Frontierstechnical team says that growers faced with rape crops at varying stages ofmaturity will need to give careful consideration to desiccation this season.The use of a pod sealant product is always advisable to increase the efficiencyof the desiccation process and prevent pod shatter but Frontier says it willprovide additional benefits to growers with inconsistent crop growth.
Brian Ross,technical manager for Frontier explains: Desiccation where extremes of cropstages are prevalent even within single fields will be difficult to manage.
Oilseedrape crops have had a torrid time, challenged by weather, slugs and incessantpigeon predation. This has resulted in variable crops with a number of growthstages apparent; from full flower and good plant stands, through to very thin,relatively short crops with some flowering but many still at bud stage. The useof a pod sealant is advised for all rape crops but will be an especially usefultool to help maintain pod integrity of those crops at inconsistent growthstages.
The mostcommon method of desiccating rape this year is likely to be chemicaldesiccation using one of three active substances: glyphosate, glufosinateammonium or Diquat.
If thecrop is even with no very difficult weeds such as sowthistles or cleavers, anapplication of straight glyphosate is a relatively inexpensive option.Glyphosate is not a true desiccant but rather removes moisture from the plantso patience is needed after application. Harvest will not be possible for up to21 days following glyphosate. Where there are difficult weeds, an addition ofBlaze (ammonium sulphate + polyacrylamide) can help speed up action againstthem.
In manyareas of the country, hard water can affect the efficiency of glyphosates bylocking up the active substance. In these regions it is important to use awater buffering product such as Aquascope, which should always be added to thetank first. If Blaze is being used it will act as a water conditioner and againshould be added to the tank first.
Forgrowers with seed crops glyphosate is not permitted. If a kinder alternativeto Diquat is required growers should choose glufosinate ammonium (Harvest)instead. This too requires patience as it takes up to 21 days to work properlydepending on the weather.
Where crops are at a wide range of stages andit is difficult to separate into areas ready for treatment the use of a podsealant such as Podium or Podstik across the field will help manage this.
Brianexplains: Sealant should be applied when the most forward part of the crop isalmost ready for desiccation. Under normal weather conditions this will holdpod integrity of those forward parts until the rest of the field is ready fortreatment. This has worked very well in the last few years and could be a veryuseful tool this year. It can also be added to the glyphosate where crops areeven. Podium and Podstik have the added advantage of drying within 3045minutes. Follow label recommendations on cleaning out after using the podsealants.
The thirdactive is Diquat which is a true desiccant and works far quicker than the othertwo. This is very useful where poor crops contain a lot of rubbish and needto be dealt with swiftly. Again, the addition of a pod sealant, either with theapplication or on its own, will help where large areas are to be sprayed. Thiswill reduce the risk of pod shatter where harvesting is delayed due to workloador weather issues.
Direct combining is, agronomically, a betterway of preserving the crops potential but requires an even crop and nerves ofsteel regarding weather conditions. It also offers the benefit of allowing thecrop to senesce naturally without the need for direct management.
Swathingis the second kindest method of desiccation with the crop cut and left to dryon top of the swath. This year, however, many crops are not going to have thelength of stubble required for good airflow to dry the laid swath. This is alsorelatively expensive compared to chemical desiccation.
Whatever the scenario, rape desiccation this year will require carefulthought and good advice from a professional agronomist.