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.

Results from a preliminary experiment in the summer of 2014 helped us improve the experimental design for this research. We planted our experimental plots in August 2014 according to the new design, which involves separating the treatments into two different experiments.

The effects of forage radish cover crops on nutrient cycling and soil fertility will be examined in Experiment 1. Experiment 2 will focus on the duration of weed suppression provided by forage radish cover crops. Cover crop treatments now include forage radish, a mix of forage radish and oats, a mix of forage radish oats and peas, and no cover crop.

The research is on track and fall cover crop growth was good. Most work will begin in the spring of 2015.

• Cover crop mix of forage radish, peas, and oats in October 2014
• Forage radish cover crop in October 2014
• No cover crop control plots in October 2014

Objectives/Performance Targets

 Our objectives are to:

1.  Measure the effectiveness and duration of spring weed suppression by forage radish on subsequent sweet corn crop;

• • On target. Fall cover crops planted, weed measurement methods established. Waiting for spring.

2.  Determine if the precocity of sweet corn planting and maturity can be improved by a preceding forage radish cover crop;

• • Will begin assessment in spring.

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;

• • Will begin assessment in spring.

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;

• • Will begin assessment in spring.

5.  Provide information relevant to both organic and conventional sweet corn producers, as well as no-till producers;

• • Research overview posted on UMass Extension website.

6.  Conduct outreach through individual communication, grower meetings and conferences, annual field day events, newsletters and cooperative extension.

• • Presented at two NRCS soil health workshops titled “Farming with Nature: Improving Soil Health on Vegetable Farms” in Amherst, MA and Dighton, MA on November 5^th and 6^th. My presentation addressed my research goals, provided information about no-till sweet corn and cover crop cocktails, and acknowledged the support of NESARE.

Accomplishments/Milestones

August 18, 2014: Fall soil samples collected from all plots

August 23, 2014: Planted forage radish cover crops for nutrient cycling experiment

August 28, 2014: Planted cover crop mixes for weed experiment

November 10, 2014: Harvested and weighed cover crop biomass and weed biomass

December 1, 2014: Weighed dried biomass samples

To be accomplished in 2015:

January and February 2015: Lab analysis of 2014 soil and cover crop tissue samples

April 2015: Measure soil temperature, measure weed germination, conduct soil testing

May 2015:  Plant corn based on soil temperature, measure weed growth

June 2015: Monitor weed growth, conduct weed control, soil testing, PSNT

July 2015: Harvest sweet corn, measure yield, CSNT, conduct soil testing, present the initial experiment at UMass Annual Field Day

August 2015: Prepare field for second year, plant forage radish cover crop, data analysis

September-November 2015: Data collection for forage radish and fall weeds

-Repeat experiment in 2016-

Updates to experimental design:

The proposed experimental design for my research on forage radish cover crops and no-till sweet corn production was based primarily on published literature. Research from the mid-Atlantic and Midwest regions indicated near complete weed suppression in spring. At the time I wrote this grant proposal in April and May 2014, I was collecting data from a preliminary forage radish cover crop experiment that had been planted in the fall of 2013. By June of 2014 weeds had germinated and weed growth skyrocketed as a result of nitrogen availability from forage radish residue. It was a surprise that the duration of forage radish weed suppression was very short. At the end of June it was clear that the weed pressure was so intense so as to obscure any yield results and any effects of fertility treatments. There were too many interactions between weed growth, nitrogen fertility, sweet corn growth, and weed treatment to see any effects clearly. Fortunately, we learned this from a preliminary experiment before starting the NESARE-funded research.            

Out of necessity, we adjusted the experimental design for this research project. We will test our original main effects, weeds and nitrogen fertility, in separate plots. The objectives remain the same; the data to be collected remains the same; however, there will be one experiment focused on soil fertility and one experiment focused on weed suppression effects of forage radish cover crops.

In addition, preliminary research found that forage radish cover crops decompose very rapidly early in the spring, prior to the planting of the cash crop. This is primarily the result of the low carbon to nitrogen (C:N) ratio of forage radish plants. Such rapid decomposition could potentially cause nitrate leaching that such cover crops are intended to prevent. Different cover crops, or mixtures of multiple cover crop species have higher C:N ratios and decompose more slowly. So in order to evaluate the rate of decomposition in more detail, we also added a treatment of cover crop mixture. Cover crop treatments will be 1) all forage radish, 2) oats & forage radish, 3) peas & oats & forage radish, and 4) no cover crop.

In Experiment 1, early sweet corn will be no-till planted following three different forage radish cover crop mixes (all forage radish, oats/forage radish, and peas/oats/forage radish). Weed population and cover crop biomass will be measured. Three fertility treatments will be used to examine the synchrony between nutrient release from decomposing cover crop and the uptake by sweet corn will be measured. An additional decomposition component will measure over-winter nutrient loss. Nitrogen sufficiency tests (PSNT and CSNT) will be performed on sweet corn and marketable yield will be assessed. In Experiment 2, three weed management methods including herbicide application, flaming, and no-till cultivation will be studied. Weed population and biomass will be measured at 3 intervals in early to late spring.

Following this experimental design, forage radish cover crops were planted for Experiment 1 on August 23, 2014. Cover crops were planted on August 28 for Experiment 2. Data was collected in November as expected. See attached plot map for update.

• Plot maps for Exp 1 and Exp 2
• Preliminary experiment: Weeds completely overwhelming sweet corn in July 2014

Impacts and Contributions/Outcomes

There is a lot of interest in the potential benefits of forage radish cover crops in western Massachusetts and in New England in general. I have spoken with several UMass Extension staff about my research and communicated with a number of farmers who are interested in forage radish cover crops.

The UMass ‘Sustainable Soil and Crop Management’ class from took a field trip to my experimental plots in October 2014. I talked with 25 students about forage radish cover crops, cover crop mixes, and nutrient cycling.

I presented at two NRCS soil health workshops titled “Farming with Nature: Improving Soil Health on Vegetable Farms” in Amherst, MA and Dighton, MA on November 5^th and 6^th. My presentation addressed my research goals, provided information about no-till sweet corn and cover crop cocktails, and acknowledged the support of NESARE. There were approximately 150 farmers and students attending these workshops. I met with several growers during lunch afterwards to talk specifically about how they might use forage radish cover crops on their farms.

I am hopeful that the results of this research will help farmers make good choices about how to select cover crops for sweet corn production systems, and provide data on achievable yields in no-till systems.

• Flier for NRCS Soil Health Workshop

Collaborators: