Poultry manure as fertiliser for deciduous fruit production.
Kotze, W. A. G.; Joubert, M.; Morkel, S.;
Deciduous Fruit Grower Year: 1992 Vol: 42 Issue: 7 Pages: 250-255 Ref: 9 ref.
1992
บทคัดย่อ
In a field trial on a sandy Clovelly 1100 soil (containing 5% clay and 1% silt) the efficacy of poultry manure applied to bearing apricot trees was evaluated in comparison with limestone ammonium nitrate (LAN). Nitrogen was applied at 66, 100 or 133% of the recommended Infruitec fertilizer rates in 1986 and changed to 100, 150 or 200% from spring 1988. The average nutrient content of the poultry manure was 2.38% N, 1.3% P and 1.7% K, with a pH of 8.7. Both the fertilizers were applied at full bloom, 6 weeks later and postharvest. As the poultry manure had a low K content, it was supplemented by KCl. Leaf and soil samples were analysed annually, trunk circumferences were measured, and total yield and mean fruit mass were recorded. The rate of volatilization from soil after application of poultry manure and the mineralization of N in the manure were also determined. Tree growth was markedly affected by the N source. With the lowest application of poultry manure, growth was less than with the equivalent amount of N from LAN and the leaf N content also indicated deficiency. Only when the amount supplied as poultry manure was doubled did tree growth correspond to that obtained with LAN. Yields were significantly lower with poultry manure than with LAN except at the higher rates of application. The leaf contents of other nutrient elements and the soil composition were not affected by the source of N. It appeared that the rate of N volatilization as ammonia from the poultry manure was rapid initially; in laboratory tests the greatest amount was lost (29%) when the manure was applied on top of the moist soil and the lowest loss (10%) was observed when it was mixed with soil. The method of application used in tests did not affect the rate of mineralization after 20 h of incubation. Poultry manure appeared to have few, if any, slow or controlled release properties and its composition and rate of application must be taken into consideration before its use in orchards can be recommended.