AGRONOMIC EFFECTIVENESS OF POULTRY MANURE COMPOSTS

Two field experiments were conducted to examine the agronomic value of poultry manure composted in the presence of both phosphate rock (PR) and elemental sulphur (SO) (sulphocompost) and PR alone (phosphocompos t). Winter cabbage and summer maize were used as test crops. For the f irst season's winter cabbage, the phosphocompost and sulphocompost wer e approximately 12% and 60% as effective as urea and both composts wer e equally effective as urea for the second season's maize crop. The gr eater agronomic effectiveness of sulphocompost could be attributed to the improved nitrogen (N)-use efficiency increased PR dissolution and improved S nutrition. Distribution of nitrate-nitrogen (NO3-N) in the soil profile of field plots indicated greater potential for winter lea ching of N from urea than poultry manure which could be the reason for the improved residual value of the manure reflected in summer maize y ields. The results from the field experiments indicated that compostin g poultry manure with SO and PR not only reduces environmental polluti on associated with manure application, but also increases the agronomi c effectiveness of manure.