The biological and chemical conditions of the rhizosphere are known to considerably differ from those of the bulk soil, as a consequence of a range of processes that are induced either directly by the activity of plan...The biological and chemical conditions of the rhizosphere are known to considerably differ from those of the bulk soil, as a consequence of a range of processes that are induced either directly by the activity of plant roots or indirectly by the stimulation of microbial population and activity in the rhizosphere. Information about phosphorus （P） fractionation in the rhizosphere soils amended with municipal sewage sludge （MSS） is limited, were We carried out greenhouse experiments using a rhizobox in order to evaluate the effects of bean rhizosphere on the various inorganic P （Pi） fractions, organic P （Po）, P in particulate fraction （PF-P）, Olsen-P, dissolved organic C （DOC）, microbial biomass P （MBP） and alkaline phosphatase （ALP） enzyme in 10 calcareous soils amended with MSS （10 g MSS was added to 1 kg soil）. Non-occluded P, occluded P, calcium phosphate and residual P were also quantitated. The results showed that DOC, MBP and ALP activity strongly increased and PF-P and Olsen-P de- creased in the rhizosphere soils compared with in the bulk soils （P〈0.05）. The contents of non-occluded P, oc- cluded P and residuaI-P fractions in the rhizosphere soils were lower than in the bulk soils, while the contents of calcium phosphate and organic P in the rhizosphere soils were higher than in the bulk soils. Simple correlation coefficients showed that P uptake had positive relationship with non-occluded P, occluded P, calcium phosphate fractions and PF-P in the rhizosphere soils. The results suggest that the short-term application of MSS to the cal- careous soils may increase Po and calcium phosphate fractions in the rhizosphere soils, and calcium phosphate fraction is potentially available to crops.展开更多
Apple cultivars’ storability could be strengthened through known techniques of cold storage, advanced industries of control atmosphere or other routine usages like fruit pre-cooling followed by immersion in CA++ solu...Apple cultivars’ storability could be strengthened through known techniques of cold storage, advanced industries of control atmosphere or other routine usages like fruit pre-cooling followed by immersion in CA++ solution, depending on genetic potential of the plant material. At the end of pomology and cold storage assessments of 93 apple cultivars, two high yielding native 'Dirras-e Mashhad' and 'Wealthy' were treated by single and combined 1-MCP and ethylene nano-absorbent (ENA) to assess eventual improvements in cold storage span, fruit eating quality and role of cultivar. For this purpose, directs effects and interactions between all sources of variance were studied. Ethylene emission and CO2 amounts were measured. The results showed that reduced weight loss and flesh firmness, were registered in the treated samples of both cultivars compared with the control. Using of 1-MCP affected significantly (p 0.05) on these characteristics. The native apple 'Dirras-e Mashhad' showed higher pH value than 'Wealthy' under the combined treatment (ENA+1-MCP). Genetic source revealed significant difference through lower 'Wealthy' storability. Ethylene emission increased to 53.64 ppm/Kg·hr after 5th month, which resulted in significant difference at p > 0.01 level related to the initial value of 3.26 ppm/Kg·hr. The combined treatment (ENA+1-MCP) affected significantly (p < 0.05) most of the fruit characteristics in both of the cultivars. The treatments demonstrated different results by cultivar.展开更多
Biochar as an organic amendment improves soil attributes,with a potentially significant effect on soil chemical fertility and quality.The main objective of this study was to quantify the effect of biochar addition on ...Biochar as an organic amendment improves soil attributes,with a potentially significant effect on soil chemical fertility and quality.The main objective of this study was to quantify the effect of biochar addition on nutrients,carbon sequestra-tion and microbial activity and understand the mechanisms of controlling biochar effects in calcareous soils.Maize residue biochars produced at 200,400 and 600℃ were added at 5 and 10 g kg^(−1)rates to sandy loam and clayey texture calcareous soils.The soil properties measured were pH and electrical conductivity(EC),plant-available potassium(K)and available phosphorus(P),total nitrogen(TN),C sequestration;and the fluorescein diacetate(FDA)hydrolysis activity.Addition of raw material and biochars increased pH(0.15-0.46 units),EC(0.14-0.38 dS m^(−1)),TN(63-120%),K(12-41%)and FDA activity(27-280%),but tended to decrease plant-available P(23-86%).Increasing pyrolysis temperature increased soil C pool index(CPI),but decreased the FDA and the changes depended largely upon the application rate and soil texture.The positive effects of biochar addition and its pyrolysis temperature on soil C sequestration potential were more pronounced at high than low application rate and in sandy loam than clayey soils.Nevertheless,the effect of biochar addition and pyrolysis temperature on the FDA activity was higher at high than low application rates,but lower in sandy loam than clayey soils.Although biochar application may successfully improve soil processes and attributes and have a high potential for C seques-tration,its effects are controlled by soil texture,pyrolysis temperature and application rate.展开更多
文摘The biological and chemical conditions of the rhizosphere are known to considerably differ from those of the bulk soil, as a consequence of a range of processes that are induced either directly by the activity of plant roots or indirectly by the stimulation of microbial population and activity in the rhizosphere. Information about phosphorus （P） fractionation in the rhizosphere soils amended with municipal sewage sludge （MSS） is limited, were We carried out greenhouse experiments using a rhizobox in order to evaluate the effects of bean rhizosphere on the various inorganic P （Pi） fractions, organic P （Po）, P in particulate fraction （PF-P）, Olsen-P, dissolved organic C （DOC）, microbial biomass P （MBP） and alkaline phosphatase （ALP） enzyme in 10 calcareous soils amended with MSS （10 g MSS was added to 1 kg soil）. Non-occluded P, occluded P, calcium phosphate and residual P were also quantitated. The results showed that DOC, MBP and ALP activity strongly increased and PF-P and Olsen-P de- creased in the rhizosphere soils compared with in the bulk soils （P〈0.05）. The contents of non-occluded P, oc- cluded P and residuaI-P fractions in the rhizosphere soils were lower than in the bulk soils, while the contents of calcium phosphate and organic P in the rhizosphere soils were higher than in the bulk soils. Simple correlation coefficients showed that P uptake had positive relationship with non-occluded P, occluded P, calcium phosphate fractions and PF-P in the rhizosphere soils. The results suggest that the short-term application of MSS to the cal- careous soils may increase Po and calcium phosphate fractions in the rhizosphere soils, and calcium phosphate fraction is potentially available to crops.
文摘Apple cultivars’ storability could be strengthened through known techniques of cold storage, advanced industries of control atmosphere or other routine usages like fruit pre-cooling followed by immersion in CA++ solution, depending on genetic potential of the plant material. At the end of pomology and cold storage assessments of 93 apple cultivars, two high yielding native 'Dirras-e Mashhad' and 'Wealthy' were treated by single and combined 1-MCP and ethylene nano-absorbent (ENA) to assess eventual improvements in cold storage span, fruit eating quality and role of cultivar. For this purpose, directs effects and interactions between all sources of variance were studied. Ethylene emission and CO2 amounts were measured. The results showed that reduced weight loss and flesh firmness, were registered in the treated samples of both cultivars compared with the control. Using of 1-MCP affected significantly (p 0.05) on these characteristics. The native apple 'Dirras-e Mashhad' showed higher pH value than 'Wealthy' under the combined treatment (ENA+1-MCP). Genetic source revealed significant difference through lower 'Wealthy' storability. Ethylene emission increased to 53.64 ppm/Kg·hr after 5th month, which resulted in significant difference at p > 0.01 level related to the initial value of 3.26 ppm/Kg·hr. The combined treatment (ENA+1-MCP) affected significantly (p < 0.05) most of the fruit characteristics in both of the cultivars. The treatments demonstrated different results by cultivar.
基金We express our thanks to Shahrekord University for providing the financial support under the grant of 93GCU2M1932。
文摘Biochar as an organic amendment improves soil attributes,with a potentially significant effect on soil chemical fertility and quality.The main objective of this study was to quantify the effect of biochar addition on nutrients,carbon sequestra-tion and microbial activity and understand the mechanisms of controlling biochar effects in calcareous soils.Maize residue biochars produced at 200,400 and 600℃ were added at 5 and 10 g kg^(−1)rates to sandy loam and clayey texture calcareous soils.The soil properties measured were pH and electrical conductivity(EC),plant-available potassium(K)and available phosphorus(P),total nitrogen(TN),C sequestration;and the fluorescein diacetate(FDA)hydrolysis activity.Addition of raw material and biochars increased pH(0.15-0.46 units),EC(0.14-0.38 dS m^(−1)),TN(63-120%),K(12-41%)and FDA activity(27-280%),but tended to decrease plant-available P(23-86%).Increasing pyrolysis temperature increased soil C pool index(CPI),but decreased the FDA and the changes depended largely upon the application rate and soil texture.The positive effects of biochar addition and its pyrolysis temperature on soil C sequestration potential were more pronounced at high than low application rate and in sandy loam than clayey soils.Nevertheless,the effect of biochar addition and pyrolysis temperature on the FDA activity was higher at high than low application rates,but lower in sandy loam than clayey soils.Although biochar application may successfully improve soil processes and attributes and have a high potential for C seques-tration,its effects are controlled by soil texture,pyrolysis temperature and application rate.
