**13. Policies and practices supporting soil and water sustainability**

Currently Federal, State, and agricultural producer partnerships are creating policies and farming practices that support ecosystem health and farm profitability [21]. The goal is to support sustainable and profitable agriculture, while identifying farming practices that are wetland suitable, even when the wetland has been altered by previous land drainage projects. A corollary is attempting to identify wetland benefits and reinstitute practices to return or augment wetland benefits to these altered landscapes while preserving agriculture productivity. One key initiative includes "soil health". Soil health (soil quality) is defined as the continued capacity of soil to function as a vital living ecosystem that sustains plants, vertebrate and invertebrate animals, microorganisms, and humans [22]. This definition speaks to the importance of managing soils to optimize living organisms that contribute to maintaining soil structure, soil organic matter, and functioning nutrient soil and plant connectivity. Considering soil as a living ecosystem reflects a fundamental thinking shift towards nutrient management for plant growth, supporting the soils ability to absorb and hold rainwater for use during dryer periods, filter and buffer potential pollutants from leaving fields, and provide habitat for soil microbes to flourish and diversify. This website [22] provides an annotated bibliography with citations of current literature on soil health initiatives that support water availability, soil structure improvement, soil organic matter optimization (including promotion of active carbon contents), nutrient availability, and limited nutrient transport of nutrients from farm fields to fresh water resources.

All soil evolution is a complex interplay between horizonation (development of diagnostic soil horizons) and haploidization (the phenomena of organisms and vegetation altering the soil profile to reduce the expression of soil horizons). Land drainage should support the intensity of soil processes to create and maintain soil horizons, particularly albic and argillic horizons. Conversely, loss of soil organic matter will alter mollic (high base saturation and high soil organic matter) and umbric (low base saturation and high soil organic matter) epipedons to orchric (low organic matter) epipedons. Wetlands are commonly acknowledged to purify surface waters and facilitate surface water transfer to shallow aquifers. There is growing concern that land drainage and the associated agriculture will promote nutrient migration and support fresh water eutrophication. Installed levees prevent river flooding in selected areas, leading to greater flooding elsewhere on lands not levee protected. Irrigation may lead to

); SOM is soil organic matter (%).

**Horizon Texture Color pH CEC SOM ESP** A Silt loam Grayish brown 6.0 14.9 4.3% <1% E Silt loam Light brownish gray 5.1 12.8 1.9% <1% BE Silty clay loam Pale brown 5.2 14.5 1.9% <1% Btg Silty clay loam Light brownish gray 5.4 26.8 1.7% 2.0% Btgn Silty clay loam Grayish brown 7.3 18.0 1.4% 18.0%

For example, the Overcup soil series from the Advance Lowlands (fine, smectitic, thermic Vertic Albaqualfs) are very deep, poorly drained, very slowly permeable soils that formed in alluvium. Soil analysis by the authors of the Overcup soil series in both long-term deciduous forest settings and modern rice production fields (unpublished) demonstrate that considerable soil organic matter contents are evident in the forest settings (**Table 1**), whereas the production fields have diminished near-surface soil organic matter contents. The Overcup soil series shows considerable gray color patterns because of seasonal or fluctuating soil water tables within the solum. Soil acidification is evident in the upper argillic horizon, a feature attributed to base removal by leaching. The lower argillic horizon shows a neutral to alkaline pH with a considerable exchangeable sodium presence because restricted drainage has not permitted base leaching, especially including exchangeable sodium. Thus, the placement of cover crops in rice production fields should re-establish soil organic matter contents in the near-surface soil horizons.

**13. Policies and practices supporting soil and water sustainability**

Currently Federal, State, and agricultural producer partnerships are creating policies and farming practices that support ecosystem health and farm profitability [21]. The goal is to support

aquifer overdraft; however, this issue is not apparent in this study area.

Btgn – Btg horizpon that has natric characteristics (high exchange sodium percentage (ESP).

**Table 1.** The essential properties of the Overcup soil series in an old growth natural forest.

CEC is cation exchange capacity (cmol kg−<sup>1</sup>

Btg – argillic horizon (Bt) that is gleied (g or low chroma colors).

164 Wetlands Management - Assessing Risk and Sustainable Solutions

A key land practice associated with soil health is the establishment of cover crops. We define cover crops as grasses and legumes cultivated to provide cropland vegetative cover during the off-season to support soil carbon accumulation, improved soil structure (including reduced soil compaction), improved water availability, and substantial reduction is both water and wind induced soil erosion. Our cover crop programs frequently rely on establishment cereal rye (*Secale cereale* L.), crimson clover (*Trifolium incarnatum* L.), and canola (*Brassica napus* L); however, many producers and extension services support other plant compositions. In early spring, the cover crops will receive chemical burndown with the new crop established with a no-till grain drill/planter into the existing cover crop residue.

USA has established the Mississippi River Basin Healthy Watersheds initiative across 13 USA states [21] to limit the Mississippi River's nutrient and sediment loads. The initiative supports direct payments to agriculture producers to establish erosion and nutrient migration mitigation, primarily through the Environmental Quality Incentives Program (EQIP) and the Agriculture Conservation Easement Program (ACEP). Nutrient reduction strategies are tailored to individual states. Wetland restoration is a key and central provision wherein marginal land is returned to a wetland status.

Southeast Missouri State University and the United States Department of Agriculture—Natural Resources Conservation Service have partnered to address nutrient transport from production agriculture. The development of Edge of Field Technologies is gaining producer acceptance and has witnessed the establishment of denitrification bioreactors to intercept tile drainage effluent to render the effluent comparatively free of NO3 -N. From 2015 to the present, the denitrification bioreactor at the David M. Barton Agriculture Research Center effectively reduced nitrate-N concentrations from between 10 and 100 mg L−<sup>1</sup> NO<sup>3</sup> -N to less than 10 mg L−<sup>1</sup> NO<sup>3</sup> -N [23]. Currently, Southeast Missouri State University and the United States Department of Agriculture—Agriculture Research Service has been active in pumping nitrate and phosphate bearing tile drainage effluent into off season water retention basins to reapply the water as an irrigated source during the growing season. The goal is to reduce aquifer depletion. This research is also investigating whether the stored off-season water may be passed through a denitrification bioreactor and then returned to the aquifer, thus limiting aquifer overdraft with high quality water replacement. Rice production is an important crop in the study area. Recently, arsenic uptake has become an issue. Aide et al. [24–26] investigated different irrigation practices and determined that furrow irrigation would provide similar yields, substantial limit transference of arsenic to paddy rice and reduce water application rates and aquifer overdraft.

[2] Epperson JE. Missouri wetlands: A vanishing resource. Water Resources Report No. 39. Missouri Department Natural Resources. Division of Geology and Land Survey. Jefferson

A Large-Scale Wetland Conversion Project in Southeastern Missouri: Sustainability of Water and Soil

http://dx.doi.org/10.5772/intechopen.81254

167

[3] Festervand DF. Cooperative Soil Survey of Cape Girardeau, Scott and Mississippi Counties, Missouri. Washington, DC: United States Department of Agriculture-Soil

[5] United States Department of Agriculture, Natural Resources Conservation Service. In: Vasilas LM, Hurt GW, Berkowitz JF, editors. Field Indicators of Hydric Soils in the United States. A Guide for Identifying and Delineating Hydric Soils, Version 8.1. United State Government Printing Office, Washington DC. 2017. [https://www.nrcs.usda.gov/

[6] Saucier RT. Geomorphology and Quaternary Geologic History of the Lower Mississippi Valley. Vicksburg, MS: U.S. Army Corps. Engineers, Waterways Experimental Station;

[7] Robnett PC. Late quaternary occupation and abandonment of the Western Lowlands valley train course in favor of the Eastern Lowlands valley train course, Mississippi River, Southeastern Missouri [Master's thesis]. Carbondale, Il: Southern Illinois State

[8] Southeast Missouri Groundwater Province. Missouri Geologic Survey. Missouri Department of Natural Resources. https://dnr.mo.gov/geology/wrc/groundwater/education/ provinces/selowlandprovince.htm?/env/wrc/groundwater/education/provinces/selow-

[9] United States Department of Agriculture, National Agriculture Statistics Service. [https://

[10] University Missouri Crop Budgets [http://crops.missouri.edu/economics/budgets/, Verified

[11] Saucier RT. Evidence of late-glacial runoff in the lower Mississippi valley. Quaternary

[12] Royall PD, Delcourt PA, Delcourt RH. Late Quaternary paleoecology and paleoenvironments of the Central Mississippi Alluvial Valley. Geological Society of America Bulletin.

[13] Blum MD, Gluccione MJ, Wysocki DA, Robnett PC, Rutledge EM. Late Pleistocene evolution of the lower Mississippi River valley, Southern Missouri to Arkansas. Geological

[14] Saucier RT. Geoarchaeological evidence of strong pre-historic earthquakes in the New

[15] Saucier RT. Evidence for episodic sand-blow activity during the 1811-1812 New Madrid

www.nass.usda.gov/Statistics\_by\_State/, Verified August 2018]

Internet/FSE\_DOCUMENTS/nrcs142p2\_053171.pdf, Verified August 2018]

City, Missouri. 1992. [https://dnr.mo.gov/pubs/WR39.pdf, Verified August 2018]

[4] Mitsch WJ, Gosselink JG. Wetlands. NY: Van Nostrand Reinhold; 1993

Conservation Service; 1981

1994

University; 1997

landprovince.htm

August 2018]

1991;**103**:157-170

Science Reviews. 1994;**13**:973-981

Society of America Bulletin. 2000;**112**:221-235

Madrid (Missouri) seismic zone. Geology. 1991;**19**:296-298

(Missouri) earthquake series. Geology. 1989;**17**:103-106

Observed and perceived carbon-cycle changes attributed to the wetland conversion project to the atmosphere-plant-soil continuum include: (i) wetland forest vegetation replaced by annual monocot and dicot agricultural plantings resulting in reduced carbon sequestration, (ii) carbon loss because of grain harvesting and because of enhanced soil oxidation by the combined effects of land drainage and tillage, and (iii) increased soil temperatures [1]. Current technologies practices recently implemented to favor restoring soil carbon levels include: (i) improved residue management and the conversion to reduced tillage practices, (ii) off-season cover crop establishment, and (iii) restricted (controlled) drainage technologies and winter irrigation to preserve organic soil carbon. Winter irrigation also provides over-wintering nesting sites for migratory water fowl.
