Published in the ECHO Journal, January 2013
Holistic land stewardship is a frame of reference for considering the larger ecology when making decisions about the design and maintenance of your landscape. The plant selection and soil conditions in modern landscape’s ecology are usually very different than the ecologies where many of the plants evolved. The holistic land stewardship’s values of promoting a stable ecology, conserving resources, and increasing biodiversity can help us create and maintain landscapes that are beautiful and beneficial to the earth’s larger ecosystem. In any living system, including landscapes, strategically doing the right things at the right times can create many benefits. Knowing when to apply and how much water and organic fertilizer a landscape needs can save resources and money in the long run. Using the holistic land stewardship model leads to sustainable landscapes that fit into the surrounding community and serve a recreational and ecological purpose.
Promote a Stable Ecology
The defining principle in practicing holistic land stewardship is to promote a stable ecology that is most like how the plants co-evolved. This is only possible when plants are grouped by their ecological relationships and needs. This is sometimes referred to as “plant community based design”. For example desert, prairie, or coastal scrub plants will not fare well in oak woodland or brackish tidal environments. A plant that has evolved to live in a rich forest floor will not do well in a rocky desert and vice versa.
In addition to climatic and geographical differences, plant ecozones are differentiated by their age or successional level. There is a natural succession from a disturbed barren landscape through weathering and biological activity that increases organic matter, deepens soils, and transitions through differently adapted populations of interdependent organisms. A landscape designed without considering plant communities will need adjustments to make it more sustainable.
Conserving Resources
Soils, hydrology, and biological diversity are the cornerstones of success. If plants are properly grouped by ecozone, it is possible to provide for the needs of these plant groups with the least amount of inputs. Modern landscape ecology often artificially speeds up soil succession through the process of adding organic matter, inoculating the ecology with new populations of organisms, addressing compaction and drainage issues, as well as mitigating or eliminating toxicities. With these techniques, the land steward can do, in a matter of hours, what nature does in thousands of years.
Fertilizer is often a problem on traditionally maintained landscapes. The problem is many-fold; the products generally used are usually made entirely of non-renewable fossil fuels, they are salty, and much of what is applied on the landscape runs off and becomes pollution in the environment. Synthetic fertilizer can be thought of as “plant drugs” that keep the plants dependent on regular doses. Excessive use promotes faster growth that causes weaker cell walls and immune systems, which make the plants more susceptible to pests and pathogens. The salt content of most fertilizers makes it harder for the plants to take up water and causes extreme harm to microorganisms in the soils. These same plants, given organic based foods, would have slower and healthier growth. The organic fertilizer also provides food and habitat for millions of microorganisms that provide adequate mineralization, nutrient holding, and nutrient cycling to create a healthy ecosystem.
Not only do the soil microorganisms help with nutrient availability and reduce pollution, but they also break down organic matter into humus and help improve soil structure. A thriving soil ecology will continually aggregate, sand, silt, and clay soil particles, into clumps. The clumps and resulting pore spaces at the soil surface increases water infiltration rates and reduces erosion. Increased pore spaces also increases the ability of the soil to absorb and retain water. Deeper in the soil, the increased oxygen levels in the pores promote deeper plant roots. Deeper roots allow for more nutrient availability, drought tolerance, and stable trees. The “washing” effect soil organisms have on water as it moves through the soil improves the quality of the water entering the aquifers.
While it is best if a land steward incorporates compost into the topmost layer of soil, applying compost on top of the soil surface is also beneficial. The compost moves deeper into the soil through natural processes. Compost is best because it adds organisms, foods, and habitat all at once. If compost can’t be used, compost teas or extracts can inoculate soils with diverse populations of organisms. Organic mulch also helps improve soils. Mulch not only provides a uniform appearance and neat aesthetic, but it helps retain moisture, encourages biodiversity, and reduces weed seed germination. The increased organic content also promotes beneficial fungi and promotes healthier conditions for woody perennials and discouraging the growth of weedy annuals.
Water is a precious natural resource, potable water even more so. Adjusting the application of water to each ecozone is where the most money can be saved. In this context the zones are called hydrozones. The goal is to increase the uniform distribution of water within each hydrozone of the landscape. When plants are not grouped based on their water needs, most of the landscape is overwatered to provide enough water to a small number of plants. Too much water may not cause visible problems, but the fast growth of the overwatered plants is more susceptible to pests and pathogens. It is also a huge waste of a precious resource and equivalent to pouring cash down the drain. In the worst cases, extreme oversaturation of the root zone can cause anaerobic conditions in the soil, creating shallower roots, increasing plant stress and in some cases, tree failure.
Advances in irrigation technology now allow us to be very uniform in the application of water within a hydrozone. “Matched precipitation rate”, “pressure compensating”, and “check valve-equipped” drip emitters, mini-stream rotors, and tree well bubblers are all investments that can greatly improve irrigation uniformity. This concept is so important that California’s Water Efficient Landscape Ordinance, or AB1881, mandates that compliant systems have high distribution uniformity (DU) of .71 or above. Old spray nozzles will not meet this requirement.
A weather based controller fine-tunes the application of water to match what is lost through evaporation transpiration (water lost through the plant leaves). This can be akin to the concept of Kaizen or continual improvement through iteration and adjustment. As the plants mature, soils are improved, or the climate changes; a weather based irrigation system will adjust automatically, ensuring the plants have just the water they need. It must be noted that leaks or breaks in any system should be addressed before any other improvements to the landscape ecology are implemented.
Biodiversity
The third part of holistic land stewardship is biodiversity. A diverse ecology is better able to withstand change and stress. A monoculture is an ecology that is vulnerable to potential pests and pathogens and a situation to be avoided. Diversity should be thought of on three scales; the macro scale would include the landscape plant diversity along with the plant’s abilities to attract and provide food and habitat for a diverse population of insects, arachnids, birds, reptiles, and mammals, ideally including us! The microarthropods and earthworms make up the middle scale. These are the “chippers and shredders” as well as the “movers and aerators” that efficiently process mulch and surface organic matter and move it into the soil. The third smallest scale is the microcosm that is found on the surfaces of leaves and roots. These are respectively called the phylosphere and the rhizosphere.
The land steward acts to promote beneficial conditions and balance on all three scales. While living systems are always changing, in a healthy, diverse system the available food is quickly assimilated, the habitats are continually occupied, and there is adequate competition to provide for natural selection. In a healthy system, a pest or pathogenic organism will have its population numbers held in check naturally. A good example would be a pathogenic fungal mildew spore landing on a leaf. If that leaf’s surface is populated with organisms such as bacteria, beneficial fungi, and nematodes, that disease-causing spore will likely be eaten and/or will not find an available niche in which to infect the plant. Greater diversity creates greater stability in the landscape and the holistic land steward can help direct the symphony.
The modern landscape is not a diverse panacea, and pest populations do get out of balance. In such situations, the knowledgeable land steward practices what has become known as Integrated Pest Management (IPM). The tenets of IPM lead the steward through a holistic process where through the strategic use of physical and cultural controls, the pest population is brought back into balance. The use of pesticides is a last resort and the collateral damage to beneficial populations within the ecology is understood. The preferred strategy is biological controls including the introduction of beneficial organisms such as bacteria, nematodes, and insect predators when physical and cultural controls miss the mark.
The offender in modern landscape ecologies is the extensive use of turf. An outdated status symbol of the ruling elite of historical Europe, turf’s only reasonable role in the modern California landscape is as a recreational surface. The desire to carpet our environments with this water-hogging, high maintenance, and polluting monoculture is understandable given our evolution on the savannahs of Africa, but makes no sense in our current situation. We live in a resource-scarce environment, pollution and pesticide-caused diseases and habitat collapses are rampant, and turf requires space and inputs that hinders rather than helps our stressed ecologies. The toxic stew that runs off lawns into our waterways contributing to the fisheries collapses and well water contamination as well as the approximately 800-million gallons of fuel used annually in the US by lawn mowers, make turf an obvious target for the holistic land steward to address. Organically transitioning turf areas to diverse, climate-appropriate plants on drip irrigation, is the best way to improve the health of your landscape, create beneficial habitat and save money by reducing water use. It can also be a surprisingly beautiful improvement.
Land stewardship is an ancient concept and embodies the understanding that our time on the planet is short. We share the earth with a large number of inter-related and inter-dependent organisms. We must make knowledgeable, responsible decisions that help improve our soils, water, and ecologies. Indigenous peoples have a tradition of considering the next seven generations when making decisions. Non-renewable resources should not be squandered for the fleeting and false sense of satisfaction from large green lawns and miles of clipped hedges. Working with nature and rejoicing in the beauty and the ineffable web of life is the way of the land steward. The land steward gets satisfaction from creating a diverse and stable habitat, having moved the successional state of the land forward, and working to reduce resource use and greenhouse gas emissions. Through a holistic systems approach, the land steward provides a healthy environment for future generations, but can also find meaning in our very existence.
Dave Phelps, ASLA, ISA is the Sustainability Manager for Cagwin & Dorward.