Effects of rubber effluent, urea and rock phosphate on soil properties and rubber seedlings in an acid sandy soil

摘要

A field experiment was conducted to compare the effect of rubber effluent and urea/rock phosphate on the growth of rubber seedlings and soil chemical properties in an ultisol. A randomized complete block design was adopted with three treatment replicated three times. T1?received no soil amendment and served as the control, T2?received 5, 3330 L/ha of rubber factory effluent while T3?received 30 kg/ha P2O5?as rock phosphate and 112 kg N/ha as urea. Pre-cropping soil analysis showed that the area was loamy sand characterised by low pH, low ECEC and low water holding capacity. There were no significant differences in the height, leaf area, leaf number and girth of the seedlings among the treatments at early growth stage, at a later stage of growth, seedlings treated with rubber effluent performed as well as those treated with inorganic fertilizers. The highest mean value was recorded in seedlings treated with urea/rock phosphate which had mean values of 19.13 and 0.77 cm for height and girth respectively. The use rubber effluent should be encouraged, since the general performance of the seedlings treated with rubber effluent is as good as that of inorganic fertilizer.