Land Degradation in South Africa – A Degradation Index Derived from 10 Years of Net Primary Production Data

2015 ◽  
pp. 247-267 ◽  
Author(s):  
Markus Niklaus ◽  
Christina Eisfelder ◽  
Ursula Gessner ◽  
Stefan Dech
Keyword(s):  
South Africa ◽  
Primary Production ◽  
Land Degradation ◽  
Net Primary Production ◽  
Production Data ◽  
Degradation Index

scholarly journals On the accuracy of official Chinese crop production data: Evidence from biophysical indexes of net primary production

2020 ◽  
Vol 117 (41) ◽  
pp. 25434-25444 ◽  
Author(s):  
Gengyuan Liu ◽  
Xueqi Wang ◽  
Giovanni Baiocchi ◽  
Marco Casazza ◽  
Fanxin Meng ◽  
...  
Keyword(s):  
Primary Production ◽  
Data Quality ◽  
Crop Production ◽  
Net Primary Production ◽  
Production Data ◽  
Physical Factors ◽  
National Statistics ◽  
Rapid Economic Growth ◽  
Self Sufficiency ◽  
Economic Statistics

With rapid economic growth and urbanization, self-sufficiency in crop production has become central to China’s agriculture policy. Accurate crop production statistics are essential for research, monitoring, and planning. Although researchers agree that China’s statistical authority has considerably modernized over time, China’s economic statistics have still been viewed as unreliable and often overstated to meet growth targets at different administrative levels. Recent increases in crop production reported by national statistics have also come under increasing scrutiny. This paper investigates crop production data quality from a planetary boundary perspective—comparing net primary production (NPP) harvested obtained from national statistics with satellite-driven NPP estimates that are supported by detailed observation of land cover, combined with observations on physical factors that limit plant growth. This approach provides a powerful means to check the plausibility of China’s grain production statistics at different administrative levels that can generate insights about their discrepancies and can contribute to improved crop production measurements. We find some evidence of potential misreporting problems from the lower administration level where the risk of manipulation of statistics is higher. We also find problems from provincial-level major grain producers. These values can also affect the national totals. Although the numbers are affected by large uncertainties, we find that improving the spatial resolution of key agricultural parameters can greatly improve the reliability of the indicator that in turn can help improve data quality. More reliable production data will be vital for relevant research and provide better insights into food security problems, the carbon cycle, and sustainable development.

scholarly journals Degradation of net primary production in a semiarid rangeland

2016 ◽  
Vol 13 (16) ◽  
pp. 4721-4734 ◽  
Author(s):  
Hasan Jackson ◽  
Stephen D. Prince
Keyword(s):  
Primary Production ◽  
Land Degradation ◽  
Land Surface ◽  
Net Primary Production ◽  
Small Areas ◽  
Small Fields ◽  
The Difference ◽  
Vegetation Models ◽  
Annual Reduction ◽  
Global Vegetation

Abstract. Anthropogenic land degradation affects many biogeophysical processes, including reductions of net primary production (NPP). Degradation occurs at scales from small fields to continental and global. While measurement and monitoring of NPP in small areas is routine in some studies, for scales larger than 1 km2, and certainly global, there is no regular monitoring and certainly no attempt to measure degradation. Quantitative and repeatable techniques to assess the extent of deleterious effects and monitor changes are needed to evaluate its effects on, for example, economic yields of primary products such as crops, lumber, and forage, and as a measure of land surface properties which are currently missing from dynamic global vegetation models, assessments of carbon sequestration, and land surface models of heat, water, and carbon exchanges. This study employed the local NPP scaling (LNS) approach to identify patterns of anthropogenic degradation of NPP in the Burdekin Dry Tropics (BDT) region of Queensland, Australia, from 2000 to 2013. The method starts with land classification based on the environmental factors presumed to control (NPP) to group pixels having similar potential NPP. Then, satellite remotely sensing data were used to compare actual NPP with its potential. The difference in units of mass of carbon and percentage loss were the measure of degradation. The entire BDT (7.45  ×  106 km2) was investigated at a spatial resolution of 250  ×  250 m. The average annual reduction in NPP due to anthropogenic land degradation in the entire BDT was −2.14 MgC m−2 yr−1, or 17 % of the non-degraded potential, and the total reduction was −214 MgC yr−1. Extreme average annual losses of 524.8 gC m−2 yr−1 were detected. Approximately 20 % of the BDT was classified as “degraded”. Varying severities and rates of degradation were found among the river basins, of which the Belyando and Suttor were highest. Interannual, negative trends in reductions of NPP occurred in 7 % of the entire region, indicating ongoing degradation. There was evidence of areas that were in a permanently degraded condition. The findings provide strong evidence and quantitative data for reductions in NPP related to anthropogenic land degradation in the BDT.

scholarly journals Degradation of net primary production in a semi-arid rangeland

2016 ◽  
Author(s):  
H. Jackson ◽  
S. D. Prince
Keyword(s):  
Primary Production ◽  
Land Degradation ◽  
Land Surface ◽  
Net Primary Production ◽  
Small Areas ◽  
Small Fields ◽  
The Difference ◽  
Vegetation Models ◽  
Annual Reduction ◽  
Global Vegetation

Abstract. Anthropogenic land degradation affects many biogeophysical processes including reductions of net primary production (NPP). Degradation occurs at scales from small fields to continental and global. While measurement and monitoring of NPP in small areas is routine in some studies, for scales larger than 1 km2, and certainly global, there is no regular monitoring and certainly no attempt to measure degradation. Quantitative and repeatable techniques to assess the extent of deleterious effects and monitor changes are needed to evaluate its effects on, for example, economic yields of primary products such as crops, lumber and forage, and as a measure of land surface properties which are currently missing from dynamic global vegetation models, assessments of carbon sequestration and land surface models of heat, water, and carbon exchanges. This study employed the Local NPP Scaling (LNS) approach to identify patterns of anthropogenic degradation of NPP in the Burdekin Dry Tropics (BDT) region of Queensland, Australia from 2000 to 2013. The method starts with land classification based on the environmental factors presumed to control (NPP) to group pixels having similar potential NPP. Then, satellite remotely sensing data were used to compare actual NPP with its potential. The difference in units of mass of carbon and percentage loss was the measure of degradation. The method is limited spatially only by the capacity to classify the land. The entire BDT (7.45x106 km2) was investigated at a spatial resolution of 250x250 m. The average annual reduction in NPP due to anthropogenic land degradation in the entire BDT was −2.14 MgC m−2 year−1 or 17 % of the non-degraded potential, and the total reduction was −214 MgC year−1. Extreme average annual losses of 524.8 gC m−2 year−1 were detected. Approximately 20 % of the BDT was classified as ‘degraded’. Varying severities and rates of degradation were found among the river basins, of which the Belyando and Suttor were highest. Inter-annual, negative trends in reductions of NPP, occurred in 7 % of the entire region, indicating on-going degradation. There was evidence of areas that were in a permanently degraded condition. The findings provide strong evidence and quantitative data for reductions in NPP related to anthropogenic land degradation in the BDT.

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