Mycorrhizal colonization and grain Cd concentration of field-grown durum wheat in response to tillage, preceding crop and phosphorus fertilization.
BACKGROUND
A 3-year field trial was conducted to investigate the effect of agricultural management practices including tillage, preceding crop and phosphate fertilization on root colonization by arbuscular mycorrhizal (AM) fungi and grain cadmium (Cd) concentration of durum wheat (Triticum turgidum L.). The relationship between grain Cd and soil and plant variables was explored to determine the primary factors affecting grain Cd concentration.


RESULTS
Mycorrhizal colonization of the roots was reduced by conventional tillage or when the preceding crop was canola (Brassica napus L.), compared to minimum tillage or when the preceding crop was flax (Linum usitatissimum L.). In contrast, grain Cd was not consistently affected by any treatment. Grain Cd was generally below the maximum permissible concentration (MPC) of 100 microg Cd kg(-1) proposed by WHO. Grain Cd varied substantially from year to year, and could be predicted with 70% of variance accounted for by using the model: grain Cd concentration = - 321.9 + 44.5x ln(grain yield) + 0.26x soil DTPA-Cd + 182.5x soil electrical conductivity (EC)- 0.98x grain Zn concentration.


CONCLUSIONS
These common agricultural management practices had no effect on grain Cd concentration in durum wheat though they impacted mycorrhizal colonization of roots. Grain yield and to a lesser extent soil conditions of EC and DTPA-Cd and grain Zn influenced grain Cd, whereas mycorrhizal colonization levels did not.
Gao
Xiaopeng
X
Department of Soil Science, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2.
Akhter
Fardausi
F
Tenuta
Mario
M
Flaten
Donald N
DN
Gawalko
Eugene J
EJ
Grant
Cynthia A
CA
D000383:Agriculture / Q000379:methods*; D029688:Brassica napus / Q000254:growth & development; D002104:Cadmium / Q000032:analysis*; D002614:Chelating Agents / Q000737:chemistry; D018556:Crops, Agricultural; D004553:Electric Conductivity; D005308:Fertilizers; D019597:Flax / Q000254:growth & development / Q000382:microbiology; D008350:Manitoba; D038821:Mycorrhizae / Q000254:growth & development / Q000502:physiology*; D004369:Pentetic Acid / Q000737:chemistry; D010710:Phosphates / Q000008:administration & dosage* / Q000032:analysis; D018517:Plant Roots / Q000382:microbiology; D025341:Principal Component Analysis; D012639:Seeds / Q000737:chemistry*; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology; D014908:Triticum / Q000737:chemistry* / Q000382:microbiology; D015032:Zinc / Q000032:analysis
D002614:Chelating Agents; D005308:Fertilizers; D010710:Phosphates; D012987:Soil; C024788:ammonium phosphate; D002104:Cadmium; D004369:Pentetic Acid; D015032:Zinc