Here's the other one of the topics I talked about for my breakthrough junior challenge! This is the one I felt wasn't "sciencey" enough. Psst... go ahead, please don't hesitate to cringe at how bad it is!
Imagine a barren land and scorching sun above the horizon. Suddenly, you walk in! With every step you take, the land transforms into a beautiful forest. Rain clouds gather atop and shower down happiness! Sounds like something that's straight off a fairy tale, doesn't it? But what if I told you that you can be that wonderful magician, in real life, who can transform barren lands into beautiful forests? You'd definitely be interested to know how to be a heroic wizard! Let me tell you how to cast the right spell then.
The answer lies in the land itself! The earth has a diverse distribution of land, the deserts, the swamps, the coasts etc. Out of all these the only land that's not cultivable is of the desert. Putting that aside, there's a ton of barren land around, which if used to grow trees, can benefit the earth and the ones that live on earth.
Usually soil loses its fertility due to natural processes such as soil erosion. We've been hearing about this term since our childhood but what exactly is it? When wind blows over land, it carries away a little of the top layer of the soil with it. When such a process occurs on and on, much of the top layer of soil is lost and this results in loss of fertility as the top layer, which is also called humus, has most of the mineral and organic content in the soil. Erosion can also cause change in texture of the soil, making it loose and unable to sustain plant growth. Soil erosion can occur due to water, too. Water, similar to wind, washes away the top layer of the soil causing texture change and infertility. The lost minerals get deposited into other lands, where they might be not useful. These are naturally occurring processes but human induced soil erosion has worse effects. Over tilling of land can lead to permanent loss of fertility. Deforestation is a major cause too since trees play an important role in reducing soil erosion. When trees are cut down for artifical agriculture, the soil's fertility is destroyed. Due to these reasons, land might lose its minerals.
The first step to take towards turning a barren land into a beautiful forest is to know the demands of a plant. It's important to know what plants require to proliferate.
Since our childhood we've been told plants require sun, water and air to grow but this is super vague.
Plants need a mineral rich and moist soil to grow. Indeed every plant needs different requirements to grow but in general they need H2O, CO2, sunlight, phytohormones and some minerals for healthy growth. They are nitrogen, phosphorus, potassium, magnesium, sulfur, calcium, manganese, iron, copper, zinc, boron, molybdenum, colbalt, vanadium, sodium, silicon and chloride. Oof! That's a long list but fortunately only three of these elements are considered to play a significant role in healthy plant growth. They are Nitrogen, Phosphorus and Potassium also called NPK.
Mineral absorption takes place in the roots that are seated in the soil. The ions of minerals enter the apparent free space of the plant. Apparent free space is the fraction of root volume in which an external solution diffuses into. When no minerals are available in the soil to be diffused into the plant, the plant starts to lose energy and die. To prevent such a thing from happening, we have to ensure that the land is mineral rich and moist. Several minerals have different roles in the plant's growth. Phosphorus helps in energy transfer through ATP. When there's a deficiency of Phosphorus, there is reduction in plant size, there might also be a failure in seed formation. H2PO4- is generally a source of Phosphorus for plants that's present in the soil.
Plants also take up K+ ions to use as a catalyst in reactions that help form carbohydrates. Potassium also helps in increasing the quality of fruits and vegetables by activating enzymes in the process of photosynthesis.
Calcium is also one of the minerals required for plants. They take up C++ which helps in cell walls and helps in plant root and tip elongation.
Out of the all the minerals, nitrogen plays a major role since it's the most absorbed mineral. It is a part of the chlorophyll molecule and amino acids in plants. Without nitrogen, plants can become weak and stunted. Plants usually take in nitrogen with the help of nitrogen fixation done by bacteria that produce NH4+ and NO3- from atmospheric N2. These are diffused into the roots and used up by the plant.
Since now we know about the important minerals for plant growth, how do we use this information to turn a barren land into a forest? The answer is pretty straightforward. Make the soil mineral rich! Sounds pretty easy, but how do we do that? This is where we cast our spell "Abra kadabra REMINERALIZATION!".
Remineralization, as the name itself states, is the process of adding minerals back into the soil. There are many ways in which this can be done!
Usually in nature, glaciers crush down mineral rocks turning them into dust. Now that's some power! Anyways, such rock mineral dust gets deposited at the end of glaciers and are called "moraines". A fancy name forsooth! Later on winds blow this dust, which is called "loess", and deposits it on land making them mineralized. The same wind which is responsible for soil erosion can also be responsible for soil mineralization, strange isn't? But anyways this is a time consuming process and wind mostly likes to erode soil than to add minerals in it. So it's for us to take matters into our own hands since we, the humans, are responsible for most of the infertility of land on earth! One source of abundant minerals are igneous rocks. They pack in up to 100 minerals and trace elements. By turning these rocks into fine dust, we can use it as rock manure to make the soil sustain plant life. One research showed that basalt (basalt rock is the most common type of igneous rock) dust application at the rate of 150 tons per hectare to forest soils resulted in four times greater tree wood volume! Such rock dusts provide a natural way to replenish soil fertility in an efficient way than any other manure. You might be thinking this is all well and good. Now we made our barren land into a mineral rich land by manually adding rock dust. Finally trees have started to grow. But what about pests that can affect plant growth? Should we resort to the deadly pesticides? The obvious answer is a big no. What we're doing also accounts for pest control. It is surprising indeed but rock dust can also prevent pests that can be a threat to plants. The rock dust fits into the category of so called "inert dusts". Inert dusts are insecticides that dry out the moisture present on the pests' skin and thus killing them due to extreme dryness. But the usual inert dusts might be hazardous to the environment, rock salt on the other hand, contains only the dust of minerals which is capable of drying out pests and also causing mechanical discomfort to the insects. Hard silicate rocks, which are very abundant on the earth, can be ground into dust and used as a cheap rock dust.
Another way to make remineralization more efficient is to use biochar. Biochar is a mixture of agricultural wastes such as wood or straw. It mainly has high charcoal levels which causes increase in the organic content of soil. Biochar increases the cation exchange capacity of the soil which is nothing but the soil's ability to hold minerals. Hence rock dust and biochar complement each other and can be used as an effective method to transform barren lands into forests.
One last measure to take is to plant legumes that have nitrogen fixing bacteria living in their root nodules. By doing so, we can increase the amount of inorganic nitrogen in the soil which can lead to good plant growth. So planting plants leads to growth of more plants!
By turning barren lands to forests, we can cause at least a tiny decrease in global warming--a major threat to the new world. You can also be a part of saving the earth from climate change by planning to plant trees instead of just planting trees. People say "plant trees". It is pretty clear that it's a vague sentence. Science is all about efficiency so we must efficiently plan how to plant trees in such a way that it has huge benefits to the earth. Planting nitrogen fixing trees such as soybeans, alfalfa, loopine, peanuts etc can cause to increase the nitrogen content in the soil which not only benefits that plant but also plants that are nearby to it. Next time you hear someone say "plant trees" don't just plant a random tree at a random place but maybe instead add in some rock dust and biochar into the soil of a barren land and then plant a lucky clover (also a legume) surrounded with your favorite plants, water it and watch the magic happen: a barren land turning into a beautiful forest!
