Project Details:

Cover Crop Effects on Soybean Yield and Soil Properties

Parent Project: Cover Crop Effects on Soybean Yield and Soil Properties
Checkoff Organization:Kansas Soybean Commission
Categories:Crop management systems, Soil fertility
NCSRP, USB, QSSB Project Code:1721
Project Year:2017
Lead Principal Investigator:Doug Shoup (Kansas State University)
Co-Principal Investigators:
Ignacio Ciampitti (Kansas State University)
DeAnn Presley (Kansas State University)
Gretchen Sassenrath (Kansas State University)
Keywords:

Contributing Organizations

Funding Institutions

Information and Results

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Project Summary

Cover crops are being utilized by more producers throughout Kansas. Reasons for the adoption of cover crops include reduced erosion, nutrient cycling, weed suppression, reduce soil
compaction, increased soil organic matter and increase biological activity. Kansas State University has evaluated cover crops for the last two decades. Some of the first modem cover crop research was conducted at the Hesston Research Station in the mid to late 1990's (Claassen, 2009). The crop rotation evaluated was a wheat/cover crop/grain sorghum rotation. The two cover crops utilized to produce residue and nitrogen for the subsequent grain sorghum were forage soybean and sunn hemp. A 7 bu/acre yield increase was observed for grain sorghum
following a sunn hemp cover crop vs. no cover crop at the fertilizer application rate of 90 lbs N/acre. Across 6 years of yield data, the sunn hemp contributed an equivalent of 50 lbs N/acre to the following grain sorghum crop. In addition to yield increases, improvements in soil organic matter and earth worm population were also observed in plots with a cover crop (Blanco, et. al, 2011).
In 2011, a cover crop study in a com and soybean rotation was established at the KSU East Central Experiment Field in Ottawa. Cover crop species were planted after com and terminated the following spring ahead of soybean. Since that time com and soybean yields following cover
crops have been determined on that research area for three growing seasons (Table 1) .
Several additional cover crop studies are being conducted in locations across the state, however few are evaluating the effect of cover crops on soybean production, especially in a soybean/com rotation. Because soybean is a legume, the impacts of nitrogen credits from a cover crop are diminished, however the other benefits of cover crops need to be evaluated.

Project Objectives

Project Deliverables

In the fall, five cover crop mixtures and one unplanted check will be established soon after com harvest to allow for adequate fall growth. Cover crop mixtures will be as follows 1. Unplanted treatment (weeds controlled in the fallow period)
2. Cereal rye
3. Tillage radish
4. Cereal rye+ tillage radish
5. Cereal rye + tillage radish + winter pea
6. Cereal rye + oat + tillage radish+ turnip+ winter pea+ sorghum+ crimson clover
Seeding rates of individual species will be reduced/adjusted as the number of species in the mixture increases to avoid extremely high plant populations and account for producer inputs. Experiments will be arranged in a randomized complete block design with 4 replications and planted at the KSU East Central Experiment Field in Ottawa and at the KSU Agronomy Ashland Bottoms in Manhattan. Locations are selected where soybean/com rotations and no-till practices are more prevalent. Fertility and pest control will be managed according to KSU
recommendations. Cover crops will be terminated in late April or early May with glyphosate at the onset of head emergence of the cereal rye. Soybean will be no-tilled into the standing residue in late May to early June. In the spring, soil samples will be taken for evaluation of nutrients, organic matter, and biological soil analysis (PLF A, Solvita, etc.). Soybean plots will be harvested and plot weights, moisture, and test weights will be determined. Data will be analyzed using ANOVA.

Progress of Work

Update:
Cover crop studies were initiated at the KSU East Central Experiment Field at Ottawa in the fall of 2016 following corn harvest. The 6 cover crop treatments were planted on September 9th, 2016. Cover crop treatments were: unplanted check, triticale, radish, triticale + radish, triticale + radish + winter pea, and a 7 way blend of triticale + radish + winter pea + crimson clover + oat + turnip + and sorghum. Good stands of covers were achieved into the fall.

Update:
No update other than cover crops continued to survive during the winter months.

Update:
A research study was established in 2011 in a soybean and corn rotation with cover crops planted soon after each crop harvest in the fall. A variety of complex cover crop mixtures were evaluated ranging from single specie to 7 specie mixtures. Cover crops were terminated in the spring soon after anthesis of the cool season cereal in the cover crop. Soybean yield responded differently among the four years of the study. In an extreme drought year of 2012 the unplanted check yielded 29.4 bu/a. Soybean yield was significantly reduced by 4.2 and 3.4 bu/a in treatments with wheat or turnip cover crop, respectively. In 2014, the unplanted check yielded 33.9 bu/a and cover crop treatments rye, rye + radish, and >6-species mix had significantly greater soybean yield at 3.7, 3.4, and 3.3 bu/a, respectively. In 2015, only the rye cover crop treatment significantly reduced soybean yield compared to the unplanted check at a 4.2 bu/a yield loss. No significant yield differences were observed in any cover crop treatment in 2016.

View uploaded report Word file

Update:
Please see attached PDF

View uploaded report PDF file

Final Project Results

A research study was established in 2011 in a soybean and corn rotation with cover crops planted soon after each crop harvest in the fall. A variety of complex cover crop mixtures were evaluated ranging from single specie to 7 specie mixtures. Cover crops were terminated in the spring soon after anthesis of the cool season cereal in the cover crop. Soybean yield responded differently among the four years of the study. In an extreme drought year of 2012 the unplanted check yielded 29.4 bu/a. Soybean yield was significantly reduced by 4.2 and 3.4 bu/a in treatments with wheat or turnip cover crop, respectively. In 2014, the unplanted check yielded 33.9 bu/a and cover crop treatments rye, rye + radish, and >6-species mix had significantly greater soybean yield at 3.7, 3.4, and 3.3 bu/a, respectively. In 2015, only the rye cover crop treatment significantly reduced soybean yield compared to the unplanted check at a 4.2 bu/a yield loss. No significant yield differences were observed in any cover crop treatment in 2016.

Benefit to Soybean Farmers

Performance Metrics

With little known about the subsequent soybean impacts from cover crops planted after corn in a soybean corn rotation, this research project adds a piece of information for growers to better help in cover crop planting decisions. The overall impact on soybean yield over the 6 years of the project is neutral so if producers want to incorporate cover crops to help reduce soil erosion, it can be conducted with little impact to soybean yield. After numerous years of cover crops planted after both soybean and corn, little to no change in soil microbial populations were observed in 2015, 2016, and 2017 (see previous final data reports for this project). In general there were no organic matter changes until the 2017 year when a 0.2-0.3% increase was seen where a cool season cereal was planted at the highest seeding rate when compared to the unplanted check.

Project Years