نوع مقاله : مقاله پژوهشی
نویسنده
استادیار گروه علوم خاک، دانشکده کشاورزی، دانشگاه ملایر
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسنده [English]
Potassium (K) fertilizer requirement is affected by crop type, land cultivation history, and properties of the soil resources. The purpose of this research was to investigate the effect of long term grape cultivation on soil fractions mineralogy and different potassium forms in Malayer region, Iran. Soil profiles in two areas with fine and coarse texture were dug and soil physicochemical characteristics and different potassium forms were determined. All soil fractions were separated and the content of minerals in the sand, silt and clay fractions was determined in some horizons. Soil soluble, exchangeable, non-exchangeable, and total K concentrations ranged from 15.8 to 62.1, 216.8 to 540.8, 395 to 1897, and 8322 to 13416 mgkg-1, respectively. Soluble and exchangeable potassium significantly correlated with soil clay content (r2= 0.42, p < 0.05) and organic carbon (r2= 0.67, p < 0.01). Calcium carbonate equivalent and silt negatively correlated with different potassium forms (r2=0.62, p < 0.05). The mineralogical studies of clay fraction showed that coarse-textured soils had higher illite content and fine-textured soils had higher vermiculite and to some extent smectite. Mixed minerals as illite-smectite, illite-vermiculite, and chlorite-smectite were observed in the silt fraction, and had the main control on the different potassium forms in this fraction. Long term cultivation of grape in the two areas had caused reduction of total potassium content compared to uncultivated neighboring lands. It is recommended that for non-exchangeable K release, K fertilizer application should be based on the soil analysis.
کلیدواژهها [English]