Seed production-The final cut
By Dave Saltman
Last summer I wrote an article with Jon Chippendale, while he was still with British Seed Houses (BSH), which started out to explain why grass seed costs so much to buy (http://www.pitchcare.com/magazine/article.php?id=799). The article was quite extensive but still left much to be explained.
Later in the year, I was invited down to IGER in Aberystwyth to meet the guys who actually develop the new seed varieties that help us, as an Industry, perform to the best of our ability (http://www.pitchcare.com/magazine/article.php?id=1097). These varieties are developed through cross-breeding, sometimes over 10-12 year time spans, to withstand more shade, stress, drought, wear etc than previous cultivars.
To finish the trilogy I visited the BSH premises near Lincoln, in February this year to see the cleaning and bagging process, which is reported below. So, having seen the science of breeding varieties such as AberImp, the subsequent crop being inspected in the field, it was interesting to track that field of grass back to the factory, where it is now bagged and ready to be delivered for use on numerous playing surfaces across the country.
I asked Sandie about her role at Lincoln. "We're what is classed as a licensed satellite seed testing station which generally means that the Ministry (DEFRA), give us powers to carry out self-certification tests. They do charge us for the privilege of doing that but, because they are allowing us this privilege, we are very closely monitored by the ministry through NIAB (National Institute of Agricultural Botany) at Cambridge. The NIAB take roughly 10% of all the samples that we process and certify for check testing. They are checking my analytical ability and checking that I am not reporting something that isn't correct.
As well as that we have the PHIS which involve occasional visits from a Plant Health Inspector. They will arrive and walk through the warehouse selecting random stock pots that may or may not be our own seed. It may be seed that we have imported. He will take a sample and send that away for testing at NIAB as well, so we are scrutinised on all angles. We then get the reports, and if things are not quite right we could get into serious trouble. Everything is very tightly controlled.
Every 5 years, I have to go for an analytical examination where I am tested on everything that I do in the laboratory. A test mark of 98% has to be achieved to be able to continue with your analytical license. I took my exams, about 24 years ago now, to be classed as an analyst, and then further exams to be classed as an analyst in charge which allows you to hold the license for the laboratory, where you are allowed to undertake tests on behalf of DEFRA. The laboratory is responsible for quality control of all seed that we bring in or any that we send out regardless of whether we are processing it ourselves. If we buy imported seed I check it so that we as a company are fully aware of what we are selling out in the bag.
When we bring our own seed in for processing, again it is tightly controlled. We will take a sample from the farm and do a 'moisture and germination' test and an analytical purity search on it, so we can decide whether we want to bring it in, whether it's a good enough standard. If it passes these preliminary standards we will bring the lot of seed in on a trailer. Again I will do a moisture test to ensure that it hasn't developed a problem in storage. Sometimes if a seed is harvested wet or too dry, in storage it can kill off the germination bacteria. There are numerous problems that could arise.
If the moisture levels are ok, I allow the lot of seed to be tipped and then it goes through the processing. Approximately half a tonne per hour can be processed, a trailer of seed will weigh anything between 10 and 15 tonnes, so it takes between 20 and 30 hours for a load to go from one end of the plant to the other. As it is going through the plant I will take a sample from the machines every 2 hours, or more if we are having any problems. I keep checking and checking so we can alter the machine settings until purification is right. If it isn't right we will put it through the machine again. Our standards are actually higher than DEFRA standards because we are producing for turf growers as well. The standards we are working to can be a little confusing because the DEFRA standards are less than our own amenity standards.
So, we have our own amenity standards. If we are processing for sports turf we look for anything that is not the seed it is supposed to be. We record anything, which allows the amenity team to make a decision on what to do with the seed. We are very strict on ourselves to produce the quality of seed the turf growers require. All of our records are open to the ministry and IS9002, audited by them once per year. With existing stock in the warehouse, we will do a germination check every six months, usually in November and June. Anything in the warehouse at the time will have a stock germination check. If it is below standard, then it is scrapped.
On my desk at the moment, I have a sample from a trailer in take load. I am taking out anything that is not a perennial ryegrass. It gives David, our Warehouse manager, an idea of what he has to clean out and, accordingly, how to set up the machines to do the job. Some impurities are easier to clean out than others. It gives us an idea of what seed we are going to end up with. I've got 3 gms here and if I'm taking out 0.3 gms then obviously we are going to lose 10%.
I also do a 60gm search. In that, I'm just looking for other seeds, so I don't take out any rubbish, I'm just looking for anything that is not perennial. Again I will make a report on that and it will be kept on record. We are building up a history all the time of the seed lot that's going through the processing plant - from the field to the bag going out to the end user. At any time we can pinpoint records and reports and relate back to the seed at that stage. With the seed purchased from others, we will have our own searches and germination tests but we don't have the same history as we do with our own seed.
When it has gone through the processing stage and we are happy with the quality, it will be certified and bagged up. We take an official sample from the lot, which is a composite sample of quite a lot of little samples. We have what we call a sampling sphere (A metal hollow rod) to take the samples. Once the seed is bagged we take a sample from 1 in 5 bags, so we end up with about 80 small samples. I then mix it and divide it into half. I then take a 60gm sample, a 6gm purity and 54gm search. On that I will carry out a germination test, a purity test and a foreign body search.
When I divide it down the excess seed is saved, and that is called our reserve portion. That is the portion the ministry may or may not take for checking. Officially, we are required to keep the reserve portion
With our own processes and certified grasses the ministry take a certain percentage for their verification check box. They are checking the variety is true to form, it's another way of checking that we are producing seeds of a high standard. They are not so much interested in purity or the fact that there are other seeds in it. They are merely interested in whether the variety performs as it's supposed to.
We measure the moisture on the seed with a Zionar moisture meter, an electronic tester. We pour in a sample and it will work out the moisture content of the seed. This current sample for example has a moisture content of 12.8. Our moisture standard for intakes is 14. If the graph shows a moisture content in excess of 14 we think very carefully about taking it because, if we process it and it stood in the bins, the quality may well deteriorate. Each 60 gm search takes about 1 hour. However, if we for example import a smooth stalk seed, a search on that may well take half a day because I have to look at each individual seed. It has to be done because I need to know if there is any other meadow grass in it. Other countries' ministry standards are just not strict enough for our standards.
If we buy in certified seed from other countries, it usually arrives in 25kg bags. We take samples and, if it is not up to standard, it goes back. We do not attempt to clean it through our processes. Fortunately, it only happens occasionally because the companies we buy from know we have and expect very high standards."
The seed is then sucked up into the main cleaner, where it is processed through a series of sieves that not only further remove chaff and foreign bodies, but also seed that is not desirable. Undesirable seed can be varieties such as annual meadow grass, different cultivars as well as seed that is unlikely to germinate and is therefore light in comparison to the rest. From the main cleaner, the batch is then dropped into a series of spinning cylinders, they spin at specific speeds, using centrifugal force to remove any remaining unwanted chaff and seeds. These cylinders are dimpled and catch the good seed in the dimples, allowing contaminates to fall out into a trap.
During these processes all the unwanted material is collected in bags under the processing plant and sold to a local pig farmer for animal feed. Nothing is wasted. The good seed is then collected in a holding hopper, ready to be decanted into bags. Depending on the quality of the original lot, anything between 10 and 30% of the weight can be lost due to the cleaning process. However, an average loss is generally around 10-15%.
The bagging process itself is quite simple, but still manual in it's design. An empty bag is put on a weighing scale, the gate at the bottom of the hopper is opened, filling the bag to the required weight. In most cases this is 25kgs. The bag is then passed through a sewing machine to seal the top.
It has always been a bug bear of mine opening up bags of seed easily, it took me a while to realize that there was a very easy way to open a bag, by cutting the string at the right end so that it pulls through the bag. If you try to open from the wrong side, it's all to easy to waste time unpicking each individual stitch. Believe me, I have watched too many people do this. Dave's advice is to look at the bag so that the flat stitching side is face up, and cut the string on the right hand side of the bag. This will allow the string to unravel effortlessly as you pull.
The bags are now on pallets being delivered to contractors and Groundsmen all over the country.