NRCS state soil specialist Jeff Hemenway explains the slake test (beakers on the right of the table) and the table top rainfall simulator (on the left of the table).
Beadle County Conservation District:
Alternative Farming Demonstrations
High saline soil on cropland is a growing concern for producers in the Dakotas, especially in the James River Valley. The Beadle County Conservation District is tackling this issue through their demonstration farm by showcasing alternative farming practices. In the 1990s, the Beadle County Conservation District acquired approximately 400 acres of crop land just south of Huron, SD. About 360 acres was seeded back to a native tallgrass prairie mix (big bluestem, indiangrass, switchgrass, sideoats grama, little bluestem, and western wheatgrass) with the intention of creating summer pasture. The remaining land was split into a 20 acre shelterbelt with different kinds of trees and shrubs to demonstrate their adaptability to the northern Great Plains climate. Two 10-acre food plots were also planted for wildlife. Over the years, high saline spots started showing up in poorly drained areas in one of the 10-acre food plots. The Conservation District decided they needed to change their practices to fix this problem (Figure 1).
Figure 1. Beadle County Conservation District Farm showing high saline spots (white) in a 10 acre crop field. Photo courtesy of Google Maps 2014.
Farm Tour: Improving High-Saline Affected Soils
On August 23, 2016 the Conservation District along with the USDA-NRCS hosted a tour of the demonstration farm working on improving high saline affected soils. Jeff Hemenway, state soil health specialist with NRCS explained, “The problem with high saline areas is a combination of parent material, poor drainage, and high evaporation rates. The salts are dissolved in the high water table and through evaporation are brought to the soil surface. Our choices in crops, corn or soybeans, don’t use the water in the early or late part of the growing season. Perennials are more effective in using the water and lowering the water table to leach the salts away from the surface”. In 2014, the Conservation District seeded the site (Figure 1) to a mixture of ‘Salinity Max’ alfalfa at 10 lbs/acre and ‘AC Saltlander’ green wheatgrass (Elymus hoffmannii,) hybrid between quackgrass and a Eurasian bluebunch wheatgrass) at 5 lbs/acre. Today the high saline spots are showing signs of improvement (Figure 2).
AC Saltlander is taking hold in the poorly drained spots and the alfalfa is using more water in the remaining areas of the field drawing down the water table. Over time, the salt tolerant grass will fill in the bare spots and the salt content of the surface should lower. The District plans to keep this field in perennial cover instead of returning it to cropland.
Figure 2. NRCS District Conservationist, Kent Vlieger explains how the cropland was seeded to salt tolerant alfalfa and grass. The bare spot is a poorly drained area of the field that has very high salinity. Photo by A. Smart.
Water Cycle Demonstration: Rainfall simulator
In addition to the saline problems, the Conservation District demonstrated the importance of the water cycle using the slake test and the rainfall simulator (Figure 3). The slake test shows the importance of aggregate stability in holding water and resisting breakdown of the soil. Soil organic carbon is used by bacteria, fungi, and other animals for food and in turn they breakdown the material into smaller fragments that essentially “glues” the soil particles together. Tillage breaks down organic matter which is then lost into the atmosphere. Hemenway handed out soil clods from a conventionally tilled field and a no-tilled field from the same soil type (Figure 4). The no-till soil maintained its integrity under the slake test while the conventionally tilled soil broke apart and sank to the bottom of the beaker.
|Fig. 3. NRCS state soil specialist Jeff Hemenway explains the slake test (beakers on the right of the table) and the table top rainfall simulator (on the left of the table). Photos by A. Smart.||Fig. 4. Soil clod from conventional tilled (left) and no-till (right). Note the conventional tilled soil clod is lacking large macro pores and larger aggregates compared with the no-till soil.|
Pasture & Rangeland Management Tour
The tour wrapped up with a drive through the pastures. Rod Voss, NRCS rangeland management specialist, shared with the group the management objectives, rangeland improvements, and the logistics of the grazing rotation. The grass stand planted 20 years ago was in excellent shape along with the owners’ cattle (Figure 5).
Figure 5. Native tallgrass planting that has been in pasture for 20 years south of Huron, S.D.
For more information about how to address soil salinity issues, planting cropland to grassland, or managing pastures in eastern South Dakota, please contact: your local NRCS district conservationists, rangeland management specialists, or a state rangeland management specialist. Programs are available to cost-share these practices. Visit SD Habitat Pays for more information regarding habitat resources.