جستجوی مقالات مرتبط با کلیدواژه « soil ph » در نشریات گروه « اکولوژی »

 Sustainable production in agriculture is closely related to the proper soil chemical, physical, and biological conditions which are considered as the main functions of soil organic matter. The amount of soil organic matter, especially soil organic carbon (SOC), in agricultural ecosystems depends on the tillage practices. Conventional tillage (CT) which generally uses moldboard plow, results in soil losses by intense erosion, a net loss of nutrients and organic carbon. Toward sustainable agriculture, decreasing plow intensity of CT through application of conservation tillage strategy in which tillage practices are omitted or limited to a considerable extent, has been reported as an essential alternative. The objective of this study was to evaluate the effect of tillage management practices and N application on soil chemical and physical properties as well as SOC in a corn-based rotation on a clay loam textured soil in semi-arid climate of Hashtgerd, Iran.

 A field experiment as the split plot design with three replications carried out in the research farm of agricultural research department of Atomic Energy Organization of Iran in two successive growing seasons during 2011-13. The tillage systems were (CT) conventional tillage (moldboard, rotary, and leveler) and; (MT) minimum tillage (disk) assigned as the main plot; and N rates of application, as the subplots, were 0, 50, 150, 250 kg ha-1. In CT treatment, moldboard plow to a depth of 25-30 cm was used as the primary tillage once in autumn and once in spring each year. As the secondary tillage, CT plots were rotavated to 10 cm depth in spring. MT treatment included two trips over the plots with disk harrow cutting to a soil depth of approximately 10 cm prior to sowing. Soil pH, bulk density (BD), total nitrogen (TN), soil organic carbon (SOC), exchangeable K and available P were then evaluated. Soil samples were collected in September 2013 after the end of three growing seasons from 0-30 cm depth at 5 locations per plot using a 3.5 cm diameter coring tube.

 The results showed that short-term (2 years) effect of tillage systems on soil pH, BD, TN, SOC and exchangeable K as well as available P, was not significant (p ≤ 0.05). However, N application rate significantly (p ≤ 0.05) changed soil TN, BD, exchangeable k and available P. Soil TN increased significantly (p ≤ 0.05) by increase in N application rate as the highest amount of TN was 1036 and 968 mg kg-1 in 250 and 150 kg ha-1, respectively. As the soil samples were taken after crops harvest, soil TN is illustrative of the residual soil N and high amount of TN implies the excessive N application. Soil BD decreased significantly in 250 kg N ha-1. Increasing the N application rate would decrease soil BD by increasing root growth. Exchangeable K and available P decreased significantly (p ≤ 0.05) by increasing N application rate. The lowest amount of soil exchangeable K, and available P was detected for N rate of 250 and 150 kg ha-1, 127 and 130 mg kg-1 for K, and 13.43 and 14.24 mg kg-1 for P, respectively. Increased N application promotes plant growth and improves nutrient uptakes such as K and P, consequently, the amount of soil exchangeable K and available P would decrease.

 Toward sustainable agriculture, conservation tillage seems to be an effective strategy to maintain crop yields as well as soil chemical, physical, and biological properties in the long-term. However, based on the results, tillage systems (CT and MT) had no significant effects on SOC as well as other investigated soil properties in the studied site in the short-term. However, N application rate increased soil TN and decreased BD, exchangeable K and available P. It seems that longer-term investigations are needed to evaluate the probable effects of different tillage systems on soil properties particularly SOC

Medicinal plants have an important role in different industries. So, increasing production of their yields is necessary. Medicinal plants contain phytochemical compounds which have demonstrated bioactive properties. The active principles of the plants are generally secondary metabolites. The use of ecological farming methods, may improve yield and quality. In the last decade, agricultural production, which is mainly based on the use of chemical material, is causing environmental problems. One of the pathways to mitigate this environmental impacts, is to apply the long-term approaches based on the principles of ecological agriculture. Soil microorganisms are the primary metabolites production in the soil can affect the results in the release of phosphorus. Compost can be used as an organic matter in controlling different types of debris and the reduction in fertilizer consumption in agricultural products and mineral absorption elements improve low consumption by plants. Present study aims to investigate the possibility of improving the growth, flower yield, shoot yield, seed yield and yield components of marshmallow as a medicinal plant affected as integrated management of organic, chemical and biological fertilizers. A field experiment was performed as factorial layout based on a randomized complete block design with three replications at Agricultural Research Station, College of Agriculture, Ferdowsi University of Mashhad, Iran, during growing season of 2012-2013. The experimental treatments were all combination of organic and chemical fertilizers in four levels (cow manure (40 ton.ha-1), urban compost (40 ton.ha-1), NPK as chemical fertilizer (114, 18 and 220, 40 kg.ha-1) and control) and inoculation with Thiobacillus and sulphur application in four levels (including inoculation with Thiobacillus, 200 kg.ha-1 sulphur + inoculation with Thiobacillus, 200 kg.ha-1 sulphur and control). plant height, leaf areal indexmax (LAImax), leaf dry weight, stem dry weight, total dry weight, flower, seed yield and yield components such as branch number, capsule number, number seed per capsule and 1000-seed weight and flower, seed and biological yield of marshmallow.
To analyze the variance of the experimental data and drawing of diagrams, MSTAT-C 8 and Excel software was used. All the averages were compared according to Duncan’s multiple range test (p≤0.05) The results showed that the effect of organic, chemical and biological fertilizers were significant (p≤0.01) on plant height, LAImax, leaf dry weight, stem dry weight, total dry weight, flower and seed yield, yield components and biological yield of marshmallow. At the end of the growing season, the highest and the lowest LAImax were observed in chemical fertilizer with Thiobacillus +sulphur (12.3) and control (1.3). The maximum flower and seed yields were recorded in chemical fertilizer with Thiobacillus +sulphur (175.33 and 99.91 g.m-2, respectively) and the minimum were obtained in control treatments (32.33 and 9.31 g.m-2, respectively). Flower yield enhanced up to 100% under chemical, cow manure and compost fertilizers without Thiobacillus +sulphur, Thiobacillus, sulphur compared to control treatment. Flower yield improved up to 106, 89 and 72% for chemical fertilizer, cow manure and compost application with Thiobacillus +sulphur, respectively. According to the results obtained in the present study, organic, chemical and biological fertilizers had significant effects on growth, shoot yield, flower yield, seed yield, biological yield and yield components of marshmallow. Therefore, due to the high pH of soils in agroecosystems, integrated application of sulphur with Thiobacillus inoculation could be considered as an effective approach for soil fertility improvement. organic matter increase soil water holding capacity, improving plant hormone-like activity, increase nutrient uptake by plants, and generally improve the growth and yield of medicinal plant.