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Synthesis and characterization of a stable humic–urease complex: application to barley seed encapsulation for improving N uptake
Author(s) -
Mvila Beaufray G,
PilarIzquierdo María C,
Busto María D,
PerezMateos Manuel,
Ortega Natividad
Publication year - 2016
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.7466
Subject(s) - urease , chemistry , germination , seedling , sowing , ammonium , mineralization (soil science) , agronomy , horticulture , nuclear chemistry , enzyme , biochemistry , nitrogen , biology , organic chemistry
Abstract BACKGROUND Most N fertilizers added to soil are not efficiently used by plants and are lost to the atmosphere or leached from the soil, causing environmental pollution and increasing cost. Barley seed encapsulation in calcium alginate gels containing free or immobilized urease to enhance plant utilization of soil N was investigated. RESULTS Urease was immobilized with soil humic acids ( HA ). A central composite face‐centered design was applied to optimize the immobilization process, reaching an immobilization yield of 127%. Soil stability of urease was enhanced after the immobilization. Seed encapsulation with free urease ( FU ) and humic–urease complex ( HUC ) resulted in a urease activity retention in the coating layer of 46% and 24%, and in germination rates of 87% and 92%, respectively. Under pot culture conditions, the pots planted with seeds encapsulated with FU and HUC showed higher ammonium N ( NH 4 + ‐N) (26% and 64%, respectively) than the control soil at 28 days after planting ( DAP ). Moreover, the seed encapsulation with FU and HUC increased the N uptake 83% and 97%, respectively, at 35 DAP . CONCLUSION Seed encapsulation with urease could substantially contribute to enhancing plant N nutrition in the early stages of seedling establishment. © 2015 Society of Chemical Industry