10: Chapter 10 Preparation

Jiang Lin carefully recalled that dark red Wasteland.

Compacted, rust-colored, a military entrenching shovel could only chip off a small piece when struck down, like hitting a permafrost layer.

There were no earthworm casts, rotted roots, or decayed leaf fragments in the overturned soil.

It was as clean as if it had never known life.

The faint sulfur smell in the air indicated that there were sulfur-containing compounds in the soil.

The Geiger counter reading averaged 1.2 microsieverts per hour, several times higher than normal background radiation.

This indicated that the soil might contain radioactive minerals, and the decay of radioactive minerals was often accompanied by the enrichment of heavy metals.

Could potatoes sprout in such soil?

Could Soybean root nodules survive?

Would Pumpkin seeds be burned to death by acid the moment they touched the soil?

He did not know.

But he could check.

Jiang Lin opened his phone and went into the browser.

He had no testing data for the Wasteland soil, no pH test strips to measure acidity and alkalinity, and no spectrometer to analyze mineral components.

He could only search based on impressions, and then piece together a roughly usable plan from the search results.

He first searched for dark red soil.

The search results popped up a bunch of popular science articles on geology.

Dark red soil is usually rich in iron oxide, the main component of rust.

Iron oxide itself is non-toxic to plants, but soil rich in iron oxide is often also rich in other metal oxides, such as aluminum oxide and manganese oxide.

This type of soil is very common in the red soil regions of the south, where the pH value is usually acidic, organic matter content is low, and it is prone to compaction.

He searched again for red soil improvement planting.

The content that popped up this time was more specific.

The characteristics of red soil are acidic, poor, sticky, and compacted, with a pH value usually between 4.5 and 5.5, an organic matter content of less than one percent, fine soil particles, hard like a brick when dry, and sticky like clay when wet.

It felt almost identical to the Wasteland.

He clicked into them one by one.

There were popular science articles from agricultural technology stations, experimental reports from agricultural universities, and videos of farmers improving red soil themselves.

The first problem with Wasteland soil was acid.

Acid rain, sulfur smell, dark red iron oxide, all clues pointed to acidity.

He saw in the search results that the pH value of red soil is usually between 4.5 and 5.5, and severely even lower than 4.5.

Moreover, acidic soil fixes phosphorus, turning it into insoluble phosphates that plants cannot absorb.

It activates aluminum ions and manganese ions, and once the concentration is high, it will poison the root system, making the roots black, short, and unable to grow.

The most direct method to improve acidic soil is to apply lime.

Quicklime, calcium oxide, reacts with water to form calcium hydroxide, which is strongly alkaline and can quickly neutralize soil acidity.

He saw the exact dosage in an agricultural extension article.

For plots with a pH value of less than 5.0, apply 50 to 80 kilograms of quicklime per mu; for those with a pH value of 5.0 to 5.5, the dosage can be halved.

However, lime cannot be planted immediately after spreading; it must be spread one to two weeks in advance, combined with tillage to thoroughly mix it with the soil, and planted only after the reaction is complete.

Moreover, lime cannot be applied only once; soil acidification will recur, and it needs to be replenished every year.

He drew a key symbol next to quicklime, and then wrote a line of small characters: "Spread one to two weeks in advance, 50 to 80 kilograms per mu."

In addition to lime, plant ash can also be used.

Plant ash is the ash after plant combustion, with potassium carbonate as its main component. It is alkaline, can neutralize acidity, and can also supplement potassium at the same time.

Spreading 40 to 50 kilograms of plant ash per mu of land can both adjust acidity and increase fertilizer.

He wrote next to plant ash: "Milder than lime, does not burn seedlings, but large dosage required, needs to be accumulated."

The second problem is compaction.

The soil on the Wasteland was as hard as compacted concrete.

A military entrenching shovel could only pry up a small piece when struck down, and looking at the fracture surface, it was smooth with no pores at all.

In this kind of soil, air cannot get in, water cannot seep down, and root systems cannot take hold.

He saw in an article about newly reclaimed land improvement that compacted soil requires deep tillage.

Plow to a depth of more than thirty centimeters, break up the compacted layer, and increase breathability and water permeability.

Organic fertilizer must be applied after plowing.

Organic fertilizer is the core of improving compaction.

Decomposed farmyard manure, compost, green manure, mixing these things into the soil can increase soil organic matter, improve aggregate structure, and make the originally compacted soil loose and breathable.

The dosage of organic fertilizer is about 2000 to 3000 kilograms per mu.

Two thousand kilograms, two tons.

Jiang Lin frowned slightly when looking at this number.

He circled the source of organic fertilizer and drew a branch arrow next to it.

What to do if there is no farmyard manure?

Plant green manure.

Green manure is directly turning plants into the soil as fertilizer.

Legumes are the best green manure.

Soybean, alfalfa, Chinese milk vetch, their roots have rhizobia, which can convert nitrogen in the air into nitrogen fertilizer. Turning them into the soil can both increase organic matter and supplement nitrogen.

He saw in a Q&A about Wasteland reclamation that newly reclaimed barren land can first be planted with a crop of Soybean or vetch, and plowed into the soil when the plants reach full bloom, which is equivalent to feeding the soil a meal of green manure.

He wrote next to Soybean: "Harvest the beans, plow the stalks into the soil."

The third problem is barrenness.

There were no fallen leaves, no earthworm casts, no dark brown, soft humus layer with a muddy, earthy smell formed by microorganisms decomposing animal and plant remains on the Wasteland.

The entire Wasteland was barren with not a blade of grass, and the organic matter content was approximately zero.

Without organic matter, the soil has no aggregate structure, cannot retain water, and cannot retain fertilizer. Relying solely on chemical fertilizers can only treat the symptoms; after chemical fertilizers dissolve in water and are absorbed, the soil will become lean again, and long-term use of chemical fertilizers will exacerbate acidification.

He saw in a Wasteland improvement case that some growers contracted newly reclaimed Wasteland and applied a large amount of chemical fertilizer. As a result, the land became leaner the more it was farmed, the crops grew worse and worse, and the diagnosis given by agricultural experts in the end was that the soil organic matter content was extremely low, and organic fertilizer must be increased.

Organic fertilizer.

Organic fertilizer again.

Jiang Lin turned his draft paper to a new page, wrote the four words "sources of organic fertilizer" at the top, and began to make a list.

First, green manure.

Plant Soybean, harvest the beans and plow the stalks into the soil.

Growing a season of Soybean can increase the nitrogen content in the soil and slightly increase organic matter.

If wild weeds or alfalfa seeds can be found and brought over, specifically planting a crop and plowing it in will have an even better effect.

Second, kitchen waste composting.

On the Wasteland, he usually ate compressed biscuits down to the last crumb, making kitchen waste completely impossible.

However, if things could be grown in the future, rotten vegetable leaves, potato peels, Pumpkin vines, all these could be composted.

He searched the internet for composting methods: one layer of kitchen waste, one layer of soil, keep moist, wait for it to rot into dark brown powder, which is organic fertilizer.

The cycle is about two to three months.

Third, plant ash.

If anything burnable could be found on the Wasteland, even some withered plant remains, burning them into ash could both adjust acidity and supplement potassium, and the carbon particles in the ash could also improve soil structure.

He drew a question mark next to plant ash.

Whether there was anything burnable on the Wasteland could only be known after going there.

The fourth problem is heavy metals.

This was the one that gave him the biggest headache.

The Geiger counter reading was 1.2 microsieverts per hour, six times normal background radiation.

This level of radiation would not kill people immediately, but it meant that radioactive minerals existed in the soil.

Radioactive minerals are often associated with heavy metals.

Uranium, thorium, radium, and their decay products exist in the soil in the form of metal ions.

In addition, dark red iron oxide soil itself easily accumulates other metal elements, such as aluminum, manganese, and chromium.

In an acidic environment, the activity of these heavy metal ions will increase, making them more easily absorbed by plant roots.

If potatoes, Soybean, and Pumpkin grown absorb heavy metals, they will accumulate in tubers and seeds.

If he ate them, it would be equivalent to eating heavy metals into his belly.

No problem in the short term, what about the long term?

Lead damages the nervous system, cadmium damages the kidneys, mercury damages the brain.

The longer he stayed on the Wasteland and the more things he ate that he grew himself, the greater the accumulated dose would be.

He searched for soil heavy metal pollution remediation methods.

The content that popped up was divided into several categories: physical remediation, soil replacement, digging away contaminated soil and replacing it with clean soil.

Unrealistic on the Wasteland, where would he find clean soil?

Chemical remediation, applying passivating agents such as lime, biochar, and humic acid to adsorb and fix heavy metal ions, reduce activity, and make them less easily absorbed by plants.

Bioremediation, planting hyperaccumulators, such as Pteris vittata which can accumulate arsenic, and Sedum alfredii which can accumulate zinc and cadmium, absorbing heavy metals in the soil into the plant body, and then harvesting and removing the plants.

Jiang Lin wrote a few words next to the passivating agent: lime, biochar, humic acid.

He already intended to use lime; while neutralizing acidity, calcium ions can compete for adsorption sites with certain heavy metals and reduce heavy metal activity.

Biochar is black charcoal powder burned from organic matter such as straw under high temperature and anoxic conditions, with a huge specific surface area, capable of adsorbing heavy metal ions.

Humic acid is the product of organic matter decomposition and can also chelate heavy metals.

He drew a question mark next to the hyperaccumulator plants again.

If some seeds of hyperaccumulator plants could be brought over, specifically planting a season to absorb heavy metals, and then harvesting and taking them away, the heavy metal content in the soil could decrease year by year.

But where to buy seeds of hyperaccumulator plants, are they expensive, and can they survive on the Wasteland?

These were all unknowns.

He temporarily listed this plan as a long-term plan.

The fifth problem is radiation.

The Geiger counter measured the external exposure dose of gamma rays and neutron rays, 1.2 microsieverts per hour.

However, the real danger of radioactive substances entering the human body comes from internal exposure: radioactive dust inhaled into the lungs and radionuclides eaten into the belly.

After radionuclides enter the human body through the food chain, they will accumulate in organs such as bones, liver, and thyroid, continuously irradiating surrounding tissues from the inside, causing much greater harm than external exposure.

He saw in a paper on the safe utilization of radioactively contaminated land that the methods for reducing radionuclides from entering the food chain are similar to heavy metal passivation.

Applying lime and organic fertilizer can reduce the activity and migration ability of radionuclides and reduce plant absorption of them.

In addition, choosing low-accumulation crops is also very important.

The absorption capacity of different crops for radionuclides varies greatly, and the absorption rate of root and tuber crops is usually lower than that of leafy vegetables.

Potatoes store absorbed radionuclides mainly in stems and leaves, while the concentration in tubers is relatively low.

As a legume, Soybean also has a lower absorption rate for certain radionuclides than leafy vegetables.

He wrote next to potatoes: low accumulation.

He added a line of small characters: peeling can further reduce intake.

He organized this information into a complete Wasteland soil improvement plan on his draft paper.

Step one, deep tillage.

Use a military entrenching shovel to turn the compacted dark red soil to a depth of thirty centimeters, break up large chunks, and pick out stones and debris.

This step is the most physically demanding, but also the most basic step.

Without plowing the land, nothing can be planted.

Step two, acid adjustment.

Spread quicklime one to two weeks in advance, about 50 to 80 kilograms per mu.

He did not know how large an area he could reclaim, but this ratio could be converted: about 0.1 to 0.15 kilograms of quicklime per square meter, which is 100 to 150 grams.

He used quicklime bought from the agricultural supplies market, combined with plant ash, spread it evenly, and plowed it into the soil.

Step three, increase organic matter.

Plow Soybean stalks in as green manure.

Kitchen waste composting, rotten vegetable leaves and potato peels all recycled for composting.

If any burnable plants can be found, burn them into plant ash.

Step four, passivate heavy metals and radionuclides.

Lime itself has a passivating effect.

It would be best if biochar could be obtained.

He saw videos online of people burning biochar themselves using nutshells and straw; the principle is not complicated, just sealed anoxic heating.

Humic acid can be bought at the agricultural supplies market, and the price is not expensive.

Step five, long-term restoration.

If seeds of hyperaccumulator plants can be obtained, specifically plant a season to absorb heavy metals.

Or continuously plant Soybean for multiple seasons, using green manure to nourish the land while legumes themselves also have a certain capacity to accumulate certain metals.

He read this plan from beginning to end, and then read it again.

Many places were vague.

He did not know the exact pH value of the Wasteland soil and could only assume it was between 4.5 and 5.5.

Lime dosage could only be estimated based on this assumption.

He did not know what heavy metals were contained in the soil, what their concentrations were, or how much effect passivating agents could have.

He did not know how high the cumulative dose of internal radiation exposure would be, or how much radioactivity would remain after potatoes grown are peeled.

But he knew one thing: if you don't do it, you will never know.

These experiences would be useful on the Wasteland.

And this improvement plan on the draft paper, although crude and full of assumptions and estimations, was a framework.

When he arrived at the Wasteland, he could try step by step according to this framework.

Adjust if trial and error fails, continue if trial and error succeeds.