Evaluation of Agro-chemical characters of wheat agro ecosystem as affected double cropping systems and bio- chemical fertilizer management

Crops cannot be sustainably produced by the exclusive use of chemical fertilizers nor can higher crop yield be obtained by using organic manure alone. Sustainable crop production is possible through some approaches such as suitable crop sequence and also the integrated use of organic manure and chemical fertilizers. Therefore, the mail goal of this study is evaluation the effect of crop sequence as double cropping system and integrated chemical and biological fertilizer on quantity and quality yield of wheat and also its soil chemical nutrients. This experiment was conducted at 2015 – 2016 in research field of Shahid Chamran University of Ahvaz. Experimental design was split plot based on RCB with three replications. Main plot was 5 double cropping systems including 1: sunflower- wheat, 2: millet – wheat, 3: maize – wheat, 4: sesame – wheat, 5: mung bean – wheat. Also, sub-plot was 3 fertilizer managements including 1: full chemical fertilizer, 2: full biological fertilizer, 3: integrated biological and chemical fertilizer. Grain yield and yield components of wheat was measured. The SAS software was used to analyses the results and Duncan methods for comparison of means. Both parameters of main ear weight (1/96 gr) and number of grain in ear (31/7) were obtained in planting mung bean before wheat. But, planting of sesame before wheat had lowest main ear weight (1/63 gr). Also, planting millet before wheat had lowest number of ear /m2 (443/6 ear/m2). In addition, characters that basically formed at early growth stage of wheat (e.g. number of ear per m2) had mostly affected by type of crop in rotation in compared than characters which formed at middle of growth stage (e.g. number of grain in ear). Present of mung bean as a legume crop caused a highest main ear weight due to highest grain per ear (31/7 grain/ear). Highest and lowest of all yield components (exception for number of ear per m2) were obtained in full chemical and full biological fertilizer management, respectively, which showed that relaying on full biological fertilizer management will not enough for obtaining the maximum crop yield. In most cases, straw yield had not affected by type of crop which planted before wheat. However, millet – wheat double cropping system had a lowest straw yield (6/22 t/ha). Also, the highest (7/57 t/ha) and lowest (6/61 t/ha) straw yield was belonged to full chemical and biological fertilizer management, respectively. In addition, the highest (0/1 %) and lowest (0/073 %) soil nitrogen was belonged to sequence of sunflower – wheat and sesame – wheat which treated by integrated fertilizer management. Also, present of sunflower, millet, maize and mung bean crops before wheat, caused by higher soil phosphorus in full biological fertilizer management than other fertilizer systems. Both treatments including type of crops before wheat and Fertilizer management had significant effect on wheat grain yield and yield components. Effect of previous crop in double cropping system had changed with change in fertilizer management from chemical to biological form. But, in short period, effect of fertilizer management was more effective than crop rotation. Highest wheat grain yield was obtained in mung bean – wheat double cropping system with and without integrated fertilizer management (i.e. 7/1 and 5/9 t/ha). Also, millet – wheat double cropping system had a lowest (0/051 %) soil nitrogen. Therefore, we concluded that in rotation with legume crops, integrated fertilizer management will better than both full chemical and full biological fertilizer managements.