After the wheat was dried, it couldn't be immediately stored. Before it could be successfully stored, there was another process: removing impurities from the wheat grains. This impurity removal process was very troublesome and tedious, a considerable cleaning project.
If impurity removal was done manually, it first involved wind selection. This meant using a wooden shovel to vigorously toss the wheat into the air, using the wind to blow away lighter impurities like chaff and straw.
After wind selection, the wheat would then be screened, using a sieve to filter out impurities like small stones and clumps of earth.
Chen Lan watched Uncle De and the elders operate, finding it both troublesome and time-consuming. Thinking ahead to the corn, rice, soybeans, and other crops that would also need to be harvested, the prospect of removing impurities from them using the same method gave her a headache. Without hesitation, she placed an order in the system for a medium-sized multi-functional grain screening machine.
With this machine, the over forty thousand kilograms of spring wheat harvested this time had its impurities cleared in just four days. The spring wheat could finally be smoothly stored in the warehouse.
By this time, several days of September had passed, and the rapeseed in the fields was mostly mature and ready for harvest. Not long after breakfast, Uncle De saw Chen Lan and urged her, "Xiao Lan! Grandpa Xu and the others checked the rapeseed fields again today. The rapeseed is mostly ready for harvest and can't be delayed any longer. You should arrange for people to go harvest it quickly."
Chen Lan replied unhurriedly, "Uncle De, you said yesterday that the rapeseed was mature and ready for reaping. I also went to the rapeseed fields to see. The rapeseed stalks haven't completely turned yellow yet; many are still yellowish-green. Hasn't the rapeseed fully matured?"
Uncle De chuckled and said, "Xiao Lan, you're right, the rapeseed hasn't fully matured. But the main purpose of harvesting rapeseed is to collect the seeds. However, harvesting rapeseed seeds also has its nuances. Generally, harvesting begins when the entire field of rapeseed is at about eighty to ninety percent maturity."
Chen Lan asked with confusion, "Uncle De, will harvesting the rapeseed at eighty to ninety percent maturity affect the yield of the seeds?"
Uncle De continued to explain, "Doing so is precisely to ensure the yield of the rapeseed seeds. If the rapeseed is fully mature, its pods are prone to splitting, and the seeds will fall out, reducing the yield."
Chen Lan asked further, "Then how can we tell if the rapeseed is eighty to ninety percent mature?"
Uncle De thought for a moment and explained, "The first point is to look at the appearance. If more than half of the rapeseed pods in the entire field are yellowish-green, or if on a single plant more than half of the pods are green, it indicates that the rapeseed is eighty to ninety percent mature."
Uncle De paused to catch his breath, and Grandpa Xu continued from where he left off, "The second point is to look at the color of the seeds. If the rapeseed seeds are brown or half brown and half red, it also indicates that the rapeseed is mature and ready for harvest. Xiao Lan, we've already delayed a day. It's now the hottest part of the day when the sun is high. We can't afford to wait. If it delays for another two days, the rapeseed will be too ripe, which will actually be detrimental and lead to reduced yields. In short, rapeseed cannot be harvested when it is too ripe, or the yield will decrease."
Grandpa Li also chimed in, "The timing for harvesting rapeseed is completely different from harvesting wheat. Rapeseed is generally harvested in the morning with dew still on it. This helps prevent the rapeseed pods from splitting and the seeds from detaching. When harvesting, we must cut, lay, bundle, and transport gently. It must be transported back to the drying area promptly and not piled or dried in the fields to prevent the pods from splitting and seeds from detaching. This is all done to prevent reduced yields."
Grandpa Xu added, "What Uncle Li said is correct. However, the rapeseed just brought back to the drying area, since it's not fully mature, cannot be dried immediately. It needs to be stacked into hollow cylindrical or square stacks and left to ripen for four to six days. Then, on a sunny day, the rapeseed is spread out to dry, threshed, and cleaned before being stored or pressed for oil."
Chen Lan felt a bit dizzy from the elders speaking one after another. She hadn't expected that eating her own home-grown rapeseed oil would be such a difficult process.
With a helpless sigh, she immediately replied, "Uncle De, esteemed elders, please don't worry. The sun has just risen, and the dew should still be on the ground. There's still time. I'll arrange for people to go harvest the rapeseed right now."
Without further delay, she hurried off to find people. Fortunately, everyone had just finished breakfast and hadn't gone far. In the distance, she saw Lin Mai chatting happily with her friends as they walked.
Chen Lan had already thought on the way that manually harvesting rapeseed sounded like a lot of trouble. So, she decided to use a combine harvester for this year's ten-odd mu of rapeseed. A combine harvester could complete the entire process of rapeseed harvesting, threshing, straw separation, and seed cleaning in one go for such an area.
Why would she need people to harvest it piece by piece when a job that takes a couple of hours could be done so efficiently? Why make things so difficult for herself? Wasn't that just asking for trouble? With machinery, why bother with such tedious work? It seemed like simple matters were being made overly complicated.
Chen Lan unhesitatingly quickened her pace and caught up. She called only Lin Mai, and together they went to the garage. Chen Lan first adjusted the combine harvester's sieve to a fine mesh, checked that all connecting and conveying parts were airtight, and adjusted the speed of the threshing drum and the fan.
Harvesting rapeseed with a combine harvester was a bit more involved and required sufficient patience and care. The speed couldn't be too fast during harvesting; it had to be operated at medium to low speeds, which was quite demanding.
So, Chen Lan asked Lin Mai to drive the multi-purpose agricultural tractor, and she would drive the combine harvester herself, letting herself endure the difficult task!
Because of the significant dust generated during the combine harvester's operation, both of them took protective measures before going into the field. Chen Lan put on a dust mask, a dust cap, and a dust suit before starting the machine and heading into the field to harvest.
The combine harvester had a straw crushing device, so as it operated, the stalks were directly pulverized and returned to the field. This was why so much dust was flying, filling the air.
The combine harvester was truly impressive. The ten-odd mu of rapeseed were harvested in less than two and a half hours, even though Chen Lan was operating it at a low speed.
Next, Lin Mai drove the multi-purpose agricultural tractor into the field and meticulously plowed it, burying the pulverized rapeseed stalks in the soil to decompose as fertilizer. Chen Lan thought, this should also count as organic green fertilizer, right?