Poorly crystalline iron and aluminium oxides contribute to the carbon saturation and sorption of dissolved organic carbon in the soil     

Tania Khandakar  Chris Guppy  Sheikh M. F. Rabbi  Heiko Daniel 《Soil Use and Management》2021,37(1):120-125

Soil carbon (C) saturation implies an upper limit to a soil's capacity to store C depending on the contents of silt + clay and poorly crystalline Fe and Al oxides. We hypothesized that the poorly crystalline Fe and Al oxides in silt + clay fraction increased the C saturation and thus reduced the capacity of the soil to sorb additional C input. To test the hypothesis, we studied the sorption of dissolved organic carbon (DOC) on silt + clay fractions (<53 µm) of highly weathered oxic soils, collected from three different land uses (i.e., improved pasture, cropping and forest). Soils with high carbon saturation desorbed 38% more C than soils with low C saturation upon addition of DOC, whereas adsorption of DOC was only observed at higher concentration (>15 g kg^?1). While high Al oxide concentration significantly increased both the saturation and desorption of DOC, the high Fe oxide concentration significantly increased the desorption of DOC, supporting the proposition that both oxides have influence on the DOC sorption in soil. Our findings provide a new insight into the chemical control of stabilization and destabilization of DOC in soil.  相似文献   

Management strategies for forage rape (Brassica napus L. cv Goliath): Impact on dry-matter yield,plant reserves,morphology and nutritive value     

M. R. Islam  Sergio C Garcia  Ajantha Horadagoda  Kendra L. Kerrisk  Cameron E. F. Clark 《Grass and Forage Science》2020,75(1):96-110

Limited information is available on the grazing management principles of forage rape (Brassica napus L.), particularly in relation to grazing height and intensity and the impact of these on dry-matter (DM) yield and nutritive value. A glasshouse study was undertaken to investigate the effect of three defoliation heights (plant height at harvest; DH: 40, 70 and 90 cm; L, M and H DH respectively) and three defoliation intensities (height at which plants were cut; DI: 5, 20 and 35 cm of residual height; H, M and L DI respectively) on forage rape (cv Goliath) yield and nutritive value at two harvests (harvest 1, H1 and harvest 2, H2), and the impact of nitrogen (N) and water soluble carbohydrate (WSC) reserves on regrowth. Increasing DH from L to H increased estimated total DM yield (H1 plus H2) from 0.5 to 4.6 t DM/ha but DI did not affect yield. Dry-matter yield was optimized at 90 cm DH, but greater nutritive value was achieved by harvesting at lower levels of DH. Despite high in vitro DM digestibility (IVDMD; 852–889 g/kg), harvesting at 90 cm DH could not meet the protein requirement of lactating dairy cows and harvesting at lower levels risks nitrate poisoning. Our results indicate the optimum DH may be between 70 and 90 cm DH, and 20 and 35 cm DI, which requires further studies.  相似文献   

Postharvest quality response of strawberries with aloe vera coating during refrigerated storage     

T. A. A. Nasrin  M. A. Rahman  M. A. Hossain  M. N. Islam  M. S. Arfin 《The Journal of Horticultural Science and Biotechnology》2017,92(6):598-605

Strawberries (Fragaria × ananassa Duch.) were coated either with chitosan (1, 1.5, and 2% solution, w/v) or aloe vera (AV) gel and the coatings were air dried. Coated strawberries were put in a polypropylene box and stored in refrigerator (6 ± 1°C and 50 ± 5% relative humidity. The success of coating in retaining the postharvest quality of the strawberries was evaluated by determining respiration rate, firmness, weight loss, external colour change, ascorbic acid content, total soluble solids, acidity, pH, microbial decay and sensory quality. The incidence of microbial rot started on day-6 in uncoated and 1% chitosan coated strawberries. Strawberries coated with 1.5 and 2% chitosan were affected by microbial decay on day-9 of storage. On the other hand, rot incidence was initiated in AV gel coated strawberries on day-15 of storage. Aloe vera gel or chitosan coating reduced respiration rate, weight loss, and microbial decay and preserved firmness, ascorbic acid content, and other quality parameters, thus delaying ripening and the progress of fruit decay due to senescence or microbial attack. Furthermore, AV gel delayed the changes in external colour and retained all other postharvest quality of strawberries compared to chitosan coated or uncoated ones throughout the storage.  相似文献   

Effects of ages of plug transplants and planting depths on the growth and yield of sweetpotato     

A.F.M. Saiful Islam  Chieri KubotaMichiko Takagaki  Toyoki Kozai 《Scientia Horticulturae》2006

Sweetpotato [Ipomoea batatas (L.) Lam. cv. Beniazuma] plug transplants produced from single node leafy cuttings under artificial light in a closed-type growth chamber were planted with roots and substrate of 11- and 15-day old (ca. two to three unfolded leaves with 0.08 m shoot length and three to four unfolded leaves with 0.11 m shoot length, respectively). The plug transplants of both the 11- and 15-day old were planted with one and three nodes depth (ca. 4 and 25 mm deep, respectively) inside the soil ridges (called one- and three-node depth, respectively, hereafter). The conventional vine cuttings (ca. 0.3 m long with seven to eight unfolded leaves) without roots were planted as Control treatment to compare the growth and yield of sweetpotato with each of the treatments of plug transplant. The main objectives of the study were to see the effects of ages of plug transplants and depths of planting for greater growth and yield of sweetpotato in the field. The yield of storage roots 115 days after planting in the field was 33 t ha⁻¹ when using 15-day old plug transplants planted with three-node depth and was 10 t ha⁻¹ greater than that in the Control. The mean storage root length was about 259 mm when using 11-day old plug transplants planted with three-node depth and was 33 mm greater than that in the Control. The mean diameter of storage roots was 70 mm when using 11- and 15-day old plug transplants planted with one-node depth and was 21 mm greater than that in the Control. The plug transplants planted either 11- or 15-day old showed greater overall performances than those of the conventional cuttings. The plug transplants planted with three-node depth showed greater performances than did the plug transplants planted with one-node depth.  相似文献   

银合欢落叶层对苗圃生长的森林一农田作物的他感作用(英文)     

Romel Ahmed  A. T. M. Rafiqul Hoque  Mohammed Kamal Hossain 《林业研究》2008,19(4)

利用随机区组试验评估了孟加拉国吉大港大学苗圃内的银合欢落叶对森林作物种白格、黄金檀和农田作物种长豇豆、鹰嘴豆和木豆的他感作用。结果表明,凋落叶诱导抑制作物的萌发和生长,该抑制作用依赖于萃取物浓度、凋落物及受体物种类型。萃取物浓度越高则他感作用越强。受体植物的生长响应随应用的凋落叶而变化。低浓度(10g·m-2)凋落叶对农田作物嫩芽生长有促进作用,而其他浓度的凋落叶则呈现明显的抑制作用,施用的凋落叶浓度越大抑制作用也越大。但是不同处理所表现出的抑制趋势并不均一,根系生长受到的影响大于嫩芽。图3表4参34。  相似文献   

Comparison of structural diversity of tree-crop associations in Peripheral and Buffer zones of Gachabari Sal forest area, Bangladesh     

M. M. Rahman  H. Vacik  F. Begum  A. Nishad  K. K. Islam 《林业研究》2007,18(1):23-26

The structural diversity of different tree-crop associations were studied at Gachabari Sal forest area of Madhupur Garh on Buffer and Peripheral Zone during 2006. The total density, basal area of trees in the Buffer and Peripheral Zone were 155.5 trees·hm^-2, 795.4 trees·hm^-2 and 3.9 m^2·hm^-2, 5.8 m^2·hm^-2, respectively. No regeneration and natural trees were found in Peripheral Zone and the Zone is totally occupied by exotic species where the Buffer Zone comprised of both natural and exotic trees. The Peripheral Zone belonged to younger and smaller trees whereas the Buffer Zone belonged to mixture of smaller, taller, younger and mature trees simultaneously. For the practicing of different agroforestry systems both Zones have lost their original characters of Sal forest.  相似文献   

Antimicrobial and cytotoxic constituents from the seeds of Annona squamosa   总被引：1，自引：0，他引：1  

Mukhlesur Rahman M  Parvin S  Ekramul Haque M  Ekramul Islam M  Mosaddik MA 《Fitoterapia》2005,76(5):484-489

Annotemoyin-1, Annotemoyin-2, squamocin and cholesteryl glucopyranoside were isolated from the seeds of Annona squamosa. These compounds and plant extracts showed remarkable antimicrobial and cytotoxic activities.  相似文献   

People’s attitude and use of forestland: Co-evolution of forest administration in Bangladesh     

Mohammad Ali  M. Alamgir Kabir  A. T. M. Rafiqul Hoque 《Small-Scale Forestry》2006,5(2):271-286

This paper explores the influence over time of past policies on people’s attitudes towards the use of forestland in Bangladesh. The discourses of the attitudes of people were captured from the observed social tradition towards forest resources. Forests were reserved systematically and solely through the Forest Department. The conservation processes were not participatory, and rights and tenure were strictly controlled. People were socially excluded and alienated from the forest, and the socio-political factors stimulated negative attitudes among people. Forests were considered to be government property, and therefore managing forests was the responsibility of the government. People only used forest resources to meet their own requirements, either with formal permission or illegally. This situation continued even after the independence of Bangladesh in 1971. As a result, the forests of Bangladesh have been degraded heavily in recent decades.  相似文献   

Does actor power impede outcomes in participatory agroforestry approach? Evidence from Sal forests area,Bangladesh     

K. K. Islam  S. Jose  Masakazu Tani  Kimihiko Hyakumura  Max Krott  Noriko Sato 《Agroforestry Systems》2015,89(5):885-899

  相似文献   

Heterotrophic and autotrophic nitrification in two acid pasture soils   总被引：1，自引：0，他引：1  

A. Islam  R.E. White 《Soil biology & biochemistry》2007,39(4):972-975

Laboratory incubation experiments, using ¹⁵N-labeling techniques and simple analytical models, were conducted to measure heterotrophic and autotrophic nitrification rates in two acid soils (pH 4.8-5.3; 1/5 in H₂O) with high organic carbon contents (6.2-6.8% in top 5 cm soil). The soils were from pastures located near Maindample and Ruffy in the Northeast Victoria, Australia. Gross rates of N mineralization, nitrification and immobilization were measured. The gross rates of autotrophic nitrification were 0.157 and 0.119 μg N g⁻¹ h⁻¹ and heterotrophic nitrification rates were 0.036 and 0.009 μg N g⁻¹ h⁻¹ for the Maindample and Ruffy soils, respectively. Heterotrophic nitrification accounted for 19% and 7% of the total nitrification in the Maindample and Ruffy soils, respectively. The heterotrophic nitrifiers used organic N compounds and no as the substrate for nitrification.  相似文献