Why Should Organic Farmers Consider Seed Cleaning For Crop Selection?
Organic farmers have to take certain factors into account like soil fertility, market demand, and balanced rotations for growing crops, specifically seasonal crops. Here, grain seed cleaning is a vital consideration that cannot be disregarded. Since at harvest, the farmers commonly have the plant mixtures, whether they are intentionally intercropping, having the previous years' volunteer plants or having weeds with escaped control; so they can usually predict the crops and weeds to dominate in the upcoming growing season just by looking at the last years' statistics and behaviour.
Now selecting a crop on the basis of how the seed gets easily separated from the weeds and likely volunteers.
Through seed cleaning, the contaminants are removed in different ways. Sieving in the combine is the first step. Further sieving is done once combining is over. Mostly sieving separates the seeds by size, but the shape is more important.
Sieves deserve particular importance for small weed seeds removal from the larger crop seed, like the pigweeds from the lentils. Alongside, separating a few crop mixtures by size, like mustard from barley or else peas, and oats or barley from peas or lentils is an easier process.
The second cleaning stage is done on a gravity table, wherein the seeds are sorted by density or weight. It is the common on-farm seed cleaning and used for operating thistle heads out of peas as well as frosted kernels out of cereals.
The final cleaning is done by a colour sorter. The grain seed cleaners use the equipment for their additional uses, as in extra hauling, which saves time and cash. For instance, a colour sorter picks out the pea chips from oats.
Concern levels regarding contamination from the unwanted seeds are different for different markets. The milling oats market will have a low tolerance for foreign materials since the consumers are against lentil or pea chips in their oatmeals. Additionally, wheat allergies concerns have caused low tolerance for wheat seeds in flax or oats in several markets.
Generally, the feed market is having the most relaxed specifications for crop purity.
Indeed mixtures, chips, splits, and other crop types are combined, while legumes add proteins needed in the cereal grains.
For instance, a pea-barley mixture could be an effective intercrop for the feed market, but these two crops might not be well separated for selling the barley either in the pearling or malting market.
It creates a bearing on rotation planning. If barley is seeded on pea stubble, then it will result in pea contamination, which will further be difficult for removing from barley. But when the grain seed cleaners carry out seeding peas on barley stubble, then it is less problematic.
According to the grain seed cleaners, cleaning any crops out of mixtures is possible, but it is categorised into the economic matter.
Usually, the majority of crop determines separation, like removing the wheat from the flax, with the settings resulting in a somewhat pure wax sample, and less pure wheat sample. Growing flax on wheat stubble results in tough contamination issues, while contamination problems are less for growing wheat on flax stubble.
During seed cleaning, the grain seed cleaners handle different difficulties from varied crop combinations. Especially from small lentils, lentil splits are difficult for removing from flax. Separating barley from either oats or wheat is too tough. Removing small-seeded lentils from wheat or oats is hard.
Weed removal is an additional concern for organic farmers since due to its small seeds, removing weeds is much difficult. Cleaning wild mustard or cow cockle from tame mustard is indeed a challenging task that the grain seed cleaners meet on time. Separating wild oats from an oat crop, is tougher, compared to other cereals.
Undoubtedly, organic farmers need the services of grain seed cleaners since along with separation and removing contaminants, seed cleaning is critical while planning for successful intercropping. The process is a must in rotation planning since the present years' crops could be mingled with the last years' crop volunteers. Planning becomes more effective when the farmers know which seeds are easily separated, and the separations in need of more effort, time and expenses.