“An Urban Agro-Ecosystem: The Example of 19^th-Century Paris”, G. Stanhill1976 (tech)⁠:

One hundred years ago a 6^th of the area of Paris was used to produce annually more than 100,000 tons of high-value, out-of-season, salad crops. This French intensive gardening cropping system was sustained by the use of ~1 million tons of stable manure produced each year by the horses which provided the power for the city’s transport system.

Sufficient surplus “soil” was produced to expand the production area by 6% yr⁻¹. In energy, mass and monetary terms the inputs and outputs of the Parisian urban agro-ecosystem exceed those of most examples of present-day, fully industrialized crop production.

The productive biological recycling of the waste products of the city’s transport system contrasts favourably with the requirements and consequences of the simplified, present-day urban ecosystem.

…The marais system of cultivation appears to have been one of the most productive ever documented. In addition to providing a large proportion of the city’s fresh food, it supplied a valuable export market and transformed the major transport pollution problem of the time into an asset by turning vast quantities of stable manure into a surplus of highly fertile soil. Following descriptions by Kropotkin1899 and Smith1911, the system became known in the English-reading world under the name of “French gardening”. However, most of the later accounts in English are derivative, unquantitative, and contain exaggerated claims.

…The year-round production of high-quality salad and vegetable crops which characterized French gardening was based on inter-cropping & successional cropping, in which as many as 6 and seldom less than 3 crops per year were harvested from each plot of land. Winter crop production was made possible, and growth rates were enhanced during the spring and autumn, by the heat and perhaps CO₂ released during the fermentation of stable manure. Additional heat was provided by glass-covered frames and bell-shaped glass cloches; by straw mats during severe weather and by the additional shelter from the 2-m-high walls which surrounded each smallholding. Frequent light irrigations were applied, adding to the high labor requirements…Very heavy dressings of stable manure were an essential feature of the marais system, providing the fermenting “hotbeds” on which out-of-season crops were produced under glass protection…straw mats…Included are seeds, fuel to operate the water pump, soap and naphtha applied in small quantities as pest deterrents, packing material, and the depreciation of hand tools and the irrigation system.

…During this same 25-year period, the population of Paris doubled from one to two million, although the total area within the city limits remained constant at 7,800 ha…The food marketed from each hectare could supply 15 persons with their caloric requirements (at 2,400 Kcal per capita per day) and 54 persons with their proteins (at 54g per capita per day). This human carrying capacity, admittedly on an extreme vegetarian diet, is equal to that of the most productive of current agricultural cropping systems (Leach1975). In terms of dry matter output, the production of the marais system 100 years ago equalled that of all but the highest-yielding sugar and cereal crops grown today (Leach 1975).

They were interested primarily in maximizing the financial returns and to this end their cropping system concentrated on high-value, out-of-season winter crops and neglected the higher-yielding but lower-value summer crops. No doubt this emphasis reduced the total volume of production per year below the potential.

…Measured monetarily, the efficiency of the marais system was high. Using the balance sheets presented by Courtois-Gerard1858, the annual profit of the typical marais at that time returned 15% of the capital investment, including in this latter term the average price of the land—40,000 fr per hectare. For rented land—the more usual case—the annual profit, including the cost of the rent, returned 58% on the working capital required. It should be noted that the expenses do not include any wages for the proprietor or his family, but do include the cost of their food and habitation.

From the point of view of labor, the efficiency of the marais system was extremely low. For the average holding, 2.34 MJ of metabolic food energy was produced on the holding per man-hour and 1.84 MJ hr⁻¹ delivered at the market. These values are one order of magnitude below those quoted by Leach1975 for a variety of preindustrial cropping systems and are 3 orders of magnitude below those of fully industrialized cropping systems as practiced in the USA and the UK today.

The very high labor requirements of the marais system can in part be attributed to the emphasis on out-of-season cropping, requiring hotbed preparation and almost continuous attention to the ventilation and irrigation of the glass-protected crops. However, even for unprotected cropping, the improvement in output per man-hour is only 1⁄3^rd.

See Also:

• Victorian Pioneers of Corporate Sustainability

• The micro-evidence for the Malthusian system: France, 1670^–₁₇₀1840_184ya

• Geography and Agricultural Productivity: Cross-Country Evidence from Micro Plot-Level Data

• Two Blades of Grass: The Impact of the Green Revolution

• Photovoltaic-driven microbial protein production can use land and sunlight more efficiently than conventional crops

• The Origin of the State: Land Productivity or Appropriability?

• Engineering photosynthesis: progress and perspectives

• Fifty years of pig breeding in France: outcomes and perspectives

• The Economic Effects of the English Parliamentary Enclosures

• Anthropological invariants in travel behavior

• Large-scale cooperation in small-scale foraging societies