عنوان مقاله [English]
Drought stress is one of the most important abiotic stresses that can seriously reduces crop yield depending on the season, intensity and time of occurrence. Corn cultivation and production in Khuzestan province faces limitations such as lack of water resources in summer, low percentage of soil organic matter, heavy soil texture and soil salinity that one of the reasons for which is the excessive use of chemical fertilizers, which can reduce some of these problems by using crop management and breed methods. Using compost fertilizer has beneficial effects on the physical, chemical and biological conditions of the soil and has positive effects on grain yield and yield components of crop plants. Also, one of the factors affecting the growth and development of crops is the method and pattern of cultivation, which affects the distribution of plants in the field, distances between plants, the use of growth sources such as light, water and soil nutrients, competition between plants, etc. that finally, these factors affect the growth and yield of crops. This study was designed with the aim to investigating the response of silage corn to the effect of the place of cultivation and different replacement ratios of nitrogen fertilizer and organic fertilizer (sugarcane residue compost) under drought stress conditions in the Agricultural Sciences and Natural Resources University of Khuzestan.
Materials and Methods
This experiment was conducted as a split split-plot arrangement in a randomized complete block design with three replications in the summer of 2021 in the experimental farm of the agricultural college of Ramhormoz in Khuzestan province. Experimental factors including irrigation regimes at three levels; Irrigation after draining 30% of available moisture in root development depth (I1: control irrigation), irrigation after draining 50% of available moisture in root development depth (I2: mild stress) and irrigation after draining 70% of available moisture in root development depth (I3: severe stress) in the main plots, five fertilizer treatments including the complete supply of nitrogen required by the plant through chemical nitrogen fertilizer (N1) (180 kg/ha nitrogen), 75% nitrogen+ 25% compost (N2) (135 kg/ha nitrogen+ 12.5 ton/ha compost), 50% nitrogen+ 50% compost (N3) (90 kg/ha nitrogen+ 25 ton/ha compost), 25% nitrogen+ 75% compost (N4) (45 kg/ha nitrogen+ 37.5 ton/ha compost) and the complete supply of nitrogen required by the plant through the sugarcane residues compost (N5) (50 ton/ha compost) in the sub plots and the planting site was by two methods of planting on ridges (P1) and planting in furrows (P2) in the sub sub plots.
Results and Discussion
Variance analysis showed that the effect of different levels of drought stress caused by different irrigation regimes, ratios of chemical and organic fertilizer replacement and cultivation methods was significant on all the measured traits. A mean comparison of the interaction effect of the cultivation method and combined application of nitrogen fertilizer and sugarcane residue compost under drought stress conditions showed that the treatment of 50% chemical fertilizer+ 50% organic fertilizer (consumption of 180 kg/ha of nitrogen fertilizer and 25 tons/ha of sugarcane residue compost) compared to other treatments, caused a significant increase in total fresh yield and total dry yield of corn. Also, in favorable irrigation conditions, the chemical nutrition treatment had the highest total dry yield and the combined nutrition treatments were in the next ranks, but in the conditions of mild and severe drought stress, the combined nutrition treatments had a higher yield than the chemical and organic treatments.
In general, based on the results of this experiment, it seems that the integrated application of chemical fertilizer along with organic fertilizer with the providing of nutrients, their gradual release, and maintaining moisture in the soil, and planting in furrows by maintaining more moisture and creating a suitable microclimate for the plant has developed growth, moderated drought stress and increased corn yield.