Agriculture is both a land use pattern that affects how the ecosystem functions, and it is a vital mechanism of our civilization--the means by which we feed ourselves.
Landscape Change under Agriculture
Historical modification of ecosystems to enable agriculture has transformed the landscape. Early farmers cleared forest and removed woody duff. Wetland soils are particularly fertile and moist but must first be drained. These changes have modified watershed hydrology, reducing interception, transpiration and percolation, increasing stream discharge and removing the buffering effects of a landcover that stores rainfall.
River and stream floodplains provide level topography, fine textured soils, and moisture that support intensive agriculture. Protection of agricultural landscapes have led to the development of Flood Hazard Management sytems. River Delta systems, affected by both tidal flood and river flood, are particularly dependant on delta flood and drainage systems involving dikes, tidegates and even pumps. Delta restoration can affect nearby farms by altering these systems.
Agricultural land naturally reverts back to wetland and forest. Drain systems clog and vegetation regrows. Maintaining agricultural functions can be constrained by the regulatory systems designed to restrict new impacts.
Ecosystem Services and Agriculture
- While agricultural landscapes require a loss of historical forest and wetlands, they may provide more ecosystem functions, goods, and services than more urbanized landscapes.
- Agricultural is not a homogeneous land use. Some agricultural systems have permanent ground and tree cover and carefully manage ever increasing soil health. Other systems are continuously disturbed and leach nutrients and toxins.
- Agroforestry designs that increase perennial cover, and woody plants in the landscape, while maintaining agricultural production are common in tropical environments, and increasingly promoted by the NRCS. Programs to require or incentive improvement in riparian buffer functions are controversial among some agricultural producers.
- Because of our dry summers, agriculture is an important end use of our water supply. Harvesting surface water for irrigation may meet agricultural water needs, while increasing the water holding capacity of the landscape, but isnot well demonstrated in the United States.
- When considering the design of public subsidies for agriculture, there is an indistinct line between supporting the maintenance of the public value of farm landscapes, and using public funds to increase the profits of individual business people.
Social Organization in Agricultural Systems for Stewardship
- File:Gilbert 2014 cooperative farming.pdf provides discussion of organizing cooperative agricultural ventures that may support management of common lands.
- https://farmcommons.org provides advice on legal frameworks for agricultural ventures
Public Management of Agricultural Systems
- Agricultural landowners are typically taxed by counties at a lower rate than other land owners.
- Counties have acquisition programs like Conservation Futures or Purchase of Development Rights programs to acquire development rights on agricultural lands. Skagit County and King County have been leaders in this work.
- WWRP has an inconsistently funded program to acquire development rights on agricultural land.
- Transfer of Development Rights systems have been developed in many counties, but depend on restriction of urban growth.
- CREP is a USDA program that leases streamside land for 10-15 years of tree production.
- NRCS has a family of programs for acquiring and restoring agricultural wetlands and subsidizing conservation practices.
- Conservation Districts provide technical assistance and may collect revenue to match state and federal programs.
- Salmon Recovery systems may acquire farmland and covert it to forest or wetland to provide habitat functions.
- The National Estuary Program began a program in 2015 to target acquisition of conservation easements in agricultural landscapes.
- King County Agricultural Drainage Assistance Program provides BMPs for drainage maintenance. These practices increase the cost compared to historical practices, while potentially decreasing impacts to fisheries.