SAFS400

The terms "organic by neglect", and "high-input organic agriculture" both refer to specific types of organic farming operations. Describe what is meant by each of these.

"organic by neglect" refers to the idea of avoiding all inputs, including pesticides - but also avoiding sound agricultural practices including good crop and soil stewardship. While this could be considered more "natural" than standard agricultural practices, it does not represent the organic farming principles promoted by the proponents of organic or sustainable agriculture. "high-input organic agriculture", sometimes called "organic by substitution" refers to the adoption of certified organic practices in combination with standard conventional practices, which include purchasing most inputs from sources far from the farm.

Why is it important to have many (abundant) diverse types of organisms living in the soil?

1) the more species are present in an agroecosystem, the less likely crop damage is to occur 2) different populations keep one another in check through predator-prey balance. 3) Different types of organisms perform different ecosystem functions... e.g. some are decomposers, some are predators, some are herbivores, etc. I didn't mention it in class, but the more ecosystem functions that are filled, the more efficiently energy is used in that system. Another way to think about it is that fewer resources are wasted.

When was the Organic Food Production Act passed? When were the National Standards first implemented?

1990, 2002

What are some different ways we can learn about a soil's physical, chemical or biological characteristics?

A penetrometer tells us how compacted a soil is. - Texture analysis (in the lab, or by feel) - A standard chemical soil test run by a lab (to determine plant-available nutrients, organic matter content, and CEC). - Various tests of aggregate stability tell us whether or not there is favorable secondary structure (or aggregation) of soil particles. - We can evaluate the elements found in plant tissues that are being grown in the soil; this gives us an indication of whether soils have sufficient plant nutrients. - Different assays for soil biological activity (like the Solvita test, or bioassays) give an indication of how much microbial activity is present in the soil.

What is the difference between annual, biennial, and perennial crop plants?

Annual plants germinate, grow, flower, and reproduce once in a single year. Biennial plants take two years to accomplish this same life cycle. Perennials live and reproduce again and again over many years.

Why is biodiversity useful in an agricultural ecosystem?

Biodiversity in an ecosystem makes that ecosystem better able to cope with change - the existing resources in the ecosystem are used more efficiently, more ecosystem functions and niches are being filled, and the ecosystem is more resilient to disturbances (physical, biological, environmental, chemical, etc.)

What is Cation Exchange Capacity (CEC) of a soil? Is it better to have soil with a high or a low CEC?

CEC refers to the ability of a soil to adsorb (or hold onto) cations in the soil. Cations are positively charged ions. Many plant nutrients, such as Calcium (Ca), Potassium (K), Magnesium (Mg), and ammonium (NH4), are present in the soil as cations. A high CEC is better because it means more ability to hold onto nutrients.

What are some of the consequences of having more physical distance between producers (farmers) and consumers? Are there any advantages?

Consequences: food travels farther, longer time between harvest and consumption, consumer is less aware of production issues (seasonality, crop losses, effects of weather, labor requirements), lower prices to farmers but higher prices for buyers Advantages: increased availability of produce out of season, permits specialization and consolidation which can increase production efficiency, making food cheaper for the consumer.

The industrial revolution had a major impact on agriculture. Give three examples of industrial revolution developments and for each, explain how it impacted agriculture and food production.

Farm mechanization - replaced animals (and therefore made manure use impractical), required capital investment by farmers, increased the amount of production possible on a given amount of land with a given amount of labor Transportation - enabled food production to take place a lot further away from population centers Manufacturing Technology - enabled mass production of farm equipment (tractors, and more specialized things that tractors pull), farm chemicals (synthetic fertilizers and pesticides), etc. Other answers possible...

If we think of the soil as a pool of available nutrients for plant growth, what are the processes by which we add nutrients to, and subtract nutrients from, the pool?

Gains: fertilizers, nutrient fixation, microbial decomposition, weathering Losses: plant uptake, volatilization, erosion, nutrient fixation, and leaching

Define gravitropism and phototropism.

Gravitropism - the process by which plant roots grow in the direction of gravitational forces, and plant shoots grow in the opposite direction. Phototropism - the process by which plants grow towards light.

How would you describe a soil that is "healthy" from a biological, physical, and chemical perspective?

Healthy soils are ones with: abundant and diverse living organisms (biologically healthy) plenty of nutrients required by plants (chemically healthy) well-aerated with plenty of pores (physically healthy)

What are macronutrients? How do they differ from micronutrients? Name the three primary macronutrients.

Macronutrients and micronutrients are both required for plant growth, but macronutrients are needed in large quantities by the plant. The primary macronutrients are: Nitrogen, Potassium and Phosphorus. Micronutrients include: boron, chlorine, copper, iron, manganese, molybdenum, zinc and nickel. Some (but not all plants) require cobalt, silicon, sodium and selenium.

Where in the soil profile are most of the soil biota found?

Most are found in the top 10-15 cm of soil, or the top 4-6 inches.

For some crop plants, it is important that the plant enter the reproductive phase of development. For others, it is actually undesirable for the plant to enter the reproductive phase. List at least ten crops that fall into each category. Hint: Think about which plant organs are harvested and consumed, and whether they are a vegetative or a reproductive organ...

Need reproduction (& pollination): tomato, pepper, melon, cucumber, apple & other pome fruits, cherry & other stone fruits, bean, pea, wheat, rice, oats, corn, sesame, safflower, nut crops, millet, etc. (anything where seeds or fruits are harvested) Reproduction is undesirable: lettuce, cabbage, celery, potato, carrot, kale, beet, leek, arugula, rhubarb, onion, etc. (any crops where roots, stems, or leaves are harvested)

What does the word "organic" mean, chemically speaking? How does this relate to "organic" agriculture?

Organic = carbon-containing. All forms of plant and animal life are carbon-based, so as they decompose they are referred to as 'organic matter'. Organic agriculture relies primarily on decomposing plants and animals, or organic matter, as a source of fertility in the soil and for the next crop.

The 'Certified Organic' label has been described as focusing on the process rather than the product. Briefly explain what that means.

Organic certification focuses on the processes that farmers and food manufacturers use to grow and produce foods, rather than on specific qualities of the foods themselves. Foods aren't tested for any particular attribute - such as absence of pesticide residues, traces of genes from GM crops, or microbial contamination. The label simply tells the consumer something about the practices used to produce the food.

What is the difference between organic and sustainable agriculture?

Organic is a federally regulated term that means something very specific. One can be certified organic in the short term. Sustainable agriculture is one that can continue indefinitely while remaining productive. Most agree that it entails several dimensions: economic, environmental and social viability. Sustainability is hard (if not impossible) to demonstrate in the short term, but it is something one can strive for.

What is Soil Organic Matter, and why is it considered important and beneficial?

Organic matter is the sum total of the dead, decomposing, and completely decomposed organisms in the soil. Decomposing OM provides food for living soil organisms. As it is broken down, it produces sticky substances which promote aggregation and good soil structure, which in turn helps water infiltration and water-holding capacity. Stable decomposed organic matter particles have high cation exchange capacity (CEC), which means they are hold plant-available nutrients well.

Plants and several soil organisms are considered primary producers, or photoautotrophic. Explain what this means, and where these organisms fit in the food web.

Photoautotrophic organisms are ones that photosynthesize, or use solar energy (plus water and carbon dioxide) to create carbohydrates. Because these organisms don't feed on other organisms, they are the foundation of the food web; all other organisms ultimately depend on them (or upon things that feed on them) as food.

Name and briefly describe the process by which plants harvest energy from the sun. List the inputs and outputs of this process, and describe when and where it occurs within the plant.

Photosynthesis occurs in the chloroplasts within plant leaf cells. Inputs are water, carbon dioxide and light energy, and outputs are glucose, water, and oxygen.

What does the plant do with the glucose that is produced during photosynthesis?

Plants use some of the glucose that is produced to fuel cellular processes. It is used during cellular respiration. During respiration, in the presence of Oxygen, Glucose is broken down into carbon dioxide and water, releasing energy in the form of ATP.

What could be some positive and negative consequences of having a consistent federally-regulated organic label? (list at least 3 of each). Does this favor smaller or larger farmers? How could this effect the consumer?

Positive: consistent meaning, interstate trade of organic produce is easier, increased value of organic, increases overall organic acreage Negative: interstate trade of organic produce is easier, makes it easier for growers driven by profits rather than philosophy to enter the marketplace, many of the ideals described in regional labels are not included in the federal standard Note - there are many other possible answers! Tends to favor larger growers, because they have the capital and infrastructure required to export organic produce out-of-state, and because there is a high return (value) in doing so Consumers can more readily get organic produce, but it may not necessarily have all the features they have traditionally associated with organic (local, fresh, etc.).

Farmers and gardeners usually till soil to prepare it before planting. What are the pros and cons of doing this?

Pros: - makes the soil fluffy and soft, good for planting and seed germinating - incorporates organic matter into the topsoil Cons: - Can result in compaction of the soil (especially if done when soil is wet), and the creating of 'plow pans'. Crop roots don't grow well in compacted soil. - Tillage can break down soil structure at the soil surface, leading to crusting and erosion.

The soil bacterium Rhizobium is a very important soil microorganism in agricultural soils. What does it do, and why is it so important?

Rhizobium is a soil bacterium that infects the roots of Legume plants in a symbiotic relationship. Infected roots make nodules around the bacteria. Within the nodules, the bacteria convert atmospheric nitrogen (N2 gas) into nitrate that the plants can use, and they use as food the carbohydrates produced by plants. Without Rhizobium, legume plants would not fix nitrogen.

What are the three fundamental soil particles, and what is the key feature that differentiates them?

Sand, silt, and clay. The major difference is particle size! Particles of sand are larger than those of silt, which are larger than those of clay.

Agricultural practices have the potential to negatively impact natural resources, and therefore reduce the ability of ecosystems to provide the services you described above. Describe a few examples of how agricultural activities can harm natural resources.

Soil degradation - soil is lost through erosion (wind and water) and loss of nutrients through overuse (mining) in some parts of the world. Water - Silt & Sediment contaminate surface waters, destroying habitats for aquatic organisms. Fertilizers contaminate water with nutrients, which can cause blooms of growth of organisms and then oxygen-starved conditions. Pesticides, Pathogens, and Heavy Metals can contaminate surface and ground waters. Overdrawing ground water can result in salinization of water near coastal areas. Genetic Diversity - Widespread use of monoculture increases the vulnerability of specific fields to epidemics (insects, diseases etc.); Genetic Diversity can be lost by wide adoption of a few high-performing varieties; this means that the population of crops grown are less able to respond to changes in their environment

What is soil texture? What is the difference between soil texture and soil structure?

Soil texture is an innate property of a soil, that cannot be changed by human activity. Soil structure refers to the arrangement of the fundamental soil particles into larger units, and is affected by mechanical and biological activities in the soil. Crop production practices affect these!

Define the following terms, which describe interactions between organisms in an ecosystem: symbiosis or mutualism, competition, antagonism, and parasitism.

Symbiosis/Mutualism - a mutually beneficial relationship Competition - demand by at least 2 organisms for limited resources Antagonism - Inhibition of or interference of a substance or organism by another Parasitism - one organism receives benefits from another by directly causing damage to it.

In the national organic standards, what is the "national list"? Give an example of an item that appears on this list and explain whether it can or cannot be used on organic farms.

The National List appears in the organic standards. In general, all synthetic materials are prohibited and non-synthetic materials are allowed for use in organic farming. The National List is the list of exceptions - synthetics that are allowed, and non-synthetics that are not allowed. There are many examples, which you could find in the reading. I discussed a few of them in class.

Who decides which inputs (fertilizers, pesticides, etc.) can be used on USDA-certified organic farms?

The National Organic Standards Board (NOSB)! The NOSB is a group of 15 individuals (consumers, farmers, scientists, organic certifiers, food processors, etc.) that are appointed by the USDA to define and update the federal organic standards.

What is the Food System?

The food system encompasses all food production and consumption, ranging from manufacturing of agricultural inputs, farming, food processing, distribution, marketing, retailing and consumption.

You take a soil sample that doesn't have any stones or large particulate matter. You give the sample to your favorite soil lab. They tell you that 30% of the sample consisted of particles that were too large to pass through a 0.5 mm sieve, and that, based on their testing methods, 40% of the original sample was silt. What is the texture of your sample? (Hint: refer to the soil texture triangle)

The sample is 30% sand, 40% silt and 30% clay. Using the soil texture triangle, this is a clay loam.

Who was Justis von Liebig, and how did his discovery affect agriculture?

Von Liebig discovered that there are 16 essential elements for plant growth (19 if you count Nickel, Silicon, and Sodium, which are not considered essential by most researchers). His discovery led to the development of fertilizers that added only the specific nutrients that were needed for plant growth, also know at the time of their development as "synthetic manures".

There are two primary types of vascular tissue in plants. What are they, and what functions do they serve?

Xylem - water and nutrients are transported from the roots to the rest of the plant. Phloem - the carbohydrates produced during photosynthesis are transported from source (the photosynthetic leaves) to sink (any part of the plant that needs energy).

List at least three functions that soils perform in agriculture.

a. Anchors plants b. Serves as reservoir for nutrients c. Allows for air and water exchange (between plant and environment)

List and describe at least four things that you would learn about your soil from a standard soil test.

a. pH - tells you whether soil is alkaline (basic) or acidic. Plants grow best, because nutrients are most available to them, at a neutral pH. b. CEC - Cation Exchange Capacity indicates the soil's capacity to hold onto nutrients. In general, higher CEC values are better. c. Organic Matter - This is the percentage of the soil that is made up of living, decomposing, or already decomposed organic material. Higher levels of organic matter mean more nutrients available to plants, and organic matter positively affects soil structure (see question 1). In general, higher values are better. d. Macronutrients - with the exception of Nitrogen, the soil test tells you the level of many plant-available macronutrients (Mg, Ca, K, P). e. Texture - we didn't talk about this specifically, but some soil tests will tell you the texture class of your soil.