Document Type : Research Paper
Authors
1 Student of the Faculty of Agriculture, Birjand University
2 Manager of Saffron Research Group
3 Department of Agronomy, Faculty of Agriculture, University of Birjand, Birjand, Iran
Abstract
Introduction: Cotton (Gossypim hirsutum L.) has a special position as one of the most important crops in the country. Considering that salinity stress is one of the most important stresses, it threatens cotton production in arid and semi-arid regions of the country and the world, it is possible to reduce the adverse effects of salinity stress through application of organic fertilizers (manure and humic acid). In addition, Organic inputs can guarantee both agricultural production and nature conservation. The current approach is to employ the organic compounds like manure and humic acid (that are cost-effective and eco-friendly) as an appropriate substitute for chemical fertilizers.
Materials and Methods: This study was carried out to assess the effect of manure and humic acid application on some elements accumulation and ions concentrations in cotton (Gossypim hirsutum L.) (cotton leaves) under salinity stress. The experiment was conducted as a factorial split plot in the form of a randomized complete block design (RCBD) with four replications in the 2019-2020 cropping year in Beshravieh city in South Khorasan. The main plot included different levels of irrigation water salinity at three levels (2.5, 5.5 and 8.5 ds.m-1) and sub-plots consisted of a factorial combination of manure at two levels (0 and 20 t/h) and humic acid at two levels (0 and 200 gr/ 100 kg of seeds as priming). In order to measure the concentration of sodium (Na) and potassium (K) elements, it was done using a film photometer and chlorine concentration based on the method provided by Johnson and Ulrich (1995). In order to assess the cotton yield, the yield of two consecutive harvests were added together and was considered as the seed cotton yield of each experimental unit.
Results and Discussion: The results of the present study illustrated that the salinity stress increased the concentration of Na+, and Cl- on cotton leaves and consequently decreased K+ concentration. The increase of salinity stress from 2.5 to 5.5 and 8.5 dS/m caused a significant concentration in yield. Manure application treatment increased Na+ (13.45%), K+ (2.67%), Cl- (18.30%) concentration in the plant leaves and seed cotton yield (13/90 %) compared to the no use of manure. Humic acid application treatment decreased Na+ (3.08%), Cl- (9.78%) concentration and increased K+ concentration (4.17%) and cotton yield (9/15 %) and improved the growth conditions compared to the treatment of no use of humic acid. The application of manure (before planting) and humic acid (as priming treatment) increased the seed cotton yield by improving the accumulation of beneficial elements in the leaves under salinity stress conditions.
Conclusion: Based on the results of this experiment, it can be concluded that the application of manure and humic acid (priming) moderated the negative effects of salinity stress on plant yield. In addition, manure and humic acid can be used as an effective and alternative fertilizer in order to reduce the consumption of chemical fertilizers and salinity stress in hot and dry climates. Therefore, manure and humic acid (organic fertilizers) are recommended to be applied under (environmental stresses) salinity stress conditions to mitigate the effects of salt stress and obtain a greater higher yield.
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