Evaluating switchgrass in marginal land as a beneficial insect habitat and as compost source for vegetable production

NOTE: No Final Report available for this project. Remainder of grant project cancelled due to weather conditions that prevented the recipient from completing the project.

• 2014 annual report

Commodities

• Agronomic: switchgrass

Practices

• Soil Management: composting

Statement of Problem: Compost benefit to soil health and sustainability is well documented. However, the cost of compost can be prohibitive to small acreage vegetable producers. National Recycling Coalition reports that 1 yard of compost weighs about 1,400 lbs. A vegetable producer wanting to spread 4 inches of compost on 1 acre of land needs 532 yards or about 745,000 lbs. At 1c per lb, that is equivalent to about $7,500, an amount not afforded by many small acreage producers. Many producers have marginal land not well suited for vegetable production and is usually left fallow at least, or used for grazing, at best. Marginal land is not profitable to the producer and end up as a habitat to small pest animals like rabbits and raccoons, and insect pests like stinkbugs and squash bugs. Also, marginal land also ends up a habitat for undesirable weeds that continually spread seeds to the production land. Biomass productivity of the marginal land is also low and not significantly suitable for forage harvesting or grazing. If grazed or harvested, it is then exposed to wind or water erosion, making it even more unproductive.  Statement of Proposed Solution: Switchgrass is well suited for Texas soil and climate. It is also known to do well in marginal land and grows well with little additional irrigation. Once established, the thick cover afforded by switchgrass will prevent any further soil erosion. In addition, switchgrass yield can reach as high as 27 tons per acre (reported in Illinois) but averages 14 to 17 tons per acre. This is not only a good source of animal feed to some growers, but is a great source also as compost material for use in vegetable production. The rule of thumb for composting is that 50% of the weight is lost during composting. If this is true, then with an estimate of 14 tons of switchgrass biomass per acre, that’s 7 tons of compost available free to the producer. This is equivalent to about $140 per acre of switchgrass available to the producer. Again, if 4 inches of compost are used in 2 ft wide beds 6 feet apart in a typical vegetable production, the 1 acre of switchgrass or its resulting 7 tons or 10 yards of compost will cover 3 acres of vegetable, which is significantly more valuable than the $140. We propose conducting research at Gnismer Farm in Riesel, TX to determine the economic cost of growing switchgrass on marginal land, conduct bimonthly insect trapping to evaluate the number and types of insects present, and conduct on-farm composting of harvested switchgrass and determine its benefit in improving soil nutrition. In other words, the requested funds we ask are to cover a 3-pronged proposal: production of switchgrass on marginal land, scouting of beneficial and non-beneficial insects, and composting switchgrass to determine its economic feasibility in vegetable production. A cost analysis of switchgrass production from seeding to compost weight will be calculated to determine whether switchgrass production for compost manufacturing is cheaper than purchasing equivalent amount of compost.Cooperators: Dr. Joseph Masabni, Extension Vegetable Specialist, Dept. of Horticultural Sciences, Texas A&M University. Dr. Masabni will make regular visits to the farm to assist with technical production questions and assist in insect identification, soil sampling, and the recommended compost rate for vegetable production, survey collection and analysis, and in field day preparation.McLennon or Falls County Extension Agent: will assist in hosting and conducting the 3 field days.

Approach and Methods:
A. Switchgrass production: equipment is available to prepare the land and seed it with switchgrass at the recommended seeding rates. Labor, time, and equipment usage will be recorded for every activity related to this project to determine the total cost of switchgrass production.
B. Once every 2 weeks, workers will sweep the switchgrass field with nets to trap insects. Insect counts and types will be recorded each time to determine how many are beneficial or pests. This will be done for the duration of the growing season of switchgrass.
C. Compost production: Gnismer farm owns a compost row turner that will be used in the composting process. Depreciation cost of the equipment and time and labor will also be tabulated. At the end of the composting process, samples will be sent to the soil testing lab at Texas A&M for nutrient analysis. Soil analysis results will be compared to current averages of compost nutrition to determine if the switchgrass compost is richer or poorer in nutrition, and to determine the cost per lb of nitrogen achieved.
D. Compost use: a 4 inch layer of compost will be spread on 2 ft rows, incorporated and beds prepared for vegetable production. Another soil sample will be taken at the end of the harvest season to determine the residual benefit in the soil from using switchgrass compost.

Timetable:

April 2014: prepare field and seed switchgrass, exact date is temperature dependant

May 1, 2014: scouting field for insects (every 2 weeks), or two weeks after planting

November 2014: harvest switchgrass and start composting

November 2014: Field Day# 1

February 2015: end of composting process, collect initial soil sample

March 2015: prepare field for vegetable production, add and incorporate compost

March 2015: Field Day #2

July 2015: Field Day # 3

July, 2015: end of vegetable harvest season, collect a final soil sample

 Outreach Plan:
In collaboration with Dr. Joseph Masabni, Extension Vegetable Specialist with Texas A&M AgriLife Extension, and local County Extension Agents, we propose to host 3 field days to show and tell the field research conducted at the farm. We propose to host the first field immediately at harvest of switchgrass, to discuss the benefit of cover crops, the value of switchgrass as a cover crop and as a habitat, and the overall purpose of this research. Producers will be encouraged to attend the second field day to be held at the end of the composting and vegetable field preparation. The purpose of this field day is to demonstrate the composting process and the resulting product from switchgrass and to discuss the benefit of switchgrass in marginal land, its growth rate, vigor, and yield per acre, and the insect habitat found in it. A third day will be held at the end of the vegetable harvest season to demonstrate the benefit of switchgrass compost use compared to areas where no compost was used. Evaluation forms will be handed out at each field day to measure whether the participants gained any knowledge and whether they are willing to adopt this production method.
Additionally, the trial will be posted and updated on the Gnismer Farm website (http://www.gnismer.com), which will provide interested parties continuous updates of this research trial. The website will have PDF files which can be downloaded.