Abstract
Turnera ulmifolia
L. is a beneficial plant mostly planted in the oil palm plantation as it is easily adapting to a variety of environmental conditions, mainly to conserve beneficial insects. ...Nevertheless, the planted plants were left without proper maintenance and less study was conducted on biological control agent conservation. Thus, this study aimed to examine the effect of NPK, silicon fertilizer and their combination on the growth and development of
T. ulmifolia
. Treatments including T0 Control (No fertilization application), T1 (0.2 g NPK), T2 (0.2 g NPK+3.9 g silicon), T3 (0.2 g NPK+4.9 g silicon), T4 (3.9 g silicon) and T5 (4.9 g silicon) were applied 20 days after transplanting at monthly interval for three months. Results revealed the greatest height and number of branches were observed in T1. Overall, the chlorophyll content ranged between 27.92 to 31.18 SPAD values. All treatments gave the same effect on morphometric measurements on the first 30 days of observation. After 60 days, the greatest value for broad tube width and length was observed in T4 which differs significantly from other treatments. The application of fertilizer in T1, T2 and T3 showed 10-20% promotive effects over the control in the amount of nectar produced per flower. For all three observation periods, a similar trend was recorded for the total sugar concentration in flowers, where the mean total sugar content was between 1.37 and 1.61 mg per flower.
We mapped tidal wetland gross primary production (GPP) with unprecedented detail for multiple wetland types across the continental United States (CONUS) at 16‐day intervals for the years 2000–2019. ...To accomplish this task, we developed the spatially explicit Blue Carbon (BC) model, which combined tidal wetland cover and field‐based eddy covariance tower data into a single Bayesian framework, and used a super computer network and remote sensing imagery (Moderate Resolution Imaging Spectroradiometer Enhanced Vegetation Index). We found a strong fit between the BC model and eddy covariance data from 10 different towers (r2 = 0.83, p < 0.001, root‐mean‐square error = 1.22 g C/m2/day, average error was 7% with a mean bias of nearly zero). When compared with NASA's MOD17 GPP product, which uses a generalized terrestrial algorithm, the BC model reduced error by approximately half (MOD17 had r2 = 0.45, p < 0.001, root‐mean‐square error of 3.38 g C/m2/day, average error of 15%). The BC model also included mixed pixels in areas not covered by MOD17, which comprised approximately 16.8% of CONUS tidal wetland GPP. Results showed that across CONUS between 2000 and 2019, the average daily GPP per m2 was 4.32 ± 2.45 g C/m2/day. The total annual GPP for the CONUS was 39.65 ± 0.89 Tg C/year. GPP for the Gulf Coast was nearly double that of the Atlantic and Pacific Coasts combined. Louisiana alone accounted for 15.78 ± 0.75 Tg C/year, with its Atchafalaya/Vermillion Bay basin at 4.72 ± 0.14 Tg C/year. The BC model provides a robust platform for integrating data from disparate sources and exploring regional trends in GPP across tidal wetlands.
Key Points
We created the Blue Carbon (BC) model, which mapped the Gross Primary Production (GPP) of all tidal wetlands within the continental United States
The BC model provides maps of tidal wetland GPP at sub‐250 m scales and at 16‐day intervals for the years 2000‐2019
The average daily GPP per m2 was 4.32 ± 2.45 g C/m2/day, and the total annual GPP for the continental United States was 39.65 ± 0.89 Tg C/year
Abstract
Soil Organic Carbon (SOC) has long been known as an indicator of soil health. This study aims to estimate the amount of SOC at Takasago-UNIMAS Educational Forest, a post-construction site, ...for forest rehabilitation. Since 2018, rehabilitation approaches have been conducted in the UNIMAS campus to restore these land areas via enrichment planting. The estimation of SOC was conducted at three sites; Secondary Forest (SF), Enrichment Planting site (2018) (EP18) and Enrichment Planting site (2019) (EP19). In each study plot, soil samples from different depths were collected for further analysis. Our findings showed that the soils in SF portray the highest amount of Total Carbon and Nitrogen, suggesting that this site may not have been considerably affected due to the past land use. Moreover, the estimation of SOC in all sites indicated that SF shows the highest mean at 2007.0 g/m
2
at the soil depth of 0-30cm, followed by EP18 and EP19. From the estimation, it can be concluded that although the period of establishment in EP18 and EP19 may have contributed to the lower SOC as compared to SF, the SOC estimation from this study could be a value-added option in determining the state of soil recovery and, possibly, the effectiveness of enrichment planting for forest rehabilitation.
•NEE during neap tides was ~ 60% greater than during spring high tides•The effect of tidal flooding on NEE varied with the degree of plant inundation•The highest CO2 flux reductions were observed in ...early and peak growing seasons•Daytime CO2 flux was reduced 20-60% in the peak growing season due to tidal flooding
Salt marshes are highly productive ecosystems and yet we have only a preliminary understanding of how net ecosystem exchange varies on daily and seasonal time scales. We used the eddy-covariance method to examine the behaviour of the net ecosystem exchange as influenced by tidal flooding in daytime conditions in a coastal salt marsh dominated by Spartina alterniflora in Georgia, USA. Two different analyses both found that the net ecosystem exchange was ~ 60% greater during neap high tides than during spring high tides; the largest differences occurred early in the growing season. The effect of tidal flooding varied continuously with the degree to which plants were inundated versus emergent. The total monthly reduction (less negative) in daytime net ecosystem exchange due to flooding was 7-38% and 1-64% in 2014 and 2015 respectively. The highest CO2 flux reductions were observed early and during the peak growing season (February, March, April and May) and the lowest during the summer season in both years. Our findings suggest that daytime CO2 flux was reduced (less negative) 20-60% during the peak growing season due to tidal flooding. A better understanding of the impact of seasonal tidal flooding on net ecosystem exchange may allow more sophisticated predictions of how sea level rise will affect marsh function and survival over the coming century.
Changes in soil carbon (C) from forest to agriculture land in Mukah, Sarawak, and Simpang Renggam (SR) Johor were studied. The changes in labile C (CL) (Mukah, 0.7–43%; SR, 0.2–20%) were greater than ...changes in the total C (CT) (Mukah, 0.5–9%; SR, 0.3–7%) as compared to the forest. In Mukah, oil palm and pineapple ecosystems showed approximately 18% and 6% increases in CL at a soil depth of 0–15 cm, respectively, as compared to the forest, and thus had greater C management index (CMI) values. In the sago ecosystem, the decline in CL was approximately 26% at the soil depth of 0–15 cm as compared to the forest. In SR, oil palm and pineapple ecosystems showed approximately 0.2% and 19% decreases in CL, respectively, at soil depths of 0–15 cm, resulting in low CMI value. The CL and the CMI can be used to monitor the rate of changes in soil C for different land uses on peat.
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