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Leaching losses of nutrients and yield and nutrient uptake by container‐grown begonia as affected by lime and fertiliser applications to a peat medium
Author(s) -
Haynes Richar D. J.
Publication year - 1982
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.2740330503
Subject(s) - peat , leaching (pedology) , lime , chemistry , nutrient , cation exchange capacity , environmental chemistry , zoology , botany , soil water , geology , soil science , biology , ecology , paleontology , organic chemistry
The effect of increased lime applications and one rate of soluble basal fertiliser on leaching losses of NH 4 ‐N, NO 3 ‐N, P, Ca, Mg and K from peat in containers was studied in the presence or absence of Begonia semperflorens plants in a greenhouse pot experiment. Percentage recoveries (leached, plus extractable nutrient remaining in the peat, plus plant uptake) of mineral N and P were in the range of 60–80% while those for Ca, Mg and K ranged from 95 to 111%. Percentage leaching losses in the absence of plants were: mineral N, 75–76%; P, 59–74%; Ca, 5–7%; Mg, 14–19%; and K, 17–31%. In the presence of plants, the average decrease in the percentage loss of nutrients by leaching was: N, 9.3%; P, 4.4%; Ca, 0.5%; Mg, 0.3%; and K, 1.3% Liming tended to decrease leaching losses of NH 4 ‐N, P, Ca and Mg but increase those of K and NO 3 ‐N. The phosphate adsorption capacity of the peat was not measurable but significant ammonia fixation from added (NH 4 )2SO 4 was demonstrated at high pH (>6.5) concomitant with high N rates (> 300 g N m −3 ). Effective cation‐exchange capacity (CEC) and CEC measured with unbuffered 1m NH 4 CI were both more than doubled with increased lime additions as the pH of the peat increased from 4.3 to 5.6. The conventional CEC measurement (NH 4 OAc, pH 7.0) and BaCl 2 ‐TEA (pH 8.2) CEC both remained unaffected by the initial lime rates, and both greatly overestimated the CEC of the peat at its unbuffered pH.