Effect of Phosphorus and Potassium in Physical Properties of Cotton Fibers Var. Lachata

Abstract

A field experiment was conducted at field of Agricultural researches center/Erbil during 2009 to study the effect of the fertilizers phosphor and potassium on cotton fiber properties, Lachata variety. A factorial experiment (3x4) was applied using randomized complete block design (RBCD) with three replicates, comprised of three levels of phosphor and four levels of potassium. Adding 240 kg P2O5 ha-1 led to increase of fiber index and percentage of early maturity (6.08 and 75.6%) respectively and decrease of maturity percentage, active fiber length, maximum fiber length and elongation percentage (90.4%, 20.2 mm, 29.4 mm and 8.38%) respectively. The linear regression formulas showed a direct relationship between phosphor levels and each of fiber index, percentage of early maturity, while there was inverse relationship between phosphor levels and each of maturity percentage, active fiber length, maximum fiber length and elongation percentage. Adding potassium had effect on some fiber traits, It produced highest value for fiber index when adding 160 kg K2O ha-1 and highest maturity percentage when adding 80 kg K2O ha-1 and highest strength (22.41 gm/tex) when adding 240 kg K2O ha-1. There was direct relationship between potassium levels and the traits; fiber index, maturity percentage and fiber strength according to linear regression formulas. There was significant interaction between phosphor levels and potassium levels over affecting all studied traits except fiber fineness. The level 240 kg P2O5 ha-1 with levels 160 and 240 kg K2O ha-1 produced highest value for fiber index, percentage of early maturity respectively, likewise, the level 120 kg P2O5 ha-1 with 80 kg K2O ha-1 produced highest maturity percentage (94.7%) and fiber elongation (9.57). The traits; active fiber length, maximum fiber length and fiber strength responded to none adding phosphor with 160 and 240 kg K2O ha-1 and produced highest value (21.3 mm, 31.7 mm and 22.77 g/tex) for the three traits mentioned respectively. Significant positive correlation appeared between maturity percentage and active fiber length (r = 0.55) and with maximum fiber length (r = 0.31), while there was a significant negative correlation between percentage of early maturity and maturity percentage and maximum fiber length (-0.37, -0.42) respectively.