Conservation Tillage and the Drought
Many conversations turn these days around the question — “how are you doing for water this year?” Water and California’s prolonged drought are subjects central to long term well- being for all who live in the Golden State. Seldom has attention been so clearly tuned to our intimate relationship with the cycles of climate and the vast system that delivers rainfall and snowpack to your tap. Drought becomes a moment for social focus and attention with the potential to re-think our relationship to resource use, when that resource seen previously as so abundant becomes constrained by scarcity.
We have built much of California’s abundance on the thinking that basic resources were unlimited. Oil and water are now mixed in the same fishbowl where abundance driven systems and design expectations are demonstrating real limits. From transportation systems, how we designed our cities, to the food systems that have evolved, patterns of consumption are based on a history of plenty and the expectation that the good of the moment and the need to keep an economic engine stoked to the maximum trumps long term thinking.
The notion that we will figure it out when we get there begs the question of conservation, responsible use and frugality. We may now be there- with water being the essential resource that makes desserts bloom, moves our effluent, provides the pathway for salmon to spawn and proliferate, or grows our rice. The design that we have created is the construction of fewer people on a land rich in the ancient accumulation of fertility and water resources that seemed endless.
My own past is like that of many others who came to California‘s rich agricultural valleys to farm – a second generation immigrant family, where my mother’s parents and my father emigrated from Switzerland and came to this country, like so many poor from so many places, into a land rich in natural resources. The land was fertile and the water abundant, energy was cheaply exploited and enterprise largely unregulated. The plow or disc were the choices for tools – bare ground the annual ‘tabula rasa’, and good agricultural practices became the adherence to a common look: neat, single crop focus with little thought about long term soil vitality.
In the past number of years Full Belly has been working with and following a UC researcher, Jeff Mitchell, as he and a group of researchers and farmers have formed CASI – California Agricultural Systems Innovation. I will quote from a couple of their recent information pieces promoting their Conservation Tillage (CT) research:
“The “Case for CT” in California has gotten considerably stronger in recent years due to progress both from research as well as from farmer innovation. Today, peer-reviewed publications have documented the following clear benefits of CT in California:
Reducing dust emissions
Cutting fuel use
Increasing soil carbon
In addition, very recent work now being prepared for publication, has shown that residues in CT systems can reduce about ½ inch of evaporation per week relative to bare ground, and that when highly efficient irrigation, such as overhead mechanized center pivot irrigation is used with CT, water savings on the order of 35 percent for wheat and also savings for corn compared to furrow irrigation can be achieved.
Mitchell and his colleagues are proponents of four tenants of conservation farming:
Don’t disturb the soil;
Maximize the diversity of plants, insects, fungi and microbiota;
Keep living roots in the soil;
Keep the ground covered with plant residues.”
[The] research plots that have been farmed continuously with conservation techniques have shown marked improvement in water conservation as well. “There’s more organic material going into the soil, more carbon and more nitrogen. There’s more capture of water, and the shade and residue reduces soil water evaporation” said Mitchell.
Soil health measurements have for many years focused on nutrient limitations and excesses. Yet long-term soil health measurements require consideration of the biological and physical characteristics of soil and the need to both identify and explicitly manage these characteristics. These biological components provide agro-ecosystem sustainability, resilience to climate variability – including drought or ability of soil to absorb excessive rainfall, healthy carbon sequestration and cycling, and ability to sustain high yields in agricultural production. Biological and physical soil characteristics stabilize plant nutrient availability and moderate nutrient loss.
The ability to adequately understand and measure the biological and physical components of a healthy soil will result in better overall nutrient and soil management practices – and may offer a new pathway in farming systems to make limited water go further.
– Paul Muller
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