The Effects of Fertilizer Runoff

Runoff from harmful algal blooms

Fertilizer Use Revolutionized Food Production

Have you ever wondered why so many people are concerned about the use of fertilizer in agriculture and the impact of field runoff on the environment?  Let’s talk about it for a minute.

The use of fertilizer in agricultural practices revolutionized food production and helped to build modern society as we know it today.  From the big, industrialized farms to the little organic plots, most producers improve the efficiency of their soil by adding sources of Nitrogen, Phosphorous, and Potassium (N, P, and K) to their cultivation practices.  These traditions have been in place since the beginning of modern farming and make it possible to feed the world.

A field can only hold as much fertilizer as its soil can capture.  Soil is made up of sand, silt, and clay.  Each of these structures have different sizes and qualities.  They mix together to form the soil’s texture.  This texture informs how a soil behaves: how crop roots develop, how much water the soil can hold, how well the field drains, and how much fertilizer can the soil structure hold.  Soil is only capable of holding a certain amount of nutrients based its structure.  Fertilizer compounds that are not contained and held by the soil structures dissolve into the water of the field and are carried away as fertilizer runoff.  It does not matter if the fertilizer is organic or not.  All added nutrients to soil have the potential to become runoff.

Lost Nutrients Increase Costs

Fertilizer runoff is a concern for both farmers and environmentalists.  Nutrients lost from fields are wasted resources for farmers.  These inefficiencies created unnecessary operational costs and limit the profitability of a farm.  The environmental impact of runoff is a concern for everyone in the community, including the farmer.  When the nutrients in fertilizer flow into local bodies of water, they can have damaging effects on local wildlife and water quality.

The nutrients found in fertilizers are not just good for crop growth.  They encourage natural biological growth as well.  Normally, more growth from fertilizer would be a good thing.  However, natural systems, like rivers and lakes, have a balanced ecosystem that keeps them healthy and clean.  When fertilizer leaves a field and enters these systems, the balance is thrown off.  N, P, and K nutrients are naturally present in these bodies of water in very small amounts. The concentrations found in field runoff are typically much higher than an ecosystem is used to.  Bacteria and algae grow extremely quickly using fertilizer nutrients.  As their population explodes, the quality of the water decreases.  The water becomes too toxic for fish and other aquatic life to live in the system.  Eventually, the water begins to stink, turn green, and become unsafe for humans to use.

Nutrients in Runoff Create Toxic Effects

The scary thing about this effect is that it does not stay in the local river.  All rivers flow to bigger bodies of water, and those nutrients travel with them.  As they flow downstream, more runoff from other fields is added to the river until it reached its end point.  In the United States, this is typically an ocean or one of the Great Lakes.  When all of the nutrients from all of the field runoff reach those big bodies of water, we see the same algae and bacteria growth we saw in the local river on a massive scale.  This growth is what causes large algae blooms in the Gulf of Mexico and on the Great Lakes.  The water surrounding these blooms becomes so toxic, so quickly that mass die offs of local fish and plants occur.  The blooms also make the water unsafe for humans to use or even touch in some cases.  This effect is commonly referred to as hypoxia.  It can cause problems at home and even bigger ones downstream.

In case you were curious about why so many people are talking about the problems of agriculture runoff, these are some of the reasons why.

Claire Haselhorst

About Claire:

I have a bachelor’s and a master’s degree in agricultural engineering from Purdue University and am currently working on my doctorate. My research focuses on improving the productivity of small scale local producers and new farmers entering agriculture.  I believe that strong and clear communication between educational bodies and agricultural producers can provide the tools and opportunities to build a better tomorrow.


Increasing Farm Wages: A Labor Crisis and the Effects on Agriculture

Labor Costs

Rising Farm Wages and Labor Costs May Lead to Higher Grocery Bills

Farms across America are struggling to secure sufficient labor and pay increasing minimum wages. This issue is most prevalent in California where the minimum wage will continue to increase to $15 in just three years. Additionally, previous exemptions on overtime for agricultural workers are now null, meaning that any person working more than forty hours a week will have to be paid time and a half. Readers from other states might be thinking “who cares about CA politics, there’s no problem here!” Think again, With 60% of the country’s agriculture in California, a rise in labor costs will inevitably lead to higher grocery bills for consumers as well as more food waste.

The Response can be Challenging and Complicated

As farm wages rise, farmers are faced with few options. To mitigate the cost of labor farmers are forced to increase productivity of their crews, raise their prices, or switch to automated processes. Each of these options has major drawbacks. Increasing productivity is difficult and there is only so much work that can be done in one day. Some farms offer production bonuses to their workers based on how many pounds of produce is harvested in the day. These bonuses can be costly, especially since the workers baseline pay is already so high. Since labor is more expensive, the price of the crop must go up. However, farmers are competing not only with other states with lower minimum wages, but with other countries that have no regulations regarding farm labor. Raising the price of the product will only result in more produce being imported from Mexico. This takes jobs away from entry level positions across the entire farm.

Automation is Costly and Can lead to Increased Market Farm Consolidation

Automation seems like a great solution to this labor crisis; however, the technology has not yet met the complicated needs of agriculture. While new options are on the horizon, we are still very far away from fully automated harvesting or planting. The initial cost of machines is very high, and most small farms lack the capital required to invest in automation. As these technologies develop, we will likely see family businesses bought out by corporate farms. In addition, the agricultural workers will not benefit from the rising minimum wages as they will be without a job completely.

Is Buying Local the Solution?

So, what can consumers do to help both agricultural workers and farm owners? BUY LOCAL. Even when produce is more expensive, buying local supports the farms in the community and reduces the ecological hazards of long distance shipping. It also provides demand for products that will lead to more production at local farms and therefore more work for agricultural laborers. Buying domestic products also guarantees that the people who produced that product were paid a fair wage, had safe working conditions, and the product passes the high safety standards of the United States. It only takes a few extra seconds at the grocery store to check the label on produce and ensure it is a product of the USA. Aside from buying local, another way to help local farms is to fully read and understand measures before voting on them. If you are unsure how a bill might affect agriculture, do research or try to speak with a farmer about their opinion. When the time comes to elect senators and representatives, consider their stance or background on agricultural policy. Human welfare and labor rights are extremely important, but food supply affects every single person in this country. When food costs rise, the poorest people are affected the most.

Author - Riley Graham

About Riley Graham

Riley is a third year Food Science student at UC Davis hoping to one day work in research and development. Her specific areas of interest are in sustainability in agricultural processing; however, she’s exploring other options in food science such as sensory science and even brewing. Being a food science student at one of the world’s premier agricultural research centers gives Riley a unique perspective on the issues we face in food production. Even when I’m outside of the classroom, Riley never stops learning. When not doing homework or working in a lab, Riley plays piano, reads science fiction, and loves to cook.


Have you Heard about Hydroponic Lettuce Farming?

Soilless Cultivation Practice

Hydroponic lettuce farming is a soilless cultivation practice that uses water and dissolved nutrient salts to grow plants. Here at Umass Hydroponics romaine lettuce is grown on 4×8 foot tables, where it floats on foam rafts. Lifting the lettuce rafts out of the water reveals a vast web of healthy white roots essential for plant growth. The roots can become over a foot long. Something you would have noticed if you lifted an individual lettuce out of the water a few months ago is something called pythium root rot. Plant diseases are a reality of hydroponic farming, just like any other type of farming. But the kinds of diseases that hydroponic crops get are different from those of more traditional farming practices. For example, powdery mildew particularly effects hydroponic lettuce; this is because the dry foliage and humid greenhouse conditions create the perfect setting for its proliferation. At the Umass Hydroponic facility, we’ve been experimenting with a few organic disease control techniques which seem to be working. The first is the inclusion of a compost tea in the hydroponic water system. This, which has an abundance of microorganisms, acts to displace the microbe population which is causing the pythium root rot, thereby restoring the health of the root microbiome kind of like a probiotic.

The second is the application of a special mix of water, potassium bicarbonate, neem oil, and soap in a sprayer. When applied generously and thoroughly to the leaf surface of the lettuce,  conditions which are hostile to growth are created for the powdery mildew fungus. This is effective because it raises the pH of the leaf surface, while also acting as a potassium supplement for the plant. Otherwise, conditions within a hydroponic greenhouse are much easier to control than, for instance, crops grown in soil.

Easy Nutrient Application & Management

Another positive attribute of hydroponic farming is the ease with which nutrients can be applied and managed. It was actually through hydroponic techniques in the 1860’s that Sachs and Knops showed that simple organic salts were essential plant nutrients (Harris). When dissolved in water, these simple nutrient salts separate into ions like K+ (potassium), P+ (phosphorus), and Ca+ (calcium), which can be easily measured by a device that senses the electrical conductivity of the water flowing through the hydroponic system. Because this is true, nutrient conditions can easily be adjusted to be optimal for whatever crop you are growing. The pH can also be managed in a like fashion. Finally, the amount of light can be easily managed, and to an extent, the humidity and temperature. This is why, it has been suggested by hydroponic professionals, that a hydroponic system is ideal for experimenting with ecological functions like testing relationships between different plants, environments, and microbes because for the most part, variables of the system can be controlled scientifically; and it is, relative to outdoor farming, a closed system.

Oxygen Helps Plant Thrive While Submerged

It may seem strange to some people how plant roots in hydroponic system are totally submerged in water, when it is common knowledge that plants oversaturated with water will drown. In that case, the plants die because of a lack of oxygen ; plant roots perform respiration through their roots, actually obtaining oxygen from pore space in soil. But in hydroponic systems, there is enough oxygen in the water to support the respiration of plant roots. In our system, the addition of oxygen is achieved by a waterfall: water flows off the side of the table and splashes into a tub. The movement and crashing of the water adds to it oxygen, which is then pumped back into the pool where the plant roots are dangling. Hydroponic farming is a fascinating and potentially lucrative way to grow crops. It applies scientific knowledge and technology to create a highly controlled environment optimal for growing. It may seem hightech, but in reality, the process is relatively simple . While requiring some input cost for materials and also space it is feasible for ordinary people to create their own system, learning from text and internet sources.

About Erik Vegeto

Erik is a student of Plant, Soil and Insect Science at Umass Amherst. He has a passion for restorative agriculture and environmental stewardship that drives him forward into new frontiers of thought. Erik loves to read, play guitar, and be creative. One day he hopes to have his own farm and write for a living.

Works cited:

Harris, Dudley. Hydroponics: Gardening without Soil: Easy to Follow
Instructions for the Flat dweller, Hobbyist and Commercial Grower . Purnell, 1971.

Life Beneath the Soil

Life beneath the soil

For the market farmer, soil health is critically important. The soil is a generic term for the upper layer of the Earth’s crust. In fact, there are six soil layers that impact market farming and even big Ag via the life within the soil, the overall soil health, and the relationship therein. Inside we discuss the life beneath the soil and how those organisms affect soil health.

Soil Biota

Biota is the life – animal or plant – that exist in a specific habitat or environment. All the fish, plants, algae and other organisms in the Pacific Ocean would be the biota of the Pacific Ocean. Soil Biota is the organisms that live in the soil of a specific area or environment, such as your garden or market farm. For most plots of land, we are talking about organisms such as bacteria, Fungi, spiders, worms, arthropods – insects, spiders, crustaceans, etc., small rodents and mammals, etc. In short, there is a lot of life in the soil – Some of it good and some a little challenging for farmers and gardeners – all of it seems to be essential for growing food.

The Layers of the Soil from top to bottom

  1. Humus — In healthy soil, there is a thick layer of humus which is the off-cast parts of plants — leaves, bark, stems, fallen fruit, etc. It is in the humus where new soil is created and nutrients within top soil replenished. That process is in thanks to the soil biota and the hydrologic cycle — rain and water.
  2. Topsoil — a nutrient-rich layer — usually — where most plant roots are found. Larger trees and shrubs may have roots that extend as deep as the subsoil layer.
  3. The Eluviation layer — Often a sink for soil nutrients as they are carried down through the humus and topsoil layers by water. This is generally a small grained layer of soil particles.
  4. Subsoil — The subsoil layer is made up of tiny grains of rock, soil, and clay. There is not much organic residue in the subsoil layer, but it can be an excellent place for the natural storage of excess water – especially in areas with a lot of clay. This can also be a place where hardpan forms.
  5. Regolith — Upper Bedrock – a broken layer of bedrock – this is where bedrock begins to decompose thanks to physical and chemical weathering.
  6. Bedrock — The bottom layer of the soil is bedrock on which the upper layers of soil rest. Bedrock is exposed due to erosion. We see that naturally on the upper reaches of the mountains. We also see it farming in extreme cases where air or water erosion is uncontrolled.

Little Creatures with a Big Impact

Bacteria and fungi are microscopic, but both do a fantastic job converting organic compounds into nutrients. Nitrogen-fixing bacteria are literally the driving force behind life on earth through a process called the nitrogen cycle. The air we breathe is nearly 78% nitrogen, yet plants cannot use nitrogen in its gaseous form. There are a few ways that nitrogen becomes usable to plants and nitrogen-fixing bacteria are one of the most efficient means.

However, it is not just nitrogen that makes soil healthy. It is also aeration thanks in part to critters like earthworms, moles, voles, shrews, and even insect larva that help to “fluff” up the topsoil and humus layers so that air is available for all organisms to use. It is also about the ratio of organic matter in the soil to the amount of moisture that the ground holds. The humus layer helps the topsoil layer to retain water and by decreasing the amount of evaporation that occurs. In the humus layer are all kinds of organisms that help to reduce plant matter so that the bacteria and fungi can do their jobs. That is a natural, organic cycle. The plants grow, shed their fruit and leaves, which become the humus layer where the organism’s consume the debris and turn it into usable nutrients.

Supplements for Soil Health

In commercial farming, the humus layer is burned off or removed. Over time, the topsoil layer becomes compacted due to the reduction of organic material and the farmer must then supplement their lands with inputs — nitrogen-based fertilizers — because there is not enough life in the soil to regenerate the nutrients. Market farming does not have to follow this path. Many small farms are using other methods such as no-till to improve the condition of their soil. There are other tricks too, such as cover crops that utilize nitrogen-fixing plants. Nitrogen fixing plants are a symbiotic relationship between specialized bacteria and the plant. Together they help to absorb nitrogen or nitrogen components and then convert it into a usable material that the plant can use to grow.

Soil health is a relationship between many small organisms, the plants that grow in the soil and the amount of water available. The small farm can take advantage of these relationships to produce more food or flowers and use fewer resources.

David Stillwell organic gardener

About: David Stillwell is an organic gardener, entomologist, writer and student. David specializes in hymenoptera – bees, wasps, and ants, and the study of cecidology – Plant galls. He has a fondness for recognizing natural circles and energy webs that exist in nature — those interconnected natural systems such as food webs. He is a native of California and an advocate for conservation, locally grown, and farmer’s markets.