How Rising CO2 Levels Are Reshaping Plant Life - Part 2

• Microclimate management: Integrating trees into agricultural landscapes not only increase carbon storage and soil health, but moderates temperature extremes and reduces water stress on crops through microclimates.  This can be applied in dry, hot environments, but also in areas receiving too much rainfall.  It is important to consider optimal tree cover in trade-off theory to balance transpiration and soil moisture retention.  

• Biodiversity enhancement: Combining both of these strategies by integrating native trees and intercropping CAM and C4 plants, promotes biodiversity.  The diverse ecosystems that are created are better at managing perturbations and can increase productivity in areas that have previously been degraded.  This is a well observed behavior in forests and in gardens.  It should be stressed that we must be careful in selecting the varieties that match our climates and ecosystems.  In certain environments, introducing the wrong species can have devastating effects on the local flora and fauna.  This is why researching prohibited or invasive species before planting is absolutely necessary.

Conservation Agriculture

Conservation Agriculture builds on the strategy of increasing biodiversity to help build natural resilience to changes in the climate.  Many of these practices are common knowledge in the alternative agriculture communities.  However, we mention them here because they are some of the most cost-effective methods that are quick and easy to implement.  Some examples include:

• Minimal tillage: Reduce soil disturbance to preserve soil structure and organic matter.  This was mentioned previously, research indicates soil biodiversity can aid in plant resilience not only through increased water capacity in topsoil, but also influencing plant adaptation to different stressors.

• Crop rotation: Implement diverse crop rotations to improve soil health and break pest cycles.  Increased CO2 and temperatures can increase pests occurrence.  This is because decreased nutritional content in plants, may require insects and pests to consume more to meet dietary needs and/or the plants become less able to deter attacks.  A minimum 3-year crop rotation has been shown to help decrease impacts.

• Cover cropping: Use cover crops to protect soil, fix nitrogen, and increase organic matter.  This method not only promotes biodiversity which conveys benefits as discussed previously,  but also helps hold moisture in the ground as higher temperatures will increase the need for more water in certain environments. 

• Wild variety conservation:  Keep conservation gardens with dedicated spaces to wild flora and fauna, or protect areas already populated by wild species.  If your areas depend on livestock, make sure to develop rotational grazing plans with your community to reduce soil degradation. These habitats can be used to maintain wild cultivars to be used for future resilient plant selection and breeding.

 So what is needed is to flip our domestic traits back to their wild counterparts, or more likely somewhere in between.  If we look at the traits of wild species we see things we can start selecting on domestic species that should yield better resilience.  Those traits include:

• Natural seed dispersal mechanisms (Example:  when the seed pod opens freely after a period of drying on the plant )

• Higher secondary metabolite content (often bitter compounds)

• Smaller but more numerous fruits/seeds

• Indeterminate growth patterns

• Higher fiber content

• Variable dormancy periods (Is flowering happening earlier?)

Propagating after selection can be as simple as implementing a seed saving program or developing a more sophisticated breeding program.

• Conventional Breeding:  This leads us to the next method of conventional plant breeding.  Traditional breeding has shown promise with the cultivation of several hybrid cultivars that demonstrate drought tolerance and disease resistance.  Although some may question the effects of hybrids on our health and ecosystems, cross-pollination is a natural occurrence and plays a significant role in maintaining biodiversity.  There is quite a lot that goes into creating a successful hybrid, and for the average person it is unlikely these methods will be worthwhile in pursuing.  However, some advances are enabling higher success rates.  One such method is inbreeding the parent through self-pollination.  The donor traits are then more likely to be conferred to the offspring when cross-pollinating with the other parent.  The usual process of breeding from the F1 hybrid continues, with backcrossing the donor as needed.  This method, although proven, often takes a long time, 5-30 years, and at the rate we are seeing the climate change this may not be a fast enough solution for developing more resilient plant varieties.

Feralization is a promising approach to creating resilient plants, but caution should be exercised.  Without comprehensive understanding of de-domestication, concern for creating invasive species is a risk.  In fact one of the biggest invasive problems in the US today is with a feral hybrid boar that has destroyed many ecosystems and is hardly coming under control.  In the tropics where biodiversity is much higher, the issue of introducing uncontrollable hybrids is less of a concern, although the chance does exist.  This hasn't stopped scientists from entertaining the use of genetic editing though, a topic we will discuss a little later.  Instead we will outline what we feel are more ecologically balanced approaches: 

• Selection - Choose varieties that may be more likely to survive.  Some visual indicators may be smaller seeds, leaves, fruits, and early flowering.  Choose plants that are perennial and/or self-pollinating, and able to be direct sowed.  Avoid planting species that may have a wild ancestor already in the environment.  If a hybrid outcompetes the ancestor, we may irreversibly lose genetic diversity that holds the key to adaptation at a later date.

• Location - Based on historical evidence, feralization often occurs at the margins, so we should plant species at the intersections of wild and cultivated areas.  Furthermore, it has been indicated that feral plants are highly correlated with disturbed soils, so we may consider planting in areas that we are just starting to rest, or leave fallow, in a rotational system.

• Timing - One of the aspects of feral plants that should be obvious is to avoid interacting and disturbing them as much as possible.  Even if working with crop plants with wild-type traits that can help it thrive on its own, we need to make sure to plant at the appropriate times.  This includes planting at the start of rainy season to make sure the plant can establish on its own.

• Adapt our Eating - Although not really a planting method, being adaptive with ones eating habits will help balance the traits in a species we are trying to de-domesticate.  As mentioned earlier, bitterness is a trait often indicative of wild plants.  So we may need to sacrifice taste preferences to maintain resilience in the plant.  Also being aware of possible toxins that may be present in any particular plant genus or species can help prevent unintentional poisoning.  Traditional knowledge can readily be applied here, since many indigenous peoples have developed menus and cooking methods to be able to consume many species that contain toxins.  A good example of this is the Indigenous Amazonians complex process for detoxing cassava.