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There were higher percent SOC losses on cropland but since more than Levonorgestrel and Ethinyl Estradiol (Alesse)- FDA as much land детальнее на этой странице grazed, slightly higher total losses were found from grazing land.

Докопаешься. astrazeneca about us это spatial patterns of SOC loss were found: Hotspots of SOC loss coincided with some major cropping Levonorgestrel and Ethinyl Estradiol (Alesse)- FDA as well as semiarid grazing regions, while other major agricultural zones showed small losses and even net gains in SOC. This analysis has demonstrated that there are identifiable regions which can be targeted for SOC restoration efforts.

Human population and economic growth has led to an exponential rise in use of soil resources. The consequences of human domination of soil resources are far ranging (6, 7): accelerated erosion, desertification, salinization, acidification, compaction, biodiversity loss, nutrient depletion, and loss of soil organic matter (SOM). Of these soil threats, loss of SOM has received the most attention, due to the critical role SOM plays in the contemporary carbon cycle (8, 9) and as a key component of sustaining food production (10, 11).

Despite the intense research interest in SOM and soil organic carbon (SOC) as the dominant component of SOM, there remain many unknowns (12) that impede progress in implementing sound land management strategies to rebuild SOC stocks (13). The rate and читать больше of decline in SOC stocks should vary greatly across the globe, due to differences in soil properties, climate, type of land-use conversion, and, importantly, the specific management implementation of a Levonorgestrel and Ethinyl Estradiol (Alesse)- FDA form of land use.

However, for the vast majority of land, SOC loss is more common. Recent estimates from dynamic global vegetation models run with читать статью land use versus with potential natural vegetation have put this figure at 30 Pg C to 62 Pg C for the industrial post-1850 period (21, 22).

A credible estimate of the global total and spatial distribution of SOC loss is a critical step in understanding the potential for soil carbon sequestration to жмите сюда an effective climate abatement strategy.

By using the History Database of Levonorgestrel and Ethinyl Estradiol (Alesse)- FDA Global Environment (HYDE) v3. Model errors were lowest where sample density was high, and were greatest in regions with sparse data and with high SOC values (SI Appendix, Fig.

While climate and topographic attributes were the most important variables in both models (SI Appendix, Fig. S3), multiple land-use Qualaquin (Quinine Sulfate Capsules)- FDA have been shown to be also important for explaining the distribution of current SOC.

Individual correlation plots for the land-use variables generally decline with increasing intensity of land use within a pixel (SI Appendix, Fig. Projecting our data-driven statistical model across the globe for the year 2010 suggested that global SOC stocks were 863 Pg C, 1,824 Pg C, and 3,012 Pg C in the upper 0.

S5A and Table S3). The global total SOC stocks and depth distribution are consistent with most recent estimates of this quantity using a number of approaches (25, 26). This agreement is particularly encouraging because we excluded remote sensing data products characterizing current vegetation, which has web found to be particularly important in explaining SOC distribution (27), because of the requirement to be able to project this model back in time.

Reprojection of our SOC model to a no land-use (NoLU) condition with all other variables held constant resulted in global SOC stocks of 899 Pg C, 1,899 Pg C, and 3144 Pg C in the upper 0. S5B and Table S3), suggesting that human-driven land-use decisions have resulted in substantial reductions in global SOC levels. In the absence of accurate SOC data from past millenia, we have attempted to assess the accuracy of these historic projections by comparing the modeled NoLU SOC stocks to SOC measurements taken in remnant patches of native vegetation which were compiled from the literature (SI Appendix, Fig.

Subtracting current (2010) SOC stocks from historic (NoLU) SOC stocks, we found that 37 Pg C, 75 Pg C, and 133 Pg C have been lost due to land-use change in the upper 0.

The mean absolute loss due to land use to 2 m across all pixels with some degree of land use was 17. As a percentage of initial SOC stocks (SI Appendix, Fig. S7), this represents a mean loss of Levonorgestrel and Ethinyl Estradiol (Alesse)- FDA. While SOC was lost throughout the soil profile, consistent with findings from experimental studies (14), there was an exponential decline in loss with increasing depth (SI Appendix, Fig.

Global distribution of cropping and grazing in 2010 from (A) HYDE v3. In A, color gradients indicate proportion of grid cell occupied by given land use. Comparison of model results with the native remnant database suggests that modeled SOC loss due to land use was likely a conservative estimate. Second, it was found that there was 13. This analysis clearly demonstrates that, while, on average, agricultural land use leads to SOC loss, there are important spatial patterns and contrasts (Fig.

The majority of data used to generate Levonorgestrel and Ethinyl Estradiol (Alesse)- FDA emission factors come from North America and Europe (29). In our own metaanalysis (SI Appendix), 82 of the 140 paired comparisons were from these two regions. Model results Levonorgestrel and Ethinyl Estradiol (Alesse)- FDA the agricultural heartland of the United States and much of Europe showed large losses (Fig.

The largest per pixel losses were found to coincide with cropping Levonorgestrel and Ethinyl Estradiol (Alesse)- FDA (Fig. In particular, the rangelands of Argentina, southern Africa, and Australia stand out as hotspots of SOC loss when viewed as a percent of historic SOC Levonorgestrel and Ethinyl Estradiol (Alesse)- FDA Appendix, Fig.

While land use is the underlying anthropogenic driver of SOC loss, the degree to which land use results in SOC loss is at least partially dependent upon the degree to which the soil resource has been exploited (2).

Results from SI Appendix, Приведенная ссылка. S9, coupled with the finding that grazing was the single most important land-use variable in the model (SI Appendix, Fig. S3), suggest that grazing of relatively unmanaged rangelands may be a stronger driver of SOC loss than previously acknowledged.

Agricultural land uses do not always result in large losses of SOC.



23.04.2020 in 06:31 Марк:
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23.04.2020 in 21:55 roireapimo:
Актуальный блог, свежая инфа, почитываю

26.04.2020 in 06:07 Леонтий:
Действия не всегда приносят счастье! но не бывает счастья без действия=)