Cumulative Impact of Crop Stand and Foliar Urea on Traits of Importance in Sunflower (Helianthus AnnusL

Abstract

In order to assess the cumulative impact of crop stand and foliar urea on sunflower, the experiment was conducted during 2016 (spring). Six treatments were formed with various ha-1 plant populations such as: T1=44289 ha-1 (75×30cm=Control), T2=29526 (75×45cm+foliar urea at development of leaves), T3=36852 (60×45cm+foliar urea at development of flower bud), T4=49284 (45×45cm+foliar urea at flowering completion), T5=55278 (60×30cm+foliar ureaat seed initiation) and T6=73926 (45×30cm+foliar ureaat seed development/maturity). The crop stand and foliar N (urea) application treatments showed remarkable (P<0.05) impact on traits contributing crop growth and yield. On the basis of seed yield ha-1, sunflower sowing in row × plant distance of 60×30cm row× plant distance with 55278 plant population + foliar urea(at seed initiation) showed most promising results grew plants upto166.5cm height having 6.8cm thick stems with more leaves (15.6 plant-1) and bigger seed heads (18.1cm) as well as more (1408.7) and heavier (60.5g) seeds head-1.The seed index was also higher (53.0g) in this treatment leading maximum yields (2181.7kg ha-1) and determined highest oil content (40.1%). Sunflower sown under T6, T4, T1, T3 and T2 ranked 2nd, 3rd, 4th, 5th and 6th in overall yield performance. Generally the crop under wider plant distances with lower per ha-1 populations of 29526 and 36852 showed better growth, but decrease in plant population caused reduction in seed yield; while 60×30cm row × plant distance providing ha-1 plant population of 55278 produced economically higher seed yield when given foliar applied urea at seed initiation.