buffer zones & buffer strips – what they are and why we need them

umrb_fig06h
photo credit: pubs.usgs

Buffer zones and buffer strips are the areas between aquatic and terrestrial zones.  The best-known buffer strips are wetlands and riparian zones.  They can consist of natural or planted vegetation and serve as a place for water and matter storage.  

The two types of limitations that impact buffer zones are internal limitations and external limitations.  Internal limitations are those that have to do with the qualities of the buffer zone itself e.g. the width, the soil qualities, the pH levels, the organic matter content and the soil porosity. The external limitations include outside influencing factors like the size of the basin, the geochemistry of a location, the climate, hydrology, slope and stream morphology.Some buffer zones can also link ephemeral (short-term) and perennial areas with non-point source loads via surface or groundwater paths.  

We need these unique natural treasures because they offer valuable services that man-made options and replacements simply cannot reproduce.  This means that existing buffer zones should be protected in an effort to benefit the majority, rather than the minority.  In areas that have buffer zones, the following benefits are enjoyed:

  • During warm periods, buffer zones cool in the summertime via evapotranspiration and shading
  • Many unique species of plants and animals have a place to live creating havens of biodiversity
  • Water is filtered water slowly through the dead and decomposing organic matter, as well as non-organic components
  • Sedimentation occurs which keeps water cleaner and reduces the likelihood that unwanted particles enter other water sources
  • Embankments are stabilized and coastlines are protected from storm and flood damage 
  • Groundwater recharge takes place which keeps aquifers full
  • Groundwater composition is changed as excess nitrogen and other nutrients/toxins are removed which improves water quality and reduces the need for artificial water filtration efforts
  • Litter and dead wood is allocated, concentrated and distributed to aquatic organisms
  • Carbon is sequestered

With so many positive benefits, it is clear that buffer zone protection is imperative.  This is especially true with the many environmental uncertainties that we are facing in the modern world making it essential to protect and preserve these valuable natural service providers.

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photo credit: elibrary.dep.state.pa.gov

 

biological control via entomophatogenic viruses: baculovirus

Entomopathogenic viruses are those that infect and kill insects.  They are superior to regular pesticides in that they are not harmful to humans or other vertebrates. Furthermore, each viral strain attacks only a limited number of insect species which helps to mitigate unpredicted damage.

baculo
Photo Credit: aibn.uq.edu.au

There are two types of entomopathogenic viruses:

  1. Baculoviridae (ds DNA)
    1. Nucleopolyhedrovirus
    2. Granulovirus
  2. Reoviridae (ds RNA)
    1. Cypovirus

However, the Baculoviridae viruses are the ones that are most commonly used.  They are found only in invertebrates and despite rigorous testing have not been shown to negatively affect vertebrates and plants.  They also have a narrow host insect range which is typically restricted to the original host genus.  

The mode of action for Baculoviridae is as followed:

Baculovirus is sprayed onto foliage –>  Caterpillar consumes the virus  –> The protein encapsulating the Baculovirus DNA dissolves and the DNA enters the stomach cells –> Baculovirus DNA is replicated by the stomach cells until the stomach cells rupture –> The caterpillar stops eating  –> Baculovirus is spread throughout the caterpillar causing a general systemic infection    –> The caterpillar dies within days

Leo turk 3 leo
Photo Credit: Leo Graves, Oxford Brookes University via oetltd.wordpress.com

 

The biggest issue related to the use of this method is the amount of time required before the pest dies.  This is noted as being the number one reason why this method is not used on a more wide scale basis.

Baculoviruses are created in vivo and production is often automated which makes it predictable and inexpensive because of the use of inexpensive growing mediums and the natural process of fermentation.  It is estimated that application in the USA costs $6-10/acre which is competitive with prices for industrialized chemical pest control options.

In order for the use of Baculovirus to expand the following improvements must be made:

  1. Genetic engineering must result in a 50% increase in the speed of the kill time
  2. Residual activity of the virus must be increased from 2 – 4 days to >7
  3. The role of Baculoviruses must be strengthened within successful IPM programs
  4. More cost-effective cell culture for the mass production of wild type and genetically modified Baculoviruses must be developed

A major example of success using a Baculovirus is the control of the Gypsy Moth (Lymantria dispar) using the entomopathogenic virus LdMNPV.

sources:

https://www.researchgate.net/publication/233795389_Genomics_of_Entomopathogenic_Viruses_Insect_Pathogens_Molecular_Approaches_and_Techniques

http://www.fao.org/docs/eims/upload/agrotech/2003/active_agents.pdf

https://www.researchgate.net/publication/263765284_Entomopathogenic_Viruses

http://web.entomology.cornell.edu/shelton/cornell-biocontrol-conf/talks/georgis.html

http://www.biopestlab.ucdavis.edu/files/131018.pdf

an introduction to integrated pest management (IPM)

Integrated pest management (IPM) is a long-term pest prevention program that focuses on ecosystem-based strategies for the control of pest related issues. This is accomplished through a combination of techniques including biological control, habitat manipulation, modification of cultural practices and the use of resistant cultivars. The use of chemical pesticides is then restricted to applications only after strict monitoring that is based on established guidelines indicates that stronger measures are required for pest management. In the event that chemical agents are required, they are applied in a targeted manner intended to minimize risks to the environment, other organisms (especially beneficial and non-target organisms) and to human health.

The 8 principles of IPM are as followed:

  1. In an effort to prevent and/or combat pests, the following intelligent production practices shall be used: crop rotation, sustainable cultivation techniques, resistant/tolerant cultivars and certified seed production systems, balanced fertilization, irrigation and drainage techniques, proper hygiene measures and the protection and proliferation of beneficial organism.
  2. The use of biological, physical and non-chemical control methods must be preferred to chemical options as long as the non-chemical options provide acceptable pest control.
  3. In the event that pesticides must be applied, they shall be target-specific and strategically applied in an effort to reduce negative health outcomes.
  4. Pesticides shall be used only on an as-needed basis and the frequency and intensity of use  should be minimized in order to reduce the risk of resistance populations.
  5. In cases where pest resistance has been established and repeat pesticide application is necessary, anti-resistance strategies should be integrated into control efforts.  
  6. Record keeping is essential and should be based on detailed records in order to determine the efficacy of pest control programs – especially in the case of chemical inputs.
  7. Monitoring efforts are essential in order to track pest presence.  This can be accomplished via observations, forecasting and early diagnosis systems and information, as well as information from professionally qualified .  
  8. The information garnered by monitoring efforts shall be used to determine when and which plant protection measures will be taken.  There should be scientifically supported threshold values upon which to base decision making.  Said values should be adapted to local conditions including climate, crop type and topographical qualities.

sources:

https://www.nap-pflanzenschutz.de/en/practice/integrated-plant-protection/general-principles-integrated-plant-protection/
http://www.ipm.ucdavis.edu/GENERAL/ipmdefinition.html
http://www.fao.org/agriculture/crops/thematic-sitemap/theme/spi/scpi-home/managing-ecosystems/integrated-pest-management/ipm-how/en/

 

 

crop wild relatives – what they are and why we need them

Nature has been doing her thing for billions of years (maybe longer, I’m not sure).  It is only since about 200,000 years ago that humans entered the picture and it is only since about 15,000 years that humans have figured out agricultural production.  It is safe to say that nature may have a few tricks up her sleeves that we Homo sapiens cannot even begin to fathom – although our incredible brains are trying.

For the first 14,850 years of the human agricultural experience, seeds were simply saved from the plants that were growing.  Some cultures chose to save the seeds from the best-looking plants and others chose to save seeds from the smallest plants, so they could eat the best-looking seeds.  The latter was not the best decision and eventually all cultures began saving the seeds from the best and strongest plants.  This helped to improve production somewhat.

Then in the 1890s, we human folk decide that it might be wise to breed two plant types together in order to get even better production.  This gave birth to modern plant breeding. Soon after, during the Green Revolution, new types of staple crops were developed that were not sensitive to the number of daylight hours, produced larger amounts of above ground biomass and saved billions of people from starvation.  It was quite an accomplishment.

However, as a result of these scientific efforts, modern crops cannot grow without inputs from humans.  They lack the necessary defenses from the many surprises that the wild world has to offer.  This brings us to Crop Wild Relatives (CWR).  These are the wild relatives of the current crops.  They contain the valuable genetic information needed to maintain genetic diversity.  Such a quality is essential as monoculture practices continue to dominate the agricultural production landscape.  CWRs also continue to evolve in adaption to natural conditions – something that domesticated crops are incapable of doing.

cwr-richness
Photo Credit: agro.biodiver.se

The information provided by the CWRs also contribute the development of more desirable qualities in domesticated crops. Pest resistance is one of these important factors, as in the case of three peanut crops that helped in the development of a crop variety resistant to the root-knot nematode that previously cost growers an estimated $100 million annually.

Furthermore, even in their wild state, some CWRs provide valuable nutrition for humans and other animals in areas that are not suitable for cultivation. Strong examples include the use of wild cowpeas and yams in Africa to help sustain the large population, and the consumption of wild fruits, such as apples, throughout Asia.  CWRs also provide valuable fodder, fiber and medicines.

origin-species-world-map

sources:

http://www.cropwildrelatives.org/cwr/importance/

http://www.bioversityinternational.org/cwr/

the greenhouse effect

The term greenhouse effect has some pretty negative connotations.  On the one side, there are those who hate all the tree-hugging hippies who are against progress and technology, and think that global warming is a giant scam developed by Al Gore in order to ruin the United States’ economy and turn the country into a communist paradise.  On the other side, there are those that think that the evil meat-eating fascists are trying to destroy the planet and the only way to stop them is by buying all the coolest, newest, greenest, most environmentally-friendly items.

sunearthdiagram
Photo Credit: wunderground.com

However, truth be told, if it were not for greenhouse gases trapping heat in the atmosphere, the world would be a very cold place.  In fact, greenhouse gases are what keeps the earth warm through a process called the greenhouse effect.

The earth gets energy from the sun in the form of sunlight.  The earth’s surface absorbs some of this energy and heats up.  This is why the surface of a road can feel hot even after the sun has gone down.  The earth cools down by giving off a different form of energy called infrared radiation.  Before this radiation can escape to outer space, greenhouse gases in the atmosphere absorb some of it, which in turn makes the atmosphere warmer.

However, it does not have to be quite so warm here on planet earth and it is best to mitigate the environmental effects of human activities when possible.  In order to do this, the discussion needs to shift to other types of greenhouse gases because CO2 is relatively harmless when compared with many others.  Furthermore, CO2 gases can be dramatically reduced simply by planting a whole lot more plants and not destroying the ones that already exist and/or ending the world’s love affair with fossil fuels.

sources-agriculture
Greenhouse Gas Production by Sector             Photo Credit: epa.gov

A few of the other types of much more concerning greenhouse gases include:

  1. Methane: produced via:
  • livestock production – sheep and cows produce methane as a byproduct of their digestion process and methane as released as manure decomposes
  • trash decomposition in landfills
  • sourcing and transport of natural gas – natural gas is mostly methane and can easily leak through pipes
  • coal mining – pockets of methane are released as the earth is mined

Methane stays in the atmosphere for 12 years and traps 20 times more heat than CO2.

2. Nitrous Oxide: produced via:

  • farming – the introduction of synthetic nitrogen which is oxidised by plants
  • the burning of fossil fuels
  • some manufacturing and industrial processes

Nitrous oxide stays in the atmosphere for 114 years and traps 298 times more heat than CO2.

3. Fluorinated gases: produced via:

  • leaking coolants – produced by certain devices, such as refrigerators and air conditioners
  • manufacturing and industry – computer chip production is a major contributor

The length of time that these gases stay in the atmosphere varies, but ranges from several to thousands of years.  The heat-trapping properties also vary but range from a few hundred to 23,000 times that of CO2.  It is expected that fluorinated gas production will increase dramatically faster than any other greenhouse gases.

So, the greenhouse effect is a cause for concern, but it also a fundamental component of our existence.  As such, it is best when we stop focusing on how to stop this process and start focusing on how we as humans can make more conscientious decisions in order to preserve this special place we live and let mother nature do her job.

precipitation

There have increasing reports of severe weather conditions throughout the world. Certain areas are facing record-breaking water shortages while others are faced with unprecedented flooding. There are a myriad of circumstances that are leading to these conditions. However, the amount of precipitation an area receives is a dominating factor.

Precipitation is part of the atmosphere and composed of water or water vapor. Atmospheric water exists mostly as vapor, but briefly and locally becomes a liquid (rainfall and cloud water droplets) or a solid (snowfall, cloud ice crystal and hails).  

Precipitation events are recorded by gauges at specific locations. Point precipitation data is used collectively to estimate the areal variability of rain and snow. Rainfall data are usually represented as mm/hr, mm/day, etc.

When precipitation falls, it provides the water necessary for groundwater recharge. This is the process of  surface water percolating through the soil to become groundwater. It is the main way in which water enters aquifers. Aquifers are the main source of potable water for humans.

Rain drops may be considered falling bodies which are subject to gravitational, buoyancy and air resistance effects. Raindrop velocity at equilibrium (also known as terminal velocity) is related to the square of rain drop diameter. Larger drops fall faster and are able to collect more water during the fall. However, if a drop is too large (greater than 6/7mm in diameter), it tends to break into smaller droplets.

090723-drop-burst-02

As with the other components of the hydrological cycle, the sun is the driving force behind precipitation. Precipitation comes from water vapor generated by the solar radiation from land and water. It requires vertical flowing air, as well. As water is composed of hydrogen and oxygen, it is lighter than the air when in its vaporous form.

Precipitation is affected by a variety of factors: wind, temperature, atmospheric pressure and local landscapes. It is created in two ways:

  1. Ice crystal process – aerosols act as the freezing nuclei. Ice crystals grow around the nuclei and fall to the ground, although they often melt before hitting the ground.
  2. Coalescence process – small cloud droplets increase in size as they come in contact with other droplets through collision.

The three major categories of precipitation include:

  1. Convective heating air near the ground expands and absorbs more water moisture. The moisture-laden air moves up and gets condensed due to lower temperatures, thus producing precipitation. Conductive precipitation ranges from light showers to thunderstorms with extremely high intensity.
  2. Orographicthe uplifting air caused by natural barriers such as mountain ranges.
  3. Cyclonic – the uneven heating of the earth’s surface by the sun results in high a low-pressure regions and air masses move from high-pressure regions to low pressure regions. If warm air replaces colder air, the front is called a warm front. If cold air displaces warm air, it is called a cold front.

Precipitation is also one of the factors that aids in the climate classification of a given area. If an area receives less than 200mm/year it is considered arid. If it receives less than 400mm/year, it is considered semi-arid. Conversely, if an area receives more than 1000mm/year it is considered humid and if it receives more than 800mm/year it is classified as semi-humid.

soil sealing: what it is and why it’s important

soil sealing2

Soil. A living, breathing fundamental component of the world.  Without it, we would not be able to grow food. There would be no trees and plants growing to provide us with the delicious oxygen so necessary to our existence. Our water would not be purified. We would more or less just be screwed. Yet, we continue to cover this valuable resource with impermeable materials like asphalt and concrete in an effort to build housing, roads, factories and parking lots.

Sure, we need those things too. There is no denying it. But, there are alternatives to impervious materials.They may cost a bit more, but how much exactly is clean water worth? To those without it, it is invaluable or at least much more valuable than a new parking lot. What is the value of a house that has not been destroyed by flooding? Certainly much less than one that is floating down a river towards the ocean in pieces because it was destroyed by flash flooding.

The main perpetrators of this crime against nature are suburban sprawl, a rapidly growing population, and increases in transportation demands. The rapid migration to urban areas is exacerbating this issue.

surface sealing

Some soils are naturally prone to sealing – like those in Southwest USA. However, this is often the result of  poor soil quality (issues with aggregation). There are also issues with soil sealing as a result of poor agricultural practices, such as driving large farm equipment over wet soils and leaving large tracts of land bare of vegetation which would typically improve the structure of the soil and mitigate issues created by rainfall.

Regardless of the source of sealing (although it is usually the fault of humans), the consequences of soil sealing are many including, but certainly not limited to:

  • Increased flood risks
  • Reduced groundwater recharge
  • Increased water pollution (caused by runoff)
  • Loss of biodiversity as a result of habitat fragmentation
  • Disrupted gas, water and energy fluxes

To deal with the issue of soil sealing, many steps can be taken.

The best option is to stop engaging in practices that lead to soil sealing. This means using land more efficiently and intelligently, as well as using existing infrastructure. However, we as humans sometimes have a difficult time changing our habits. This may require that alternatives to impervious concrete and asphalt be more widely used (as alternatives already exist.  see: http://www.perviouspavement.org).

In regards to agricultural causes, crop rotations should be employed, heavy machinery should not be used on wetlands, and cover crops should be planted to encourage aggregate formation and water absorption.

Should we as a species work to address the issue of soil sealing (or even take preventative measures), a myriad of negative consequences could be mitigated. Then maybe one less family will lose everything because of a flood, one less crop will be destroyed taking us one step closer to food security, and mother nature can continue to do her thing – something we can all appreciate (even if we don’t know it).

sources:

http://www.agprofessional.com/news/soil-sealing-crusting-water-erosion-and-poor-soil-health
http://www.concretenetwork.com/pervious/
http://ec.europa.eu/environment/soil/pdf/guidelines/pub/soil_en.pdf