جستجوی مقالات مرتبط با کلیدواژه "گچ" در نشریات گروه "مکانیزاسیون کشاورزی"

Introduction:

 In Khuzestan province, Iran, huge amounts of organic waste is generated annually, leading to challenges for its safe disposal, with the waste being usually either burned or land filled.Agro-industrial wastes such as sugarcane pith, have been recognized as important renewable sources of value-added organic products such as compost.Compost is a mixture of decayed organic material decomposed by microorganisms in a warm, moist, and aerobic environment that release nutrients into readily available forms for plant use. Recycling of organic wastes by the process of composting in agriculture brings in the much needed organic matter to the soils and improves the overall soil fertility and soil productivity Thus, composting is a process for appropriate disposal of waste and is also beneficial from ecological and economic point of view. Lignocellulosic materials are not easily degraded due to the lignin, crystalline and structural complexity of cellulose matrix. Application of chemical and biological treatments may increases waste degradation and decrease composting process time. Bacteria and fungi are the two main microbes that help in decomposition of organic waste and forces of composting. In addition, efficient composting is dependent on the microbial activity. The objective of this research was to investigate the effect of chemical (gypsum) and microbial treatments (consortium of bacteria and fungi) on reduce C/N and shortening process of compost maturity which is used in agricultural fields. 

Materials and Methods:

 In this research, an incubation experiment was carried out in laboratory condition as a factorial experiment based on a randomized complete design with two factors: 1) gypsum application in three levels including, 1%, 5% and 10% w/w, and 2) microbial inoculation in four levels including control (without microbial inoculation), inoculation of substrate with consortium of bacteria, consortium of fungi and consortium of bacteria + fungi, with three replications. The sugarcane pith for compost production was collected from Dehkhoda sugarcane Agro-industry, Ahvaz, SW Iran. The sugarcane pith was initially boiled for 2h, then air-dried. Sugarcane pith samples were sterilized in an autoclave and 1% w/w urea were added to each samples to reduce their C/N ratio. Then, sterilized gypsum and microbial treatments were added to samples in plastic jars. Samples were incubated for 90 days at constant temperature of 25 ± 2 °C. Samples moisture content was maintained at 80% of field capacity. The samples were weighted every day and the required amounts of distilled water were added. At the end of incubation period, sample properties such as organic matters loss percent (OM loss), ash content, carbon (C), nitrogen (N), hydrogen (H) and sulfur (S) content were measured. Also oxygen (O) content and atomic ratio including carbon to nitrogen (C/N), hydrogen to carbon (H/C), oxygen to carbon (O/C) and hydrogen to oxygen (H/O) ratio were determined. All statistical analyses were performed using SAS software. Means of different treatments were compared using the Duncan’s test at probability level of 5%. 

Results and Discussion:

 The results of variance analysis showed that the gypsum levels and microbial treatments significantly affected the organic matters loss percent, carbon, nitrogen, hydrogen and sulfur content and O/C, H/O and H/O ratio. In addition interaction effect of gypsum and microbial treatments was significant on nitrogen, hydrogen content and C/N ratio. The results indicated that the gypsum addition and inoculation of bacteria and fungi consortium to sugarcane pith significantly (P < 0.05) decreased the carbon content and C/N, H/C and H/O ratio, while significantly (P < 0.05) increased nitrogen, oxygen and hydrogen content as well as O/C ratio. With increasing gypsum levels (from 1 to 10% w/w) the carbon content and C/N, H/C and H/O ratio significantly (P < 0.05) reduced, while nitrogen, oxygen and organic matter loss percent, hydrogen content and O/C ratio significantly (P < 0.05) increased. Comparison of microbial treatments showed that consortium of bacteria + fungi had higher effect on changes in organic matter loss percent, carbon and nitrogen content and C/N, H/C, H/O and O/C ratio. Maximum organic matter lost and nitrogen content as well as minimum and C/N, H/C and H/O ratio were recorded for co-inoculation of bacterial and fungi consortium combined with application of 10% gypsum treatments. Reduction of C/N, H/O and H/C as well as increasing O/C in the above mentioned treatment, indicating that maturation of sugarcane peat composting was completed three months after composting process.

Conclusion:

 From the results of this study, it can be concluded that inoculation of consortium of bacteria and fungi with 10% gypsum led to hasten the sugarcane pith degradation and shortening composting process duration.

Pistachio is one of the most economical cash crops in Iran that is located in arid and semi-arid regions with low soil organic matter and very harmful ions. The enhancement of the 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 which are essential, 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 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 the soil profile. Sulfur oxidation and gypsum produce acid in the soil and lead to the reduction in pH and the amending of the soil condition. The present study investigated the effects of two organic matters (MSWC and cow manure), two chemical matters (gypsum and sulfur) on some nutrient concentrations in different soil depths (0-20, 20-40, and 40-60 cm depths) and the leaf of pistachio seedlings at the field condition.  A field experiment in a randomized complete block design (split-plot) with three replications was conducted for two years in Izadyaran Company (30 km south of Sirjan, Kerman Province, Iran with hot and dry climates). 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 subplot factor, and soil depths (0-20, 20-40, and 40-60 cm) as the sub-subplot. The organic and chemical matter were poured into the pit of planting and mixed well with soil and a one-year-pistachio seedling was planted (February 2012). In the middle of the summer (August 2013) and at the end of winter (February 2014), plant leaves and soil sampling were done respectively and macro elements’ (Na, K, Ca, Mg, N, and P) concentrations were measured and then statically analyzed with SAS software. MSWC and sulfurs cause the increase of available K in 40-60 cm depth, because of more mobility of K in comparison to other ions. MSW contains K and sulfur through the reduction in pH that leads to MSW decomposing and increases the available K. Sulfur application rises Ca of soil solution more than gypsum because of common ion effect. MSWC and gypsum also enhanced Mg of the soil solution in 20-40 cm depth. Not only MSWC contained Mg but also SO42- solved some parts of solid MgCO3 and increased Mg in soil solution. On the other hand, mineralization of cow manure increased the available P in 20-40 cm depth. None of the treatments were significant on the concentration of soil Na and N. Probably Na was leaching in primary irrigation and mineralized N was quickly absorbed by the plant. Results of this experiment showed that treatments were not significant on the concentration of Na, K, and Mg of pistachio leaves. The application of cow manure increased Ca and P, and cow manure and sulfur increased the N concentration of leaves. The enhanced concentration of elements may be attributed to the increased nutrient levels in cow manure. Sulfur because of sulfuric acid production in soil solution, declined soil pH and led to more nutrient uptake. This phenomenon continuously provides available nutrients in usable form to the plants. These results may be illustrated by the postulated slow release and contiguous storage of nutrients from organic wastes, such as MSWC and cow manure that increased soil nutrient content after a year. Gypsum, with replacing Na with Ca, decreased harmful ions, such as Na and both gypsum and sulfur and because of sulfuric acid production in soil solution, declined soil pH and then led to soil reclamation and more nutrient uptake. The interaction effect of organic and chemical matters’ treatments ,in the same way, can increase some essential nutrients in the soil and plant significantly because of the synergic effect of the organic and chemical soil reclamation.  Results of this study illustrated that it is possible to improve the fertility of saline-sodic soils and plant nutrition with cheap and available organic and chemical materials, such as cow manure and MSWC, gypsum, and sulfur. However, due to the difference in mobility of ions, their concentrations vary in different depths, but with the proper planning, the essential elements can be reached to plants at the right time, especially for a strategic plant like pistachio.

Salinity limited plant growth and will decrease the yield with decrease in solution osmotic pressure, nutrient imbalance and toxicity of some specific elements. Application of amendment materials such as gypsum and cattle manure can adjust the undesirable effects and increase the nutrient elements in leaf and grain. In this regard a pot experiment was conducted during 2009 growing season based on split factorial with four replications in complete randomize design. In this experiment the main factor was inclusive different level of salinity in irrigation water {0, 3, 6, 9 and 12 dS/m as NaCl and CaCl2 (1:1 w/w)} and subsidiary factors were inclusive gypsum (0, 15 and 30 ton/ha) and the cattle manure (0 and 30 ton/ha). The results showed that increasing the salinity content of irrigation water causes reduce the amount of phosphorus and increase nitrogen and potassium in wheat leaves. Also, with increasing in salinity of irrigation water the amounts of phosphorus and potassium in grain decreased and the amount of nitrogen in grain increased. Application of gypsum increased the amounts of the nitrogen, phosphorus and potassium 6.31, 10.89 and 14.82 percent in leaves and the amounts of the nitrogen, phosphorus and potassium 10.32, 10.84 and 3.45 percent in grain, respectively. Using manure at different salinity treatments was significant affecting on the amounts of nitrogen and phosphorus in leaves and phosphorus and potassium in grain. The highest amounts of nitrogen and phosphorus in leaves and grain were obtained using 15 and 30 tons of gypsum per ha while the highest amount of potassium in leaves and grain were obtained using 30 tons of gypsum per ha.