Effect of Nitrogen,Phosphorus and Water Coupling on Celery Yield in the Semiarid Cold Region of Northwest of Hebei Province

Artificial water control experiments in the shed of rain-free condition were conducted in semiarid cold region of northwest of Hebei Province to study the effect of water and fertilizer coupling on celery yield with 3 factors and 5 levels of the secondary regression of orthogonal block design.Results showed that the main factors affecting the celery yield was irrigation quantity,phosphorus quantity and nitrogen quantity.Yield effect was higher in the middle level of water and fertilizer,lowest in low level of water and fertilizer.The effect order of interaction is as follows:nitrogen and phosphorus couplingphosphorus and water couplingnitrogen and water coupling.When celery yield reached 150 000~180 000 kg/hm2,amounts of water and fertilizer were nitrogen 0~540 kg/hm2,phosphorus 36~180 kg/hm2,water 1 311~6 500 m3/hm2.Amounts for highest yield 171 645.9 kg/hm2 were nitrogen 243 kg/hm2,phosphorus 97 kg/hm2 and water 1 311~6 500 m3/hm2.