With disappointment, Marin left Cologne with the team and returned to Texel. Along the way, the little girl Angela saw that Marin was unhappy and couldn't help comforting him. He even sang and danced to relieve Marin's boredom, which made Marin feel a lot better.
When he returned to Den Burg, Marin found that the spring plowing on the five big islands had already started. Of course, what unfolded was the first step—plowing the land...
Marin owned most of the horses—except for war horses and pregnant mares, all of which had been pulled off the fields. In addition to these draft horses, a lot of cattle were bought on the island, put on nose rings, and pulled off the fields for plowing.
After plowing the land, it is time to apply base fertilizer. In fact, the manure that has been extracted from the nitrate in the cesspool is mixed with plant ash, fish bones, leftovers from killing fish and dead fish, etc., and sprinkled on the fields. Then, in a few more days, it's time to plant the seeds.
In fact, after the nitrate is extracted from the manure, the nitrogen content is reduced, which affects the fertility. But this is not a problem, because as long as you apply more, you can also make up for the problem of the decrease in nitrogen content.
Now that the island has such a large population, many horses have been raised, and sheep have been raised on a large scale. Therefore, there is no shortage of feces on the island. And because of the large-scale fishing in the Wadden Islands, there is no shortage of fish bones, leftovers and dead fish. Therefore, it can be said that there is no shortage of nitrogen and phosphorus fertilizers among the three major fertilizers.
However, potassium fertilizer among the three major fertilizers is not enough. Because there are few vegetation on the islands, and there is not much ash. Also, plant ash is a bit low in potassium. Although it is said that the potassium salt in plant ash is potassium carbonate, it is the best potassium fertilizer, stronger than potassium chloride. In the case of the same potassium content, the fertilizer effect of plant ash is stronger than that of special potassium fertilizer.
However, the quantity of plant ash in the Wadden Islands is limited. The plant ash mainly comes from residents lighting fires for cooking. But Marin promoted coal burning on the island, which reduced the production of plant ash by a lot. In addition, there are few plants and trees on the archipelago, and there is not enough to burn them. Therefore, Marin feels that there is a lack of potassium fertilizer now...
Coincidentally, good news came from Kohler at this time...
It turned out that Marin had asked Kohler to send people to the Harz Mountains to buy bitter salt mines. So, according to Marin's instructions, Kohler hired Jewish businessmen to come forward and go to the Harz Mountains to find bitter salt mines...
After a long period of searching, the Jewish businessman hired by Kohler's men finally found the Bitter Salt Mine. However, the first bitter salt sample was sent back, and Marin was tested by flame reaction and found that it was not potassium salt. (Potassium salt flame reaction is purple)
Then, after a simple experiment, Marin discovered that the bitter salt was Glauber's salt (a hydrate of sodium sulfate) at all, not the potassium sulfate he needed.
So, Kohler sent people to look for other bitter salt mines again...
When Marin was worried about the lack of plant ash, a new batch of bitter salt samples was sent back. After the flame reaction test, Marin discovered that it was potassium salt...
However, this potassium salt seems to have a lot of impurities. Because, when the potassium salt reacts with the flame color, the lavender color cannot be seen clearly, and it is greatly disturbed by the yellow color of the sodium element. Fortunately, last time Marin brought back a lot of stained glass from Venice, including blue cobalt glass specially used to filter yellow. Through the cobalt glass, Marin saw the long-awaited purple flame...
Marin can now confirm that this bitter salt contains a lot of potassium, but it is also doped with a lot of sodium. Because it is bitter salt, there must be a lot of sulfate ions in it. However, Marin suspects that it may also contain a lot of chloride ions...
Marin just wanted to use this bitter salt as a potassium fertilizer. Therefore, sodium ions and chloride ions are unnecessary things. Therefore, he began to think of ways to separate the sodium and chloride ions as much as possible to increase the content of potassium.
Therefore, Marin found a few large pots and a few workers who boiled salt, and began to use the principle of different solubility of salt to separate sodium elements and chloride ions...
The solubility of sodium chloride is relatively stable and changes little with temperature. The solubility of potassium salts varies greatly with temperature. Marin is using this principle to start a simple separation.
First of all, Marin took out the salt and prepared saturated salt water. Then, he asked the workers to heat the cauldron with saturated salt water.
After the saturated salt water boiled, Marin began to add bitter salt...
At the beginning of adding bitter salt, a lot of crystals were precipitated. Marin can conclude that these are sodium chloride - because sodium chloride is saturated in this solution...
Marin asked the workers to filter out the crystals that precipitated at the beginning, that is, excess sodium chloride. Then, guessing that it was almost saturated, Marin stopped adding bitter salt and filtered off the excess sodium chloride crystals.
Then, Marin removed the flame and let the brine cool down to normal temperature. At this time, a lot of salt precipitated out of the pot...
Marin knew that the precipitated salt was probably a mixture of potassium sulfate and sodium sulfate. However, Marin had no way to separate the sodium sulfate. If it is a mixture of potassium nitrate and sodium chloride, it is easy to separate. Potassium sulfate and sodium sulfate are too similar in solubility to be separated.
Moreover, even if some sodium ions are mixed with potassium sulfate, it will not have any effect. Anyway, it's only used as agricultural fertilizer, not for chemical experiments, so it's not that strict.
After purification, Marin performed the flame reaction again. After observation, Marin found that the yellow flame was much dimmer, while the purple flame became more obvious. Therefore, Marin can conclude that the content of potassium ions is much higher now, and it can be used as a higher-level potassium fertilizer than plant ash.
Coincidentally, this time Kohler's men brought back a lot of bitter salt, about ten tons. Marin simply used this method to separate. Then, more than a dozen tons of bitter salt were extracted to produce a mixture of about seven or eight tons of potassium sulfate and sodium sulfate.
Marin sent people to pack all these mixtures in sacks. After that, he arranged for another group of uninformed people to pour the mixture of seven or eight tons of potassium sulfate and sodium sulfate into each septic tank under the cover of night... Except for a few people, no one else knew...
But Marin knew that this time, because of the addition of phosphorus-containing fish scraps and potassium-containing bitter salt and plant ash, in autumn harvest, because the three major fertilizers are complete, the rye production will definitely increase...
I dare not say that the yield of thousands of catties per mu is like that of later generations, but the yield of four to five hundred catties per mu can still be achieved. This is mainly because the fertilizer effect of these soil fertilizer mixtures cannot catch up with purified fertilizers after all. Moreover, the seed varieties of this era are really bad. Therefore, it is not bad to have a yield of four to five hundred catties per mu. This is also because Marin promoted the method of seed selection by soaking in salt water and selected excellent seeds for sowing.
Although a lot of potassium fertilizer was added this time, Marin was also very dissatisfied. Because he has no way to separate potassium sulfate and sodium sulfate.
Therefore, Marin ordered Kohler to send someone to find non-bitter mineral salt (without sulfate ions), and bring it back for him to check with the flame reaction method. If there is a purple flame, it contains potassium chloride. And because salt is not bitter, there must be no sulfate ions. Using the solubility method to separate potassium nitrate and sodium chloride is very simple, and the purity is high...
Of course, this is a later story. Now, Marin also has a potash mine with low purity. Marin still ordered people to buy the bitter salt mine and use it as potash fertilizer.
Because the Bitter Salt Mine has no use for hesitation, and the price is not high. The kind of non-bitter potassium salt mine that does not contain sulfate ions, because potassium chloride can actually replace sodium chloride as table salt. Therefore, the cost of buying such a salt mine is too high, and it is not cost-effective. It is better to use this bitter salt mine first. Marin has heard that the price of this bitter salt mine is basically the price of cabbage. In the past, only some unscrupulous profiteers used these useless bitter salts as table salt and sold them to consumers. Other than that, there is no other use for this bitter salt. Even if unscrupulous businessmen use it as salt, the market is not good. Because consumers are cheated once, it is impossible to buy this kind of bitter salt next time. Therefore, this kind of bitter salt mine is useless, so the selling price is very low. Marin can win it for a small amount of money, so why not do it