Optimum Cultivation and Establishment Methods for Growing Oilseed Rape in Soil Conditions in the UK - Literature review Example

THE OPTIMUM CULTIVATION AND ESTABLISHMENT METHODS FOR GROWING OILSEED RAPE (BRASSICA NAPUS) IN A VARIOUS SOIL CONDITIONS WITHIN THE UNITED KINGDOM LITERATURE REVIEW 2.0 Introduction As sustainability and the greening of the ecosystem become very important to global agencies and nations, the focus of most countries have turned to the role that plants can plan in achieving this goal. But as important as plants help in the greening of the solar system, they have also become very important sources of food for both plants and animals, including humankind (FAOSTAT, 2013). Plants have actually accounted for major parts of the export made by most countries in the form of raw edible food, processed wood, refined products, and drugs. In the United Kingdom (UK), the role that various plants play in the socio-economic wellbeing of the country cannot be underestimated. It is not surprising that studies have continued to go on about the best ways by which various plants and crops can be well researched into to find the best practices, conditions and establishments under which they are best cultivated for optimum output (Freer, 2002). It was with such motivation that the current research was conducted into finding out about the optimum cultivation and establishment methods for the growing of oilseed rape also known as Brassica napus in various soil conditions within the U.K. As part of secondary data collection for the research work, the review of related literature is taken seriously to know what has already been done in this field and the gaps that exist in literature. This way, the best ways by which this research can fill the gaps can be rightly identified. The review will therefore focus on the background of the crop, the relevance of it to UK and the best practices in its cultivation. 2.1 Overview of the Oilseed Rape Crop The oilseed rape crop is known by many names including rapa, Brassica napus, and sometimes just called rape. The origin of the seed in the UK is raced to the 14th century when the bright yellow flowering was first brought to the European region (Davies and Finney, 2002). The oilseed rape crop belongs to the family Brassicaceae, commonly known as the mustard or cabbage family. The crop belongs to the order Brassicales and genus Brassica (Soeparjono, 2008). Since arriving in the U.K., the plant has been known as a very important crop, which has been cultivated over the years since the 14th century. In one study, FAOSTAT (2013) argued that the oilseed rape is one of the longest most adored plants to have been cultivated in the U.K. This emphasis is given to the plant because of the continuous attention it has received over the years for the need to maximise the production of the crop. In a related study, Bullard et al. (1996) emphasised on the fact that the oilseed rape has remained a competitively important plant in the U.K because of its dynamism in terms of how useful the plant is. This is because the plant is very useful in several areas of the lives of ordinary Britons. It is even said that in the 19th century, the plant was used as a source of lubricant for steam engine. On the other side of the argument however, Freer (2002) indicated that in comparison with other edible crops, the oilseed rape has not been fully discovered in terms of its usefulness to U.K., given the depth of organise spending done on the plant. The oilseed rape is not only popular in the U.K. as U.K. is not even one of the highest producers of the plant in the world. Currently, the European Union, Canada, India, China, and France have all produced oilseed rape in higher volumes than the U.K. (FAOSTAT, 2013). This may perhaps be a reason that not all agricultural researchers back and support the level of funding that is given to the oilseed rape in the U.K. This notwithstanding, it is common knowledge that the crop has been an important crop that cannot be eliminated from the count of U.K’s major crop productions. In the opinion of Soeparjono (2008), the problem that the U.K. has exhibited over the years about the oilseed rape is the approach to getting more yield. This is because not much has been done in terms of basic cultivation research that will lead to the understanding of basic cultivation and establishment methods that will ensure increased production (Freer, 2002). Most of the time, the attention of institutions and researchers have been on laboratory based researches that will ensure increased yield through unconventional means such as artificial insemination and other crop mutilation techniques (Bullard et al., 1996). Meanwhile, there are examples from countries like India who have 13% of its cropped land grown with oilseed rape that very common conventional farming practices can actually be the solution to the search in the U.K. for higher yield of the oilseed rape crop. As it is now, even though the U.K has seen a rise in production level comparing current levels to precious levels like 1965, there has not been a very steadily and consistent growth trend as shown in the figure below. Figure 1: Production Yield of Oilseed Rape in U.K. Source: FAOSTAT (2013) 2.2 Cultivation strategies suitable for soil conditions The soil conditions within the U.K are very important determinants in the approach to focusing on conventional strategies to increase the yield of oilseed rape in the country. But to do this effectively, there are various cultivation strategies that must be considered with respect to the U.K. soil condition. Four of these cultivation strategies or factors are considered below. 2.21 Cultivation Environment Freer, Carver and Phillips (1999) that in the U.K, there are two major cultivation environments or soil conditions, which are dry soil condition and wet soil condition. Depending on the soil condition however, farmers would have to use different strategies and approaches to cultivation. Arguing on the types of soil conditions, Blake, Spink and Bullard (2004) admitted to the existence of the two types mentioned earlier. In their opinion however, the commonly situations are seeds and seedlings that are exerted to pressure as a result of combined forces such as heavy clay soil which are dry and have been previously planted with cereal crop. They also said that rainfall has been very low in most of the planting seasons and so it is common to find more cultivation being done in dry soil as compared to wet soil. In these dry soils, Freer, Carver and Phillips (1999) noted that there have always been vulnerability to young seedlings, emanating from moisture stress and desiccation. With this noted, Blake, Spink and Bullard (2004) focused on cultivation strategies that can best made seeds and seedlings survive. In the first place, Blake, Spink and Bullard (2004) maintained that right after planting, there is the need to introduce 40% by weight of water before any metabolic processes that are needed for germination can take place. Davies and Finney (2002) however believed that most seeds can withstand conditions of desiccation that take place from delayed onset of moisture without exhibiting any adverse effects. In their opinion, the strategy on dry soils should therefore be the introduction of seed advancement and priming technologies that directly affect the seed directly in terms of DNA repair, protein synthesis and RNA synthesis. Even though the latter argument is also shared by Blake, Spink and Bullard (2004), the writers maintained that seed advancement and priming technologies are never enough if there will be a disregard for further water uptake at various points of seed maturity such as the time that there is radicle protrusion. In their opinion, once this is not done, there will significant reduction in plant population due to desiccation. Blake, Spink and Bullard (2004) went ahead to argue that within the cultivation environment, “different soils need different gravimetric water contents to provide the same amount of available water (measured as ψm) due to the different strengths of attraction between soil particles and water molecules” (p. 11.3). From the table below, it would be noted that McWilliam (1998) supported the view held by Blake, Spink and Bullard (2004) as they presented the average clay content in percentage in relation to soil moisture content in percentage at 1.5 MPa. Table 1: Soil Moisture at 1.5Mpa in Relation to Clay Content Soil Texture Average Clay Content (%) Calculated Soil Moisture Content (%) at 1.5MPa Sandy Loam 10 5 Silt Loam 15 7 Sandy Clay Loam 30 15 Silty Clay 35 17 Clay 50 25 Source: McWiliam (1998, p. 78) Based on the table above, one would appreciate the fact that growers have to take into consideration the marginal soil moistures available to them when undertaking germination tests ahead of their cultivation (Soeparjono, 2008). With this known, Blake, Spink and Bullard (2004) again emphasized on the strategy of allowing good surface with seed from seedbeds as a fine approach to ensuring yield in dry soil areas. 2.22 Cultivation Conditions Whiles undertaking the main process of cultivation, there are a number of factors and conditions that Davies and Finney (2002) observed can affect the success and yield of oilseed rape. Generally, some of these factors are mentioned to include the type of sowing done, whether shallow sowing, drilled sowing or direct sowing. For the best of outcomes however, Bullard et al. (1996) advocated for the use of direct drilled especially when they are done after shallow cultivations (FAOSTAT, 2013). In an agreement, Blake, Spink and Bullard (2004) noted that such situations create a natural tilth resulting from self mulching whether in dry or wet cycles. When sowing is done after shallow cultivations, McWilliam et al. (1995) maintained that the effect of dry conditions is not felt much as there is often retention of soil moisture when shallow and direct sowing follow such cultivations. In literature, there continues to be a divided school of thought about the place of ploughing in cultivation, whether it promotes or hinders the retention of soil moisture for onward usage by the seed or seedling. Whiles Freer (2002) maintained that ploughing opens the soil up for the least remaining moisture in the soil to be well used, McWilliam et al (1995) opposed this and said that ploughing actually reduced soil moisture from 16% to 6%. According to Bullard et al. (1996), the reduction in soil moisture results from the fact that turning the soil up exposes the little remaining water in the soil to the sun. Consequently, McWilliam et al. (1995) demonstrated that in cases of direct drilled and disced treatments, only 7mm of rainfall was need to trigger germination but in ploughed land, up to 40mm of rain was needed. 2.23 Biotic Factors There are two major biotic factors associated with the cultivation of oilseed rape that farmers ought to consider in order to find the best strategies that can match these up. These two biotic factors are diseases and pests. Investigating different diseases and pests that often trouble the cultivation of oilseed rape, Soeparjono (2008) noted that the type of soil, or planting is taking place accounts for the type of diseases and pests that will be experienced. This means that the U.K has its own cases of diseases and pests it has to deal with as far as oilseed rape is concerned. Being very specific with cases of pest in U.K soil, Blake, Spink and Bullard (2004) identified three major pests, which are slugs, cabbage stem flea and flea beetles, and pigeons. Each of these has been noted to cause different kind of havoc to the oilseed rape plant (Freer, Carver and Phillips, 1999). The activities of slugs however continue to be debated in literature as it is not clear the specific damage they do to the plant. Whiles some researchers say the slugs attach oilseed rape in the same way as they attach wheat (Bullard et al., 1996), others believe the attacks and damage are different from what is done with wheat. All the same, Blake, Spink and Bullard (2004) maintained that slugs graze the plants post-emergence and that the plants are mostly able to survive this damage. As for flea, they are known to hatch their eggs into larvae, which feed on the stem of the plant and possibly causing the death of the plant (HGCA, 2004). Pigeons also graze and have been found to be hard to control (Stokes et al., 2000). As a strategy to controlling pests, Hardwick et al. (1991) recommended the use of pesticides and pest resistant seeds. The use of pest resistant seeds have however been criticized to be useful only in selected cases of pests such as slugs (Freer, Carver and Phillips, 1999). The need for farmers to directly identify the pests and use the right pesticides on them would thus be the best way for them. On diseases, there are several diseases in U.K soil that militate against the successful production of oilseed rape. Among these however, fungi are found to be the most reported cases with fungi such as Alternaria brassicae and brassicicola, Peronospora parasitica, Pyrenopeziza brassicae and Leptosphaeria maculans causing different seed-borne diseases (Hardwick et al., 1991). The best strategy to control these fungi has been noted with the use of fungicides which are applied to the mother crop and seed dressings (Blake, Spink and Bullard, 2004). As seed-borne fungi, the diseases caused are found to have very little adverse effect on germination. This means that germination can still take place even when these diseases are present. For the worse of effects, Hardwick et al. (1991) observed that the fungi are seen to be most dangerous at the seedling stage as these are airborne. Blake, Spink and Bullard (2004) however made mention of some pest that actually cause pre-emergence decay. The implication is that unlike the types of fungi listed earlier these can actually hamper germination and must therefore be strategically combated before they set off on the seeds. Examples of such pre-emergence decay causing fungi include Fusarium spp., Pythium spp. and Rhizoctonia solani. Because of how dangerous the pre-emergence diseases are, any hopes of increasing oilseed rape yield cannot be achieved without applying pragmatic steps in controlling them. This is because unlike those that are not able to affect germination directly, there cannot be any hopes of controlling the disease post-germination. HGCA (2013c) therefore recommended the use of fungicidal seed dressing including thiram, iprodione and fenpropimorph to check the activities of pre-emergence diseases. But even with these fungicidal seed dressings, Blake, Spink and Bullard (2004) observed that they do not confer extended protection post-emegence. But should they work effectively at the pre-emegence state then certainly their efficacy will not be needed at the post-emergence stage. At the post-emergence stage of oilseed rape, there are specific diseases that have been identified in U.K soil that must be controlled for cultivation successes. Three of these are mentioned by Blake, Spink and Bullard (2004) to include “downy mildew (Peronospora parasitica), phoma (Leptosphaeria maculans/Phoma lingam) and light leaf spot (Pyrenopeziza brassicae/Cylindrosporium concentricum)” (p. 11.10). What makes these post-emergence diseases harmful is that they are easy to spread, using means such rain splash dispersal or even through the air (Bullard et al., 1996). Over the years, farmers in the U.K. have depended on the use of fungicide sprays to fight such airborne diseases that affect the oilseed rape plant. Other forms of diseases that are worth controlling are soil-borne diseases caused Fusarium, Pythium and Rhizoctonia. As soil-borne diseases, these are noted to have a direct effect on the roots of plants, thereby leading to root girdling defects (HGCA, 2004). 2.24 Seed Factors In the works of McWilliam (1998) and Stokes et al. (2000), it was found that seed quality is an important variable in determining the yield and for that matter the establishment of oilseed rape. These studies however showed two major intra-varietal differences that determines the outcome of seeds. The first set or group of intra-varietal differences focused on the site of growth, season of production, husbandry, and storage. The other set of intra-varietal differences focused on the genetics of the seeds. Among these two however, the first set that deal with the seed quality emanating from conditions having to do with site, season, husbandry, and storage were found to have greater turnover effects than those based on genetics (Bullard et al., 1996). This means that even though seed quality is an important cultivating factor for U.K soil in the production of oilseed rape, it is important for researchers to focus on improving seed quality based on their acceptability with conventional factors such as site, season and husbandry rather than focusing so much on genetics. Once the conventional factors are given a wider consideration, Blake, Spink and Bullard (2004) give the assurance that “seed quality would enable better establishment across a wide range of seed-bed and environmental conditions” (p. 11.8). On the part of FAOSTAT (2013) the singular dependence on seed quality was challenged as it was posited that there are always combined factors that optimize the performance of seed if seed quality is to be used as strategy for increasing oilseed rape yield in the U.K. Some of the combined factors noted are seedbed structure and soil type. Even though the emphasis on genetics has been found not to be as viable as the other factors mentioned earlier when focusing on seed quality, there have been instances where induced laboratory experimentations have been found to have very promising scales of improved establishment for oilseed rape (Hardwick et al., 1991). In one of such studies that sought to justify the controlled environment studies, Blake, Spink and Bullard (2004) posited that genetic improvement of seed quality that focus on increasing seed size and protein content can lead to improved establishment. But even with this, FAOSTAT (2013) noted that there were dependent factors that make such controlled environment laboratory studies successful. A typical example of this has been showed to include the presence of moisture stress conditions. By and large, the debate boils down to the fact that researchers who have already condemned the over dependence on laboratory based interventions for achieving higher yields in oilseed rape may not be far from right. This is because for almost every case of a non-conventional intervention proposed to support the growth and development of oilseed rape in U.K soil, there seem to be the need for some higher levels of connection with the same oil conventional strategies bordering on improvements in basic farm practices that focus on site, season, soil, and water. For example in the very experiment referred to by Blake, Spink and Bullard, water potential was controlled by use of various concentrations of polyethylene glycol (PEG 8000) in water. Germination tests also had to be conducted using different water potentials to find which gave the best outcomes. 2.3 Establishment Systems for Oilseed Rape As important as all the cultivation strategies discussed above are to ensuring improved yield, Horstine Chafer (2013) noted that much of the conditions needed for successful cultivation start after emergence of oilseed rape. In effect, conditions to guaranteed development of strong root system is what is need to start the whole process. In the light of this, some establishment systems for oilseed rape that focus on getting roots strongly established in the soil are reviewed in this paper of the literature review. 2.31 Methods of Establishment Soeparjono (2008) noted that there are several ways in which farmers can approach the quest to establish oilseed rape. Searching through literature, it can be seen that the use of different methods have been justified by different researchers under different circumstances and based on different provisions. For example, HGCA (2013c) mentioned the use of broadcasting as a very effective method of establishment that is suitable for large farm lands, where the moisture levels of the soil can be trusted to be even and widespread. Freer, Carver and Phillips (1999) also maintained that where the ambition of farmers is to replant after the seedling stage, broadcasting can be deemed as a very useful establishment system. There are other researchers who have also mentioned the plough or drill based cultivation system as a very helpful method of establishment that ensures early germination and firm long term establishment (Freer, Carver and Phillips, 1999). The basis for the benefits derived from this type of establishment is that the ploughing exposes the seed to deeper levels within the seedbed. Consequently, it is easier to get a gained guarantee for the roots of the seed to be easily attached to the deeper soil. As much as Horstine Chafer (2013) accepts the first two methods of establishment, they are quick to point to their weaknesses and suggest a more modernised method of establishment that guarantees renewed benefits that are not in place with the old methods. This modern method is the use of tined cultivator or subsoiler. Unlike the previous methods that may possibly disturb the soil when seedbed is created, this system is said to have no such outcome. Elaborating on the tined cultivator, Horstine Chafer (2013) noted that there is often the employment of a front tine, which cultivates a strip of soil with the oilseed rape seed. After this is done, there is then the even metering of the seed into the cultivated area of land. There are other separate operations that are performed including the consolidation of the soil by the use of a packer or roller. There are numerous ways in which this method has been noted to be favourable with the U.K soil and thus guaranteeing improved establishment. In the first place, HGCA (2013) made mention of the importance of free drainage to improving establishment for oilseed rape. Rightly so with the tined cultivator method, Horstine Chafer (2013) noted that the soil presented below the seed after the rolling is also not compact. Consequently, the loose soil allows for free drainage and root passage. Once there is such free drainage and root passage, Bullard et al. (1996) added that it is possible for the root to go as deep as the drainage can allow, thereby improving establishment. Have critics have however questioned if this same benefit can be achieved where there is dry soil cultivation (McWilliam, Stokes and Scott, 1998). This means that where cultivation is not done in wet soil, farmers must ensure periodic supply of water. Still touching on the benefits of the tined cultivator method, Horstine Chafer (2013) observed that there is the retention of moisture for fast and consistent germination. Even though this benefit may also be present for a method like the plough and drill method, the difference that has been found with the plough and drill method is that it requires so much presence of water, especially rain water to achieve this benefit (Hardwick et al., 1991). Writing on the effect of straw and chaff on the establishment of oilseed rape, Stokes et al., (2000) cautioned that straw and chaff always compete with the roots for space, nutrients and moisture. As a result, having so much of these in the soil is problematic for improving establishment. Meanwhile, Horstine Chafer (2013) actually noted that with the tined cultivator, there is the guarantee that there will be the minimisation of concentration of straw and chaff residues. This is another situation that has been found to be absent in most of other establishment methods such as the broadcasting method. This is because in the broadcasting method, there is virtually no control over what should happen with the straw and chaff residue. But the systems of rolling in the tined cultivator method actually address this problem squarely. According to Horstine Chafer (2013), because the tined cultivator method is more of a mechanised establishment method, it allows for high work rates just as most forms of ploughing does. The extra benefit with the tined cultivator that the use of plough may not have however has to do with the fact that in the tined cultivator, not only is there high work rate but also an excellent timeline that is motivated as a result of the single pass establishments. Lastly, Horstine Chafer (2013) was emphatic about the fact that unlike the ploughing and broadcasting methods, the tined cultivator can guarantee that cultivation only takes place in the seeding or root zones. Once this is achieved, it can be assured that there will be the minimisation of unnecessary weed, which compete for root space. 2.32 Adding Nutrients at Establishment Even though the selection of the right establishment method may go a long way to help in improving establishment, HGCA (2013b) warned that the establishment method is not an end in itself but a means to an end. By implication, there are other important processes that must be considered for improved establishment. One of these has been noted to be the application of nutrients at establishment (Stokes et al., 2000). The reason the application of nutrients at the establishment is considered to be particularly important for improving establishment is that it plays a direct role in ensuring that the crop gets the ability to develop a strong root system (McWilliam, Stokes and Scott, 1998). It would be noted that it takes the root system getting fully established to bring about the whole process of improved establishment. According to Davies and Finney (2002), one factor that makes the application of nutrients at establishment crucial is the development nature of the root system. This is because until 2-3 weeks after emergence, the root of oilseed rape continues to be a primary root. Such primary roots; unlike the tap root that is developed later is very fragile, vulnerable to pests and diseases that have been reviewed earlier and highly dependent on environmental factors for survival (Davies and Finney, 2002). Adequate supply of nutrients at the early stages of the oilseed rape is therefore a vital process that farmers cannot forfeit if they really wish for higher yields. One effective procedure to undertake the application of nutrients has been noted to be the band fertiliser application method (HGCA, 2013). Generally, the band fertiliser application method has been described as an integrated or multi-variant method that comprises the application of several or many types of nutrients to the oilseed rape at a go (Davies and Finney, 2002). Based on some of the most common needs of the oilseed rape however, HGCA (2013b) recommended the dominance of three major types of nutrients namely nitrogen, phosphate and potash. Horstine Chafer (2013) explained that the band fertiliser application is done in such a way that the three major nutrients are placed in a band where the seed is drilled with concentration of pool of nutrients that can easily get to the young plant. More specifically, the target of the concentration of the pool of nutrients must be the root of the young plant. Achieving this ensures that the state of the young root, which is a primary root does not in any way become a hindrance to the prospect of the main plant to achieve a firm establishment later on in its development when it acquires a taproot. The application of fertiliser by use of the band fertiliser application has been noted to be possible through a number of means including solid application, liquid application and air application. The Horstine Chafer (2013) has actually developed machinery that takes care of each of the available methods. There are other known mechanised ways of also doing same. In the figure below, the Horstine’s AirStream, which undertakes air application of band fertiliser is showed. The advantage with the air application is its range of coverage, which can be as far as possible (McWilliam, Stokes and Scott, 1998). Figure 2: Horstine's AirStream Source: Horstine Chafer (2013). Farmers that use any of the three forms of application namely solid, liquid and air application are sure to get some outstanding benefits from the band fertiliser application. Firstly, because this is a combined method, it has been noted to reduce fertiliser rates. In effect, it saves cost and enhances efficiency (Stokes et al., 2000). What is more, there is no need to emphasise on the dominance of one form of nutrient requirement, especially nitrogen requirements. The band fertiliser application method has also been noted to be responsible for the quick development of tap roots, which is an important feature of ensuring the improvement of establishments (McWilliam, Stokes and Scott, 1998). 2.4 Summary of the Review The review that has been conducted has been very important in establishing various cultivation and establishment methods needed for ensuring high yield of oilseed rape in the U.K. Very consistently in the review, the use of laboratory based genetic manipulations were compared with the use conventional methods that are based on basic farm practices. In these, it has been established that as much as the laboratory based genetic manipulations may work in achieving improved establishments, most of these processes are highly dependent on the use of presence of conventional factors such as soil type and moisture levels. Meanwhile, it is possible to focus entirely on conventional methods for the purpose of achieving improved yield. Consequently, it can be said that the conventional methods are independent, whiles the nonconventional methods are dependent. The review also focused on the role that biotic factors including pests and diseases play in counteracting the aim of ensuring higher yield. Very fortunately, the types of pests and diseases in UK soil, though come in different forms have been noted to have known and workable controls in fighting them. With advancements in technology, it has been emphasised in the review that there continues to be various establishment systems that are directed towards the good of ensuring higher yields in oilseed rape in the UK. Most of these are either solid, air or water based establishment systems. Each of these however have their own merits and demerits, meaning that the farmers always have to be knowledgeable in the selection of particular methods. References Blake J.J., Spink J.H. And Bullard M.J. (2004). Successful establishment of oilseed rape. HGCA conference 2004: Managing soil and roots for profitable production Bullard M J, Heath M C, Clare R W, Mcwilliam S C, Stokes D T, Scott R K, Davies D B, (1996). Optimising Establishment of Winter Oilseed Rape On Clays. 1st ed. HGCA: United Kingdom. Davies D B Finney J B, (2002). Reduced Cultivations For Cereals: Research, Development And Advisory Needs Under Changing Economic Circumstances. 1st ed. HGCA: Cambridge. FAOSTAT. (2013). Global Production of Oilseed Rape. UN Food & Agriculture Organisation: Geneva Freer B, (2002). Non-tillage establishment of oilseed rape using the 'Autocast' technique. 1st ed. HGCA: Norfolk Freer B, Carver M, Phillips H, (1999). The influence of drilling date on the performance of winter oilseed rape. 1st ed. HGCA: United Kingdom. Hardwick, N.V., Fitt, B.D.L., Wale, S.J. and Sweet, J.B. (1991) Oilseed rape diseases. Oilseeds Research review No. OS4, Home-Grown Cereals Authority. London. HGCA (2004) Establishment of winter oilseed rape [ONLINE] Available at: http://www.hgca.com/publications/documents/cropresearch/TOPIC15.pdf. [13th April, 2014] HGCA (2013). Soil conditions and oilseed rape establishment [ONLINE] Available at: http://www.hgca.com/document.aspx?fn=load&media_id=5372&publicationId=6460. [13th April, 2014] HGCA (2013b) No-Till: opportunities and challenges for cereal and oilseed growers [ONLINE] Available at: http://www.hgca.com/document.aspx?fn=load&media_id=7733&publicationId=8902 [13th April, 2014] HGCA (2013c) Successful establishment of oilseed rape [ONLINE] Available at: http://www.hgca.com/publications/documents/events/Paper11_0204.pdf. [12th April, 2014] Horstine Chafer (2013). Oilseed Rape Brochure. [Online] Available at http://www.cropsprayers.com/Horstine/wp-content/uploads/2013/07/Oilseed-Rape-brochure-2013.pdf [14th April, 2014] McWilliam, S.C., Stokes, D.T., and Scott, R.K. (1998). Establishment of oilseed rape: the influence of physical characteristics of seedbeds and weather on germination, emergence and seedling survival. Project Report No. OS31, Home-Grown cereals Authority, London. McWilliam, S.C., Stokes, D.T., Scott, R.K., Norton, D.G., Sylvester-Bradley, R. and Davies, D.B. (1995) The relationship between establishment and yield of autumn-sown oilseed rape. Project Report No. OS13, Home-Grown cereals Authority, London. Soeparjono, S. (2008). Effects of agronomic management on growth and yield of hybrid oilseed rape (Brassica napus L.). University of Newcastle upon Tyne: Newcastle upon Tyne Stokes, D.T., Bullard, M.J., Lunn, G.D., Basu, K.R., Clare, R.W. and Scott, R.K. (2000). Establishment of oilseed rape: seed crop management effects on seed quality and performance. Project Report No. OS42, Home-Grown Cereals Authority, London. Read More