Asian Soil Research Journal

Copper is a naturally occurring trace element present in all environmental media, including soil, sediment, air and water. It is an essential micronutrient critical for cell function, playing a vital role in processes. Copper contamination to agricultural soils is of great concern due to its wide and continuous use in agriculture and horticulture as fertilizers and fungicide. Copper contaminated soil is mainly attributed to agriculture activities such as continuous application of copper-based fungicides and pesticides application. A minireview was carried out using peer-reviewed articles published from 2000 to 2017, which methods of remediating copper soil. The AGORA and Google Scholar databases were used to conduct the search for articles using the terms copper and phytoremediation, Copper and Biological remediation, Copper and soil washing OR physical methods. Following these searches, 19 journal articles out of a total of 191 articles satisfied criteria for inclusion and were used in the final systematic review. The study showed that remediation technology for copper contaminated soil is divided into physical, chemical and biological categories. Physical methods are laborious and costly but can be applied to highly contaminated site; chemical methods have high efficiency and effective to remove the copper, but mostly popularized in a large scale; bioremediation methods including phytoremediation and microbial remediation are appropriate for large areas of soil contaminated by low concentrations of copper. The bioremediation methods are economical, eco-friendly but time consuming.

Phosphorus levels in the soil are easily fixed and rendered unavailable to plants even if they are found to be high and therefore, its influence on uptake of other nutrients such as nitrogen, and potassium cannot be overemphasized. In that view, an experiment was set out at KALRO-Mwea to investigate on the effect of phosphorus levels on soil properties and plant tissue nutrient contents of Nerica rice variety. The experiment was laid out in a Randomized Complete Block Design in split-split plot arrangement and replicated thrice. Two rice varieties (Nerica 11 and Nerica 4) formed the main plots and 4 phosphorus levels (0 kg P/ha, 25 kg P/ha, 50 kg P/ha and 75 kg P/ha) formed the sub plots. Highest net pH decreases of 0.20 and 0.22 units were recorded at 75 Kg haˉ¹ P₂O₅ in season 1 and season 2 respectively, while the lowest net decreases of 0.12 and 0.16 were elicited at 50 Kg haˉ¹ P₂O₅ treatment in season 1 and season 2 respectively. A net decrease was observed in all the CEC levels where phosphorus was applied in all the seasons in which the highest net decrease of 1.09 and 1.03 during season 1 and 2 respectively was elicited on the control treatment, while the lowest net decrease of 0.61 and 0.59 was elicited by the 50 Kg haˉ¹ P₂O₅ rate in season 1 and 2 respectively. There was an inverse relationship exhibited between the phosphorus level of applications and the soil phosphorus net decrease across the two seasons. The net decrease was highest at 0 Kg haˉ¹ P₂O₅ and increased significantly with increasing phosphorus rate. That content of soil nitrogen were low with a marginal increase recorded with application of phosphorus across the seasons. The highest net increase of 0.05% was observed at the 75 Kg haˉ¹ P₂O₅ rate and control in season 1 while the application rate of 50 Kg haˉ¹ P₂O₅ had the lowest net increase of 0.02% in season 2. Highest mean plant-tissue phosphorus of 62.05 ppm was recorded in Nerica 4 under 75 kg P/ha treatment. Highest plant tissue nitrogen of 0.686% and 0.713% for Nerica 4 and 11 respectively were elicited at 75 kg haˉ¹ P₂O₅  in season 1, whereas in season 2 the highest plant tissue nitrogen of 0.721% and 0.691% at 75 kg haˉ¹ P₂O₅  for Nerica 11 and 4 respectively was recorded. Application of phosphorous led to the highest plant-tissue phosphorus in both seasons indicating the importance of proper P fertilizer application where from this study 50-75 kg haˉ¹ P₂O₅ rate is recommended in rice growing.

Knowledge of the infiltration characteristics of soils could play a significant role in the choice of appropriate soil management practices that is capable of alleviating the production constraints of soils. The infiltration characteristics of soils in Owerri under four different lands uses viz: secondary forest, plantain plantation, continuously cultivated land and the grazing land was investigated with the aid of a double ring infiltrometer. Results showed that the secondary forest, plantain plantation, continuously cultivated land, as well as the grazing land all, recorded low infiltration rates of 26.54 mm/hr, 26.0 mm/hr, 18.87/hr and 21.35 mm/hr respectively. There were also significant differences in the soil physical and chemical properties notably the hydraulic conductivity, bulk density, water content, organic matter, total nitrogen, as well as available phosphorus (P<0.05). The results obtained suggest that the inherent land uses in the area affected the infiltration of water as well as the soil quality indices. Land use practices that will improve the organic matter, as well as the water transmissivity of the soils such as conservation tillage, fallowing and controlled grazing, should be adopted and sustained.

Aims: Two field experiments have been carried out to study the effect of different irrigation periods in the presence of compost as an organic amendment on the yield and quality of lupine (Lupinus termis L.) under the sandy soil conditions.

Study Design: Split-plot design. 

Place and Duration of Study: The successive winter seasons of 2016/2017 and 2017/2018 at the Ismailia Agricultural Research Station, (30°35'30" N 32°14'50" E elevation 3 m), Agricultural Research Center (ARC), Egypt.

Methodology: Compost has been applied at the rates of 11.90, 23.81 and 35.71 ton/ha before planting. Three irrigation intervals were assigned after planting by 3, 6, and 9 days; the applied water volume for each was 4761.91 m³/ha.

Results: After harvesting, some parameters were estimated. As the compost rates increased, the soil EC significantly decreased while the available N, P, K, and Fe were significantly increased by 9.51, 12.79, 5.17, and 5.8%, respectively. For same compost rate, the irrigation intervals (3, 6, and 9 days) significantly decreased the available N relatively by 2.88, 5.16, and 6.96%, respectively and the available K by 3.45, 5.06, and 4.37%, respectively. The 6 days interval showed that most significant increase in the seeds' content of nutrients at different compost rates and the seed yield has increased by 19.59, 22.31, and 21.88% for the compost rates of 11.90, 23.81, and 35.71 ton/ha, respectively. The relative increase was by 20.48, 7.63, 4.49, 10.89, and 14.92% for the crude protein, crude lipids, total ash, TSS and the amino acids, respectively. The effect of treatments on the relative shoot moisture (%) and the field water use efficiency (F.W.U.E.) (kg/m³) was discussed.

Conclusion: The 6 days irrigation interval along with a compost application rate of 23.81 ton/ha can be recommended for lupine grown in sandy soil as they showed the most significant increase in the nutrients content of seeds by 22.31%.

A laboratory incubation experiment was carried out to investigate the influence of soil salinity and organic matter on inorganic phosphorus transformation with times in two different soil series such as Barisal and Dumuria located in Ganges Tidal Floodplain sites of Bangladesh. Two representative soil samples were collected from surface soil (0-15 cm) with composite sampling. The salinity and organic matter treatments were 4 dS m^-1 and 5 t ha^-1 (decomposed cow dung) with three replications. The treated soils were then incubated in the laboratory at field capacity moisture condition. To determine the transformation of different forms of inorganic P, sampling was done for 0, 7, 15 and 30 days. Different forms of inorganic P such as soluble and exchangeable phosphorus (SE-P), iron and aluminium bound phosphorus (Fe and Al-P), calcium bound phosphorus (Ca-P) and residual phosphorus (RE-P) were determined at different days of incubation. For Barisal soil series, the sequence of different forms of inorganic P was Ca-P>RE-P>Fe and Al-P>SE-P according to their amount. For Dumuria soil series, the sequence was Ca-P>RE-P>Fe and Al-P>SE-P, respectively. The sequence clearly indicates that the soluble and exchangeable P increases with time due to a combination of salinity and decomposed organic matter which increases the uptake of P and ultimately increases the yield. The changes were statistically significant (P < 0.001) in the case of all three soils.