Soil fertility research
Dry bean N requirements are not easily determined. Studies were conducted in 1995 at both Carrington and Crookson, MN to gather more information on inoculation and N fertilization of dry beans. These results and the results from another thirty site-years of data in northwest Minnesota and North Dakota suggest that N recommendations may be too high, especially with the current high fertilizer N prices, and that the response curves for inoculated and uninoculated dry beans are different. Dry bean N research, D. Franzen, B. Schatz, B. Holder and R. Severson. 1996. North Dakota Crop Production Guide.
Winter application of urea is not recommended due to the frozen soils in nearly all years and the possibility of runoff, however, many growers wondered if this really happened. A study was conducted in Fargo and Carrington during the winter of 1994-95, using urea applied from late fall to spring wheat seeding. The results at Carrington showed that very large yield reductions were possible from winter application compared with earlier fall application or spring application. A summary of this data appears in the North Dakota Soil and Fertilizer Handbook and in “Effect of fall and winter urea application on spring wheat yields.1996. D. Franzen, G. Endres, B. Schatz, and A. Cattanach.1996 North Dakota Crop Production Guide.
Soil Factors Affecting Iron Chlorosis- Soybeans in the region have been particularly susceptible to iron deficiency chlorosis (IDC). A study from 1996-1999 was conducted to determine the causes for the unusually severe IDC, and to propose solutions. Through a series of transects on a number of fields each year, the results showed that calcium carbonate levels and soluble salts (EC) were the dominant factors contributing to the problem. It was proposed that fields be screened for these soil factors through soil testing, and if the soil factors were high, either seed a variety particularly tolerant to the problems, or consider seeding another crop.
Interaction of soybeans stressed from iron chlorosis and postemergence herbicides. During the soybean IDC studies, it became clear that a growers’ choice of herbicide might be important in the degree of chlorosis the field experienced. A study using ten herbicide treatments over three years showed that the herbicide choice did indeed affect the degree and severity of chlorosis. In general, herbicides that had a harsh contact effect and those with a longer soil residual activity tended to be result in lower yields than other herbicide choices. Although it would be ideal to select the herbicide with the lowest possible effect each year, ultimately, the weed spectrum of the field factors prominently in the choice of products used for weed control.
Copper response of spring wheat and durum- There was some indication from Alberta, Canada, that there might be a need for copper fertilization of some of our soils, particularly those with low soil Cu levels, sandy textures and low in organic matter. A study was initiated in 1997 to investigate the effect of Cu fertilization spring wheat and durum. Over twenty site-years of data were collected from sites throughout North Dakota, including Bowman and Crosby, from soils thought to be most susceptible to the problem. In addition, there was some evidence in the literature that low copper levels could contribute to the development of head diseases, such as ergot, or even Fusarium head blight (scab), and so measurements were conducted at several locations to determine whether copper fertilization might help head disease control. The results showed that copper increased yields about 15% of the time at susceptible sites. Copper also tended to reduce scab incidence and severity at some locations, however, the resulting levels would have been unacceptable control compared to fungicide applications.
Mapping levels of soil pH, and plant available Cu, B, Zn, Cd and Se- As part of the copper project, a soil sampling survey was conducted in 1997 to determine the spatial levels of copper and other micronutrients and soil factors across the state. Although gross state surveys had been conducted in the past, the ability to georeference actual samples and the possible effect of landscape position on state results compelled me to conduct this study. Three sites from each county were sampled in three landscape positions- upland, slopes and depressions. The results showed that most nutrients or factors varied with landscape position, but some did not. Zinc, cadmium and copper were nutrients or factors that tended to be higher in depressions, while boron did not seem to be affected by landscape position, although there were certainly regions in the state that were higher or lower than in other areas.
Sand-syndrome in sugarbeets- A series of studies at several locations from 2002-2004 were inconclusive in finding a nutrient specifically associated with poor early sugarbeet growth. The poor growth was most often associated with coarser-textured soils, lower in organic matter. The poor growth was evident from the time the sugarbeets emerged until about the 6-leaf stage. Although growth improved after the 6-leaf stage, the plants never caught up in vigor, yield or sugar tonnage to plants in the same field without the syndrome. Fertilizer and amendment applications had some degree of success, especially sugarbeet spent lime and various Mg and dolomitic lime treatments. At Crookston, work by L. Smith and A. Sims indicated P and spent lime were most effective. After a particularly heavy rain at the Galchutt site threatened to destroy that location with root disease, plant counts of diseased plants were made to try to salvage something positive from the trial. The results indicated that the treatments were having an effect on root diseases, which indicated that if the syndrome were caused by a disease, then perhaps the fertility deficiency symptoms were only a secondary effects. If the deficiency symptoms were secondary effects, that would help explain the reason that treatments differed in effectiveness at different sites, because each site was a little different in native fertility and susceptibility to certain deficiencies. The research on sand-syndrome today tends to focus on the possibility of a low-level Aphanomyces infection, that for some unknown reason is alleviated by the application of fresh spent lime.