Comparison of Biological Inoculants and Stimulants on Snap Beans
Columbia County, 2003
Carl Shaffer, Producer
Ron Hoover, On-Farm Research Coordinator
Norm Conrad, Penn State Extension
Rik Paulsen, AgroPro LLC
New products carrying claims of improving plant production efficiency continue to be introduced to U.S. farmers. The rate at which these products are being introduced has increased rapidly since the early 1990's. Products can consist of single ingredients or blends of several materials. Some of the ingredients are recognized by the scientific and farming communities as being capable of improving crop yields and/or quality. Others are often of unknown value to production agriculture and should be evaluated for their ability to deliver upon manufacturers' claims.
HiStick N/T is marketed by Becker Underwood as a seed treatment that is applied to seed with or without water. It contains a blend of nitrogen-fixing rhizobium and Bacillus subtilis (marketed as a biofungicide). The relatively low cost of using this product has made it a standard practice for many snap bean growers. Kodiak is another Bacillus subtilis that is marketed as a biofungicide by Gustafson, LLC. These biofungicides were applied to bean seeds at recommended rates without first mixing with water.
A relatively new biological inoculant has been introduced into the US from China. It was first tested as ZX, but the product is now marketed under the trade name Biogren by AgroPro, LLC. Biogren is a powdered vermiculite and zeolite product that contains selected soil-borne bacteria that is cultured in a multi-stage liquid fermentation process. The manufacturer claims that improved plant growth results when the bacteria increase the rate of conversion of macronutrients (N, P, K, etc.) into forms that are more easily and readily taken up by the crop. Promising results have been reported from trials on tomato, cucumber, bell pepper, eggplant, melon, potato, carrot, cabbage, and onion. No data had been collected from trials on snap beans.
To comparatively evaluate the biologically based products, HiStick N/T, Kodiak, and Biogren on snap beans grown on a production scale. Plant vigor and bean pod yield were of greatest interest.
- Carl Shaffer
- Mifflinville, Columbia County, Pennsylvania
- Soil Type:
- Sandy loam
- Previous crop:
- 300 lbs/ac of 15–13–13
- Planting date:
- July 3, 2003
- Seeding rate:
- 60–65 lbs./ac (1870 seeds/lb)
- Heavy disc harrow followed with field cultivator
- Harvest date:
- August 28, 2003
The field site was conventionally tilled prior to planting. Fertilizer was broadcast applied prior to the final tillage operations. A two-row drawn planter fitted with chemical application equipment was used to plant the large field plots of snap beans. The treatments consisted of the three products applied individually to seed prior to or during the planting process. Plots were four rows wide and varied in length from approximately 700 to 900 feet, the length of the field. HiStick N/T and Kodiak were applied in the powder form to seed at 7.0 and 1.25 ounces per acre, respectively. Biogren was mixed with water to create a slurry, carried on the planter and metered into the furrow during planting. Rate of application was 8 to 8.5 pounds of product in 45 gallons of water per acre. The three treatments were replicated five times in a randomized complete block design. A typical herbicide program for the farm was used across the test site. No other inputs were used.
Individual plots were mechanically harvested with commercial snap bean pickers equipped with stripper brush heads. Harvesting heads were wide enough to harvest the four rows of a plot during a single pass across the field. After each plot was harvested, the pickers were driven onto four large-capacity electronic wheel weighers and gross weights recorded. Picker tare weights were subtracted from plot gross weights to determine net weights. Plot lengths were measured and used to calculate yield of snap beans.
Overview of snap beans at early flowering.
The rainfall experienced at this location was greater than average during the two months this bean crop was in the field. Plentiful moisture in the warm soils during early July promoted rapid emergence and establishment. Bean growth was good and a uniformly heavy foliar canopy was produced. Observations were made for visual differences between treatments for early, mid-season, and mature plant height. No consistent height differences between treatments were observed. Several depressed areas in the field appeared to have suffered from standing water after several heavy rains. Canopy density and heights were slightly reduced while leaves on some plants showed signs of chlorosis.
The measurement of greatest importance to the farmer was harvested yield of snap beans. There were no differences between the three products tested for yield of mature snap beans pods. Average yields are shown in Table 1.
|Treatment||Snap Bean Pod Yields¹
pounds per acre
|¹ Pod yields did not differ significantly between treatments (p< 0.05).|
|Hi Stick N/T||9023|
Machine harvesting of snapbeans from 4-row wide plots.
Weighing beans after harvest of one plot.
Space limitations in the field did not allow the inclusion of an untreated control in this experiment. Because the host farmer uses the HiStick N/T product as a standard practice, this product was considered the standard to which the other products would be compared. While comparisons between products can help determine which product might be more effective than another, the lack of an untreated control eliminates the possibility of determining if any product is truly helpful in producing bigger plants, larger total crop yields, or crops of higher quality. Caution should be exercised in using these results to make future management decisions. Data from more than one comparison should be included in that decision.