Tissue p-contents and yield assessment in phosphorus fertilized sunflower (Helianthus annuus L.) in Maiduguri, Sudan Savanna, Nigeria

Abstract

Field trials were conducted during the successive rainy seasons of 2010 and 2011 at University of Maiduguri Teaching and Research Farm, Faculty of Agriculture in Sudan savanna, Nigeria. This was aimed at studying the tissue P contents of sunflower roots, stems, leaves and grains cultivated under artificially applied phosphorus. The treatments (0, 20, 40, 60 Kg P₂O₅ ha^-1) were arranged in Randomized Complete Block Design (RCBD), replicated three times. The treatments were incorporated at land preparation as single super phosphate (SSP) in order to achieve its efficacy and fields were kept weed-free to avoid nutrient loss to weed uptake. Data were subjected to statistical analysis of variance using “statistix” software version 8.0 and the treatment means were compared using DMRT at 5% level of probability. Result from plant tissue analysis revealed that phosphorus treatments did not significantly influence P contents of roots in the mean for 2010 and 2011 rainy seasons. Similarly, tissue analysis for stem reveals non significant values (P>0.05) for P contents among the phosphorus treatments in the two years mean. Result for leaf tissue analysis however indicates that higher phosphorus treatment of 80 Kg P₂O₅ ha^-1 resulted in the highest phosphorus uptake and recorded mean leaf P content of 21.31%. Grain phosphorus uptake also increased with the highest phosphorus rate (80 Kg P₂O₅ ha^-1) and recorded P tissue content of 26.64% for the two years mean. Application of 80 Kg P₂O₅ ha^-1 gave the highest value for 1000-grain weight in the two years mean (50.37g). Phosphorus applied at lower rate of 40 Kg P₂O₅ ha-1 however gave statistically higher grain yield in the two years mean (1565.2 Kg ha^-1). It is concluded that P uptake increases in sunflower with higher phosphorus application; and higher P content recorded in leaves and grains herein, relative to lower part of the plant clearly suggests that phosphorus was mobilized up in large amount to meet the plants physiological demand at the reproductive phase since phosphorus plays higher role in grain development.