title: The effects of weed-crop competition on nutrient uptake as affected by crop rotation and fertilizers.
abstract: A field study at the Agricultural University of Timiriazev, Moscow, was conducted to determine the effect of crop rotation and Long-term fertilizer application on differences in the competitive ability of spring barley and weeds to nutrient uptake in 2004 and 2005. Spring barley was cultivated in continuous and in crop rotation with winter rye, potato, clover, flax and fallow, with and without NPK application since 1912. Spring barley, especially in no fertilizer plots grown in crop rotation has greater dry mass than spring barley grown in continuous. While dry weed mass markedly decreased in crop rotation. Decrease dry weeds mass was greater when NPK had applied. The statistical analyses show that when spring barley grew in competition with weeds in the no fertilizer plots, crop rotation significantly increased nutrient content in spring barley, but when fertilizer applied the content of N, P2O5 and K2O in barley did not change. Lowest weeds nutrient content observed where soil fertility was increased by crop rotation and NPK application. Crop rotation significantly increased total nutrient uptake of soils by spring barley, but decreased total nutrient uptake by weeds.
authors.affiliation: Department of Agronomy and Plant Breeding, Faulty of Agriculture, University of Mohaghegh Ardabili, Ardabil, Iran.
authors.forename: Hamid Reza
authors.initials: HR
authors.lastname: Mohammaddoust-E-Chamanabad
authors.forename: Ali
authors.initials: A
authors.lastname: Asghari
authors.forename: Aleksander Mikhailovic
authors.initials: AM
authors.lastname: Tulikov
mesh_terms: D000383:Agriculture / Q000379:methods*; D018533:Biomass; D018556:Crops, Agricultural / Q000254:growth & development / Q000378:metabolism; D005308:Fertilizers; D019597:Flax / Q000502:physiology; D001467:Hordeum / Q000502:physiology; D029902:Medicago / Q000502:physiology; D009584:Nitrogen / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry; D010944:Plants / Q000378:metabolism*; D011188:Potassium / Q000737:chemistry; D012621:Seasons; D012434:Secale / Q000502:physiology; D012987:Soil; D011198:Solanum tuberosum / Q000502:physiology
chemical_list: D005308:Fertilizers; D012987:Soil; D010758:Phosphorus; D009584:Nitrogen; D011188:Potassium