The effect of nitrogen, phosphorus and potassium fertilizer applications on the seed yield of sunflower (Helianthus annuus L.) grown on sandy soils and the prediction of phosphorus and potassium responses by soil tests

Effects of potassium supply on growth and yield of safflower as compared to sunflower§

“…It is speculated that this stems from the higher P and, particularly, N supply used in the second year known to increase the number of achenes per capitulum (El-Nakhlawy, 1991;Abdul Sadiq et al, 2000). The positive effect of K supply found in our results on the number of achenes per capitulum in sunflower agrees well with earlier studies (Chaudhry and Mushtaq, 1999;Abdul Sadiq et al, 2000;Lewis et al, 1991). In agreement with our findings, positive effects of K supply on achene yield being accompanied by increased SAM have been described for sunflower (Chaudhry and Mushtaq, 1999;Abdul Sadiq et al, 2000;Lewis et al, 1991), cotton (Sawan et al, 2006), and rapeseed (Khan et al, 2004).…”

“…The positive effect of K supply found in our results on the number of achenes per capitulum in sunflower agrees well with earlier studies (Chaudhry and Mushtaq, 1999;Abdul Sadiq et al, 2000;Lewis et al, 1991). In agreement with our findings, positive effects of K supply on achene yield being accompanied by increased SAM have been described for sunflower (Chaudhry and Mushtaq, 1999;Abdul Sadiq et al, 2000;Lewis et al, 1991), cotton (Sawan et al, 2006), and rapeseed (Khan et al, 2004). A possible explanation for increasing SAM owing to the application of K may be due in part to its favorable effects on photosynthesis and phloem loading (Marschner, 1995).…”

Effect of Potassium Levels on the Yield of Sunflower (Helianthus annuus L.)

“…Evidently, the highest seed yield was due to the highest seed index in case of potassium application at the rate of 150 kg K 2 0 haG 1 . These results are in accordance with the results of Lewis et al (1991), Sirbu and Ailincai (1992), Harmati (1993), Shinde et al (1993) and Annadurai et al (1994) who all found that potassium application alone or in combination with phosphorus and nitrogen increased seed index, seed yield and seed oil content of sunflower. It may be concluded from the above discussed results that potassium at the rate of 150 kg K 2 0 ha alone or in combination should be applied to get maximum yield of sunflower.…”

“…Osman and Abo Lila (1984) found that maximum 1000-seed weight was recorded in the crop fertilized with potassium in combination with phosphorus and nitrogen. Lewis et al (1991) reported that potassium application boosted up seed yield of sunflower. Sirbu and Ailincai (1992) found a direct correlation between potassium and seed yield of sunflower.…”

Efeito de NPK na produtividade e componentes químicos do girassol

“…Em outras culturas foi observado que com o incremento da adubação fosfatada aumenta o teor de fósforo nos grãos, principalmente na forma de fitatos, sendo que em condições normais de disponibilidade de fósforo, o fitato representa mais de 80% do fósforo total (BUERKERT et al, 1998;MÖLLERS et al, 1999). O ácido fítico está presente em muitos grãos na forma de fitato como sais de potássio-magnésio (LOLAS; PALAMIDAS; MARKAKIS, 1976). O ácido fítico forma complexo insolúvel com cálcio, zinco e magnésio e também com proteínas e portanto, considerado como antinutriente que reduz a biodisponibilidade desses minerais (MAGA, 1982).…”