Plant available potassium assessment through chemical prediction methods

Evaluation of potassium soil tests and methods for mapping soil fertility properties in Iowa corn and soybean fields

“…Beegle and Oravec (1990), working in field calibration studies conducted at 67 sites in Pennsylvania, also reported a significant relationship between nh4oac and M3 extractable K. Correlations between the amounts of K extracted by NH 4 OAc or M3 and the NaBPh4 test were not as high (Fig. 2), a finding to be expected because different soils have variable amounts of potentially extractable nonexchangeable K. Schindler et al (2002), working with six soils from east-central South Dakota, found a higher correlation (r = 0.95) between K measured by NH 4 OAc and NaBPh 4 (5-min incubation). The amounts of K measured using NaBPh* test in our study were 45 to 518% higher than K measured by the NH 4 OAc test, and 50 to 515% higher than K measured by M3 test, averaging 239 and 254% higher, respectively across all soils and sites.…”

“…Cox et al (1999) also showed that K measured by the modified NaBPlit test was a better predictor of K uptake by winter wheat than NH4OAC because of the inability of the latter to measure plant-available nonexchangeable K. However, most published studies evaluating NaBPhu as a soil test for K have been conducted in the greenhouse under controlled conditions. Schindler et al (2002), working in South Dakota under field conditions, found no advantage of using NaBPh* over the common NH 4 OAc to predict plant K concentration in corn. The reason NaBPh4 was not a better test was that the clay fraction mineralogy of the soils studied was montmorillonite, which would not be expected to contribute much plant-available nonexchangeable K.…”

“…There is a lack of adequate field correlation and calibration data for the NaBPtu K test and commonly used soil tests for K. , based on a national survey of land grant universities in charge of conducting the majority of the research that supports fertilizer recommendations, strongly suggested a need to update the soil test calibration data supporting recommendations for many regions. Difficulties of getting funds for soil-test calibration research and publish this kind of research are among factors that explain a lack of extensive recent soil-test calibration data for many crops and different regions (Hanlon and Johnson, 1984;Michaelson et al, 1987;Gartley et al, 2002;Wang et al, 2004), but few have used field calibration studies to compare common soil tests for K such as M3 and nh4oac (Beegle and Oravec, 1990;Mallarino and Blackmer, 1994), and even fewer have compared field calibrations for these tests and the NaBPhu test (Schindler et al, 2002). Furthermore, no field calibrations of soiltest K for soybean have been published in or around the north central region of United Sates during the last 20 years.…”

Relationship of soil potassium forms with maize potassium contents in soils derived from different parent materials

“…This advantage can increase accuracy in predicting plant K uptake, especially when plants obtain considerable amounts of K from nonexchangeable forms. On the other hand, some researchers reported that NaTPB has no advantage compared to the traditional methods for assessment of plant available K (Schindler et al, 2002;Fernandez et al, 2008). The effectiveness of solute used for assessment of available soil K seems largely dependent on the nonexchangeable K extracting power and extraction period of the method that different researchers employed.…”

Four‐Year Dynamic of Potassium on Two Sites Interpreted by Different Soil Tests

“…The comparison of different soil tests for K extraction is often done among soil scientists (Salomon 1998;Armesto, and Sotres 1993;Csathó 1998;Øgaard and Krogstad 2005;Sardi and Fuleky 2002;Schindler, Woodard, and Doolittle 2002;Woods, Ketterings, and Rossi 2005). Some of them compared the AL K test (Salomon 1998;Csathó 1998;Øgaard and Krogstad 2005;Sardi and Fuleky 2002) or AA K test (Armesto and Sotres 1993;Csathó 1998;Øgaard and Krogstad 2005;Schindler, Woodward, and Doolittle 2002;Woods, Ketterings, and Rossi 2005) to each other or to other tests.…”