Soil physicochemical parameters are the physical and chemical characteristics of soil such as pH, bulk density, organic carbon, nitrogen content, and nutrient levels at different soil depths. These parameters vary fro...Soil physicochemical parameters are the physical and chemical characteristics of soil such as pH, bulk density, organic carbon, nitrogen content, and nutrient levels at different soil depths. These parameters vary from one vegetation to the other and from one soil to the other. The study assessed the variations in soil physicochemical parameters of the natural forest and plantations in Agu Eke (Eke bush) in Etti village, Nanka and Umunnebo village, Ufuma both located in Orumba North Local Government Area, Anambra State. The experimental research design and stratified random sampling methods were used for the study and a total of 12 soil samples were collected at 30 cm depth from the selected locations of natural forest, cashew and palm plantations. The samples were analyzed using laboratory Varian AA240 Atomic Absorption Spectrophotometer, after which the result was subjected to statistical analysis—Analysis of Variance (ANOVA). The study found that there was no significant difference (variation) between the moisture contents of natural forests and the plantations;that is, the moisture contents were the same. It was also found that there was no significant variation between the bulk densities of the natural forest, oil plantation, and cashew plantation, meaning that the bulk densities were significantly the same. However, there were significant variations in nitrogen, potassium and phosphates, with p-values: sig = .000 < .05, sig = .010 < .05 and sig = .000 < .05, respectively. That is, the nitrogen and phosphate contents of the natural forest significantly vary more than those of the oil palm and cashew plantations, which probably means that by reducing natural forest to plantation, the nitrogen and phosphate contents of the natural forest reduced from what it used to be when the lands were mere forests. This shows that plantations do not have the same function of maintaining or improving soil quality as natural forests. The study recommended adopting a sustainable plantation agricultural system, such as using diverse nutrient sources (manure and compost), in order to maintain the desired soil quality.展开更多
The study dealt with the assessment of impact of deforestation on soil through a comparative analysis of soil physicochemical properties of natural forest and deforested areas. Soil samples from three depths （top, mi...The study dealt with the assessment of impact of deforestation on soil through a comparative analysis of soil physicochemical properties of natural forest and deforested areas. Soil samples from three depths （top, middle and bottom） under natural forest and nearby deforested areas were collected to investigate soil properties. Forest soils show no sig-nificant change in particle size distribution. Bulk density of forested soils shows the significant differences in top and middle layers. Soil pH in top and middle soil, organic matter in top soil and available phosphorus in middle soil of the forest site are found to be significantly higher than that of the deforested soils. Forest soils also have significantly higher level of exchangeable Ca2＋, K＋ in top and middle soil and Mg2＋ at all depth than those of deforested site. Exchangeable Na＋ and cation exchange capacity （CEC） are observed unchanged in both sites. The results suggest that change in soil properties was more obvious in surface and sub surface portions of both areas. The study shows that deterioration of physicochemical properties occurred due to deforestation.展开更多
In order to understand the effects of increasing atmospheric nitrogen （N） deposition on the subtropical bamboo ecosystem, a nearly six-year field experiment was conducted in a Pleioblastus amarus plantation in the r...In order to understand the effects of increasing atmospheric nitrogen （N） deposition on the subtropical bamboo ecosystem, a nearly six-year field experiment was conducted in a Pleioblastus amarus plantation in the rainy region of SW China, near the western edge of Sichuan Basin. Four N treatment levels---control （no N added）, low- N （50 kg N ha-1 a-l）, medium-N （150 kg N ha-1 a-l）, and high-N （300 kg N ha-1 a-1）--were applied monthly in the P. amarus plantation starting in November 2007. In June 2012, we collected intact soil cores in the bamboo plantation and conducted a 30-day laboratory incubation experiment. The results showed that the soil N net miner- alization rate was 0.96 4- 0.10 mg N kg-1 day-1, under control treatment. N additions stimulated the soil N net mineralization, and the high-N treatment significantly increased the soil N net mineralization rate compared with the control. Moreover, the soil N net mineralization rate was significantly and positively correlated with the fine root biomass, the soil microbial biomass nitrogen content and the soil initial inorganic N content, respectively,whereas it was negatively correlated with the soil pH value. There were no significant relationships between the soil N net mineralization rate and the soil total nitrogen （TN） content and the soil total organic carbon content and the soil C/N ratio and the soil microbial biomass carbon con- tent, respectively. These results suggest that N additions would improve the mineral N availability in the topsoil of the P. amarus plantation through the effects of N additions on soil chemical and physical characteristics and fine-root biomass.展开更多
The efficacy and reliability to use humic substances for increasing crop yields have not been widely established in the scientific literature. The aim of the research isto increase pomegranate cutting survival rate an...The efficacy and reliability to use humic substances for increasing crop yields have not been widely established in the scientific literature. The aim of the research isto increase pomegranate cutting survival rate and the number of quality saplings in nursery production through humic and fulvic acid application during the growing period. The application of humic substances in the pomegranate nursery resulted in a significant positive effect for the quality of the sapling increasing both diameter and height. The data about yield indicates that reducing fertilizer use is balanced by the humic acid through the increase of nutrient uptake by the plant. It also showed that organic matter decomposition and the mineralization processes in the soil increases. The humic substances also tend to regulate soil pH and soil salinity and help to retain organic matter in the surface layer, meanwhile the salt content is leaching out from the surface layer accumulating in the layers below.展开更多
文摘Soil physicochemical parameters are the physical and chemical characteristics of soil such as pH, bulk density, organic carbon, nitrogen content, and nutrient levels at different soil depths. These parameters vary from one vegetation to the other and from one soil to the other. The study assessed the variations in soil physicochemical parameters of the natural forest and plantations in Agu Eke (Eke bush) in Etti village, Nanka and Umunnebo village, Ufuma both located in Orumba North Local Government Area, Anambra State. The experimental research design and stratified random sampling methods were used for the study and a total of 12 soil samples were collected at 30 cm depth from the selected locations of natural forest, cashew and palm plantations. The samples were analyzed using laboratory Varian AA240 Atomic Absorption Spectrophotometer, after which the result was subjected to statistical analysis—Analysis of Variance (ANOVA). The study found that there was no significant difference (variation) between the moisture contents of natural forests and the plantations;that is, the moisture contents were the same. It was also found that there was no significant variation between the bulk densities of the natural forest, oil plantation, and cashew plantation, meaning that the bulk densities were significantly the same. However, there were significant variations in nitrogen, potassium and phosphates, with p-values: sig = .000 < .05, sig = .010 < .05 and sig = .000 < .05, respectively. That is, the nitrogen and phosphate contents of the natural forest significantly vary more than those of the oil palm and cashew plantations, which probably means that by reducing natural forest to plantation, the nitrogen and phosphate contents of the natural forest reduced from what it used to be when the lands were mere forests. This shows that plantations do not have the same function of maintaining or improving soil quality as natural forests. The study recommended adopting a sustainable plantation agricultural system, such as using diverse nutrient sources (manure and compost), in order to maintain the desired soil quality.
文摘The study dealt with the assessment of impact of deforestation on soil through a comparative analysis of soil physicochemical properties of natural forest and deforested areas. Soil samples from three depths （top, middle and bottom） under natural forest and nearby deforested areas were collected to investigate soil properties. Forest soils show no sig-nificant change in particle size distribution. Bulk density of forested soils shows the significant differences in top and middle layers. Soil pH in top and middle soil, organic matter in top soil and available phosphorus in middle soil of the forest site are found to be significantly higher than that of the deforested soils. Forest soils also have significantly higher level of exchangeable Ca2＋, K＋ in top and middle soil and Mg2＋ at all depth than those of deforested site. Exchangeable Na＋ and cation exchange capacity （CEC） are observed unchanged in both sites. The results suggest that change in soil properties was more obvious in surface and sub surface portions of both areas. The study shows that deterioration of physicochemical properties occurred due to deforestation.
基金supported by the National Natural Science Foundation of China(No.31300522)Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20125103120018)
文摘In order to understand the effects of increasing atmospheric nitrogen （N） deposition on the subtropical bamboo ecosystem, a nearly six-year field experiment was conducted in a Pleioblastus amarus plantation in the rainy region of SW China, near the western edge of Sichuan Basin. Four N treatment levels---control （no N added）, low- N （50 kg N ha-1 a-l）, medium-N （150 kg N ha-1 a-l）, and high-N （300 kg N ha-1 a-1）--were applied monthly in the P. amarus plantation starting in November 2007. In June 2012, we collected intact soil cores in the bamboo plantation and conducted a 30-day laboratory incubation experiment. The results showed that the soil N net miner- alization rate was 0.96 4- 0.10 mg N kg-1 day-1, under control treatment. N additions stimulated the soil N net mineralization, and the high-N treatment significantly increased the soil N net mineralization rate compared with the control. Moreover, the soil N net mineralization rate was significantly and positively correlated with the fine root biomass, the soil microbial biomass nitrogen content and the soil initial inorganic N content, respectively,whereas it was negatively correlated with the soil pH value. There were no significant relationships between the soil N net mineralization rate and the soil total nitrogen （TN） content and the soil total organic carbon content and the soil C/N ratio and the soil microbial biomass carbon con- tent, respectively. These results suggest that N additions would improve the mineral N availability in the topsoil of the P. amarus plantation through the effects of N additions on soil chemical and physical characteristics and fine-root biomass.
文摘The efficacy and reliability to use humic substances for increasing crop yields have not been widely established in the scientific literature. The aim of the research isto increase pomegranate cutting survival rate and the number of quality saplings in nursery production through humic and fulvic acid application during the growing period. The application of humic substances in the pomegranate nursery resulted in a significant positive effect for the quality of the sapling increasing both diameter and height. The data about yield indicates that reducing fertilizer use is balanced by the humic acid through the increase of nutrient uptake by the plant. It also showed that organic matter decomposition and the mineralization processes in the soil increases. The humic substances also tend to regulate soil pH and soil salinity and help to retain organic matter in the surface layer, meanwhile the salt content is leaching out from the surface layer accumulating in the layers below.
