Study of Agronomic Traits, Yield Performance and Economical Indices in Intercropping of Spinach with Chickpea

Introduction  Due to the limits of the conventional agricultural system, intercropping is important in terms of production sustainability. Intercropping plays an important role in increasing production and performance stability to improve the use of resources and environmental factors. Spinach (Spinacia oleracea L.) is an important leafy vegetable, of which the leaves and tender shoots are consumed fresh or processed. Spinach is native to Iran. Spinach contains different flavonoids that function as antioxidants and anticancer agents. Also, spinach may be used in the prevention of Alzheimer's disease. It is an annual plant and as well as chickpea, spinach is grown as both an early spring and late fall crop in order to have growth at the coolest parts of the season. Spinach seed yield varies based on the climatic conditions, optimum sowing date and chose of the best planting pattern. Considering that the intercropping of this plant has not been studied with legumes such as chickpe, this experiment was designed to determine the possibility of intercropping spinach with chickpea using agronomical and economical indices, as well as determining the best planting pattern.   Materials and Methods  In order to investigate agronomic traits, yield and economical indices in spinach intercropping with chickpea, an experiment was carried out as a randomized complete block design with four treatments and three replications in 2017-18 growing season in Tuyserkan city, Hamedan province. In this city, spinach is mainly cultivated for seed production. Experimental treatments included additive intercropping of 20% chickpea with spinach, replacement intercropping of 60% spinach + 40% chickpea and pure stand of spinach and chickpea. Plant height, number of branches per plant, number of seeds per plant, 1000 seed weight, grain yield and biological yield in spinach, as well as plant height, number of branches per plant, number of pods per plant, number of seeds per pod, 1000 seed weight, grain yield and biological yield in chickpea were measured. To compare the advantages of intercropping of spinach with chickpea, the land equivalent ratio (LER), dry matter equivalent ratio (DMER), system productivity index (SPI), competitive ratio (CR), aggressivity (AG), actual yield loss (AYL ), relative value total (RVT), monetary advantage index (MAI) and intercropping advantage (IA) were calculated and evaluated. SAS 9.1 software were used for analysis of variance (ANOVA) calculations. The difference between the means was evaluated by the least significant difference (LSD) method at the level of 5% probability.   Results and Discussion Plant height, number of branches per plant, 1000 grain weight and grain and biological yields of spinach were significantly affected by intercropping. The highest plant height and the lowest number of branches per spinach plant were obtained from the replacement intercropping. Additive intercropping and pure stand of spinach without significant difference had the lowest plant height and the highest number of branches per plant. The highest 1000 grain weight and grain yield of spinach were associated with the additive intercropping method. However, in terms of biological yield, the pure stand of spinach showed the highest results. Notably, there were no significant differences between the treatments of additive intercropping and pure stand of spinach concerning grain and biological yield of spinach. On the other hand, in chickpeas plants, intercropping had a notable impact on various parameters. Specifically, plant height, number of branches per plant, number of pods per plant, 1000 grain weight, and both grain and biological yields were affected by the intercropping method. Among these, the additive intercropping treatment resulted in the highest plant height, while it had the lowest number of branches and number of pods per chickpeas plant.The highest 1000 grain weight and grain yield of spinach were related to the additive intercropping. Pure stand of spinach had the maximum biological yield. Treatments of additive intercropping and pure stand of spinach were not significantly different in terms of grain and biological yield of spinach. In chickpeas plant, plant height, number of branches per plant, number of pods per plant, 1000 grain weight, grain and biological yields were affected by intercropping. The highest plant height and the lowest number of branches and number of pods per chickpeas plant were obtained at the treatment of additive intercropping. Maximum grain and biological yields of chickpea were belonged to the pure stand of chickpea. Spinach and chickpea were dominant and recessive plants, respectively. Evaluation of the economical indices also showed the advantages of spinach intercropping with chickpea at both intercropping design (replacemet and additive intercropping). So that the highest values for land equivalent ratio, dry matter equivalent ratio, system productivity index, actual yield loss, relative value total and monetary advantage index were achieved at additive intercropping system. But, the lowest values for these indices (1.13, 1.06, 1.20 and 1321 for LER, DMER, RVT and MAI, respectively) were revealed at replacement intercropping.   Conclusion  Overall, the results indicate that chickpea is a suitable plant for intercropping with spinach. So that the intercropping of 20% chickpea with spinach improved the yield performance of spinach and land-use efficiency and can lead to the greatest economical profit

Sandstone matrix acidizing knowledge and future development

To meet rising global demands for energy, the oil and gas industry continuously strives to develop innovative oilfield technologies. With the development of new enhanced oil recovery techniques, sandstone acidizing has been significantly developed to contribute to the petroleum industry. Different acid combinations have been applied to the formation, which result in minimizing the near wellbore damage and improving the well productivity. A combination of hydrofluoric acid and hydrochloric acid (HF:HCl) known as mud acid has gained attractiveness in improving the porosity and permeability of the reservoir formation. However, high-temperature matrix acidizing is now growing since most of the wells nowadays become deeper and hotter temperature reservoirs, with a temperature higher than 200 °F. As a result, mud acid becomes corrosive, forms precipitates and reacts rapidly, which causes early consumption of acid, hence becoming less efficient due to high pH value. However, different acids have been developed to combat these problems where studies on retarded mud acids, organic-HF acids, emulsified acids, chelating agents have shown their effectiveness at different conditions. These acids proved to be alternative to mud acid in sandstone acidizing, but the reaction mechanism and experimental analysis have not yet been investigated. The paper critically reviews the sandstone acidizing mechanism with different acids, problems occurred during the application of different acids and explores the reasons when matrix stimulation is successful over fracturing. This paper also explores the future developing requirement for matrix acidizing treatments and new experimental techniques that can be useful for further development, particularly in developing new acids and acidizing techniques, which would provide better results and information of topology, morphology and mineral dissolution and the challenges associated with implementing these “new” technologies

A case study to optimum selection of deliquification method for gas condensate well design: South Pars gas field

Optimum decision making is an ongoing problem in production engineering. Dynamic well characteristics during the project life, different reservoir and well conditions, and policies of the companies lead to complex problems. Today, the most effective liquid-removal devices are pumping, the combination of liquid-diverter with gas lift and velocity string. Considering mentioned complexities, the most efficient method of liquid removal is different from one well to the others. This paper discusses a multi-criteria decision making (MCDM) strategy for ranking these methods based on ELECTRE and TOPSIS techniques in a gas condensate reservoir. The most efficient model in this case, regarding its high efficiency and level of reliability is continuous gas lift. These procedures can be extended to other cases easily by changing the comparison matrix and user defined weights

In-situ characterization of capillary pressure during three-phase flow in porous media

We characterize the pore-scale fluid distributions, phase connectivity, and local capillary pressures during three-phase flow in a water-wet Berea sandstone sample. In this investigation, we use a set of x-ray micro-tomography images acquired during three-phase core-flooding experiments conducted on a miniature core sample. We use several image analysis techniques to analyze the pore-scale fluid occupancy maps and use this information to develop several insights related to pore occupancy, oil and gas cluster distribution, and interfacial curvature during the gas injection process. The results of our investigation show that the large-, intermediate-, and small-sized pores are mostly occupied with gas, oil, and brine, respectively, which is consistent with the wetting order of the fluids (i.e., gas, oil, and brine are the nonwetting, intermediate wetting, and wetting phases, respectively). In addition, the connectivity analysis reveals that a significant amount of the gas phase was in the form of disconnected ganglia separated from the connected invading cluster. The presence of these trapped nonwetting phase clusters during the drainage process is presumably attributed to Roof snap-off and Haines jump events, as well as the anti-ripening phenomenon. Moreover, the average local oil-water capillary pressures are found to be greater than the gas-oil counterparts. This observation is then related to the relative location of the interfaces in the pore space and the threshold capillary pressures at which the various displacement events take place

Application of the third medium method for frictionless contact problems in geomechanics

Traditional approaches in contact mechanics demand complicated search algorithms at the interface between the contacting bodies. Recently, a new contact method based on the concept of a third medium has been developed, which overcomes the drawbacks of conventional contact mechanics techniques. This new scheme is based on a space filling mesh, in which the contacting bodies can move and interact. The ability and accuracy of this method in predicting displacements, as well as the contact forces, is validated by solving selected numerical examples. The potential merits of this method for analysing geotechnical problems by the finite element method are addressed

Spatial correlation of contact angle and curvature in pore-space images

We study the in situ distributions of contact angle and oil/brine interface curvature measured within millimeter-sized rock samples from a producing hydrocarbon carbonate reservoir imaged after waterflooding using X-ray microtomography. We analyze their spatial correlation combining automated methods for measuring contact angles and interfacial curvature (AlRatrout et al., 2017, https://doi.org/10.1016/j.advwatres.2017.07.018), with a recently developed method for pore-network extraction (Raeini et al., 2017, https://doi.org/10.1103/PhysRevE.96.013312). The automated methods allow us to study image volumes of diameter approximately 1.9 mm and 1.2 mm long, obtaining hundreds of thousands of values from a data set with 435 million voxels. We calculate the capillary pressure based on the mode oil/brine interface curvature value and associate this value with a nearby throat in the pore space. We demonstrate the capability of our methods to distinguish different wettability states in the samples studied: water-wet, weakly oil-wet, and mixed-wet. The contact angle and oil/brine interface curvature are spatially correlated over approximately the scale of an average pore. There is a wide distribution of contact angles within a single pore. A range of local oil/brine interface curvature is found with both positive and negative values. There is a correlation between interfacial curvature and contact angle in trapped ganglia, with ganglia in water-wet patches tending to have a positive curvature and oil-wet regions seeing negative curvature. We observed a weak correlation between average contact angle and pore size, with the larger pores tending to be more oil-wet