A Method for Incorporating Soil Test Measurements Into Fertilizer Response Functions 1

1962 ◽  
Vol 54 (2) ◽  
pp. 152-154 ◽  
Author(s):  
William G. Brown ◽  
T. L. Jackson ◽  
Roger G. Petersen
1995 ◽  
Vol 25 (2) ◽  
pp. 208-214 ◽  
Author(s):  
J.S. Shumway ◽  
H.N. Chappell

The Diagnosis and Recommendation Integrated System (DRIS) has been used successfully in agricultural crops and holds promise for use in forest stands. This study used soil tests to develop DRIS norms and evaluate their effectiveness in coastal Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) forests. DRIS norms for nitrogen, phosphorus, potassium, and calcium were developed using soil test and site index data from 72 soil series that commonly support Douglas-fir in western Washington. The norms were tested using soil test and stand basal area growth response data from 20 thinned and 30 unthinned N fertilizer test sites in coastal Washington and Oregon. Response to urea fertilizer in thinned stands averaged 34% and 43% for 224 and 448 kg N•ha−1, respectively, when N was identified as the most limiting nutrient. When N was not the most limiting nutrient, N response averaged 8% and 10% for 224 and 448 kg N•ha−1, respectively. Results were similar in unthinned stands and thinned stands, although response to fertilizer appeared to be slightly less in unthinned stands when N was the most limiting nutrient. DRIS correctly classified 25 of the 33 sites (76%) where N fertilizer increased growth by more than 15%. More importantly, 13 of the 17 (76%) sites that responded by less than 15% were correctly identified by DRIS. The results clearly indicate that N fertilizer response is dependent on the interactions (balance) between soil nutrients at a given site. Future soil diagnostic work needs to focus on techniques, like DRIS, that provide an assessment of these interactions.


2003 ◽  
Vol 83 (4) ◽  
pp. 443-449 ◽  
Author(s):  
R. H. McKenzie ◽  
E. Bremer

Soil tests for available P may not be accurate because they do not measure the appropriate P fraction in soil. A sequential extraction technique (modified Hedley method) was used to determine if soil test P methods were accurately assessing available pools and if predictions of fertilizer response could be improved by the inclusion of other soil P fractions. A total of 145 soils were analyzed from field P fertilizer experiments conducted across Alberta from 1991 to 1993. Inorganic P (Pi) removed by extraction with an anion-exchange resin (resin P) was highly correlated with the Olsen and Kelowna-type soil test P methods and had a similar relationship with P fertilizer response. No appreciable improvement in the fit of available P with P fertilizer response was achieved by including any of the less available P fractions in the regression of P fertilizer response with available P. Little Pi was extractable in alkaline solutions (bicarbonate and NaOH), particularly in soils from the Brown and Dark Brown soil zones. Alkaline fractions were the most closely related to resin P, but the relationship depended on soil zone. Inorganic P extractable in dilute HCl was most strongly correlated with soil pH, reflecting accumulation in calcareous soils, while Pi extractable in concentrated acids (HCl and H2SO4) was most strongly correlated with clay concentration. A positive but weak relationship as observed between these fractions and resin P. Complete fractionation of soil P confirmed that soil test P methods were assessing exchangeable, plant-available P. Key words: Hedley phosphorus fractionation, resin, Olsen, Kelowna


1967 ◽  
Vol 47 (3) ◽  
pp. 175-185 ◽  
Author(s):  
R. F. Bishop ◽  
C. R. MacEachern ◽  
D. C. MacKay

In field experiments, conducted at 18 locations during a 3-year period, tuber yields on zero-P plots ranged from 49.7–95.5% of those obtained with optimum P fertilization. Each of three chemical methods used to estimate available soil P showed a wide range of values for the different locations.When Bray's modification of the Mitscherlich equation was used to express the relationship between soil test values and yield response to applied P, there were appreciable differences in c1 values which varied with soil series and soil test methods.Polynomial response curves showed that, irrespective of the chemical method used, if soils were grouped on the basis of available P into "high", "medium" and "low" classes, response to applied P was much less in the high than in the medium and low classes. Response curves also showed that both P requirements and maximum yields varied with different soil series.


2003 ◽  
Vol 83 (4) ◽  
pp. 431-441 ◽  
Author(s):  
R. H. McKenzie ◽  
E. Bremer ◽  
L. Kryzanowski ◽  
A. B. Middleton ◽  
E. D. Solberg ◽  
...  

Crop responsiveness to P fertilizers on the Canadian Prairies has likely declined during the past three to four decades due to regular application of P fertilizer and reduced tillage. Its relationship to extractable soil P as determined by various soil tests may also have changed. The objective of this study was to evaluate five soil test P methods for three major crops across a wide range of soil types and environmental conditions. Small-plot P fertilizer trials were conducted at 154 locations across Alberta from 1991 through 1993. At each location, fertilizer responses were determined for one, two, or three crops: barley (Hordeum vulgare L.), spring wheat (Triticum aestivum L.) or canola (Brassica napus L.). Fertilizer treatments consisted of seed-placed monoammonium phosphate at rates of 0, 6.5, 13.1 and 19.6 kg P ha-1. The average increase in seed yield due to application of P fertilizer was 10%, with little difference among crop types. Relative yield increases were significantly greater in Gray soils (Dark Gray Chernozemics, Dark Gray-Gray Luvisols) than in Black (Black Chernozemics) or Brown soi ls (Brown and Dark Brown Chernozemics). The maximum variation in P fertilizer response accounted for by any soil test P was 27% for barley, 15% for wheat and 7% for canola. The Kelowna method and its derivatives generally provided the best fit with P fertilizer response. Only a modest increase in the proportion of variation that could be accounted for by soil test was achieved by multiple regressions with soil pH, clay or organic matter or by separate analyses of different soil types or years. The probability of a profitable yield response due to P fertilizer application did decline with increasing soil test P. However, profitable yield responses were frequent at all levels of soil test P for the first increment of 6.5 kg P ha-1 and low at all levels of soil test P for the third increment of 6.5 kg P ha-1 (19.6 kg P ha-1). The poor relationship of soil test P to fertilizer response was attributed to frequent but variable starter effects of P fertilizer and the infrequent occurrence of highly responsive sites. Key words: Soil testing, Olsen, Bray, Kelowna, fertilizer response functions, Hordeum vulgare, Triticum aestivum, Brassica napus


1964 ◽  
Vol 44 (3) ◽  
pp. 310-318 ◽  
Author(s):  
D. C. MacKay ◽  
C. R. MacEachern ◽  
R. F. Bishop

In experiments conducted at 46 locations over a 6-year period soil potassium levels ranged from 46 to 361 p.p.m. in exchangeable potassium and from 1.1 to 9.6% K saturation. The average yield of tubers on zero-K plots was 86.2% of the maximum (yield obtained from optimum K fertilization) and the zero-K plots produced less than 75% of the maximum at only two locations.Utilization of Bray's modified Mitscherlich equations indicated high variability in c1 values and poor correlation of relative yields (as percentages of the maxima) with soil test values. Expressing soil K as % K saturation provided only slightly better correlations than exchangeable K.The polynomial response equation relating absolute yields (bu/acre) with rates of applied potassium was highly significant, and near maximum yields of tubers were obtained at 150 lb/acre of K. When soils were grouped according to exchangeable K values into "high" (> 230 p.p.m.), "medium" (230–130 p.p.m.), and "low" (< 130 p.p.m.) classes, similar responses to application of K fertilizers were obtained for each. However, greater yields of tubers resulted on the higher soil test classes throughout the entire range of treatments.A highly significant linear depression in dry matter content resulted from potassium applications, with each 50 lb/acre increment of K depressing dry matter by 0.5%.


1963 ◽  
Vol 43 (2) ◽  
pp. 242-249 ◽  
Author(s):  
D. C. MacKay ◽  
C. R. MacEachern ◽  
R. F. Bishop

Bray's modified Mitscherlich equation was utilized to determine the relationship of potato yields (expressed as percentages of the maximum) to soil nitrate production and to rates of nitrogen fertilization at 18 locations over a 3-year period. A closer relationship was obtained using fresh soil samples than using those air-dried for 6 months.The influence of various factors on absolute tuber yields (bushel/acre) was also assessed by analysis of variance. Highly significant effects were obtained for "rates of nitrogen" and for "soil test values" but not for the interaction of these two factors. The polynomial response curves derived from the analysis of variance showed that maximum yields were approached at a rate of 200 pounds/acre of applied N, whether soil nitrate production values were low, medium or high. Tuber yields were also influenced by “soil series" and the amount of N fertilizer required for maximum yield was greater for some series than for others.


1959 ◽  
Vol 39 (2) ◽  
pp. 144-150 ◽  
Author(s):  
D. C. MacKay ◽  
C. R. MacEachern ◽  
R. F. Bishop

The ability of soil to produce nitrate nitrogen was determined by an incubation method and values obtained were related to potato yields at 21 experimental locations by Bray's modified Mitscherlich equation. The mean c1 value (proportionality constant) for a total of 58 tests, which included three varieties during a 2-year period, was 0.0182. The standard error of the mean was 0.0014. While differences between c1 values for years were not significant, differences between locations and varieties were. When the soils were grouped, the c1 values for those from the Annapolis Valley were approximately twice those for soils from the adjacent North and South Mountains, and the values within each group were remarkably uniform. The appropriate equations for relating soil test values and crop yields were log (A-y) = log A − 0.0112b1 and log (A-y) = log A − 0.0204b1 for Mountain and Valley soils respectively.


2010 ◽  
Vol 90 (3) ◽  
pp. 305-310 ◽  
Author(s):  
E G Smith ◽  
B M Upadhyay ◽  
M L Favret ◽  
R E Karamanos

Hybrid (HY) canola (Brassica napus L.) produces a higher seed yield than open-pollinated (OP) canola. While it is expected higher-yielding HY canola may require higher total available nutrients, especially nitrogen (N), the evidence is not conclusive. This study used canola yield data from several site-years and fertility experiments to determine whether HY and OP canola types require different rates of total available N (TAN) and total available phosphorus (TAP). The yield response of the two canola genotypes to TAP was the same, but for TAN the yield response was greater for HY canola. The quadratic yield response results were confirmed using three plateau equations. Optimal TAN for HY canola was higher than for OP canola. Soil test laboratories and producers growing HY canola need to modify N fertility for HY canola, compared with OP canola for which most of the current N fertilizer recommendations were developed. Key words: Economics, fertilizer, yield response, canola, hybrid, open-pollinated


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