RT Journal T1 MAIZE PRODUCTION AND NITROGEN USE EFFICIENCY IN RESPONSE TO NITROGEN APPLICATION WITH AND WITHOUT HUMIC ACID A1 A. Niaz A1 M. Yaseen A1 M. Shakar A1 S. Sultana A1 M. Ehsan A1 A. Nazarat JF Journal of Animal and Plant Sciences JO JAPS SN 1018-7081 VO 26 IS 6 SP 1641 OP 1651 YR 2016 FD 2016/12/01 DO DOI NA AB

Humic acid (HA) extracted from poorly weathered Pakistani coal finds effective use in crop production and soil fertility management against low organic matter and soil nutrient depletion problems. An experiment with three HA levels (H0 = without HA, H1 = 2.5 L HA ha-1 and H2 = 5 L HA ha-1), four N rates (N1 = 125 kg ha-1, N2 = 150 kg ha-1, N3 = 175 kg ha-1, N4 = 200 kg ha-1) and two controls N0P0K0 (No addition) and N0P1K1 (150 kg P2O5 ha-1 + 100 kg K2O ha-1 without N) was conducted in 2010 at Research Farms, University of Agriculture Faisalabad, Pakistan using randomized complete block design and three replications to compare the effect of N use with and without HA on growth, yield, N use efficiency and economic feasibility of hybrid maize production. Results indicated that H1 rate could not provide promising results compared to urea only treatment (H0), while application of 5 L HA ha-1 provided maximum (P < 0.05) plant height (169.45 cm), leaf area index (3.71m2 m-2), total nitrogen uptake (183.17 kg ha-1), grain protein concentration (9.99%), grain oil concentration (4.24%), N partial factor productivity (53.99 kg kg-1), N-agronomic efficiency (40.15 kg kg-1), N uptake efficiency (1.03 kg kg-1), N-physiological efficiency (39.18 kg kg-1) and N-internal utilization efficiency (37.37 kg kg-1). The degree of synchrony between N demand and supply also increased with increase in HA application rate. When integrating with 5 L HA ha-1, upper levels of N (175 & 200 kg ha-1) were at par (P > 0.05) providing maximum grain yield (9.72 & 9.86 t ha-1, respectively) and post-harvest total soil N concentration (1.53 & 1.57 g kg-1). Upper N level of 200 kg ha-1 could not improve N use efficiency indices over application rate of 175 kg N ha-1. The supreme value cost ratio (17.04 Rs. Rs.-1) was also obtained with combination of 5 L HA and 175 kg N ha-1. Against sole use of inorganic N, usual practice of common maize growers, results of this study recommend combined use of urea and HA for higher yield and better soil health.

K1 Humic acid, Maize, N use efficiency, Synchrony between N demand and supply, Economic analysis PB Pakistan Agricultural Scientists Forum LK https://thejaps.org.pk/AbstractView.aspx?mid=2016-JAPS-216