Mehdi Kousehlou; Mehdi Rahmati; Iraj Eskandari; Vali Feiziasl
Abstract
Introduction: Soil is one of the nonrenewable resources (in human being life time scale) that is important to be protected. Tillage operations are carried out in a variety of ways, which in general can be divided into two comprehensive classes of conventional and conservation tillage practices. The tillage ...
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Introduction: Soil is one of the nonrenewable resources (in human being life time scale) that is important to be protected. Tillage operations are carried out in a variety of ways, which in general can be divided into two comprehensive classes of conventional and conservation tillage practices. The tillage has a very important impact on soil physical, chemical and biological properties. Different tillage systems can have conflicting effects on soil physical properties, which is thought to reflect the impact of different weather conditions. Therefore, it seems necessary to study the effects of different tillage practices on the soil attributes in different climatic conditions.
Materials and Methods: This experiment was conducted for five years from 2011 to 2016 in a randomized complete block design (RCBD) with repeated measurements in two different locations and four replications. The applied tillage practices included no-till in standing residue (NT1), no-till in entire residue (NT2), chisel plow plus disc harrow (CH), minimum tillage with mulch cultivator (MT) and conventional plowing with moldboard plowing (CT). The experiment was carried out at Dryland Agricultural Research Institute (DARI) in Maragheh. Soil samples were taken at the end of fifth year and then soil texture were determined by hydrometer method, weight and geometric means of aggregates diameters by wet-sieving (MWDwetو GMDwet) and dry-sieving (MWDdry GMDdry) procedures, the stability of 1 to 2 mm aggregates (WAS) by wet-sieving, total soil organic carbon (TOC) by wet oxidizing method, dissolved soil organic carbon (DOC) using carbon analyzer and mass fractal dimension aggregates using Tyler and Wheatcraft model. The soil bulk density (Db) was also measured by intact samples (from two depths of 0-15 cm and 15-30 cm) prepared from the study area using sampling cylinders with a diameter of 5 and a height of 4 cm.
Results and Discussion: In general, the results showed that the interaction of depth and location on Db was significant at 5% probability level. The measured Db in 15-30 cm was greater than the measured Db in a depth of 0-15 cm. Also, in spite of the significance of the main effects of location and tillage and the interaction of tillage-location on soil dissolved organic carbon (DOC), tillage treatments and their interaction effects on total organic carbon (TOC) were not significant. The results showed that conventional tillage, CT, had the highest amount of DOC. However, no-till in entre residue (NT2) and minimum tillage (MT) showed the lowest amount of DOC. Further, the main effects of tillage practices on MWDdry and GMDdry were significant at 5% probability level. No-till (NT1 and NT2) practices had the highest MWDdry with values of 1.17 and 1.25 mm. Tillage practices and location had no significant effect on WAS, Dm, and MWDwet and GMDwet.
Conclusion: It seems that the reason that DOC content of CT was higher than conservation tillage practices is due to the preservation of crop residues on the soil surface in conservation and no-till systems and less mixing of them with soil and consequently their less decomposition. While in conventional tillage, plant residues were mixed with soil, and the effect of biological degradation increased soil DOC. The greater MWDdry in NT1 and NT2 practices suggests that tillage, even at a minimum or reduced state, breaks down the aggregates and produces smaller particles or aggregates. It also seems that the main reason for GMDdry reduction in minimum tillage is due to the further degradation of aggregates by the tillage agent. Therefore, to better and more accurately observe the effects of different types of tillage, sampling should be done at the end of each growing season.
mehdi nourzadeh haddad; Akbar hasani; mehdi karami mighadam
Abstract
Introduction: Water shortage in arid and semiarid regions is the most serious factor in limiting agricultural activities as it leads to the rapid reduction of yields from both a quantitative and qualitative perspective. Under conditions of water scarcity, leaf temperature rises, which causes plant wilting ...
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Introduction: Water shortage in arid and semiarid regions is the most serious factor in limiting agricultural activities as it leads to the rapid reduction of yields from both a quantitative and qualitative perspective. Under conditions of water scarcity, leaf temperature rises, which causes plant wilting and premature senescence of leaves and, eventually, severes reduction of dry matter production. Use of high-efficient irrigation practices, improvement of soil's physical properties, and use of soil amendments such as superabsorbent polymers are some ways of compensating for water shortage, especially during the growing season. Some materials such as plant residues, manure, various types of compost, and superabsorbent polymeric hydrogels can store various amounts of water and thus increase water retention and storage capacity of soils. Superabsorbent hydrogels, which are also called superabsorbent polymers (SAPs) or hydrophilic polymeric gels, are hydrogels that can absorb substantial quantities of water. Hydrogels are a class of polymeric materials having network structures (with physical or chemical crosslinks) that are very capable of swelling and absorbing large amounts of water. These materials are formed from water-solublepolymers by crosslinking them either using radiation or a crosslinker. Superabsorbents are widely used in many products such as disposable diapers, feminine napkins, soils for agricultural and horticultural purposes, gel actuators, water blocking tapes, medicine for the drug delivery systems and absorbent pads where water absorbency or water retention is important. Water is a major constraint for crop growth in arid and semi-arid regions, as the precipitation is low and uncertain in these areas. Efficient utilization of meager soil and water resources necessitates the adaptation of appropriate water management techniques. Suitable soil moisture increases the biological activities as result of physical and chemical condition of soil improving the crop production finally.
Material and Methods: This experiment was conducted under greenhouse conditions in Shushtar city at northern Khuzestan Province using the randomized complete block design using 13 treatments and with 3 replications. Soil samples were taken from a field in the study area, air dried, and passed through a 2 mm sieve. Seven concentration (0, 0.25, 0.5, 0.75, 1.0, 1.25, and 1.5 percentage) of superabsorbent polymers (Aquasorb and Accepta) were used in greenhouse condition. Superabsorbent and 10 Kg soil thoroughly mixed in each pot. All treatments were irrigated when the plants at control showed sign of wilting. There were three replications of each treatment. NPK fertilizers were applied as urea, diammonium phosphate (DAP) and potassium sulphate (K2SO4) based the soil test. Soil samples were again collected which were analyzed for nitrate-N, total organic carbon (TOC), phosphorus and potassium, bulk density, particle density and saturation percentage.NPK of plant samples were also determined. Data were statistically analysed by Duncan test using SPSS.
Results and Discussion: Results had shown that the highest bulk density (1.515 gr/cm3) seen in control treatment and with increasing the polymer, bulk density decreased significantly to 0.91 gr/cm3 in treatment No.2. Also the treatments No. 4 and 11 shown decreasing EC significantly from 0.9 in control treatment to 0.68 in No.4. Adding superabsorbent had significant effect on Potassium amount of soil. Using superabsorbent had no significant effect on real density, pH, N amount, Phosphorous, soil organic carbon after yield harvesting in soil and amount of Phosphorous in plant. Significant increasing in number of leaves, branches, fresh weight of plant, and fruit weight with using superabsorbent polymers and the highest used polymer level (treatments No. 7 and 13) had the highest effect on fresh weight of plant which reported 47.2 g for No.7 and 90.47 g for No.13. Also using 1 percentage of Accepta superabsorbent (No.12) caused the significant increasing of fruit weight (502.9 g) instead of control (73.5 g). Based on the presented results No. 2 and 9 had the most effects on N of plants, which the N amount in control was 1.31 percentage and in No.2 and 9 were 2.88 and 2.82 measured respectively. Treatments No. 7, 8, 9, and 11 had the most measured plant potassium. Final results had shown the number of bacteria and fungi increased significantly using superabsorbent and the number of bacteria increased to 215 × 104 in No.13 and the number of fungi to 176500 in each gram of soil.
Conclusion: The overall results of this research had shown the promotion of physical, biological, and finally increase the yield as results of using superabsorbent especially Accepta type. Using these superabsorbent polymers in farms need more studies because of more effective climate parameters.
zakieh pahlavan yali; M. Zarrinkafsh; A. Moeini
Abstract
Introduction: The increasing Greenhouse Gases in atmosphere is the main cause of climate and ecosystems changes. The most important greenhouse gas is CO2 that causes global warming or the greenhouse effect. One of the known solutions that reduces atmospheric carbon and helps to improve the situation, ...
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Introduction: The increasing Greenhouse Gases in atmosphere is the main cause of climate and ecosystems changes. The most important greenhouse gas is CO2 that causes global warming or the greenhouse effect. One of the known solutions that reduces atmospheric carbon and helps to improve the situation, is carbon sequestration in vegetation cover and soil. Carbon sequestration refers to the change in atmospheric CO2 into organic carbon compounds by plants and capture it for a certain time . However, the ecosystems with different vegetation have Impressive Influence on soil carbon sequestration (SCS). Soil as the main component of these ecosystems is a world-wide indicator which has been known to play an important role in global balance of carbon sequestration. Furthermore, carbon sequestration can be a standard world trade and becomes guaranteed. Costs of transfer of CO2 (carbon transfer From the atmosphere into the soil) based on the negative effects of increased CO2 on Weather is always increasing, This issue can be faced by developing countries to create a new industry, especially when conservation and restoration of rangeland to follow. This research was regarded due to estimation of SCS in three land use types (orchard, paddy rice and forest) in a Part of Ramsar Lands, Northern Iran.
Materials and Methods: Ramsar city with an area of about 729/7 km2 is located in the western part of Mazandaran province. Its height above sea level is 20 meters. Ramsar city is situated in a temperate and humid climate. Land area covered by forest, orchard and paddy rice. After field inspection of the area, detailed topographic maps of the specified zone on the study were also tested. In each of the three land types, 500 hectares in the every growing and totally 1,500 hectares as study area were selected .For evaluation the sequestration of carbon in different vegetation systems,15 soil profile selected and sampling from depth of 0 to 100 centimetres of each profile was done by collecting 15 samples with the total number of 45 samples. Soil sampling (at the 0-100 cm depth) was carried out following determination of points on map. Some of soil features (i.e., Soil structure, Bulk density ,Texture, Acidity, CEC, total Nitrogen and Organic Carbon) were measured in the laboratory. Then, the ANOVA and Duncan tests were employed due to statistical analysis using of SPSS software package. Also The map of carbon sequestration was prepared using of GIS approach.
Results and Discussion :According to obtained results, the amounts of SCS were imposed by different land uses as non-significant. The amounts of SCS were found in forest (4532.35 ton/ha), orchard (2997.66 ton/ha) and paddy rice (2682.55 ton/ha) land use, respectively. The differences may be resulted from the variation among the ecosystem types and plant species. Forests are located in wetlands in the high forest and agricultural land more organic carbon levels (0 to 20 cm), but non-significant difference was observed in the soil depth in these areas. The Increased amount of carbon sequestration in the Orchard of the Paddy Rice can be interpreted due to long-term use of fertilizer in the orchards. In Paddy Rice of study due to deep plowing, results showed more decline of organic matter and the loss of carbon from soils.In addition, the maximumtotal nitrogen, organic and sequestrated carbon in top soil (0-10cm depth) were detected in forest (866.968 ton/ha),whereas the least amount dedicated in paddy rice (393.4 ton/ha) land uses. Four classes of detected soil in the study area were included AlfiSols, Inceptisols, Entisols and Mollisols
Conclusions: We found no significant differences in terms of carbon sequestration in land use due to the impact of climate, annually high rainfall and washing clay seems logical. The plant communities in forest ecosystems can become more capable to absorb and retain carbon than other vegetation cover. Agriculture and farming operations are due to dispersion aggregates, reduce of organic matter and carbon sequestration compared to forest intact soils. Considering the vital role of soil carbon sequestration as one of the known values in terms of natural ecosystems and the importance of soil conservation programs, further research works are recommended on the effects of biotic factors such as grazing and land-use changes.
zahra dianat maharluei; ali akbar moosavi
Abstract
Introduction: In arid and semi-arid soils, low organic matter is one of the barriers to achieving optimal performance. The soils with more organic matter have a better structure and are more resistant to erosive factors such as water and wind. Soil organic matter has a particular importance and has significant ...
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Introduction: In arid and semi-arid soils, low organic matter is one of the barriers to achieving optimal performance. The soils with more organic matter have a better structure and are more resistant to erosive factors such as water and wind. Soil organic matter has a particular importance and has significant impact on the stability of soil aggregates, the extension of plant root system, carbon and water cycles and soil resistance to erosion. This substance acts as a cementing agent and plays an important role in soil flocculation and formation of resistant aggregates.Also, the addition of organic matter to the soil increases soil porosity and decreases soil bulk density.
Materials and Methods: In this research, the effect of the two types of organic matter (compost and the ripe fruit waste of fig) on some soil physical properties was studied. A factorial experiment based on completely randomized design, including the four levels of compost and the ripe fruit waste of fig (0, 1, 2 and 4 by weight %) and three soil types (loamy sand, loam and silty clay loam) with three replications was carried out. The soil samples were collected from the three territories of Fars Province: loamy sand soil from Shiraz, loamy soil from Maharlu and Silty clay loam soil from Zarghan area. The soil samples were air dried and passed through a 2 mm sieve. The physical properties including the bulk density, particle density, porosity, moisture content and soil crust strength was measured. In this research, the soil texture by hydrometer method, Electrical conductivity of the soil saturated paste extract by electrical conductivity meter, saturated paste pH by pH meter, seedling emergence test, soil crust strength by a pocket penetrometer (HUMBOLDT MFG.CO.) bulk density by cylindrical sample and particle density by pycnometer method were measured. The fig fruit treatments were prepared by thoroughly mixing the dried powder of ripe fig fruit passed through a 2 mm sieve (with the rates of 0, 1, 2, and 4 % by dry weight) with the air dried soils. Also, the compost treatments were prepared by thoroughly mixing the dried powder of compost passed through a 2 mm sieve (with the rates of 0, 1, 2, and 4 % by dry weight) with the air dried soils. The test measurement PVC cylinders with an inner diameter of 12.5 cm and a height of 20 cm were prepared. The bottom ends of the cylinders were closed with a screened PVC plate. These cylinders were uniformly filled with the treated soils and irrigated a few times to make a homogeneous soil column. About 3 cm of the top end of the cylinders were left empty.
Results and Discussion: The results showed that all the rates of the ripe fruit waste of fig and the compost treatments significantly decreased crust strength of all soils compared to control at 1% probability level. The results also showed nearly the greater effect of all the treatments on crust strength of loamy sand soil compared to the other soils. All the rates of the ripe fruit waste of fig and compost treatments significantly increased the moisture content of all the soils compared to control at 1% probability level. Moreover, the greater effect of all the treatments on the moisture content of silty clay loam soil compared to other soils was generally observed. All the rates of the ripe fruit waste of fig and compost treatments decreased the bulk density and particle density of all the soils compared to control. Tthe greatest impact was observed in the compost treatments at the level of 4% by dry weight and silty clay loam texture. Also, all the rates of the ripe fruit waste of fig and compost treatments increased the porosity of all the soils compared to control, and the greatest impact belonged to the compost treatments at the level of 4% by dry weight andsilty clay loam texture.
Conclusion: The results showed that the use of the ripe fruit waste of fig and compost in the soil increased moisture content and decreased crust strength significantly compared to the control. Also, the ripe fruit waste of fis and compost in the soil increased porosity and decreased bulk density and particle density compared to the control, but this increase and decrease were not significant.Reduction in crust strength caused by the ripe fruit waste of fig application was more than compost application. However, the effect of compost application on the soil bulk density, particle density, porosity and moisture content was more than the ripe fruit waste of fig application.
F. Moradi; B. KhaliliMoghadam; S. Jafari; S. Ghorbani Dashtaki
Abstract
The objective of this study was to evaluate the long-term effects of mechanized sugarcan cultivation on some soil physical properties in several lands of Khozestan Sugarcane Agro-Industries. According to this, the experiment was carried out statistically as a randomized complete block design at 38 points ...
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The objective of this study was to evaluate the long-term effects of mechanized sugarcan cultivation on some soil physical properties in several lands of Khozestan Sugarcane Agro-Industries. According to this, the experiment was carried out statistically as a randomized complete block design at 38 points in each of Deabal-Khazaei, Amir-Kabir, Karoon and Haft-Tapeh Agro-Industries with 5, 15, 40 and 50 years service. Measured soil variables included soil texture, electrical conductivity, sodium adsorption ratio, organic matter, equivalent calcium carbonate, acidity, bulk density (BD), resistance of soil penetration (PR) at 16.82-17.96 moisture interval at two depths 0-40 and 40-80 cm and mean weight diameter (MWD) at soil surface and 40 cm depth. The results showed that BD and PR increased with numbers of years service and also, MWD increased caused by improvement soil organic matter content. The PR values increased with depth, which achieved to the greatest value at 55 to 80 depth interval. Also, results showned that the significant effect of number of years service on BD, PR and MWD, so that BD, PR and MWD with increasing the number of years service from 5 to 50 years were increased from 1.57 to 1.7 gr/cm3, 0.98 to 1.16 MPa and 0.98 to 1.76 mm at first depth and 1.58 to 1.79 gr/cm3 and 1.29 to 2.15 MPa at second depth, respectively. Whereas, non-significant change was found in MWD related to increase the number of years service at first depth.
