نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی کارشناسی ارشد زراعت دانشکده کشاورزی دانشگاه تربیت مدرس و عضو باشگاه پژوهشگران جوان دانشگاه آزاد
2 استادیار گروه زراعت دانشکده کشاورزی دانشگاه تربیت مدرس
3 استاد گروه خاکشناسی دانشکده کشاورزی دانشگاه تربیت مدرس
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
In order to study the effect of Iranian natural zeolite application on reducing nitrogen leaching in light soils, a field experiment was carried out during 2006-07 in the research farm of Tarbiat Modares University Iran. A factorial experiment was used based on RCBD with 3 replications., The variables included rates of zeolite (0, 3, 6 and 9 t.ha-1) and nitrogen rates (90, 180 and 270 kg ha-1) in the form of urea. Winter canola (Brassica napus L. Cv. Okapi) was sown in October 2nd and for assessment of forage production of the plant, aboveground biomass of canola was harvested in the early pod formation stage. Amount of nitrogen leaching was calculated by measuring NO3 - and NH4+ concentration in drainage water under root extension zone of canola multiplied by the total amount of deep percolation. The result showed that effect of nitrogen and zeolite on forage yield of canola and prevention of nitrogen leaching were significant (p≤0.01), but interaction effect of the two factors was not statistically significant. Application of zeolite in rates of 6 and 9 ton ha-1 caused significant decrease inNO3 - concentration in leachate sample, but different levels of zeolite had no significant effect on decreasing NH4+leaching. Increased application of zeolite from 3 t ha-1 to 9 t ha-1 diminished concentration of nitrogen in the plants. The highest fresh and dry forage yields were, respectively,70.66 and 11.33 t.ha-1 and were obtained from 270 kg N ha-1. Increasing N rates from 90 to 270 kg ha-1 increased nitrogen content of plant and amount of leaf chlorophyll by as much as 6% and 15%, respectively. According to our findings, application of natural zeolites indirectly increased yield and prevented nitrogen leaching from soils. Further research is needed to understand probable role of zeolite in prevention of nitrogen leaching.
کلیدواژهها [English]