Central Coast Grown’s Comment on San Luis Ranch’s December 2016 DEIR on Proposed Topsoil Grading

I. Introduction

This comment expresses the views of Central Coast Grown(CCG), the non-profit organization selected by the SLO City Council to manage City Farm San Luis Obispo under the terms of 1) a 20-year nominal-fee lease and 2) of the 2011 Master Plan for the Calle Joaquin Agricultural Reserve (www.slocity.org/home/showdocument?id=1916). City Farm SLO is a 20-acre parcel zoned Agricultural Open Space and owned by the City, adjacent to San Luis Ranch

CCG has a strong interest in the development plans for the Agricultural Land belonging to San Luis Ranch for several reasons. As an immediate neighbor, City Farm’s operations are directly impacted by the treatment of soil and water resources on the adjoining property, in particular by any grading activities affecting land contours and soil conditions.  As custodian of City Farm and a continuous onsite presence, CCG has a responsibility to uphold the intentions and terms of the Calle Joaquin Agricultural Reserve under which it operates and to which the agricultural land of San Luis Ranch will be subject, if and when it is annexed into the City. Those terms include:

The City General Plan’s “50% preservation” requirement also extends to the third and largest property in the area, known as the Dalidio property (approximately 130 acres). Upon development of that property, an additional 65 acres wll be potentially added to the Agricultural Reserve. The ultimate size of the Reserve is therefore anticipated to be approximately 90 acres.

According to the United States Department of Agriculture Natural Resource Conservation Service’s Soil Survey of San Luis Obispo County (Coastal Part), the Master Plan area is composed of mostly Cropley clay and Salinas silty clam loam. The Cropley clay is a Class II soil and the Salinas silty clay loam is a Class I soil. Both of these soils are considered “prime” soils, and the City of San Luis Obispo considers their loss to be a significant environmental impact requiring mitigation. Preservation of an approximately equal area of such soils in perpetuity was considered to be appropriate mitigation in the City’s 1994 General Plan Update and is the legal basis for the requirement of such preservation in conjunction with development of the surrounding land with urban uses. http://www.slocity.org/home/showdocument?id=1916

CCG has been following the development plans of the San Luis Ranch and has offered suggestions and comments at each stage. CCG is particularly concerned about the developer’s proposal to remove up to two feet of topsoil from up to 52 acres of the land it is required by the General Plan to place into the Calle Joaquin Agricultural Reserve.

From the outset we have found this proposal unacceptable for reasons presented earlier and elaborated below.  At this point we are disappointed that this proposal continues to be reaffirmed in the DEIR, despite our objections and those expressed by the Planning Commission.

CCG urges that the applicant be required to offer alternative plans for providing fill to raise the elevation of portions of its site and for dealing with possible floodwater drainage and/or detention requirements that does not involve either removal or disturbance of topsoil on portions of the property that are to remain in Agricultural Reserve.

II. CCG Testimony and Planning Commission Responses to Previous Proposal

In both verbal and written presentations to the SLO Planning Commission in March 2016, CCG Treasurer Wendy Brown requested alteration in project’s cut & fill procedures, as well as other changes protecting water resources and requesting clarification of offsite mitigation proposals.

The Planning Commission Minutes for that meeting record that

Commissioner Fowler commented on ¦shared concerns about topsoil and drainage issues;

Commissioner Malak shared concerns about 18-inches of topsoil and considered the idea of garnering fill from elsewhere.

Acting Chair Draze¦ discouraged moving Class 1 soils and recommending consulting heavily with City Resource Manager¦(opengov.slocity.org/weblink/1/doc/59501/Page1.aspx)

In a letter to Tyler Corey responding to CEQA Scoping Suggestions dated November 16, 2016, Steven Marx, CCG President, commented: “- According to the Preliminary Specific Plan dated August 28, 2015, p. 7-13, the developer proposes a conceptual grading plan in which “The agricultural area will be lowered to offset the diverted flows from Areas 2 and 3¦”  Determine what impacts such cutting will have on soil quality and on water pooling on SLR agricultural land and on neighboring City Farm. A similar cut and fill operation, moving subsoil from Calle Joaquin Ag Reserve to raise the level of adjoining commercial lots, has had considerable unanticipated negative consequences.” In addition he requested, “conformity with City requirements of City Farm for organic standards on farmland.”

III. San Luis Ranch’s December 2016 DEIR’s Inadequate Responses to CCG Testimony and to Planning Commission Responses to Previous Proposal

The grading proposal in the Project DEIR does not adequately address these concerns. Rather than reconsidering the grading plan as requested earlier by Central Coast Grown, the DEIR presents their hired consultant’s lengthy “Agricultural Suitability Memorandum” justifying such removal:

Project grading activities may remove up to two feet of soil at the north end of the agricultural area proposed to be retained with the project. However, on-site farmland would remain viable even if up to 2.5 feet of topsoil were removed, on-site soils will retain prime agricultural soils status¦ As such, agricultural viability will be retained after removal of topsoil resulting from implementation of the proposed grading and drainage plan for the project site. Therefore, potential impacts to the agricultural viability of on-site soils would be less than significant. http://www.slocity.org/Home/ShowDocument?id=14317

We take issue with the findings of this Agricultural Suitability Memorandum and on the statement of absence of Agricultural Impacts of the project it supports on several counts.

First, it does not specify how much acreage will be affected and where on the project site it is to be located. However, a diligent search produces this information from section 4.8: “In total, earthwork for buildout of the Specific Plan area is estimated to require 817,200 cubic yards (CY) of cut, and 569,200 CY of fill, resulting in a need for approximately 248,000 CY of soil import.” Without further explanation, these figures don’t make sense: why would the larger amount of cut than fill require additional soil import?  In any case, this is a projection of the removal of an unacceptably large quantity of topsoil.

Another significant absence is created by the lack of any response to this passage in the DEIR: “Section  4.14   Issues Addressed in the Initial Study  — 4.14.5 Geology and Soils Would the project result in substantial soil erosion or the loss of topsoil;”

IV. Rejection of the applicant’s claim that the removal of the top two feet of topsoil has no Deleterious Effects on Agriculture and Ecology.

Of most concern about this proposal is the claim that removal of the top two feet of topsoil on class 1 farmland will have no effect on agricultural viability:

Impact AG-4: Re-grading of the project site would not result in significant degradation of viability of on-site agricultural land. Therefore, this impact would be Class III, less than significant. (4.23)

This claim appears implausible on the face of it.  However, the applicant presents a lengthy “Agricultural Sustainability Memorandum” from its hired consultant to justify it, a report approved and certified by retired Cal Poly Soils Science Professor Tom Rice, PhD(1981). We believe that the evidence and arguments presented to support the conclusion of this memorandum are fragmentary, contradictory, based on antiquated and discredited science and don’t take into account the organic agricultural practices that are required once the land falls under a conservation easement.

In what follows we present testimony from a wide variety of sources to refute the Agricultural Sustainability Memorandum’s general claims that the removal of the top two feet of topsoil has no Deleterious Effects on Agriculture and Ecology.

Unpaid testimony from local experts:

Dr. Cristina Lazcano, PhD (2010), current Assistant Professor of Soil Science at Cal Poly (http://nres.calpoly.edu/personnel.ldml?email=lazcano), author of 23 published articles and referee for more than 20 journals in the  field (https://www.researchgate.net/profile/Cristina_Lazcano), in a separately submitted letter to the Planning Commission.

The importance of soil organisms and their ecological interactions in the top 30 centimeters of topsoil has recently become recognized as crucial for agricultural productivity, regenerative fertility and general environmental health, including carbon sequestration that mitigates greenhouse gas emissions. This recognition has come along with the realization of the limits and long term dangers of excessive inputs of synthetic fertilizers.  On the basis of my knowledge and research and that of colleagues in my field, I must strongly disagree with the idea that any removal of topsoil, let alone to the depth two and a half feet, would be without serious long term negative consequences for the farmland in question.  Were such removal undertaken it would require massive inputs of compost and many years of intensive soil restoration practice to recover soil fertility, before the soil could be considered suitable for organic farming.

I strongly urge you to require the applicant to find alternative sources of fill for construction on sections of the property in question not reserved for agriculture and to find alternative solutions for drainage that will not involve the waste of precious soil resources now to be found there.

John Phillips, Ph.D. Professor Emeritus of Crop Science Cal Poly

“While it may be true that the soil in the flood plain there is several feet deep, to assume that removal of 2.5 feet of the topsoil will have no adverse effect on crop production ignores the reality that the organic matter and the living organism component of the soil exists in a stratified manner, with aerobic organisms, bacteria, mycorrhizal fungi, actinomycetes, protozoa, nematodes, arthropods, and earthworms occupying the several inches near the soil surface.  These creatures living in the soil are critical to soil health. They affect soil structure and therefore soil erosion and water availability. They can protect crops from pests and diseases. They are central to decomposition and nutrient cycling and therefore affect plant growth. Thus, this living component of soil contributes to agricultural productivity and air and water quality.  The proposed grading at San Luis Ranch would eliminate the vast majority of this living component of the soil. Following the removal of 2.5 feet of topsoil, one could expect that at least a few years would be needed for the living component of the soil to regenerate, even with management specifically aimed at promoting soil health.”

Tim LaSalle, Ph.D. Former CEO of Rodale Institute  (http://www.csuchico.edu/vpaa/documents-short/mpp-job-postings/lasalle_cv.pdf)

“The top foot of any topsoil has the most life, organic matter, and fertility because of the oxygen, microbiome, and vegetation that is deposited back¦. It is impossible to take topsoil and not do permanent damage.  Anyone who then says just bring in fertilizers is coming from a decades old soils class that is chemical based not a biological living soils education that teaches us how whole systems work.  How fungi bring needed elements to the plant, how they liberate minerals like P, how the whole system fixes N without the need for fertilizers that will leach into the water ways, let alone significantly contribute to climate change.”

Rob Rutherford, Professor Emeritus, College of Agriculture Cal Poly

“ANYTIME we disturb topsoil – we increase the release of CO2. A massive movement of that portion of the soil which contains the most carbon (organic matter) will send a significant amount of greenhouse gases to the atmosphere – and that doesn’t even count the emissions of the vehicles that are doing the earthwork.”

From National and International authorities:

The National Resource Conservation Service of the U.S. Department of Agriculture on the loss of topsoil (https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053285.pdf)

The loss of topsoil, either by actual removal with heavy equipment or erosion by wind and water, is the worst on-site damage in urban areas. This layer of soil has the highest biological activity, organic matter, and plant nutrients”all key components of healthy soil. The on-site loss of this upper layer of soil nearly eliminates the soil’s natural ability to provide nutrients, regulate water flow, and combat pests and disease. Loss of nutrients and nutrient holding  capacity, results in a less fertile  environment for lawns and landscape  plants. The organic matter and finer soil particles are responsible for soil fertility and are washed away first, leaving larger, less reactive particles such as sand and gravel.

As organic matter is lost, soil density increases and compaction occurs. Compaction lowers the infiltration rate of water and reduces the available water holding capacity. This results in poorer growth of lawns, gardens, flowerbeds, shrubs, and trees, as well as making the site more susceptible to drought and requiring more frequent watering. Additionally, soil amendments such as fertilizer and pesticides cannot move into the soil and, instead, run off into nearby lakes and streams. Lower organic matter levels are also associated with weaker soil aggregates and therefore greater risk of further erosion and soil crusting.

The surface organic matter is also the food source and habitat for beneficial microorganisms and insects. The loss of this material drastically reduces the soils natural ability to control disease and pest outbreaks, increasing the need for pesticides. These microorganisms are also key to removing or buffering toxic elements or contaminants.

NRCS graphic representation showing how microbial life diminishes with depth. 


The Food and Agriculture Organization of the United Nations (FAO). FAO Soils bulletin 50, “Soil erosion – its causes and cures.” (http://www.fao.org/docrep/t0389e/t0389e00.htm)

Soil teems with life

All soil is full of life, and good soils are teeming with it. Plants and animals help keep the soil fertile. Plant roots tunnel through the soil and break it up, and decaying plants form humus. Burrowing animals mix the soil; the excrete of animals contribute nutrients and improve soil structure.

Besides the soil’s more obvious inhabitants, which include rodents, insects, mites, slugs and snails, spiders, and earthworms, there are countless microscopic residents, some helpful to man and his crops, some harmful.

Good soils seem to hold the greatest populations of bacteria. Almost without exception, bacteria are involved in basic enzyme transformations that make possible the growth of higher plants, including our food crops. From man’s point of view, bacteria may well be the most valuable of the life forms in soil.

Chemical reactions occur in the soil as a result of exchange of positive ions, or cations. More exchanges take place in clay soils than in any other type. These chemical reactions are also essential to plant growth and development and are a good index of soil fertility.

From Academic Technical Studies:

Soil erosion and crop productivity: topsoil thickness (Integrated Crop Management News) http://www.ipm.iastate.edu/ipm/icm/2001/1-29-2001/topsoilerosion.html

“Many studies have been conducted on the effect of depth of topsoil on corn yields in the Corn Belt states. Figure 1 (from Stallings, J.H. 1964. Phosphorus and water pollution. Journal of Soil Water and Conservation 22: 228-231) summarizes the relationship between topsoil depth and crop productivity. There is a direct relationship between topsoil depth and yield. The decline in yield with the reduction in topsoil depth can be related to A horizon thickness.”

Immediate effects of topsoil removal on crop productivity loss and its restoration with commercial fertilizers   http://www.sciencedirect.com/science/article/pii/S0167198798000919

Abstract: A field experiment was conducted on a Typic Cryoboroll (Site 1) and a Typic Cryoboralf (Site 2) in north-central Alberta, Canada, to determine the influence of simulated erosion (artificial topsoil removal) on loss in yield of hard-red spring wheat (Triticum aestivum L. cv. `Roblin’), and to determine to which extent fertilizers N and P will restore the lost crop productivity of two artificially-eroded soils. There were three depths of topsoil removal (0, 10, and 20 cm) as main plot treatments, and a factorial combination of four levels of N (0, 50, 100, and 150 kg N ha−1) and three levels of P (0, 9, and 18 kg P ha−1) as sub-plot treatments. Wheat yields at both sites were markedly reduced by increasing depth of topsoil removal. The erosion effects were more pronounced at Site 2 where average yield on the 20 cm cut decreased to less than half of that obtained under non-eroded conditions. At both sites, additions of fertilizer N and P to eroded soil increased wheat yield, but the yields did not match those obtained in non-eroded soil under the same fertilizer treatment. Plants growing on eroded soil responded differently to application of fertilizers N and P, not only in terms of yield but also in N and P concentration and uptake. The implication of these findings is that fertilization programs for fields with varying degree of erosion would require optimization of rates so as to restore yield and, at the same time, minimize nutrient losses (e.g., N leaching) and improve soil tilth.

V. The Agricultural Sustainability Memorandum uses ambiguous, obscure and contradictory language.

The claim that “on-site farmland would remain viable” is ambiguous.  The present soil makes for much more than viability”this farmland is exceptionally productive and maintaining viability and continuation in its present soil classification doesn’t take that into account. In addition, the Memorandum assumes that viability after topsoil removal will be provided by substantial inputs of chemical fertilizer.  This assumption ignores the provision of the City’s 20-year lease with Central Coast Grown stating that “the purpose of this agreement is to put the majority of the Premises into active sustainable agricultural use” and the language contained in all subleases at City Farm: “CCG will not require organic certification, but Lessee must manage the site in such a way so as to not preclude future tenants from seeking certification.”

While acknowledging that “Organic matter and phosphorus concentrationsdrop significantly between the surface and sub-surface horizons,” the Memorandum maintains that the “surface horizon of a typical Cropley clay profile is 36 inches,” without indicating where in between those horizons the drop occurs or whether the typical profile applies to specific locations on this site.

The study also asserts that “The northern field proposed as a floodway near U.S. Highway 101 may be farmed on the subsoil material,” again using the ambiguous language, “may be farmed,” which ignores the present exceptional agricultural productiveness of the land and refers to subsoil rather than topsoil.

VI. Previous Activity at the Calle Joaquin Agricultural Reserve to remove subsoil and replace topsoil has had deleterious effects on agriculture, requiring expensive remediation by the City. Removal of topsoil without replacement at San Luis Ranch would have more extensive and more serious effects.

As detailed in the Agricultural Master Plan for the City of San Luis Obispo’s Calle Joaquin Agricultural Reserve,

As part of the development plan for the McBride property, the 13-acre open space portion was graded to avoid displacement of flood capacity. This was a City requirement imposed upon the project. This grading was performed in a manner that retained the top three feet of soil while removing approximately two feet of subsoil, and was done to retain a slope of 2% or less, 2% being the maximum slope considered acceptable for farming soils.

Outcomes of that grading have since had two serious consequences.  Pooling of water in the lower section of the fields in Winter 2015-2016 made farming impossible for several months for subtenants, Green Gold Organics, at City Farm and created a major factor for their terminating their lease and moving operations elsewhere.

In an effort to remediate this condition on its property, the City of San Luis Obispo undertook the construction of a swale in order to drain pooled water away from the fields,improve its quality and conduct it toward Prefumo Creek, at a cost of  $25,500. The success of this remediation effort remains to be seen.

This example demonstrates the high environmental impact of changing the contours of agricultural fields in order to mine them for subsoil fill to raise the elevation of nearby land for the purpose of development.  It does not take into account the much greater impact of using topsoil for that purpose, as proposed in the DEIR.

 VI. Conclusion

According the prospectus and Preliminary Specific Plan for San Luis Ranch,

Everything about San Luis Ranch grows from the project’s foundation in four guiding principles identified as the CORE 4: The first of these guiding principles is stated as follows:

San Luis Ranch will maintain and promote San Luis Obispo’s agricultural heritage.From continued cultivation to “u-pick-it” farming and an agricultural education center, San Luis Ranch will offer residents and visitors an opportunity to connect with agriculture and continue to enjoy the views of this pastoral setting. (http://www.slocity.org/home/showdocument?id=8013)

We hope that this principle will serve to guide the developer to avoid the serious mistake of following the present plan to use the irreplaceable agricultural resource of fertile, living, precious topsoil as mere dirt.  If not, we hope the City’s regulatory bodies will have the wisdom to prevent that from happening.




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