Influence of different levels of humic acid application by various methods on the yield and yield components of maize.

摘要

The use of humic acid (HA) as an organic fertilizer source for increasing crop production on sustainable basis has become imperative because of high chemical fertilizer costs. An experiment was conducted in silty clay loam soil at the Research Farm of NWFP Agricultural University, Peshawar, Pakistan, during 2003, to evaluate the influence of different levels of HA applied by different methods on the yield and yield components of maize (Zea mays cv. Kissan). HA at 200 and 300 g/ha were applied by three different methods i.e. soil mixing (broadcast), band placement and soil spray along with basal NPK at 120, 90 and 60 kg/ha, respectively. The addition of 200 g HA/ha applied as soil spray caused significant (P<0.05) increases of 28% in grain yield (4508 kg/ha), 23% in total dry matter yield (10 793 kg/ha) and 25% in total cob weight (5509 kg/ha) compared with the control (no HA). The number of grains per cob, 1000-grain weight, stover yield and number of cobs per hectare increased nonsignificantly with different levels of HA applied by different methods. Soil organic matter was slightly increased while a decreasing trend was recorded in soil pH values. Soil P concentration improved significantly (P<0.05) by the addition of 200 and 300 g HA/ha applied as broadcast, whereas plant P accumulation was not significantly increased over control. Soil N concentration and plant N accumulation significantly (P<0.05) increased over control having no significant differences with in the treatments of different levels of HA applied by different methods. Zn, Cu, Fe and Mn concentration of soil and Zn accumulation by maize plants increased non-significantly, whereas significantly maximum accumulations of Cu and Fe by maize plants were recorded in treatments receiving 200 g HA/ha and Mn in treatments receiving 200 and 300 g HA/ha applied as soil spray. Results suggest that application of 200 g HA/ha as soil spray along with basal dose of NPK has great potential to improve maize yield, nutrients accumulation by maize plants and soil physicochemical properties..