Research Paper
a.h j
Abstract
Loss of arable land and irrigation water quality was evident in many parts of the country in recent years, and certainly this non-living stress will be one of the main challenges various crop will be confronted. Soil and water salinities’ effects on agricultural production can be studied from different ...
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Loss of arable land and irrigation water quality was evident in many parts of the country in recent years, and certainly this non-living stress will be one of the main challenges various crop will be confronted. Soil and water salinities’ effects on agricultural production can be studied from different aspects. Physiological disturbances in nutrients’ absorption are one of the main disadvantages of salt accumulation. Due to the different needs of crops to various nutrient elements, the importance of salinity and its impact on nutrient uptake may also be subject to different forms. Potato is sensitive to the soil and water salinity. Reduced uptake and transport of K is one of the main reasons for the decline of potato’s yield in the salt stress condition. Regarding this, conventional methods of K fertilizers application cannot fulfill high needs of this plant. Foliar K fertilizer application can be considered as an appropriate approach to ensure the production of potato in the medium salinity stress condition. Regarding potato’s physiology, role of K fertilizer in potato yield formation and its application management in saline condition will be reviewed in the current paper.
Research Paper
m a
Abstract
Soil erosion in a given area depends on natural characteristics of the place as well as the rate of human impact. In Iran, the Mediterranean precipitation regime and relatively high erosivity of rain, wide area of erodible soils/lithological formations, sparse natural vegetation in many regions ...
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Soil erosion in a given area depends on natural characteristics of the place as well as the rate of human impact. In Iran, the Mediterranean precipitation regime and relatively high erosivity of rain, wide area of erodible soils/lithological formations, sparse natural vegetation in many regions and mountainous topography are main natural factors that affect soil erosion by water. Accelerated soil erosion is due to inaccurate human activities particularly by land misuse without considering its capability and capacity. Wast changing in land uses and removing surface protective cover are common phenomena in many parts of the country. Some features such as over grazing in ranges and ploughing inefficient dry farms in agricultural and natural resources areas; implementation of development projects such as road construction, building and mining, without taking into account principles of soil conservation are increasingly exacerbate the rate of soil erosion. Poor enacted legislation on the area of soil conservation as well as improper implementation should be considered as an important issues too which worsen the erosion situation. This article reviews and discusses above mentioned factors by means of some quantitative and qualitative data and examples countrywide.
Research Paper
f r; h a.r; k kh; a a; a e
Abstract
Carbonatic origin of most arable land in the country, caused to decrease phosphatic fertilizer use efficiency and because of this phenomenon, farmers annually add a large amount of these chemical compounds to their field to get proper results. International shortage and increasing prices create some ...
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Carbonatic origin of most arable land in the country, caused to decrease phosphatic fertilizer use efficiency and because of this phenomenon, farmers annually add a large amount of these chemical compounds to their field to get proper results. International shortage and increasing prices create some problems for importing phosphorus fertilizers to the country. On the other hand using more and more of these compounds caused environmentally pollutions .By changing unavailable forms of soil concentrated phosphorus to the available forms, in parallel to lower need of phosphatic fertilizers, plant growth and yield also can be guaranteed .In rhizospheric soil some of microorganisms including bacteria and fungi have ability to change soil fixed phosphorus to soluble one by specific mechanisms. Isolation, recognition, their production and formulation of these microorganisms constitute the main frame of production of a kind of biofertilizers which is named phosphatic biofertilizers. In developed countries, the new formulations of these biofertilizers contain different kinds of microorganisms for multiple purpose including supply plant mineral needs and help to their host to be more resistant against biotic and abiotic stresses. These kinds of biofertilizers including sulfur oxidizing, phosphate solubilizers and mycorrhizal fungi were used in the country from 10 years ago. Research results showed that these microorganisms efficiencies are in relation to plant host and soil physical and chemical properties. In over all they can supply 25 to 50 percent of plant phosphorus demand. Trying to use modern technologies to produce these microorganisms and their formulation caused to develop using them in the country and help us to decrease usage of phosphatic chemical fertilizers.
Research Paper
m.r b
Abstract
In the Netherlands, serious soil investigations were started in the mid-1800s and in the mid-1900s with university courses and the establishment of research institutes soil science rapidly expanded. The Dutch and Western European society have changed dramatically in the past century from and early industrial ...
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In the Netherlands, serious soil investigations were started in the mid-1800s and in the mid-1900s with university courses and the establishment of research institutes soil science rapidly expanded. The Dutch and Western European society have changed dramatically in the past century from and early industrial society with a dominantly rural and agricultural character to a post-industrial society where services play a key role. The aim of this paper is to contribute to an analysis of the historical developments in soil science, confined to the broad relations between soil science and developments in society in this special context to provide some notes on the future of soil science. To this end, three development waves including the production wave (1945-1970), the environmental wave(1970-late 1980s) and the third wave(late 198s-present) were distinguished that have taken place in the Netherlands and in other Western European countries since World War II in relation to the land. These successive waves gradually come and disappear and may overlap overtime. Regarding development in soil science as a reflection of general developments in society, two waves including supply-driven wave and market-driven wave were distinguished on the basis of shifts in research topics, in quantity of soil research, focus of attention, or modes.
Research Paper
h kh
Abstract
Atmospheric nitrogen fixation as an exclusive phenomenon is accomplished by nitrogenase enzyme of prokaryotic microorganisms namely diazotrophs including bacteria, actinomycets and cyanobacteria. Nitrogen fixation is accomplished as form of symbiotic, associative and free-living systems. In free-living ...
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Atmospheric nitrogen fixation as an exclusive phenomenon is accomplished by nitrogenase enzyme of prokaryotic microorganisms namely diazotrophs including bacteria, actinomycets and cyanobacteria. Nitrogen fixation is accomplished as form of symbiotic, associative and free-living systems. In free-living systems nitrogen is fixed without the help of plants. Azotobacter, the first diazotroph was discovered over a century ago and application of it was started in agriculture about half a century ago. Nowadays, in some countries a large amount of diazotrophs are used as inoculums. In recent years, some companies produce diazotroph inoculums in Iran. Some kinds of organic and inorganic such as torb, perlite, and charcoal, bran and cane molasses are suitable for diazotroph inoculums careers. The population of inoculums is reported as number of microorganisms per milliliter or gram of inoculums and recommended for a certain amount of seeds or in hectare. The diazotroph inoculums’ are used in form of soil or seed and seedless application or in rhizosphere of trees.
Research Paper
e gh; b k
Abstract
This study was carried out to determine the best rotation with using plants as wheat, soybeans, canola and tomatoes for field planting area of 35 hectares, in 15 kilometers northwest of Galikesh in 2010. To this end, by using the CropWat software, appropriate model was selected in terms of net profit ...
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This study was carried out to determine the best rotation with using plants as wheat, soybeans, canola and tomatoes for field planting area of 35 hectares, in 15 kilometers northwest of Galikesh in 2010. To this end, by using the CropWat software, appropriate model was selected in terms of net profit and performance (output per unit of water used), in irrigated and rain fed conditions. According to the percentage of cultivated crop in the selected model a five-year rotation was offered. Regarding results of this experiment, although fourth proposed rotation (included: wheat, canola, tomatoes and soybeans with, 50, 50, 40 and 60 percent share in rotation, respectively) in terms of performance (with the 35609.9 Rial per cubic meter of water) was in the second rank, introduced as the appropriate crop rotation in the region. This is because the proposed rotation in terms of net profit was highest in irrigated condition and that was highest one in terms of net income in compared with other patterns (with 566751458 Rial) in dry condition.