PUPUK KANDANG DAN LARUTAN AIR KELAPA MENGUBAH NITROGEN TANAH SERTA PRODUKTIVITAS JAGUNG MANIS

Abstract

Sweet corn requires a timely nitrogen (N) supply, whereas organic amendments often release nutrients more slowly than crop demand develops. This study evaluated animal-manure type, coconut-water liquid organic fertilizer (LOF) dose, and their interaction on soil N, growth, phenology, and yield. A 3 x 3 factorial randomized complete block design combined cattle, goat, or poultry manure at 12.5 kg plot-1 with 200, 400, or 600 mL LOF in three blocks (27 plots). Plant height and leaf number were recorded at 2, 4, 6, and 8 weeks after planting and analyzed using rank-based longitudinal procedures. Single-time traits and Kjeldahl total soil N were analyzed by blocked factorial analysis of variance, followed by Tukey or Dunnett comparisons. Soil N relationships were examined using Spearman correlation and redundancy analysis (RDA). Poultry manure produced the highest marginal soil N (0.3233%), compared with goat (0.1966%) and cattle manure (0.1611%). The 600-mL dose produced 0.2433% soil N, and poultry manure plus 600 mL reached 0.3666%, a 358.33% descriptive increase over the 0.08% baseline. Most vegetative, phenological, and ear traits were not significantly affected, although yield per plot differed between poultry and goat manure (p = 0.0295). Soil N was not significantly correlated with any agronomic trait. RDA identified manure type as a significant term (p = 0.006), while the full model was not significant (p = 0.301). Poultry manure therefore strengthened the soil N pool, but short-term crop responses remained constrained by nutrient-release timing and other growth-limiting factors.