پديد آورندگان :
رضوي نسب، اعظم دانشگاه فردوسي مشهد - دانشكده كشاورزي , فتوت، امير دانشگاه فردوسي مشهد - دانشكده كشاورزي - گروه علوم خاك , آستارايي، عليرضا دانشگاه فردوسي مشهد - دانشكده كشاورزي - گروه علوم خاك , تاج آبادي پور، احمد دانشگاه ولي عصر (عج) رفسنجان - دانشكده كشاورزي - گروه علوم خاك
چكيده لاتين :
Introduction Pistachio is one of the most economically cash crop in Iran located in arid and semi-arid regions with low soil organic matter and very harmful ions. Enhancement of organic matter in sufficient quantity and quality plays an important role in agricultural production and soil sustainable management. The application of organic matter promotes physical, chemical and microbial soil conditions, such as soil aggregate stability, water holding capacity, productivity, and fertility, particularly in the arid and semi-arid regions of Iran. Municipal solid waste compost (MSWC) and cow manure are two cheap, available, and effective organic materials that can be used in pistachio orchards to improve the soil condition and better root growth and more effective nutrient uptake. Gypsum is a chemical material that can replace Ca with Na especially in saline and sodic soil and cause Na leaching from soil profile. Sulfur oxidation and gypsum produce acid in soil and reduce pH and amend soil conditions. Besides, humic acid may benefit plant growth by improving nutrient uptake and hormonal activity. Humic acids are important the soil components that can ameliorate nutrient availability, stimulate cell division, increase root development and influence other important chemical, biological, and physical properties of soil. With the effect of humic acids, plants also become more resistant to diseases. The present study investigated the effects of two organic matters (MSWC and cow manure), two chemical matters (gypsum and sulfur) and different methods of humic acid applications (soil and foliar) on some morpho-physiological properties of pistachio seedlings at field conditions.
Materials and Methods A field experiment in randomized complete block design (split split plot) with three replications was conducted for two years in Izadyaran Company (30 km south of Sirjan, Kerman province, Iran with a hot and dry climate). Treatments were two organic wastes (MSWC and cow manure,15 Mg ha-1 as the major factor, two chemical amendments (gypsum and sulfur, 10 Mg ha-1) as the subplot factor and methods of humic acid applications (control, soil application 40 L ha-1, and foliar application 2.5 L ha-1), as the sub-subplot. Organic and chemical matters were poured in to the pit of planting and mixed well with soil and a one-year-pistachio seedling was planted (February 2012) and three months after planting, humic acid was applied (June 2012) and repeated in the following year (June 2013), and in the middle of summer (August 2013) some morpho-physiologial parameters were measured and then statishcal analyses were carried out using the SAS software.
Results and Discussion MSWC stimulated plant growth indirectly by improving soil physical, chemical and biological conditions, increased lateral branches number and leaf surface and cow manure increased cell membrane resistance, and declined leakage percentage. The enhancement in some morphological properties may be attributed to increasing nutrient levels in MSWC and cow manure. This phenomenon continuously provides available nutrients in usable forms to the plants, consequently increasing growth and improving morphological parameters. These results may be illustrated by the postulated slow release and contiguous storage of nutrients from organic wastes, causing increased cell elongation, cell division, and leaf-area duration thus promoting increased rates of chlorophyll content after a year. Gypsum and sulfur also increased different parameters, so that gypsum enhanced the lateral branches length, internodes distance and chlorophyll a in comparison to sulfur wereas sulfur increased chlorophyll b and carotenoieds compared with gypsum. Gypsum, by replacing Na with Ca, decreased harmful ions such as Na and both gypsum and sulfur because of sulfuric acid production in soil solution, declined soil pH and led to soil reclamation and nutrient uptake (specially micro nutrient) there by increasing efficiency and considerable plant growth and development. On the other hand, soil application of humic acid increased stem height and total chlorophyll, chlorophyll a, b and carotenoieds, and decreased leaf number and lateral branches length and number whereas foliar application of humic acid decreased stem diamere and increased leakage. Humic acid can produce various morphological, physiological and biochemical effects on higher plants and is made up of heterogeneous and complex molecules that are ubiquitous in the environment. Numerous studies have shown that humic substances not only increase root, leaf, and shoot growth but also stimulate the germination of diverse crop species. The explanation of these positive effects is related to the direct interaction of humic acid with physiological and metabolically processes. Nutrient uptake was increased with the addition of humic acid, cell permeability and modified mechanisms involved in stimulation of plant growth. Humic acid application increased water consumption, confirming a significantly enhanced global plant growth. Moreover humic acid seems to accelerate plant development. The interaction effect of treatments such as organic with chemical matters, organic matter with humic acid application methods and chemical matter with humic acid application methods increased different parameters significantly because of synergic effect of organic and chemical soil reclamation matters, hence the considerable effect of humic acid in decreasing stress and promoting growth.
Conclusion Results of this study illustrated that the best result of increasing the mentioned properties was obtained from combination of cow manure with gypsum, MSW with sulfur, cow manure with foliar application of humic acid and sulfur with soil application of humic acid, improving soil conditions and plant development, specially plant physiology properties.
