To turn a high-yielding harvest of winter oil-rich seed colza, a figure of factors must be considered before even taking your seed. The best assortment must be chosen for the state of affairs of the field, instead than merely choosing a high surrenderer.
The HGCA produce a Recommended List for winter oil-rich seed colza, ranking assortments by output corrected for per centum oil content, and agronomic informations including opposition to housing, nine root, light foliage topographic point and root canker, every bit good as root shortness and stiffness, earliness of blossoming and adulthood. Some agriculturists want a low input government, or organic system, so high disease opposition is of import for these.
Geographic facets must be taken under consideration besides, such as phoma infections being sighted in West registered under 10 % , even to 0 % being noted, in east it may be 80 % + , or light foliage topographic point is seen much more in the North and Scotland than southern England. ( Crop Monitor, 2009. ) Besides, weather conditions instead than the day of the month should be chief factor for taking a boring day of the month. This will let good conditions to be created prior to seeding to give the seed the best opportunity at constitution and to promote good wellness of the harvest from the beginning. OSR has a little seed, with limited seed militias and intial rooting ability, hence dirt wet keeping and seed to dirty contact are the critical factors in finding the proportion of seeds that will shoot. The fall energy shown by most loanblends is an of import consideration government works endurance over winter, instead, choice of big high protein seeds more capable of turning in dry fall conditions may be a better option.
Different facets of the seedbed besides need to be considered anterior to seting, such as pH, dirt compression, organic affair content and the seed rate needed for the assortment. Slug pin downing to happen out rates should be done when the old harvest is in to cognize if intervention is needed when the seed is planted, before harm can be done to emerging seedlings. It is better for future direction to make good conditions for the seed instead than to trust on increased seed rates.
An effectual rotational sequence is of import for harvest wellness direction. Continuous production of a individual harvest, or short sequences of harvests with similar direction patterns promote the addition of weeds adapted to those conditions. The ensuing weeds can be extremely competitory and hard to command. ( Froud-Williams, 1988. ) In contrast, utilizing a diverse rotary motion using harvests with different planting and crop day of the months, different growing wonts and different direction patterns will let weeds to be challenged with a broad scope of emphasiss and mortality hazards. ( Liebman and Dyck, 1993 ; Derksen, 1997 ; Liebman and Ohno, 1998. )
Sieling ‘s 2003 survey showed that OSR grown after peas and barley yielded the most ( 3.9 T haE‰A? and 3.8 Ts haE‰A? ) , but with wheat in the preceding season, the output was reduced to 3.6 T haE‰A? . The harvest grown in the twelvemonth old affected seed output, but so did the harvest grown two old ages old, though a smaller consequence was seen than the straight preceding twelvemonth. OSR clearly responds to a favorable preceding harvest. As it is frequently grown as a interruption harvest with wheat, this may be a ground for reduced output even if other factors are ideal.
To till or non to till:
Seed output ( t haE‰A? 91 % dry affair ) of oil-rich seed colza in different cultivated land systems 1991-2000
Cultivated land System
Experimental Year Relative 1991 1994 1997 2000
Plough ( 25cm )
Cultivator ( 25cm )
Plough ( 15cm )
Cultivator ( 15cm )
Rotary harrow ( 10cm )
Zero cultivated land
Adapted from Christen et Al. 2003.
From this tabular array it is demonstrated that preservation cultivated land can give respectable seed outputs compared to conventional cultivated land. This 2003 survey by Christen et Al. suggested the undermentioned amendments to most preservation cultivated land cultivations:
A diverse harvest rotary motion is needed, the more spring seeded harvests and legumes the easier it is for weed and voluntary direction.
Correct harvest engineering: the combine reaper in old cereal crop demands to hold first-class straw chopper and husk spreader qualities, particularly as climatic conditions which merely allow a short decomposition of harvest residues after crop
Depending on straw distribution it may be necessary to utilize a comb harrow one time or twice to better spacial straw distribution in the field.
These betterments to current minimal cultivated land practise, combined with a assortment suited to minimal cultivated land, such as the ideal timing for seeding after the old harvest, root systems and energy to acquire off from the husk should give respectable sums compared to traditional cultivation methods.
Minimal cultivated land under dry conditions may besides forestall inordinate wet loss, bettering the chances of early sprouting and growing. However, under really wet conditions, and where dirt construction has been damaged, plowing may still be the most appropriate scheme, to speed up drainage, facilitate dirt drying and take compression. Boring seed into uncultivated dirt under dry conditions can forestall inordinate wet loss from the dirt, as over 90 % of colza is sown in late August or early September when the predating cereal harvest has usually dried the dirt profile. ( Lunn et al. 2001 )
Soil type is an of import factor for taking cultivation patterns, for illustration, clay dirts when cultivated at the extremes of wetness and waterlessness, tend to bring forth cloddy seedbeds unsuitable for the little OSR seeds, makes it hard to accomplishing unvarying works constitution, and creates a good home ground for bullets to travel in and set downing countries for wood pigeons to assail the harvest. Sandy light dirts may be over dried by plowing.
Timing of cultivated land or cultivation determines how effectual it is for weed direction. Cultivation of dirt is more effectual in hot conditions since under those conditions uprooted weeds dessicate rapidly without rerooting. ( Terpstra and Kouwenhoven, 1981 ) Weedss are adapted to work the brief pulsation of alimentary handiness that follows perturbation ( Qasem, 1992 ) and hence leting them to turn, so spraying with a broad-spectrum weedkiller before outgrowth of the harvest allows the harvest a opportunity to turn before the weeds begin competition once more.
Sowing more seed does non get the better of patchiness normally merely few excess workss set up where the dirt conditions are poorest. However, in the parts of the field where the seedbed is better, higher seed rates result in excessively many workss, taking to thin roots and terrible housing ( McWilliam et al.1998 ) . Established seed company seed rates for each assortment should be followed.
When to works:
Weather conditions for constitution drama an of import function. In wet conditions, straw Acts of the Apostless as a mulch and increases the dirt H2O content, taking to anaerobic conditions and the production of
acidic leachates during its decomposition. These are damaging to ravish workss immature seedlings. However, waiting for the ideal seting conditions can present other jobs, winter OSR output has been found to worsen with ulterior fall planting ( Lutman and Dixon, 1986 ) . Planting excessively early may do a frontward harvest, but this can be modified with growing regulators. Although OSR has a good capactiy to counterbalance for harm, an optimum base constitution efore the oncoming of winter is a requirement for both high output and high output stableness. ( Sierts et al.1987 ) The current guidelines are to works in the UK are to seed prior to the 1st of September, to let the OSR to hold good constitution before winter.
How to works:
Airing seed will give a more dispersed out growing form, but early inter-row hoeing is impossible, so a unfertile seed bed is needed, therefore broadcast medium is unsuitable for organic systems.
Organic systems could transfer seedlings instead than seed seed as oilseed colza is a little seed and establishes easy and remains non-competitive for an drawn-out period when turning from seed. If some weedkillers are lost due to resistance, or due to miss of re-registration, conventional agriculturists may get down to transfer every bit good. ( Libeman et al. 1991 )
The presence of weeds change the cultural conditions that result in upper limit harvest output. Optimum pick for harvest denseness, cultivatar and planting day of the month frequently depends on whether or non the agriculturist can anticipate signifcant weed competion with the harvest. Crop output in the presence of weeds additions with the difference in the tallness, biomass and leaf country of the harvest relation to that of the weeds on the oncoming of competition. The harvest needs a headstart compared to the weeds, factors such as increased planting denseness, choosing for larger seeds, transplating, larger or more quickly turning cultivars and seting day of the months that maximise early season growing of the harvest demand to be considered.
Desired action on weeds need proper clocking relation to season and conditions. A given weed species will be more susceptible to a certain type of perturbation at some phases in its development than at others. The phase of the harvest ‘s development will find what disturbance it can take.
Adhering weeds such as cliverss damage reaping equipment, and taint of weed seeds consequence oil content particularly if they are similar species such as jointed charlock, field mustard or other Brassica. Weedss can be hosts to a figure of diseases and plagues, such as other Brassica being hosts for white-leaf topographic point, downy mold and powdery mold. Volunteer colza workss may be hosts to sclerotinia.
To keep the effectivity of weedkillers as weed direction tools, weeds should be exposed to them every bit infrequently as possible. Besides, certain weedkillers can endanger enivronmental quality and human wellness. Herbicides besides constitute a lifting proportion of harvest value. To understate these factors, effectual weed direction systems that are less reliant on weedkillers are needed. ( Liberman et al. 2001 )
Residual weedkillers are reliant on wet for activity, every bit good as holding a good, even seedbed, so cloddy dirt cut down their activity, on the other manus, visible radiation dirts allow better activity so doses may be reduced in early sprays. Their effectivity is besides reduced if the dirt has a high organic affair content. ( SAC 2005 )
Seedbed readying and quality are at least and potentially more of import than chemical control of bullets. In add-on, bullet damaged winter colza harvests are more susceptible to damage from insect plagues such as pollen beetle, as the energy of the harvest is reduced, and its ability to get by with farther plague harm is diminished. Cloddy seed beds are easier for bullets to travel on, so seedbeds need to be rolled to cut down balls after seeding, espeically if seting in clay dirt which is prone to clodding, and most OSR is grown on it due to it ‘s H2O keeping belongingss.
Traping can assist to measure the hazard of bullet activity. It may be deserving pin downing in the old cereal harvest up to 10 yearss earlier harvest as conditions conditions during the brief period between reaping the old cereal harvest and boring winter oilseed colza may non accommodate pin downing. If the hazard is high, broadcast slug pellets instantly after boring, do non wait for outgrowth. OSR seeds wo n’t be eaten, but it will be attacked from cotyledone phase up to 4 true foliages, so monitoring is needed after that phase. Future intervention can be applied if harvest growing is slow due to bullets.
HCGA thresholds for pollen beetles on winter OSR are rather high compared to spring thresholds, 15 pollen beetles per works in good adult harvests, 5 in backward, compared to merely 3 beetles per works in the spring. While the good adult winter harvest can counterbalance for harm by bring forthing more and larger seeds in lower cods. This threshold
It has been estimated that conveying blooming frontward by 1 hebdomad, cut downing flower screen by 0.25 and increasing leaf country so the addition in photo-assimilate during the period of seed detemination is estimated to increase by 39 % . ( Berry and Spink, 2006 )
A heavy unvarying harvest is needed to forestall pigeons set downing in the harvest, hence direction of other plagues to forestall harvest decease and hence patchiness is of import. Rabbits will eat OSR in terrible winter conditions due to hunger.
Trap harvests have been defined as “ works stands grown to pull insects or other beings like roundworms to protect mark harvests from pest onslaught, forestalling the plagues from making the harvest or concentrating them in a certain portion of the field where they can be economically destroyed ” ( Hokkanen, 1991 ) Carcamo et Al. ‘s 2006 survey shows that the seed weevils clearly preferred the trap harvest Brassica rapa to the chief harvest Brassica Tragulus Javanicus with a factor of 3-5 times more weevils nowadays in the trap than the chief harvest. Cabbage seed weevils are good known ( Dosdall et al. 2006 ) for invasion from the exterior of Fieldss into the field, so administering throughout the harvest, and a field strip of trap harvests on the exterior of the field is a successful scheme here. There would be extra nest eggs of clip and potentially other plagues with the same invasion scheme such as flea beetles would be sprayed off besides in this field trap strip.
For other plagues and Brassica species, grounds for successful trap cropping is based on the trap harvest physically taking the function of the host for a important portion of the plague ‘s life rhythm. Cabbage root fly ( Delia radicum ) is a plague of economic significance for all members of the genus Brassica in Europe, and the most important plague of Brassica species for Scotland ( Evans, 2003 ) . In a research article by Kostal and Finch ( 1994 ) it was shown that normal female chou root fly flight behaviour is interrupted by the non-host workss environing the hosts, when important host-plant stimulation predating oviposition is lost, therefore ovipositioning on hosts is reduced by at least 50 % . This experiment was carried out on a assorted Brassica cropping, with au naturel dirt, peas, trefoil, grass and four inanimate stuffs. The consequences proved their hypothesis, and showed that ocular breaks are much more of import for pest decrease that chemical repulsive force, which could intend the cheapest and easiest to turn of local screen harvests or mulches could be used for pest decrease, which would be an economic benefit to husbandmans.
An alternate method, though non one licensed in the EU is that of modifying OSR with the Bt toxin. The Bt toxin is expressed within the works tissue: chou root flea beetle larvae, weevil larvae and cod midge larvae all provender within the works and are hard to command with a surface pesticide spray.
Another option is that of biocontrol. Harmonizing to informations from booby trap traps in Goltermann ‘s 1994 survey, the marauder community in OSR field is dominated by land beetles and roll beetles in spring and early summer, the clip when many of the larvae of OSR plagues have dropped to the land from the flower stands. Spiders dominate in the fall and early winter when aphid virus vectors and grownups and larvae of chou root flea beetles and the Brassica rapa sawflies are present. Constitution of elements such as hedges and beetling Bankss will help their season-to-season endurance ( Sotherton, 1984 ) . However feeding wonts outside the OSR plagues are non good known, Kroo? ‘s 1996 survey is one of the few comphensive surveies on rove beetles, this could intend imported populations to command plagues may decease in the seasons without plagues available. Insects that are highly utile in other harvests for aphid control, such as hover flies and lady birds are of no usage in OSR due to their populations being highest in the summer, long after the aphid settlements have become established. ( Buchner, 1995 ) Pollen beetles are besides attacked by 3 chief groups of parasitioids, with estimites that 25-50 % of larvae are killed by parasitoids on unsprayed harvests in the UK, these could be introduced to a harvest for natural control, espeically with the rise of pyrethroid insecticide opposition. ( HCGA 2008 )
In the close hereafter these methods, and others based on the same rules of chemical input decrease will go standard as our usage of pesticides are reduced for fiscal, wellness and environmental grounds, but besides due to new statute law in the EU due to come into consequence in 2011 farther cut downing the list of allowed agricultural chemicals ( European Parliament Press Release, 2009 ) . The guidelines for this statute law specifically references integrated pest direction schemes to be used whenever possible alternatively of pesticides. Sustainability is the cardinal factor, these methods are improbable to do any construct up of plague opposition, specific trap harvests will non interfere with beneficals, or honey bees, and the decrease of chemicals will cut down fiscal spendings throughout the cropping seasons every bit good as cut downing negative homo and environmental effects.
Phoma root canker is the most detrimental disease of winter OSR in the UK ( BASF, 2008 ) . Cultural controls are of import, early sowing led to smaller root cankers, whereas high N handiness during the vegetive phase led to higher root canker development “ cultural patterns greatly influence phoma root canker development and that the version of cropping systems may be an effectual manner of commanding the disease. ” ( Aubertot et al. , 2004 ) Infected stubble can merely bring forth primary incolum at dirt surface so burying OSR residue can restrict the production of ascospores, it may decelerate the spread of disease within a cropping country, or between Fieldss. Phoma topographic point phase seen in fall demands sprayed as crop-dusting is uneffective one time pathogen has spread to the root.
Light foliage topographic point needs to be treated in the autum excessively, suspected infection can be revealed by puting foliages in polyethylene bags at 10-15A°C for three yearss to bring on sporolation.
Guidelines for effectual opposition direction, adapted from BASF
Use the active ingredient in combination with one or more antifungals of a different type or instead as one constituent in a plan of consecutive antifungal interventions.
Restrict the figure of interventions applied per season, and apply merely when necessary. Maintain maker ‘s recommended dosage.
Avoid eradicant usage.
Increasing N dosage systematically reduced seed oil content. Changing application timing, by using more in early spring, or detaining some until April, gave no advantage.In most well-established harvests, N applications can be delayed to March. However, growing of ill established harvests may be boosted by late winter/early spring N dressing if dirt conditions allow and ordinances permit. Normally no more than 190kg N/ha should be applied. ( HGCA, 2006. )
At a deficient site, non using a sulphur-containing fertilizer well reduced both seed output and oil content. Application of sulfur increased output and sometimes besides oil content at sulphur-deficient sites. The extra or definiciency of one or both the N and S elements may distrub protein synthesis ( Anderson, 1990 )
Crop size and canopy direction:
Many oilseed ravish harvests are excessively thick. Tests carried out jointly by ADAS and Nottingham University, and funded by HGCA, BASF, Bayer ( and in sort by CPB Twyford ) aimed to place such harvests in early spring and trial effects of several interventions to cut down canopy size. An application of tebuconazole or metconazole, applied in March or April, can cut down canopy size and disease incidence.This frequently leads to increased output. ( HGCA Topic sheet 82 )
A fresh method is that of digital canopy analysis, designed by Harket et Al. 1993, utilizing digital exposure of the country every hebdomad and a C++ plan in Windows to anylayse, a agriculturist can quantify effectual harvest canopy closing and in concurrence with other agronomic indices this can be a speedy, accurate and utile tool to foretell crop/weed competition, and to find the influence of agronomic and environmental factors on the growing and energy.
Proposed direction program for maximal output:
Favorable preceeding harvest.
Well prepared seedbed.
Good timing for planting.
Paying attending to prediction of plagues and diseases and implenting controls if required.
Application of tebuconazole or metconazole, applied in March or April, to cut down canopy size and disease incidence.
Pest, weed, disease, harvest canopy and alimentary application thresholds must be established for the peculiar demands of a peculiar harvest.
Control weeds: demand strongly competitory harvest, with a vigorous, unvarying works population.
Decision models based on specificed interventions for specific plagues should be utlisied instead than general crop-dusting, such as the one below.
Decision model for future OSR pest direction
Assortment and sowing day of the month
Previous pest history
Need for insect powder
Repeat insect powder intervention