Journal of Crop Production and Processing

To investigate the effect of humic acid application on agronomic characteristics of canola (Brassica napus L.) genotypes in different plant densities, a factorial split-plot experiment was performed using a randomized complete block design with three replications in the Seed and Plant Improvement Institute, Karaj, Iran. Plant density at three levels of 40, 60 and 80 plants/m² and humic acid at two levels of 0 (non-application) and application of 0.3% were considered the main plots and canola genotypes including RGS003, Zafar, Julius, Jerry, Zabol10 and Hyola4815 were the sub-plots. The interaction effect of plant density × humic acid × cultivar was statistically significant for seed yield, oil yield, number of seeds per pod, number of pods per plant, biological yield and harvest index. Moreover, the interaction effect of plant density × cultivar was significant for oil percentage, 1000 seed weight, chlorophyll a, chlorophyll b and total chlorophyll. Generally, increased competition at the highest plant density caused an adverse effect on the tested traits of the canola cultivars. The Jerry cultivar with 40 plants/m² (lowest density) and application of humic acid had the highest numbers of seeds per pod and pods per plant (with an average of 24.6 and 200.7, respectively) and 1000 seed weight (with the average of 4.9 g). Moreover, in the lowest plant density (40 plants/m²) and application of humic acid, the Jerry cultivar had the highest amounts of seed and oil yields (with an average of 5412 and 2196 kg ha^-1, respectively). Accordingly, the examined canola cultivars had a positive reaction to the application of humic acid in different plant densities in particular at 40 plants/m². Jerry cultivar had the maximum seed and oil yield under humic acid application condition when sown at 40 plants/m².

In order to investigate the effect of quinoa seed inoculation on photosynthesis rate, yield and competitive ability with weeds, an experiment was conducted as split-plot based on a randomized complete block design with three replications at experimental farm of School of Agriculture, Shiraz University, Shiraz, Iran during 2020 growing season. Treatments were three levels of weed management as main-plot (weedy, weed-free and weeding) and five levels of seeds inoculation with biofertilizers (humic acid, bioumic, seaumic, organic herbicide, and no biofertilizers) as subplots. The results showed that the highest rate of photosynthesis in all weed management levels was achieved in the presence of seeds inoculated with seaumic biofertilizer. The highest grain yield (259.63 g/m2) and grain yield components (1000-seed weight, number of seeds per panicle, and number of panicles per plant) and harvest index (48.73%) were also obtained in weed-free plots when seeds were inoculated with seaumic biofertilizer. Leaf area index and dry weight of the main weed species (wheat) was significantly reduced in inoculation of seeds with biofertilizers compared to the no biofertiliuzer condition. The highest crop’s competitive ability was achieved when the seeds were inoculated with seaumic treatment. The quinoa’s competitive ability was increased by 2.8 times and 94.11% at weedy and weed-free treatments, respectively, compared with control in seed inoculation with seaumic treatment. Thus, our finding suggests that seed inoculation with biofertilizers, especially seaumic treatment is an effective strategy that can be used to enhance germination rate, growth, yield and weed competitive ability in quinoa.

The study aimed to investigate the response of bean yield and yield components to  the application of growth stimulants under different irrigation levels. A field experiment was conducted in the Khoy, Northwest of Iran. The experiment was conducted as a split-plot design using a randomized complete block design (RCBD) in three replications. Irrigation was the main factor in three levels, including once every 8, 11, and 14 days and growth stimulating compounds as subfactors in 5 levels, including the use of humic acid with irrigation water, amino acid foliar spraying, rooting stimulant, potassium, and no growth stimulants (control). Drought stress (irrigating once every 14 days) led to the reduction of the absorption of essential plant elements such as nitrogen, potassium, and phosphorus, as well as decrease in the lateral branches/plant, grains/pod, hundred-seed weight (HSW), harvest index (HI), leaf area index (LAI), protein yield, and grain yield. Application of growth stimulants both under normal irrigation conditions and under drought stress increased the examined traits, compared to the control treatment. The results indicated that the impact of mild drought stress during the pod development and grain filling stages has a more pronounced effect on the yield and yield components of red kidney beans. Application of growth stimulants, particularly humic acid, during these stages mitigates the adverse effects of stress and leads to a notably higher grain yield compared to other growth stimulants. The highest grain yield (3076 kg/ha) and protein yield (746 kg/ha) were achieved at the presence of irrigating every 8 days and the application of humic acid. It appears that the use of humic acid can be highly effective in enhancing the agronomic, qualitative, and physiological attributes of red kidney beans, contributing up to 95% improvement under both normal irrigation and stress conditions.