تاثير سطوح مختلف فشردگي خاك و فسفر بر عملكرد و اجزاء عملكرد ذرت دانه اي رقم سينگل كراس 704

Effects of different levels of soil compaction and phosphorus fertilizer on yield and yield components of corn (zea mays L.)

In order to study the effects of soil compaction and phosphorus (P) fertilizer on yield and yield components of corn (Zea mays L.) an experiment which had a randomized complete block design with four replications was carried out. In this study, four levels of soil compaction including 0, 250, 500 and 750 kPa and three levels of P fertilizer including 0, 250 and 500 kg ha-1 super phosphate triple were used. P fertilizer was applied in a banding method with 10 cm deep from soil surface and 10 cm distance from sowing line. Soil compaction treatment was carried out with a John Dear tractor, model 3140 with pace of going and coming back among cultivated rows. The results of this study indicated that compacting the soil to a penetration resistance of 250, 500, 750 and 900 kPa had a significant effect (p ? 0.01) on economical and biological yield and yield components of corn plant. However, P application and interaction between P and soil compaction had no significant effects on yield and yield components of corn. The highest economical and biological yields of corn observed in control treatment (no compaction) were 819 and 1496 g m-2, respectively. Economical and biological yields of corn decreased 28% and 23% respectively as the soil was compacted to a penetration resistance of 900 kPa. The greatest effect of soil compaction on yield components was on the number of seed per row (23% reduction ) and the smallest effect of soil compaction was on seed weight (5% reduction). Increasing soil compaction decreased the rate of grain filling (37 % ), but increased the duration of grain filling (13% ), which the final weight of corn seeds was significantly affected by the rate of grain filling.