I attended the Milan NoTill Field Day (MNTFD) this past July 26 for the first time. I am a native Northwest Tennesseean and worked for 30 years at the Stoneville, Miss. USDA-ARS facility, but for some unknown reason had motored neither south nor north to attend this iconic event.
One of my reasons for attending the MNTFD was to meet with Dr. Grover Shannon, Midsouth Soybean Board (MSSB) Research Coordinator, and Dr. Michele Reba, Research Hydrologist, and Dr. Joe Massey, Research Agronomist, both at the USDA-ARS Delta Water Management Research Unit at Jonesboro, Arkansas. The purpose of our meeting was to explore opportunities for regional activities designed to address the agricultural issues related to water conservation that is of paramount importance to crop production in the Midsouth.
The four major crops in the Midsouth–soybeans, cotton, rice, and corn–have significant irrigated acreages. In fact, irrigated soybean acreage alone accounts for an estimated 4+ million acres in the region. Add this to the 1.75-2.0 million acres of rice (all irrigated) and the estimated corn and cotton acres that are irrigated in the region, and the total irrigated acres of the four crops likely approaches 7 million acres. The primary source of water to irrigate these crop acres is the shallow lower Mississippi River Valley Alluvial Aquifer (MRVAA). Numerous sources indicate that the amount of water withdrawn from the MRVAA to irrigate Midsouth crops significantly exceeds its recharge capacity.
Following our meeting, Dr. Reba sent me two articles that she authored/coauthored about current efforts to monitor/document both water quality and quantity issues in Arkansas and the Lower Mississippi River Basin (LMRB). These articles are linked below. I have provided brief summaries of their contents.
The first article titled “A statewide network for monitoring agricultural water quality and water quantity in Arkansas” (Reba et al., J. Of Soil and Water Cons., Vol. 68, 2013) provides details about the setup and conduct of a statewide (Arkansas) monitoring network designed to collect water quality and quantity data. Pertinent details of the network follow.
• The network is comprised of 30 monitoring sites on 12 separate farms that grow/produce rice, soybean, cotton, corn, poultry, and beef. Irrigation of crops at pertinent sites is from either groundwater or surface reservoirs with a tailwater recovery system. The monitoring network is focused on field- to farm-scale quantification of water resources related to production of Arkansas’s major cropping systems.
• The network is directed toward providing data that will contribute to water resource management practices that will sustain production of farm commodities.
• The premise for this work is that competition for water use in the region may force agricultural producers to modify their water use practices.
• The network is supported by Arkansas universities, USDA-ARS, USDA-NRCS, state commissions and Conservation Districts, and agricultural producers representing the major commodities in the state, including the Arkansas Soybean Promotion Board.
• The objectives of the edge-of-field installations are to automatically collect water samples for subsequent laboratory analyses and to measure runoff volume. Additional sensors at select monitoring locations include atmometers, soil moisture sensors, turbidity meters, and flow meters.
• The conservation practices of interest include nutrient management, water management, irrigation planning, tillage practices, and cover crops.
• Though specific to Arkansas, the activities associated with this network are representative of those that can be conducted in the entire Lower Mississippi River Basin.
• Results from these activities will be used to identify/develop innovative water resource management techniques that will lead to maintaining or increasing crop yields with existing or possibly dwindling water resources, while simultaneously maintaining water quality for non-farm uses.
The second article titled “Delta-Flux: An eddy covariance network for a climate-smart lower Mississippi basin” ( Runkle et al., Agric. Environ. Lett., Vol. 2, 2017) provides details about the setup and use of a network of towers to provide site-level measurements to quantify carbon and water fluxes in the LMRB.
• The network is comprised of a consortium of researchers representing US government agencies and state universities in the LMRB.
• The network is comprised of 17 monitoring towers spread across 11 sites in Arkansas, Mississippi, and Louisiana. The network towers are placed in commercial fields of rice, soybean, corn, cotton, and sugarcane, plus pasture, grasslands, and forests.
• The overall goal of the network is to integrate site-level findings about carbon and water fluxes into cohesive data sets that can be used for determining coordinated regional needs related to the measured variables, and to use the resulting standardized observations and their analyses to provide a foundation to regionalize those findings so that optimal agricultural production strategies can be developed across a variety of land uses in the LMRB.
• Three specific goals of the Delta-flux network are to: 1) create a high-quality, consistent dataset from these tower-based carbon and water flux measurements; 2) generate a regional carbon balance that is sensitive to local variation in land use; and 3) facilitate research on the relationship among agricultural management, water use, and carbon sequestration.
• Results from these activities will be used to: 1) encourage sustainable agricultural practices by providing data that demonstrate the results from using alternative land use and/or crop management practices; 2) aid decision making with respect to climate variables such as drought and flood tolerance/frequency that affect agriculture so that their effect or impact is minimized; and 3) coordinate data collection and sharing to support sustainable agriculture production.
• The network will improve the efficiency of data collection, storage, and analysis through cross-site collaboration that supports uniformity/standardization of data collection and labeling, reduced duplication of effort, and use of a consistent working vocabulary.
It is the hope of this author that the above examples of coordinated networks in the Midsouth can provide the impetus for both university and government administrators, plus those in private industry, to take the lead in establishing region-wide water resource management networks that go beyond state lines. Since the crops produced and the practices used in their production, plus irrigation water use patterns, are similar throughout the Midsouth, it seems logical that regional bodies such as the MSSB and similar regional groups should support these efforts so that region-wide adoption of sustainable irrigation and water management practices can be developed and adopted. It is only through such coordinated, region-wide efforts that this important task can be accomplished.
All the states in the Midsouth have qualified, competent agricultural researchers and practitioners, but not all of the states have all of the resource persons needed to conduct all phases of a region-wide effort such as those highlighted above. Thus, the states joining to bring together resource persons from the various disciplines into a cohesive, coordinated working group will provide the depth of expertise needed to solve agricultural problems and issues in the region.
Composed by Larry G. Heatherly, Aug. 2018, email@example.com