Effect of NPK fertilization on yield of maize and potato

Two field experiments were conducted at the College of Agriculture, University of Baghdad in a silty clay loam soil The 1st trial included five combinations of elements N-P-K 0-0-0,100-100-100,200-100-100,200-100-200, and 300-100-200 Kg ha-', and two irrigation scheduling regimes by application of water when 50 and 75 of available water depletion and maize plants were used as plant indicator. The 2n (i trial included three combinations of elements N-P-K 0-0-0,100-100-100, and 200-100-200, Kg ha-1 with potato used as plant indicator. Results of the 1sl trial indicated that significant effect of nutrient applied on plant height. The treatment 200-100-200 gave the best results with 7.3 % increase in plant height compared to control treatment. Plant height was higher in the 75 % compared to 50 % water depletion treatment. Neither nutrient combinations nor water regimes alone gave any significant differences effects on dry matter yield and grain yield. However, there was a significant interaction effect on grain yield with control treatment at 50 % water depletion giving best results (250 gm plant1). The results of 2nd trial indicated significant effect of nutrients application on potato tuber yield with treatment 200-100-200 giving showed a highest yield with 20.16 ton ha-1. It was concluded that crop genus, soil type, method of irrigation, and surrounding environmental conditions have affected plant responses to treatments applied. However, generally speaking the treatment 200-100-200 was almost the best treatment in both trials in terms of plant height of maize and grain and tuber yield of maize and potato respectively. The lacks of clear cut response to water regime treatments in the 1 st trial signify the rationalization of water applications especially for spring sawn corn crop. نفذت تجربتان حقليتان في الحقل المخصص للبحوث في كلية الزراعة-جامعة بغداد في تربة مزيجة طينية غرينية. تضمنت التجربة الأولى خمس معاملات لمستويات مختلفة من NPK هي القياس و 100-100-100 و 200-100-100 و 200-100-300، 200-100-200 كغم هـ-1. تم ذلك تحت نظامين لإضافة المياه تمثلت بإضافة الماء عند استنزاف 50 % و 75 % من الماء الجاهز للتربة و تأثير ذلك في إنتاجية الذرة الصفراء. أما التجربة الثانية فإنها تضمنت ثلاث معاملات لمستويات NPK هي القياس و 100-100-100 و 200-100 -200 كغم هـ-1 و تأثير ذلك في إنتاجية البطاطا. بينت نتائج التجربة الأولى أن هناك تأثيرا معنويا للمغذيات المضافة في ارتفاع النبات و أعطت المعاملة 200-100-200 أفضل النتائج مع 7.3 % زيادة في ارتفاع النبات مقارنة مع معاملة القياس. ارتف