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Winter wheat water productivity evaluated by the developed remote sensing evapotranspiration model in Hebei Plain, China.

Zhang S, Zhao H, Lei H, Shao H, Liu T - ScientificWorldJournal (2015)

Bottom Line: The spatial variations indicated that the major distribution of ETa ranged from 350 to 450 mm, which trended downward within the study area from west to east.In the study period, the winter wheat CWP was mainly distributed between 0.29 and 1.67 kg/m(3).In space, the CWP was higher in the west than in the east.

View Article: PubMed Central - PubMed

Affiliation: Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot 010018, China.

ABSTRACT
Agricultural water is the main reason for the rapid decline of the NCP groundwater levels. It is of vital importance for the NCP sustainable agricultural development to master the ETa and its CWP. In this paper, the EBEM model was developed according to the theory of energy balance. From 2001 to 2006, the winter wheat ETa and CWP were estimated, and the spatial and temporal variations and their influencing factors were studied in the Hebei Plain. The results indicate that the EBEM model performed well by applying MODIS data to estimate the daily net radiation and ETa. For the daytime net radiation, the relative error between the estimation and the measurement amounted to 8.2% and the SEE was 0.82 MJ m(-2)/day. The average ETa deviation between the estimates and the measures amounted to 0.86 mm daily, and the SE was 1.2 mm. The spatial variations indicated that the major distribution of ETa ranged from 350 to 450 mm, which trended downward within the study area from west to east. In the study period, the winter wheat CWP was mainly distributed between 0.29 and 1.67 kg/m(3). In space, the CWP was higher in the west than in the east.

No MeSH data available.


The relationship between yield and CWP (a) and the relationship between ETa and CWP (b).
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Related In: Results  -  Collection


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fig7: The relationship between yield and CWP (a) and the relationship between ETa and CWP (b).

Mentions: Through studying the relationship between the yield and the ETa with the average CWP in many years, it can be concluded that the CWP was positively correlated with the yield, with an R2 of 0.9, as shown in Figure 7. Although the relationship was more complex between the CWP and the ETa, it was nearly a cosine curve. In the eastern region, the ETa was low, while the decrease of yields of the regions was lower than the decrease of ETa. Thus, CWP was maintained at a relatively high level. In contrast, both the ETa and yield increased, whereas the CWP declined. In the middle region, the magnitude of the increasing yield was greater than the ETa and the CWP also increased. When the range of the ETa was 410 to 430 mm, the CWP was maximized. With a further increase in the ETa, the yield began to lower the rate of increase and the CWP also declined.


Winter wheat water productivity evaluated by the developed remote sensing evapotranspiration model in Hebei Plain, China.

Zhang S, Zhao H, Lei H, Shao H, Liu T - ScientificWorldJournal (2015)

The relationship between yield and CWP (a) and the relationship between ETa and CWP (b).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4302380&req=5

fig7: The relationship between yield and CWP (a) and the relationship between ETa and CWP (b).
Mentions: Through studying the relationship between the yield and the ETa with the average CWP in many years, it can be concluded that the CWP was positively correlated with the yield, with an R2 of 0.9, as shown in Figure 7. Although the relationship was more complex between the CWP and the ETa, it was nearly a cosine curve. In the eastern region, the ETa was low, while the decrease of yields of the regions was lower than the decrease of ETa. Thus, CWP was maintained at a relatively high level. In contrast, both the ETa and yield increased, whereas the CWP declined. In the middle region, the magnitude of the increasing yield was greater than the ETa and the CWP also increased. When the range of the ETa was 410 to 430 mm, the CWP was maximized. With a further increase in the ETa, the yield began to lower the rate of increase and the CWP also declined.

Bottom Line: The spatial variations indicated that the major distribution of ETa ranged from 350 to 450 mm, which trended downward within the study area from west to east.In the study period, the winter wheat CWP was mainly distributed between 0.29 and 1.67 kg/m(3).In space, the CWP was higher in the west than in the east.

View Article: PubMed Central - PubMed

Affiliation: Water Conservancy and Civil Engineering College, Inner Mongolia Agricultural University, Hohhot 010018, China.

ABSTRACT
Agricultural water is the main reason for the rapid decline of the NCP groundwater levels. It is of vital importance for the NCP sustainable agricultural development to master the ETa and its CWP. In this paper, the EBEM model was developed according to the theory of energy balance. From 2001 to 2006, the winter wheat ETa and CWP were estimated, and the spatial and temporal variations and their influencing factors were studied in the Hebei Plain. The results indicate that the EBEM model performed well by applying MODIS data to estimate the daily net radiation and ETa. For the daytime net radiation, the relative error between the estimation and the measurement amounted to 8.2% and the SEE was 0.82 MJ m(-2)/day. The average ETa deviation between the estimates and the measures amounted to 0.86 mm daily, and the SE was 1.2 mm. The spatial variations indicated that the major distribution of ETa ranged from 350 to 450 mm, which trended downward within the study area from west to east. In the study period, the winter wheat CWP was mainly distributed between 0.29 and 1.67 kg/m(3). In space, the CWP was higher in the west than in the east.

No MeSH data available.