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Soil Moisture Effect on Potassium Uptake by Corn 1
Author(s) -
Mackay A. D.,
Barber S. A.
Publication year - 1985
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1985.00021962007700040005x
Subject(s) - loam , soil water , agronomy , moisture , water content , chemistry , silt , shoot , potassium , mollisol , zoology , environmental science , soil science , biology , geology , paleontology , geotechnical engineering , organic chemistry
Soil moisture influences K uptake by corn ( Zea mays L.) by affecting root growth rate and the rate of K diffusion in soil. The extent each affects K uptake has not been resolved. The objective of this study was to determine the effect of soil moisture on each of the parameters of a mechanistic‐mathematical model that simulates K uptake by corn. Corn was grown for 7, 14, and 21 days at three volumetric soil moisture levels, 0.22 ( M 0 ), 0.27 ( M 1 ), and 0.32 ( M 2 ), the water held at potentials of −7.5, −33, and −170 kPa, respectively, with three soils (S 0 and S 1 , Raub, fine‐silty, mixed, mesic Aquic Argiudolls, and S 2 , Chalmers, fine‐silty, mixed, mesic Typic Haplaquolls, silt loams; S 0 was low in K, S 1 and S 2 were medium in K), in 3‐L pots in a controlled‐climate chamber. Root growth and K uptake by corn were measured. Raising soil moisture from M 0 to M 1 increased shoot K uptake by 81, 70, and 68%, with the S 0 ,, S 1 , and S 2 soils, respectively. Raising soil moisture further, from M 1 to M 2 resulted in a further increase of 13% in K uptake by corn with the S 0 soil but small decreases of 13 and 8%, with the S 1 and S 2 soils, respectively. Raising moisture from M 0 to M 1 also increased root growth, however a further increase to M 2 decreased root growth. There was a relation between root surface area and K uptake, but this varied with soil. The relation between mean K influx and K uptake ( r = 0.85**, significant at the 0.01 level), however, was independent of soil. Soil moisture did not significantly (P<0.05) affect K influx. Raising soil moisture from M 0 to M 2 , increased the effective diffusion coefficient, D e , for K an average of 2.1 times across the three soils. When all the data were used in the simulation model, calculated K uptake ( y ) in mmol pot −1 agreed with observed K uptake ( x ) by corn ( y = 0.9 x ‐ 0.08; r = 0.95**), indicating that the model is a useful method for studying the effect of soil moisture on each of the mechanisms involved in K uptake by corn.