Evaluating Nitrogen Fertilizer Rates on Kidney Bean Yields and Surveying Root and Foliar Diseases of Several Dry Bean Types in Minnesota.
April 06, 2006
Principal Investigators: James A. Percich, Professor, Plant Pathology, Becky Sheets, Research TechnicianUniversity of Minnesota
Benefits to North Dakota and Minnesota Dry Bean Growers:
* Nitrogen fertilizer field studies (2003, 2004, and 2005). The use of nitrogen fertilizer, regardless of amounts, in the form or urea did not significantly increase bean yields when compared to biological seed treatments with no nitrogen.
* New formulations of rhizobium inoculants were significantly better than other types and easier to work with in the field with significant dark red Kidney bean yields.
* A preliminary disease survey indicated that Anthracnose in Minnesota was extremely rare. Levels of white mold were low and the root rots and bacterial diseases were the most widespread regardless of bean types grown or location.
A. Effects of Nitrogen Fertilizer Rates on Dark Red Kidney Bean Yields.
A study to evaluate the effects of nitrogen fertilizer and biological seed treatments on yields was established on a farm with a history of root rot at Perham, MN in 2005. The experiment consisted of a completely randomized design (30 acres) with each treatment plot being500 ft in length and consisting of four rows, replicated four times. There were seven treatments were the following:
1. Nitrogen 30 lb./A applied once at sowing.
2. Nitrogen 30 lb./A applied once at pre-bloom.
3. Nitrogen applied at 30 lb./A at sowing and pre-bloom.
4. Nitrogen applied at 30 lb./A at sowing and 60 lb./A at pre-bloom.
5. No nitrogen applied, but seed treated with Apron/Maxim/ + Lorsban + Rhizobium tropici
6. No nitrogen applied, but seed treated Bacillus subtilix + Rhizobium tropici
7. No nitrogen applied, but seed treated with Maxim/Apron + Lorsban
Replicated field studies in 2003, 2004, and 2005 clearly showed that the addition of more than 30 lb of total N/acre did not significantly increase bean yields in root rot infested soil, regardless of soil pH (Table 1). Field research conducted on grower farms in 2003 and 2004 showed the addition of nitrogen fertilizer did not significantly increase yields when compared to seed treated with Bacillus subtilix +Rhizobium tropici and or with R. tropici alone without the addition of nitrogen fertilizer (Table 2). The same lack of nitrogen response was demonstrated on both acid and neutral soils at Staples and Perham, Minnesota, respectively (Table 2).
All the dark red Kidney seed sown, regardless of treatment, contained Apron/Maxim + Lorsban. Nitrogen was applied in the form of urea. The soil contained 10 lb/A of nitrogen as carry-over from the previous cropping season at the time of sowing. The soil pH was 6.2. Standard agricultural practices were performed throughout the experiment.
B. Rhizobium Inoculants
A preliminary experiment was conducted in a growers field (pH 6.2) having a history of edible bean production, and a history of root rot in 2005. A completely randomized experimental design consisting seven different formulations were evaluated. Formulations 1 and 6 were applied to the seed, formulations 2, 3, 4, and 5 were applied as granular in-furrow, and treatment 7 consisted of untreated seed.
All seed, regardless of experimental treatment had Apron/Maxim + Lorsban applied. Each treatment plot consisted of two middle rows each 40 feet in length. All treatments were replicated four times and statistical analysis (ANOVA) was performed. Standard agricultural practices were used throughout the experimental period.
C. Disease Survey:
The first year of a two-year Minnesota dry bean disease survey was established and cooperative grower sites identified in 2005. The disease survey will evaluate foliar, vascular, and root diseases. Information to be recorded will focus on pathogen and disease identification, incidence and severity. Cropping history, soil type, pH and fertility program as well as disease management strategies, if employed, at each site will be recorded.
A. Effects of Nitrogen Fertilizer Rates on Dark Red Kidney Bean Yields:
Results of a three-year field (30 acre sites) study comparing the recommended use of nitrogen fertilizer at 30, 60, and 90 lb/A clearly showed that nitrogen fertilization, regardless of level, except for 30 lb./A urea at pre-bloom in 2005, did not result in significant yield increases when compared to seed treated with B. subtilix and R. tropici inoculants without nitrogen (Table 1).
B. Rhizobium Inoculants:
Our preliminary study clearly showed that rhizobium treatments 1, 2, and 3 resulted in significant yield increases when compared to all the other treatments (Table 2). Where as treatments 4, 5, and 6 did not differ significantly from each other or from the untreated control (treatment 7) (Table 2). Treatments 2 and 3 were granular in-furrow applications. All rhizobium treatments resulted in higher yields than the untreated control (Table 2). The granular in-furrow rhizobium formulations may offer the bean grower an easy and effective means of using dry bean rhizobium inoculants in the future. Again, it should be noted that no nitrogen fertilization was used in this study.
C. Preliminary Minnesota Disease Survey:
Root rot caused by the soil fungus Fusarium solani f. sp. phaseoli was found in on all dry bean types examined and in all production fields (Table 3). Fusarium wilt, caused by Fusarium oxysporum attacks the plants vascular system, was observed in 50% of all diseased plants and in all fields. Common bacterial blight and brown spot were found on all plants surveyed, regardless of bean type (Table 3). Unlike the reports from North Dakota State University, the presence of Anthracnose was extremely low with less than one percent of all the plants and fields observed (Table 3). The recent discussion of soybean rust and other emerging diseases has often resulted in statements that cannot be supported scientifically. Dry bean disease reports from North Dakota State University are different than our observations of Minnesota farms in 2005. A more intensive survey of Minnesota dry bean productions areas is needed.
Table 1. A review of nitrogen fertilization and biological seed treatments on the yield of dark red Kidney beans in 2003, 2004, and 2005 with similar nitrogen applications, seed treatments, and in-field experimental designs at Staples and Perham, Minnesota.