1992; Fernández-Quintanilla 1988).

The species composition of the weed seed bank is also influenced by the use of herbicides, as it may increase or decrease the composition depending upon the chemicals used (Ball 1992) and can also cause species shifting (Roberts 1968). Overall, it can be determined that the interaction of herbicides, land preparation, and cultural practice have altered the size and nature of seed banks (Roberts 1981). Murphy et al. (2006) stated that the seedbank declined in no-tillage systems from 41,000 to 8000 seeds m−3 over 6 years of rotation (corn-soybean-winter wheat) and the crop yields were not affected by tillage or crop rotation. Schweizer and Zimdahl (1984) observed that there was 98% reduction in the seed bank after application of atrazine in a corn field during 6 years of cultivation. The continuous use of triazines in corn in Ontario, Canada, altered the species composition and resulted in an increase in resistant plants to the products (Cavers and Benoit 1989). In practical terms, reduced tillage in combination with a good crop rotation and cultural practices may reduce weed density and expenditures on weed management. Thus, the seed bank reflects the historical process of the plant life cycle, from its establishment in the environment to the distribution in time and space (Fig. 12.3).

Fig. 12.3
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Vertical position of the seedbank with respect to different types of tillage practices being adopted (Clements et al. 1996)

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12.8 Distribution of Weed Seed in the Soil Profile

Weed seeds disperse both horizontally and vertically in the soil profile. The horizontal distribution of weed seeds in the seed bank generally follows the direction of crop rows, while type of tillage is the main factor determining the vertical distribution of weed seeds within the soil profile. In plowed fields, the majority of weed seeds are buried 10 to 15 centimeters below the surface. Under reduced tillage systems such as chisel plowing, approximately 80–90% of the weed seeds are distributed in the top 10 centimeters of the soil profile. In no-till fields, the majority of weed seeds remain at or near the soil surface. Although very few studies have assessed the effect of tillage systems on the vertical distribution of weed seeds in different soil types, evidence exists that soil characteristics influence weed seed distribution (Fig. 12.4).

Fig. 12.4
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Vertical distribution of weed seeds in a loamy sand (top) and silty loam soil (bottom) (Clements et al. 1996)

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Therefore, understanding the effect of management practices on the vertical distribution of seeds is important as it can help us predict the weed emergence patterns, e.g., in most soils small-seeded weeds like Amaranthus retroflexus, Digitaria sp., Bassia scoparia, Cirsium arvense, Chenopodium album, etc. germinate at very shallow depths (less than 2 cm), while large-seeded weeds such as common sunflower (Helianthus spp.) have more seed reserves and may germinate from deeper depths.

12.9 Management of Weed Seeds

Management of weed seed offers the most practical long-term management of hard to control weeds, including wild oats (Avena spp.), wild radish (Raphanus raphanistrum), and annual ryegrass (Lolium spp.). The decrement in the input of seeds into seed bank is the most apparent way to reduce the weed seed bank. Any method which diminishes the magnitude and number of weeds producing seeds will also lessen the quantity of seeds dropped into the seed bank. Obviously, the weed seed bank can be accomplished by using other methods that surge the death of the seeds in seed bank or encourage germination when the weeds can be easily controlled.

Even though most of the agronomic practices have an indirect consequence on the weed seed bank, a few important methods can directly affect the input of weed seeds, seed bank persistence, and germination from the seed bank. Control strategies include destroying or burying set seeds, encouraging germination, and tactical herbicide use and crop agronomy. There is not a single weed management program ideal for all conditions. The set of strategies selected to reduce weed seeds depends on the soil type, rainfall pattern, crop rotation, equipment available, and budget and farmer preference. The initial phase is to recognize the problematic weeds and develop a multi-year approach to their management. The subsequent step is to control the weeds that undergo early weed control or germinate in-crop and seed-set reinfesting the seed bank.

When the weed seed bank has been diminished, the use of crop competition is one of the best tools to combat weed germination and seed-set. Strong crop competition combined with rotation of herbicides having different modes of action and the use of suitable agronomic practices for crop nutrition and disease management are the best approaches of keeping seedbank low. Wherever the weed populations are high or seed bank life span is extended, multi-year approaches are required to control the seed-set and to drive populations down. Therefore, efforts to control the seed bank must be sustained for years to be successful. The research with lamb’s quarters (Chenopodium album) found that a 6-year effort to control the weeds reduced the seed bank 94–99%, whereas after 1 year without control, the seedbank increased to 90% of its pre-control size (Di Tomaso and Healy 2007). In another experiment conducted in Canada for 6 years, Beckie et al. (2005) observed that weed patches expanded in size by 35% when standard weed management practices were combined with weed seed shed prevention, while when only standard weed management approaches were applied, the weed patch expansion reached 330%. The best tactic to ease the forthcoming weed management is to limit present contributions to the weed seed bank. In a 5-year period experiment conducted at Nebraska, broadleaf and grass weed seed bank was reduced to 5% of their original density when weeds were not allowed to produce seeds. However, in the sixth year, weeds were not controlled, and the seedbank density increased to 90% of the original level (Burnside et al. 1986).

12.9.1 Weed Resistance

The resistance in different weed species develop as a result of overuse of any single strategy is called weed resistance. Herbicides experience the least risky option for weed control and are used by most of the farmers. Rotating the herbicide with different modes of action and tumbling the dependence on herbicide control by the use of physical and biological control methods will aid to curb the development of herbicide resistance. Integrated weed management is not a replacement for herbicides but adds other control strategies throughout the season in order to create a system that maintains weeds at low levels while minimizing current and future financial risks.

12.9.2 Prevention

The most efficient approach to reduce weed seed banks is to not allow weeds to set seed in the field. Care should be taken to avoid bringing new weed seeds into a field through irrigation, equipment, or animals. This can be achieved by screening irrigation water, washing equipment before bringing it into the field, and keeping grazing animals in quarantine before moving them from a weedy field to a clean one.

12.9.3 Reducing Seed Inputs into the Soil Seed Bank

Reduction not only minimizes future weed problems, it also reduces the speed at which weed patches expand across crop fields. Increasing crop interference by increasing seeding rate and filling empty niches with cover crops helps minimize weed seed inputs into the seed bank. Other approaches include mowing weeds prior to seed production and controlling weeds with herbicides or cultivation.

12.9.4 Herbicides

Herbicides have, and continue to be, the most effective weed management tool of the twenty-first century because of their ability in reducing weed populations very effectively as well as at the same time reduces the number of seeds added to the seed bank. Weed seed bank densities lean to be greater in organic management systems than in systems reliant on herbicides, although this is not always the case as other factors such as crop rotation also strongly influence weed seed production. In production systems that use herbicides as the principal tool to manage weeds, seed bank densities are typically between 1000 and 4000 seeds m−2 (Blackshaw et al. 2004; Clements et al. 1996). When herbicide-tolerant crops are used extensively in cropping systems, weed seed banks will be near the low end of this range; however, despite lower weed seed bank densities in these systems, weed seedling emergence still remains significant in following years. Preharvest applications of glyphosate can decrease seed production and impact seed viability in late-flowering weeds. However, the slow action of glyphosate means that weeds must be managed well before the plant sheds its seed near maturity.

12.9.5 Crop Rotation

Crop rotation is also an effective means of managing the weed seed bank. Introducing perennial crops in annual cropping systems tends to deplete the soil seed bank of annual species over time. This method is more effective on weed species which have low levels of longevity such as kochia and many of the grassy weeds like wild oat and green foxtail. Likewise, crop competition is also important for decreasing weed seeds being recruited to the seed bank. Studies near Saskatoon, SK, conducted in the late 1970s showed that seed bank populations were greatest in summer fallow (about 1600 seeds m−2) versus wheat stubble (about 500 viable seeds m−2) (Archibold 1981). Weed seed bank additions are high in fallow fields impart due to incomplete weed control by tillage and the absence of a competitive crop (Archibold and Hume 1983).

12.9.6 Chaff Collection

Chaff collection is an effective method for reducing inputs into the weed seed bank. Weed seeds generally weigh less than crop seeds and therefore end up in the chaff fraction which is typically spread evenly across the field. Even for large weed seeds such as wild oat, chaff collection can prevent upward of 90% of the weed seed numbers added to the seed bank during the harvest operation (Shirtliffe and Entz 2005).

12.9.7 Seed Longevity

While burying weed seeds by tilling increases the longevity of the seeds in the seedbank, leaving weed seeds on the soil surface exposes them to predation, reducing their abundance in the seed bank.

12.9.8 Manure

Composting manure reduces the viability of weed seeds, minimizing weed seed inputs into the seed bank.

12.10 Conclusion

Weed seed banks are a vital constituent of the weed life cycle. There are many fates and processes that occur in the weed seed bank, many of which are not very well understood. The absolute difficulty of monitoring a process that occurs mostly underground has deterred weed scientists from gaining a full understanding of the weed seed bank. Nevertheless, current knowledge about weed seed banks has shown some potential management options. Reducing inputs to the seed bank is an important component of seed bank management, while other strategies like using a no-till cropping system can be used to directly affect germination, persistence, and mortality of weed seeds. Managing weed seed banks should be an important component of integrated weed management, but more often than not, seed bank management is not being exploited to its fullest potential.