Integrating no-till and forage radish cover crops for sustainable early sweet corn production

Integrating no-till and forage radish cover crops for sustainable early sweet corn production

Summary

Fall-planted forage radish cover crops have shown successful suppression of winter annual weeds and spring pre-plant weed growth as well as recycling of fall-captured nutrients. Data from this research will be used to develop an innovative no-till production system for early sweet corn to take full advantage of the benefits of a fall-planted forage radish cover crop. Cover crop treatments include forage radish, a mix of forage radish and oats, a mix of forage radish oats, and peas, and no cover crop.  

The effects of forage radish cover crops on nutrient cycling and soil fertility were examined in Experiment 1. In fall, cover crop biomass and soil nitrate scavenging were measured. In spring, soil temperatures and soil nutrient availability were measured. Sweet corn yield and quality and were evaluated at harvest in late July/early August. Experiment 2 is focused on the duration of weed suppression provided by forage radish cover crops.

The second year of these experiments was completed in 2016. Lab analysis is now complete and data is currently being analyzed.

Objectives/Performance Targets

Project objectives were to:

1. Measure the effectiveness and duration of spring weed suppression by forage radish on subsequent sweet corn crop;
2. Determine if the precocity of sweet corn planting and maturity can be improved by a preceding forage radish cover crop;
3. Assess the feasibility and success of earlier planting of sweet corn into a no-till seed bed following winter-killed forage radish cover crop mixes;
4. Measure the sweet corn yield and date of maturity to determine the effectiveness of a forage radish/sweet corn cropping rotation for producing high quality, early sweet corn;
5. Provide information relevant to both organic and conventional sweet corn producers, as well as no-till producers;
6. Conduct outreach through individual communication, grower meetings and conferences, annual field day events, newsletters and cooperative extension.

Having repeated this experiment in 2014-15 and 2015-16, these objectives have been met. Measurements of soil nutrient cycling, weed pressure, cover crop productivity, spring soil temperature, and sweet corn yield were recorded and are being analyzed. Outreach has been conducted and now that there are results to share, more publications and presentations are planned.

Accomplishments/Milestones

The second year of this project was successful, despite severe drought conditions. Cover crop treatments, planted in late August, consisted of three different forage radish mixes: all forage radish (FR), oats/forage radish(OFR), and peas/oats/forage radish (POFR) plus a control of no cover crop (NO CC). Cover crops established successfully and grew well in the fall of 2015. Fall weed population and cover crop biomass were measured just prior to winter-kill in late November 2015. 

Experiment 1: Nutrient cycling

In Experiment 1, early sweet corn was no-till planted following the afore-mentioned cover crop treatments. In spring, soil temperatures are measured for 2 weeks, from late April to early May, and compared among cover crop treatments. There were no significant differences amongst cover crops, which means that these cover crop mixtures do not have a cooling effect on spring soil temperatures.

Three nitrogen fertility treatments are used to examine the synchrony between nutrient release from decomposing cover crop and the uptake by sweet corn will be measured. Fertility treatments include:

• 0 lbs N/acre
• 0 lbs N/acre at planting and 25 lbs N/acre side-dressed
• 25 lbs N/acre at planting and 25 lbs N/acre side-dressed

Sweet corn ‘Trinity’ was seeded in early May after plots were sprayed with a burn-down application of RoundUp. In mid-June the side-dressed nitrogen treatments of urea were applied. Sweet corn plots were protected from raccoons with electric fencing.

Sweet corn was harvested twice, on July 28 and August 3, 2016. Fresh weight, number of ears, and tip fill were measured. Results showed that nitrogen treatment had a significant effect on yield, but cover crop treatment did not. All cover crop treatments yielded more sweet corn by count than NO CC, although differences were not statistically significant.

Soil samples were taken monthly in mid-April, May, June and early August, 2016. Soil nitrate analysis has been conducted (see Tables 1-4), and I am currently running analysis on soil concentrations of other elements (Ca, Mg, P, and K). Nitrogen sufficiency tests (CSNT) were performed on dried sweet corn stalks. Sweet corn quality, as measured by ear length and percent tip fill were not significantly different between cover crop treatments or nitrogen fertilizer treatments.

More analysis remains to be done to analyze interrelated variables, such as soil nitrate, cover crop treatment, and date of sampling.

Experiment 2: Weed suppression

Spring weed biomass was taken in spring 2016. Across sampling dates, the lowest weed biomass occurred under the forage radish cover crop treatment. Statistical analysis of weed biomass remains to be done.

Year Two Timeline, 2015-16

2015:

August 14: Fall soil samples collected from all plots

August 24: Planted cover crops, both experiment for Year 2

October 27: Soil samples collected and dried

October 23: Harvested and weighed cover crop biomass and weed biomass

December 4: Harvest final cover crop biomass samples and dry

2016:

January and February: Lab analysis of remaining 2015 samples (corn stalks, soil phosphorus)

March: Purchased corn seed & fertilizer, hire summer help

April 18: Measured soil temperature, measure weed germination, soil sampling

May 10: Planted corn based on soil temperature

May 14: Measured weed growth

June 13: Soil testing, PSNT

July 28: Harvest sweet corn, measure yield, CSNT, conduct soil testing

August-December: Analyze samples in lab, data analysis

Impacts and Contributions/Outcomes

This year I presented research and results through several presentations and publications (see list concluding this section). The UMass Cover Crop Tour at the NOFA Summer conference in July allowed me to share my research and initial results with approximately 30 farmers and agricultural service providers. One article published in the UMass extension newsletter was sent to thousands of growers.

On January 4, 2017 I will compete in the graduate student oral presentation competition at the Northeastern Plant, Pest, and Soils Conference in Philadelphia, PA. I will present all of my results at the University of Maine Cooperative Extension In-Service Training for Agricultural Service Providers in Portsmouth, NH on February 2, 2017.

The results of this research will demonstrate how cover crop mixtures can provide resiliency in sweet corn production systems, over a range of fertility and weather circumstances. No-till sweet corn production could enhance sustainability over 12,000 acres of production in the Northeast.

Presentations & Publications:

Collaborators: