جستجوی مقالات مرتبط با کلیدواژه "کاربرد تلفیقی" در نشریات گروه "اکولوژی"

Drought stress is one of the most important abiotic stresses that can seriously reduce crop yield depending on the season, intensity, and time of occurrence. Corn (Zea mays L.)  cultivation and production in Khuzestan province face 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 of 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 (Saccharum officinarum L.) residue compost) under drought stress conditions in the Agricultural Sciences and Natural Resources University of Khuzestan.

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-1 nitrogen), 75% nitrogen+ 25% compost (N2) (135 kg.ha-1 nitrogen+ 12.5 ton.ha-1 compost), 50% nitrogen+ 50% compost (N3) (90 kg.ha-1 nitrogen+ 25 ton/ha compost), 25% nitrogen+ 75% compost (N4) (45 kg.ha-1 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-1 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.

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-1 of nitrogen fertilizer and 25 tons.ha-1 of sugarcane residue compost) compared to other treatments, caused a significant increase in total fresh yield and total dry yield of corn. Under favorable irrigation conditions, the chemical nutrition treatment resulted in the highest total dry yield, with the combined nutrition treatments ranking next. However, under conditions of mild and severe drought stress, the combined nutrition treatments produced a higher yield compared to both 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.

The environmental and economic impacts of chemical fertilizers application have encouraged agronomists and growers to evaluate the use of alternative nutrient sources. The objectives of this study were to evaluate the effects of biological, chemical and organic fertilizers, as alone and integrative application on yield, yield components and physiological traits of sunflower under different irrigation levels.  

A two- field experiments were carried out as split plot based on randomized complete blocks design (RCBD) with three replications at the Piranshahr agricultural research station, West Azarbaijan province, Iran, during during 2016 and 2017. The main plots included different irrigation levels (Irrigation at 85, 70 and 55% field capacity) and the sub plots were including different fertilization levels: 100% of recommended chemical fertilizer (255, 25 and 25 kg ha-1 urea, triple superphosphate and potassium sulfate, respectively), 10 ton ha-1 vermicompost, 15 ton ha-1 vermicompost, biosuper+ azotobacter biofertilizer, 10 ton ha-1 vermicompost+ biosuper+ azotobacter, 15 ton ha-1 vermicompost+ biosuper+ azotobacter, 10 ton ha-1 vermicompost+ biosuper+ azotobacter, 10 ton ha-1 vermicompost+ biosuper+ azotobacter+ 50% chemical fertilizer and 15 ton ha-1 and vermicompost+ biosuper+ azotobacter+ 50% chemical fertilizer.   

The results demonstrated that the irrigation at 55% of field capacity significantly decreased the plant height, stem diameter, head diameter, thousand seed weight, seed yield, biological yield, chlorophyll a, chlorophyll b, relative water content, head weight and number of seeds per head of sunflower. The highest achene yield of sunflower (4230 kg ha-1) was achieved in the normal irrigation with application of 15 ton ha-1 vermicompost+ biosuper+ azotobacter+ 50% chemical fertilizer. Also, the lowest achene yield (3051 kg ha-1) was observed in the severe stress conditions (Irrigation at 55% of field capacity) with application of chemical fertilizer. In addition, the highest (46.3 g) and the lowest (41.4) thousand seed weight was achieved in the irrigation at 85% field capacity with application of 15 ton ha-1 vermicompost+ biosuper+ azotobacter+ 50% chemical fertilizer and irrigation at 55% field capacity with application of chemical fertilizer, respectively.  

The results of this study showed that the highest gross return was achieved by application of 100% chemical fertilizer (255, 25 and 25 kg ha-1 urea, triple superphosphate and potassium sulfate, respectively) and biofertilizers in the normal irrigation conditions (85% of field capacity).