Effects of tree species diversity and stand structure on carbon stocks of homestead forests in Maheshkhali Island, Southern Bangladesh.

BACKGROUND: The homestead forests of Bangladesh occupy 0.27 million hectares (10% of the total forested area) and have potential to store carbon (C) and conserve biodiversity. Small scale forestry practices, however, are lacking reliable estimation of C stocks and tree species diversity. This may hinder successful implementation of REDD + and similar mechanisms as they concentrate on large-scale forests. This study aimed to estimate the above- and below-ground carbon stocks in homestead forests of Maheshkhali Island in Bangladesh and how tree species diversity and stand structural variation affect these C stocks. We randomly surveyed a total of 239 homestead forests in the hillside, beachside, and inland in 2019. RESULTS: Tree biomass C stocks were 48-67% greater in the inland and hillside forests than in the beachside due to significantly greater stand density, basal area, tree diameter. In total we found 52 tree species, but most abundant species in the inland and hillside forests, Mangifera indica, Samanea saman, and Artocarpus heterophyllus stored the most C in tree biomass. Greater tree species richness and diversity index in the inland and hillside forests indicated greater above- and below-ground tree biomass C stocks. An increase in tree species richness and diversity index by one unit was found to increase the tree biomass C stock by 22 and 30 Mg C ha-1, respectively. The total soil C stock was also affected by tree species diversity, stand density, and their interaction with soil properties. Total soil C stocks were greatest (51 Mg ha-1) in the inland forests, having also the greatest stand density and tree species richness. C stock in soil surface was greatest in the hillside forests due to the greatest litterfall, but the average share of litterfall from the total biomass C was only 0.1%. CONCLUSIONS: Homestead forest ecosystems could store 96 Mg C ha-1 in total, which can contribute to climate change mitigation by generating C credits for small-scale homestead forests owners. Above- and below-ground tree biomass C stocks were found to correlate with tree species diversity, which may also contribute to biodiversity conservation in the REDD + in Bangladesh and countries alike.

Nitrogen use efficiency and critical leaf N concentration of Aloe vera in urea and diammonium phosphate amended soil.

Aloe vera L. is widely cultivated in many countries due to its importance as an all-purpose herbal or medicinal plant. The growth and yield of this plant can be enhanced by application of fertilizer. It is expected that a higher and balanced nutrient supply will result in higher crop production maintaining soil health, which is possible when the applied fertilizers are done in way that is efficient. So, there is a need to understand the amount of applied and type of fertilizer that will give the best output for farmers and to formulate economical market products. This study was conducted to investigate the effect of N fertilizer on leaf yield, its uptake and requirement, critical concentration, use efficiency and economics of Aloe vera L. Plants were grown at six levels of N: 0, 40, 80, 100, 150 and 200 kg ha-1 from urea and diammonium phosphate (DAP) following completely randomized design with three replicates under field condition. The highest values of yield and yield attributes and profit based on benefit cost ratio (3.81 for urea and 2.91 for DAP) were obtained with 150 kg N ha-1 (urea) and 100 kg N ha-1 (DAP). Leaf biomass yield increased by 18-128 % in urea-N and 30-139 % in DAP-N fertilized plant over control while DAP > urea by 7.59 %. Sucker production (mean number) was urea-N (4.95 Plant-1) > DAP-N (2.28 Plant-1). Both gel and leaf N concentration and uptake was highest at 200 kg ha-1 for both sources. For 80 % leaf biomass yield, minimum requirement of N was ca 74.90 (urea) and 89.60 kg ha-1 (DAP). Growth and yield parameters to N application exhibited significant and positive correlations. Critical leaf N concentration was ca 0.88% (DAP) and 0.90% (urea) while mean and maximum NUE was 34% and 64 % (urea) and 43% and 69% (DAP), respectively. Farmers can be advised to apply N at the rate of 150 kg ha-1 from urea for producing economically higher yield and better-quality A. vera leaves.

Sulphur fertilization enhanced yield, its uptake, use efficiency and economic returns of Aloe vera L.

Sulphur plays a vital role in the formation and biosynthesis of protein, chlorophyll, and few amino acids. To investigate the effect of sulphur fertilizer on leaf biomass yield, critical sulphur concentration, sulphur requirement and uptake by Aloe vera L., a pot experiment was carried out following completely randomized design with six levels of sulphur viz., 0, 15, 30, 45, 60 and 80 kg ha-1 with three replications. The results of the study revealed that the growth attributes, leaf and gel yield, and sulphur uptake significantly improved with sulphur application and the best results were obtained from the application of 45 kg sulphur ha-1. On average, addition of sulphur enhanced the leaf biomass yield by 47.5% and sulphur use efficiency by 38% compared to control. The effect of sulphur on the growth parameters and their significant and positive correlations with yield signifies the importance of sulphur on the yield and quality of A. vera. The calculated minimum amount of sulphur for 80% leaf biomass production was 21.1 kg sulphur ha-1 with a critical leaf sulphur concentration of 0.23% in A. vera. Moreover, sulphur addition to soil substantially enhanced the economic returns of A. vera. Therefore, addition of 45 kg sulphur ha-1 could be a better option for obtaining higher yield and economic return of A. vera.

A Comparative Study on Knowledge about Reproductive Health among Urban and Rural Women of Bangladesh.

OBJECTIVE: To compare the level of knowledge on reproductive health among urban and rural women of selected area of Bangladesh. MATERIALS AND METHODS: A descriptive cross-sectional study was undertaken among 200 women selected purposively from different rural and urban areas of Bangladesh. Data were collected using a semi-structured interviewer-administered questionnaire by face to face interview. Knowledge level was analyzed according to poor, moderate and good knowledge by pre-defined knowledge scoring. RESULTS: Mean age of the respondents was 26 years and majority (66%) of them was housewives. Most of them (61%) had completed their primary level education. Around three-fourth of them belongs to lower-middle income group. Overall level of reproductive health knowledge was more evident among urban reproductive aged women than rural counterparts (p < 0.001). Moreover, significant knowledge gap was found regarding family planning (p = 0.005), care during pregnancy (p < 0.001), safe motherhood (p = 0.002), newborn care (p = 0.009) and birth spacing (p <0.001) between urban and rural women. Family members were the major source of information in both groups. CONCLUSION: A wide knowledge gap was found between Bangladeshi urban and rural respondents regarding their reproductive behaviors. Government and concerned organizations should promote and strengthen various health education programs to focus on reproductive health, especially among reproductive aged women in rural area.