rafiq islam - Academia.edu (original) (raw)

Papers by rafiq islam

The activity of hydrolases in the rhizosphere soil are involved in the decomposition of organic r... more The activity of hydrolases in the rhizosphere soil are involved in the decomposition of organic residues, cycling of nutrients, and in maintaining soil fertility and plant productivity. Rhizosphere microrganisms release extracellular enzymes for the initial degradation of high molecular polymers, that can also result in the suppression of plant pathogenic fungi directly. Root exudates including plant growth promoting regulators have different stimulatory effects on microbial growth and on hydrolase activities in the rhizosphere. Possible causes for lower enzyme production in the rhizosphere of trace element contaminated soils and/or saline soils could be microbial metabolic stress and osmotic potential of the soil due to higher salt concentrations. In spite of increasing knowledge on the microbial community composition, no comparisons with the enzyme activity are normally carried out in order to reveal relationship between microbial diversity and enzyme activity in the rhizosphere.. This kind of comparative work may be of great interest from theoretical and practical aspects.

Biology and Fertility of Soils, 2010

Secondary soil salinilization is a big problem in irrigated agriculture. We have studied the effe... more Secondary soil salinilization is a big problem in irrigated agriculture. We have studied the effects of irrigation-induced salinity on microbial biomass of soil under traditional cotton (Gossypium hirsutum L.) monoculture in Sayhunobod district of the Syr-Darya province of northwest Uzbekistan. Composite samples were randomly collected at 0–30 cm depth from weakly saline (2.3 ± 0.3 dS m−1), moderately saline (5.6 ± 0.6 dS m−1), and strongly saline (7.1 ± 0.6 dS m−1) replicated fields, 2-mm sieved, and analyzed for pH, electrical conductivity, total C, organic C (COrg), and extractable C, total N and P, and exchangeable ions (Ca2+, Mg2+, K+, Na+, Cl−, and CO 32−), microbial biomass (Cmic). The Na+ and Cl− concentrations were 36-80% higher in strongly saline compared to weakly saline soil. The COrg concentration was decreased by 10% and CExt by 40% by increasing soil salinity, whereas decrease in Cmic ranged from 18-42% and the percentage of COrg present as Cmic from 8% to 26%. We conclude that irrigation-induced secondary salinity significantly affects soil chemical properties and the size of soil microflora.

Energy Sources, 2005

Contamination in drinking water is the most common form of environmental problems encountered in ... more Contamination in drinking water is the most common form of environmental problems encountered in water resources management. Some contaminants, present accidentally in drinking water, are very difficult to remove, such as heavy elements that are products of industrial waste. Lead is one of the most difficult-to-remove elements. This paper proposes a novel process for removal of lead compounds contaminants from water. The proposed method shows great efficiency.

International Journal of Solids and Structures, 2001

The objective of the study presented is to provide an analytical solution for determining the sta... more The objective of the study presented is to provide an analytical solution for determining the stability of a flexible rock layer overlying a circular opening. This problem is of general interest to the mining community but is particularly relevant to the oil and gas industry ...

Archives of Agronomy and Soil Science, 2012

The phosphorus-use efficiency of crops in high pH soil is low. A randomized complete block design... more The phosphorus-use efficiency of crops in high pH soil is low. A randomized complete block design in a 3 × 2 split-plot experiment was conducted on a high pH silt loam (Typic Ustochrepts) to evaluate whether P-solubilizing microbial (PSM) inocula were able to improve the P fertilization effects on irrigated cotton (Gossypium hirsutum L., cultivar CIM-482). Cotton was planted after seed treatment with PSM inoculation at 0, 22 and 44 kg P ha−1. Results showed that soil microbial populations were significantly higher throughout the cotton-growing season in response to P fertilization and PSM inoculation. Both P fertilization and PSM inocula exerted a significant effect on cotton biomass and Puptake without an interaction. Economic analyses suggest that PSM inocula alone significantly increased P-use efficiency (8%), reduced cost and improved net income (by $36 ha−1) of irrigated cotton production. Moreover, the relationship between relative yield and P fertilization with PSM inocula showed that 95% of the maximum yield of cotton was produced at 22 kg P ha−1, whereas in the absence of PSM inocula, 95% relative yield was obtained at 36 kg P ha−1, asaving of ∼39% applied P with PSM inoculation.

The activity of hydrolases in the rhizosphere soil are involved in the decomposition of organic r... more The activity of hydrolases in the rhizosphere soil are involved in the decomposition of organic residues, cycling of nutrients, and in maintaining soil fertility and plant productivity. Rhizosphere microrganisms release extracellular enzymes for the initial degradation of high molecular polymers, that can also result in the suppression of plant pathogenic fungi directly. Root exudates including plant growth promoting regulators have different stimulatory effects on microbial growth and on hydrolase activities in the rhizosphere. Possible causes for lower enzyme production in the rhizosphere of trace element contaminated soils and/or saline soils could be microbial metabolic stress and osmotic potential of the soil due to higher salt concentrations. In spite of increasing knowledge on the microbial community composition, no comparisons with the enzyme activity are normally carried out in order to reveal relationship between microbial diversity and enzyme activity in the rhizosphere.. This kind of comparative work may be of great interest from theoretical and practical aspects.

Biology and Fertility of Soils, 2010

Secondary soil salinilization is a big problem in irrigated agriculture. We have studied the effe... more Secondary soil salinilization is a big problem in irrigated agriculture. We have studied the effects of irrigation-induced salinity on microbial biomass of soil under traditional cotton (Gossypium hirsutum L.) monoculture in Sayhunobod district of the Syr-Darya province of northwest Uzbekistan. Composite samples were randomly collected at 0–30 cm depth from weakly saline (2.3 ± 0.3 dS m−1), moderately saline (5.6 ± 0.6 dS m−1), and strongly saline (7.1 ± 0.6 dS m−1) replicated fields, 2-mm sieved, and analyzed for pH, electrical conductivity, total C, organic C (COrg), and extractable C, total N and P, and exchangeable ions (Ca2+, Mg2+, K+, Na+, Cl−, and CO 32−), microbial biomass (Cmic). The Na+ and Cl− concentrations were 36-80% higher in strongly saline compared to weakly saline soil. The COrg concentration was decreased by 10% and CExt by 40% by increasing soil salinity, whereas decrease in Cmic ranged from 18-42% and the percentage of COrg present as Cmic from 8% to 26%. We conclude that irrigation-induced secondary salinity significantly affects soil chemical properties and the size of soil microflora.

Energy Sources, 2005

Contamination in drinking water is the most common form of environmental problems encountered in ... more Contamination in drinking water is the most common form of environmental problems encountered in water resources management. Some contaminants, present accidentally in drinking water, are very difficult to remove, such as heavy elements that are products of industrial waste. Lead is one of the most difficult-to-remove elements. This paper proposes a novel process for removal of lead compounds contaminants from water. The proposed method shows great efficiency.

International Journal of Solids and Structures, 2001

The objective of the study presented is to provide an analytical solution for determining the sta... more The objective of the study presented is to provide an analytical solution for determining the stability of a flexible rock layer overlying a circular opening. This problem is of general interest to the mining community but is particularly relevant to the oil and gas industry ...

Archives of Agronomy and Soil Science, 2012

The phosphorus-use efficiency of crops in high pH soil is low. A randomized complete block design... more The phosphorus-use efficiency of crops in high pH soil is low. A randomized complete block design in a 3 × 2 split-plot experiment was conducted on a high pH silt loam (Typic Ustochrepts) to evaluate whether P-solubilizing microbial (PSM) inocula were able to improve the P fertilization effects on irrigated cotton (Gossypium hirsutum L., cultivar CIM-482). Cotton was planted after seed treatment with PSM inoculation at 0, 22 and 44 kg P ha−1. Results showed that soil microbial populations were significantly higher throughout the cotton-growing season in response to P fertilization and PSM inoculation. Both P fertilization and PSM inocula exerted a significant effect on cotton biomass and Puptake without an interaction. Economic analyses suggest that PSM inocula alone significantly increased P-use efficiency (8%), reduced cost and improved net income (by $36 ha−1) of irrigated cotton production. Moreover, the relationship between relative yield and P fertilization with PSM inocula showed that 95% of the maximum yield of cotton was produced at 22 kg P ha−1, whereas in the absence of PSM inocula, 95% relative yield was obtained at 36 kg P ha−1, asaving of ∼39% applied P with PSM inoculation.