- Agronomic: cotton, peanuts, soybeans
- Crop Production: double cropping, intercropping
- Production Systems: general crop production
The overarching goal of this on-farm research project is to assist cotton, soybean, peanut and small grain producers with adoption of innovative conservation technologies for crop production to enhance environmental quality, farm profits, and soil properties, while reducing energy consumption and pest occurrence.
One major advantage the southern U.S. has over other crop production areas is a long growing season, making it possible to double-crop winter and summer crops. The most popular double-cropping system is winter wheat followed by soybean. Some growers are currently double-cropping cotton and peanut after wheat; however, the longer growing season requirements for cotton and peanut limit the yield potential for these cropping systems.
Recently, growers in the southern U.S. are facing new production problems that are either reducing farm profits and sustainability or threatening soil conservation practices:
- Herbicide-resistant weeds are the most pressing concern for growers throughout the Southeast. Soil-applied residual herbicides have become the most widely adopted method to manage herbicide-resistant weeds. An aggressive herbicide program can cost up to $50/acre; however, hand-weeding, cultivation, and crop abandonment can cost growers over $900/acre in lost revenue and increased production costs if weeds are not controlled using herbicides. Soil conservation gains achieved in the last 20 years are threatened by herbicide resistant weeds (Shaw et al., 2012). For example, inversion tillage has been demonstrated as an effective tool in reducing soil seed-bank levels of glyphosate-resistant Palmer amaranth; however, this practice significantly increases soil erosion potential and energy requirements. Cover crops can be used effectively to suppress herbicide-resistant weeds without resorting to aggressive tillage (Hoffman et al., 1996); however, growers have expressed frustration with the poor performance of their planting equipment in dealing with cover crop residue;
- Control costs for and damage caused by insects also pose production problems perennially. According to loss estimates provided in the Proceedings of the Beltwide Cotton Production Conferences, cotton producers across the USA lost about $100 million to thrips during 2008-2010 (Williams, 2011). With at-plant preventative treatments and foliar applications combined, control costs during the same period are in the tens of millions as well. Thrips were ranked as the second most important group of cotton insect pests in 2011 across the USA (Williams, 2012), but represented the most important group in the Southeast last season;
- Nematodes cause hundreds of millions of dollars in yield losses annually to USA cotton, soybean, and peanut. Nematode management relies heavily on the use of nematicides such as Temik 15G ($15-18/acre) or Telone II ($42/acre); however, the most effective tool for managing nematodes and thrips (Temik 15G) curently is no longer available and currently there is a shortage of Telone II nematicide in the USA; and
- The cost of fuel represents over 30% of the total costs of owning and operating farm equipment. This portion will increase further as the price of fuel rises in the future.
Therefore, there is a need to assist southern growers to understand and adopt sustainable agricultural practices through on- farm research and outreach activities.
Project objectives from proposal:
We propose to: a) establish two on-farm research sites “Prototype Fields” to directly train growers in the use, benefits, and effectiveness of interseeding technology; b) modify farmers’ equipment (or utilize our own equipment) to allow for interseeding, and provide training and support to ensure proper use; and c); implement an aggressive training program for crop consultants and county Extension agents to become the primary providers of interseeding technology for growers beyond the geographic and time limitations of this project;
On-farm Research: Two Farmers in South Carolina, Jason Still (Bamberg County) and Brent Hage (Barnwell County) have agreed to participate in this project. These farms will be used for on-farm research and outreach activities “Prototype fields.” At the initiation of the tests, a commercially available electrical conductivity (EC) meter (Veris 3100) will be used to map soil texture variation in the fields. In the Still Farm, we will establish interseeded peanut, cotton, and soybean, side-by-side with standard crop production practices for comparison. In the Hage Farm, only soybean will be interseeded and compared to conventional methods.
For each crop, a 20-acre section of the production field will be divided into management zones based on soil EC, and within each zone large research plots (12-rows wide by 100 ft.) will be established to compare interseeded and conventional cropping methods side by side. Experimental design will be a randomized complete block with a minimum of 10 replications for comparison. Data will be analyzed using generalized linear mixed modeling. Skip-row wheat or oat will be planted in these farms using Growers' modified grain drills. The appropriate row pattern will be achieved by blocking every other seed tube on the grain drill for interseeding narrow-row soybean (distance between skip rows: 15 inches) or every fifth seed tube for interseeding cotton, peanut or mono-crop soybean (distance between skip rows: 38-inches).
To make this technology more adoptable by growers, a 4-row John Deere (JD) 1700 vacuum planter (used by most of the row crop farmers) has been modified for interseeding cotton, peanuts, and wide-row soybeans (38-inch rows) into standing wheat. The standard width JD row units on this planter have been replaced with commercially available narrow row units which perfectly fit in narrow skips between wheat rows. We will either modify growers’ planting equipment or use our own interseeding machines to plant row crops in these farms.
Soybean, peanut, and cotton will be interseeded into standing small grain, around mid-May (approximately two to three weeks before harvesting small grain). The interseeding technology will be compared side by side with conventional full season and double-cropped production methods at these sites. The producers will contribute the cost of growing crops, which includes seed, fertilizer, pesticides, fuel, etc. Both growers are providing tractors equipped with RTK guiding systems which will allow for successful intercropping of soybean, peanut, and cotton into standing small grain crops:
- Because many pesticides labeled for use in row crops are not labeled in wheat, no insecticides will be applied to the interseeded row crop before wheat harvest. Interseeded cotton plots will be divided into sub-plots for monitoring thrips and other potential insect pests. The results will be compared with those obtained from adjacent plots planted using conventional production methods.
- No nematicides will be applied for the interseeded row crop. Nematode samples will be taken at planting and crop harvest from plots of interseeded and conventional cotton, soybean, and peanut plots.
- Weed populations will be quantified in the conventional and interseeding systems using two sets of interseeded sub-plots, with and without an appropriate herbicide management system. These results will be compared with those obtained using conventional crop production.
- The effects of interseeding technology on enhancing soil health will be demonstrated. A DGPS-based, hydraulically operated penetrometer system mounted on a JD Gator will be used to quantify geo-referenced soil resistance to penetration in interseeded and conventionally planted crop zones. Soil compaction values will be calculated from the measured force required to push a 0.5-in2 base area, 30-degree cone into the soil.
- Physiochemical properties of soils will be determined at Clemson’s Soil Testing laboratory. All soils will be air dried and passed through a 2 mm sieve for further soil nutrient and chemical analyses. The analysis of soil samples is to determine nutrient and contaminant content, composition. Tests are usually performed to measure the expected growth potential of crops grow in the soils. Soil pH will be determined in water using a soil: solution ratio of 1:1. Loss-on-ignition will be used to measure % organic matter (OM) (Sims, 1991). Cation exchange capacity (CEC), acidity and % base saturation will be measured using an unbuffered salt extraction method (Grove, 1982). Mehlich 1 (0.05 N HCl + 0.025 N H2SO4) extractable minerals (e.g., P, K, Ca, Mg, Zn, Mn) will be analyzed using inductively coupled plasma-atomic emission spectroscopy (ICP-AES).
- Fuel consumption for the interseeded and conventional crop production systems will be quantified using a JD 4050 instrumented tractor.
- Crop yield maps, using combine or picker equipped with a yield monitor, will be generated based on soil EC management zones at harvest to determine the effects of this new technology on farm profits.
- Reduction in pesticide use, fuel consumption, and pest pressure due to interseeding technology would be one indication of the success of this project.
- The interseeding equipment will be upgraded to match growers’ current planting and harvesting equipment.
Prototype fields: The “Prototype Fields” will be used to provide a setting for a series of field days and hands-on training workshops. These farms will be used to directly train cotton, soybean, peanut, and wheat growers in the use, benefits, and effectiveness of interseeding technology for enhancing soil health and reducing energy consumption and pest occurrence while optimizing farm profits. The producers will be trained to operate interseeding equipment. It is our intent to rapidly deploy these techniques throughout grower and consultant communities by their direct involvement in testing, outreach, and other project activities.