Soil contamination

Farming is a challenging activity that requires management and knowledge to deal with specific situations. Each kind of crop requires certain types of soil, nutrients, water and light exposure, these are natural factors that are essential to assure the success of production. However, not just the treatment of the land is the key to having good results, it is also necessary to care about external impacts such as weeds and insects. These organisms can change the behavior of plants and decrease quality of production. For example, weeds can compete for space with crops. Some insects can attack plants causing problems such as chlorosis, wilting of leaves, reduction of root growth, and can also introduce parasites that can cause plant diseases.

In order to solve these problems, producers resort to the application of pesticides and herbicides. The problem is that every chemical put in the soil will have some kind of impact. The formula of these products are generally composed of elements that can be pollutants and cause contamination not just to the area of application, but also to the surrounding cities and land. The pollutants contained within the products can be carried by water and air, an example of this is a case in Washington.

The Innovation Trail website reports a case that happened in Washington. Since the 1950’s, apple producers were spraying pesticides that contain arsenic and lead in its content (Schick, Flatt, & Earthfix, 2016). These are heavy metals that naturally occur in the soil, but when their quantity is increased they can be very hazardous and cause problems such as high risks of cancer, birth defects, and changes in the soil organisms’ behavior. What happened is that the continuous application of pesticides increased the levels of lead and arsenic on the soil and recently was related to child’s blood problems, diabetes and heart diseases in people around the apple production field. Children in this area were contaminated directly by ingestion of soil and indirectly by dust exposure. A similar case happened in the Adelaide City Council where a playground was closed because of contaminated soil and one of the complaints is that people do not really care about that, mostly because of the lack of knowledge about the risks, and producers do not try to decrease the amount of contamination they cause.

In Washington, the state’s Department of Ecology is working with the neighborhood teaching them the risks of heavy metals exposure and how they can prevent it. They are analyzing soil samples to measure the amount of contamination and also created child care centers to help children that were affected by pollutants. The treatment to this problem requires a huge effort, especially in this case, since the land was contaminated for so long. It costs money and it requires changes in the actual agricultural production, but it is necessary to keep the land likely to live and to prevent further problems.

References:

Schick, T. , Flatt, C., & Earthfix (2016, Feb. 8). Where apples once grew contaminated soil lingers.

Retrieved from http://innovationtrail.org/post/where-apples-once-grew-contaminated-soil-

Lingers

Staff writers. (Feb 8, 2016). Council confident glover east playground closed due to soil contamination will reopen soon. Retrieved from 

http://www.adelaidenow.com.au/messenger/city/council-confident-glover-east-playground-closed-due-to-soil-contamination-will-reopen-soon/news-story/5380f3392d89e166f07ed80897d846ac

Relation between water and soil

It is known that the natural resources are important elements from Earth that provide all of the conditions to support humanity, animals in general and plant growth. These elements are related and must be used consciously in order to keep turning life healthy and even possible. Agriculture is one of the sectors that use water the most. Water is necessary to all of the processes to produce food and some crops cannot grow without large amounts of water, rice is an example of that.

It is possible to see the direct use of water in agriculture for instance in irrigation, as components of fertilizers, pesticides and herbicides and in more specialized processes. For examples, the US and Europe require that mangoes exported by Brazil have to be free from a specie of larvae that commonly attacks this fruit. The treatment to prevent the appearance of larvae in mangoes consists of immersing the fruit in hot water at a very precise temperature. The point is that a large amount of water is used. Furthermore, water is used indirectly in agriculture. For example, it is used in plastic production on packing.

Water is extremely related to soil and its usage can also affect soil behavior. It the soil is not well structured it can hinder water penetration and movement, causing a barrier to plant uptake of nutrients, as nutrients are available to plants in water solution. Also, when water is contaminated, contaminants will infiltrate in the soil. In soils of mangrove ecosystems, Oliveira et al (2007) states that soils are pollutants accumulators several orders of magnitude higher than the water in the same area.

The Atlantic website explains a case of contamination of water by lead that happened in Flint, Michigan. The salty water corroded the pipes that was being used to supply the city, making available notorious amounts of lead in water, which means contamination in high levels that can cause several problems in the human biological system. The treatment of this contaminated area must be directed not just to the water, but also to soil. This because, as we can see, soils retain the contamination and it can be available in water again later and, in consequence, it can affect human healthy.

References:

http://www.scielo.br/pdf/qn/v30n3/02.pdf

http://www.theatlantic.com/politics/archive/2016/01/what-did-the-governor-know-about-flints-water-and-when-did-he-know-it/423342/

Soil structure and impacts

Producing food requires planning from all sides, since which type of fruit or vegetable is better to a particular location, or what pests that must be fought, even the best season to plant and what are the amount of essential nutrients for each crop type. However, if we stop to observe all of these aspects of agriculture, we will soon realize that it is impossible to achieve it without the most basic point: the soil.

Soil works as a physical support and contains all the nutrients that plants need to grow. Each kind of crop requires a specific type of soil. In order to provide the best conditions for plants to grow, techniques such as tillage, use of pesticides and fertilization are used continually in agriculture.

However, these techniques to increase production can change the soil structure in different aspects, causing problems such as contamination, erosion and degradation. For example, the AgWeb powered by Farm Journal has demonstrated the decrease of healthy in similar soils managed by two different farmers in central Illinois. One of them is constantly practicing tillage before producing soybean and the other farmer did not till for 30 years. In the first case, the constant use of tillage has caused erosion and made hard the movement of water in soil pores that were compressed with time. The University of Nebraska-Lincoln extension program described some of the impacts of the tillage operation on soils in large scale of time, some of them are the break of soil structure and destruction of residue.

The structure of soil is essential to provide the best conditions for mineral uptake by plants and physical support. Continuing impacts on soil structure can change its properties and, in consequence, make it difficult to be used for agriculture. In the cases that happened in Illinois, the farmer that had the unhealthiest soil started to change the treatment in his land with no-till and analysis that guided him about how to improve soil pH and in about 5 years it was possible to recognize an improvement in the soil quality.

It is known that conservative activities on soil for agriculture are not easy to achieve, but with studies and development of sustainable technologies it is possible to restore soils that were impacted by damaging agricultural treatments in order to continue the production of food.

References:

http://www.agweb.com/article/nurture-sick-soil-back-to-health-naa-darrell-smith/

http://cropwatch.unl.edu/tillage 

What about soils?

Before I start studying Agronomy, my vision about agriculture was very limited. I understood the final function of this area, which is to feed the world, but I could not imagine the large amount of processes that food needs to go through before it gets to our table. After being accepted in an university at my hometown, in Brazil, I learned more about some of these processes and I realized that agriculture has other functions.

As I realized during my internship in a laboratory of environmental chemistry of soils, the soil passes through many interventions during agricultural production. With enough time, these interventions can change the natural behavior of soils and turn it into unproductive or dangerous lands, in extreme situations. For instance, in some places the agricultural waste is released irregularly in rivers, contaminating the soil. With this blog I would like to demonstrate where contamination of soils can be found in the United States and other countries, and also emphasize the importance of protecting this natural resource in order to continue to fulfill its function.