Effect of rates and forms of potassium fertilization on rice under salt affected soil conditions in North of Nile Deltad

摘要

Two field trials were carried out in the North of Nile Delta region between the growing seasons of 1999/2000 and of 2003, to compare the effect of potassium sulphate (SOP) and potassium chloride (MOP), each at three rates (0, 70 and 140 kg K_2O/ha). Alatin square design with five replicates was used. Rice (Oryza sativa L.) was grown as a summer crop in crop rotation during one season (2001) at El-Serw 1 and during two seasons (2000 and 2002) at El-Serw 2. The results indicated that both SOP rates (70 and 140 kg K_2O/ha) and the low MOP rate (70 kg K_2O/ha) gave significant increases in both grain and straw yields over control, while the high MOP rate (140 kg K_2Q/ha) showed significant reductions in some years, compared to other treatments. Potassium sulphate achieved higher N, P and SO_4% in rice grain, while potassium chloride gave higher Cl% in rice grain. Soil surface samples taken after rice harvesting at El-Serw 1 showed lower TSS and Cl contents under the two forms of K fertilizer. The same trend was observed at El-Serw 2 under the two SOP rates and the lower MOP rate, but the higher MOP rate gave higher TSS and Cl contents. At both sites, the available soil K content was higher with K fertilizer application in the form of MOP.