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Cao X.,Northwest University, China | Wu P.,Northwest University, China | Wu P.,National Engineering Research Center for Water Saving Irrigation at Yangling | Wang Y.,Northwest University, China | And 3 more authors.
Paiguan Jixie Gongcheng Xuebao/Journal of Drainage and Irrigation Machinery Engineering | Year: 2012

In order to evaluate the water use efficiency in agriculture in China, the data relevant to the water used for crop production of 459 large irrigation districts in 31 provinces in the years of 1998, 2005 and 2010 were collected; then the values of Grain Irrigation Water Productivity (G) was calculated. The spatial autocorrelation analysis was carried out to study the spatial and temporal variation of G during 1998-2010. The results revealed that G is increased with year in every large irrigation district in all the provinces; meanwhile, the G for a representative year is 1.03 kg/m 3, the maximum one is 2.15 kg/m 3 in Henan and the minimum is 0.25 kg/m 3 in Hainan. There is a clear spatial clustering phenomenon, i.e. a higher G is in Huang-Huai-Hai region whilst a lower one is found in the south of China. The amplitudes of change in G in Jiangxi, Anhui and Chongqing are different from their neighbors, a localized effect is presented. The reasons for such spatial and temporal variation of G were elaborated.


Sun S.K.,Chinese Ministry of Water Resources | Sun S.K.,Northwest University, China | Sun S.K.,National Engineering Research Center for Water Saving Irrigation at Yangling | Sun S.K.,University of Chinese Academy of Sciences | And 8 more authors.
Water Resources Management | Year: 2013

The water footprint (WF) of crop production is a comprehensive indicator that can reflect water consumption types, quantities and environmental impacts during the crop growth period. This study assesses interannual variability of green, blue and grey WFs of maize production in Beijing from 1978 to 2008. Results indicate that: (1) The multi-year average WF of maize was 1,031 m3 ton-1 which was 56 % green, 25 % blue, and 19 % grey; (2) the climate experienced a warm-dry period in Beijing during the period from 1978 to 2008, and this lead to the increase of crop water requirement and irrigation water requirement for maize with trends of 0. 52 mm a-1 and 2. 86 mm a-1, respectively; (3) under the combined effects of climate change and agricultural inputs, the total WF and green WF presented decreasing trends. The blue and grey WFs had clear increasing trends; (4) statistical analysis revealed that interannual variability of green and blue WFs were caused by both climatic factors (effective precipitation) and non-climatic (agricultural inputs) factors. The grey WF was mainly associated with non-climatic factors, such as chemical fertilizers consumption. © 2013 Springer Science+Business Media Dordrecht.


Bai Y.,Northwest Agriculture and Forestry University | Bai Y.,National Engineering Research Center for Water Saving Irrigation at Yangling | Shao M.,Northwest Agriculture and Forestry University
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2011

The analysis of temporal stability of soil water storage (SWS) is a theoretical basis for the accurate prediction of the soil moisture which can provide help for the vegetation restoration and reconstruction. The profile SWS on a slope was obtained by neutron probe from October 2005 to September 2006 in Liudaogou watershed on rain-fed region of Loess Plateau. The temporal stability of the SWS was conducted by classical statistical and temporal stability analysis. The results showed that SWS in the different months had moderate variability. The coefficients of variation of SWS under dry condition were lower than that under wet condition. The cumulative frequency of 0-4 m SWS changed less than that of the other depths. The mean relative differences of the 0-4 m SWS ranged from -39% to 53% with lower standard deviation (5.6%). The 0-4 m SWS had higher spearman rank correlation coefficients up to 0.8 with significant correlation. The results of the temporal stability preliminarily determined the representative sites. The spearman rank correlation coefficients were small when the SWS varied greatly, but increased when the SWS remained more or less stable. The spearman rank correlation coefficients can provide a convenient way to estimate the temporal stability of SWS in the study area.


Li P.,Northwest University, China | Chen J.,University of Idaho | Wu P.,Northwest University, China | Wu P.,National Engineering Research Center for Water Saving Irrigation at Yangling
Agronomy Journal | Year: 2011

Drought is an important environmental stress limiting wheat (Triticum aestivum L.) productivity in water limited regions. Our aim was to understand the relationships between target agronomic traits and grain yield (GY) responses to drought, and to prioritize genotypes for high yield under different water conditions. Thirty spring wheat genotypes were evaluated over 2009 and 2010 for GY and agronomic traits under T1 (non-irrigated), T2 (50% evapotranspiration [ET] irrigated), and T3 (100% ET irrigated) irrigation regimes. Drought stress caused noticeable fewer days to physiological maturity (PMD), shorter plant height (HT) and exposed peduncle length (EPL), smaller grain volume weight (GVW), higher grain protein content (GPC), smaller kernel weight (KW) and kernel diameter (KD), and less GY. All target traits were significantly correlated with GY except for days to heading (HD) in 2010. Selected traits for 2009 (PMD, HT, GVW) and 2010 (PMD, HT, GPC) together explained 82 and 93% of the total phenotypic variation of GY, respectively. Selected genotypes were classified into four types based on their agronomic and yield performance across three irrigation regimes. High-yield (HY) genotypes IDO599, Alturas, and IDO702 had better agronomic performance and produced high GY across different water conditions; drought-resistance (DR) genotypes Agawam, McNeal, and Alpowa exhibited drought resistance in target traits and produced higher GY than other genotypes under drought. Preliminary results indicate that GY could be estimated on the basis of agronomic performance including PMD, HT, GVW, and GPC, and selecting HY and DR genotypes for water limited environments may be important for improving yield productivity. © 2011 by the American Society of Agronomy.


Zhang B.,Northwest Agriculture and Forestry University | Zhang B.,National Engineering Research Center for Water Saving Irrigation at Yangling | Wu P.,Northwest Agriculture and Forestry University | Wu P.,National Engineering Research Center for Water Saving Irrigation at Yangling | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2011

Time-series GIMMS and SPOT VGT NDVI datasets, which served as an evaluation index of the vegetation cover, were used in this paper to detect and analyze the spatial and temporal variation of vegetation cover in the Loess Plateau from 1982 to 2009.Results showed that before the large-scale implementations of vegetation construction (1982-1998), the annual mean NDVI of the Loess Plateau fluctuated in a narrow range yearly; most places indicated no significant changes in NDVI except for some improvement in a few places. However, since the large-scale implement of vegetation construction in 1999, the annual mean NDVI of the Loess Plateau has increased significantly. Most regions (covering 66.12% of the total area) on the Loess Plateau showed significant positive correlation between NDVI and time over the past decade, especially in the part traversed by the Loess Hilly-gully Region, where the achievements of vegetation construction were quite noticeable. Moreover, the vegetation cover in 15°~25° and 6°~15° slope areas experienced great improvement from 1999 to 2009, which may be helpful to control soil and water losses. The large-scale implementations of vegetation construction accelerated the vegetation restoration in the Loess Plateau. Nevertheless, regions with sparse vegetation on the Loess Plateau still covered a great part by 2009, so it is necessary to further strengthen the ecological environment construction in the future.


Huang J.,Northwest Agriculture and Forestry University | Wu P.,National Engineering Research Center for Water Saving Irrigation at Yangling | Wu P.,Chinese Ministry of Water Resources | Zhao X.,National Engineering Research Center for Water Saving Irrigation at Yangling | Zhao X.,Chinese Ministry of Water Resources
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2010

In order to research the impact of rainfall intensity, slope, vegetation coverage and the interaction between multiple factors on the soil infiltration, the soil infiltration law was researched under different biological regulated measures through the artificial simulated rainfall. The results indicated that the stable infiltration rate of hillslope with biological regulated measures was larger than those of hillslope without biological regulated measures, and the difference was extremely significant, however, the differences were not obvious among those hillslope with biological regulated measures. It was not a simple linear single-valued function between rainfall intensity, slope and the soil stable infiltration rate. There were critical rainfall intensity and critical slope to make the soil stable infiltration rate reach a maximum. The increasing speed of the stable infiltration rate with the increasing of vegetable coverage was not constantly, there was a critical vegetable coverage. Before the critical vegetation coverage, the increasing speed of the stable infiltration rate was very fast, while after that, the increasing speed of the stable infiltration rate reduced quickly and tended to stabilization. Runoff regulating degree decreased with the increasing of rainfall intensity. The sequencing of runoff regulating degree under different control measures in the same rainfall intensity was as follow: ryegrass> wheat> alfalfa> Bare. On that basis, by the stepwise regression analysis, the impacts of each factor and the interaction between the various factors on the stable infiltration were analyzed by using the t test to eliminate the item of independent variable insignificant, and a multiple non-linear model including rainfall intensity, slope and vegetation coverage was established. Finally, the measured data were used to prove this model fitness and feasibility.


Huang J.,Northwest University, China | Huang J.,National Engineering Research Center for Water Saving Irrigation at Yangling | Huang J.,Chinese Ministry of Water Resources | Wu P.,Northwest University, China | And 5 more authors.
Catena | Year: 2013

Knowledge of infiltration patterns and process is very important in understanding and managing slope hydrological processes, crop irrigation, soil erosion, and so on. This paper describes a study in which simulated rainfall events were used to study the effects of various factors (vegetation cover, rainfall intensity, and slope angle) on the soil moisture increase after rainfall and the infiltration recharge coefficient. Soils hosting three different plants (purple medic, PM; spring wheat, SW; and ryegrass, RS) were considered, along with bare soil (BL). These soil surfaces were tested with four different slopes (8.8, 17.6, 26.8 and 36.4%) and subjected to five different rainfall intensities (0.5, 0.75, 1.0, 1.5 and 2.0mmmin-1). The following key results were obtained: (1) The water distribution in BL boxes differed significantly from that in boxes with vegetation cover, but all boxes with vegetation cover exhibited similar distributions. Vegetation cover significantly increased the depth of the wetting front: under very similar conditions, the wetting front in the RS box reached a depth of more than 35cm, while that in the BL box reached only 25cm. (2) Vegetation cover (especially ryegrass) yielded a greater soil moisture increase than did bare land. The overall average soil moisture increase for RS boxes was 36.7±5.1mm, about twice than that of BL. (3) The water storage after rain across the whole soil profile initially increased and then decreased as the rainfall intensity rose. No differences in the average soil water content increase were found between various rainfall intensities. (4) As the slope increased from 8.8% to 36.4%, the water storage increase initially rose but then fell sharply. There were significant differences (p=0.05) between the water storage increases for gradual slopes (8.8 and 17.6%) and steep slopes (26.8 and 3.4%). (5) The recharge coefficient increased with increasing vegetation cover but decreased with increasing rainfall intensity, slope gradient, and initial soil water content. The average value for boxes with vegetation cover was 1.5 times that for BL boxes. The vegetation cover was the most important factor in determining the recharge coefficient. © 2012 Elsevier B.V.


Zhao X.,CAS Institute of Soil and Water Conservation | Zhao X.,Northwest University, China | Zhao X.,National Engineering Research Center for Water Saving Irrigation at Yangling | Wu P.,CAS Institute of Soil and Water Conservation | And 6 more authors.
Land Degradation and Development | Year: 2015

Better understanding of how the loess soils respond to topography and land use under catchment-scale vegetation restoration is needed to enable science-based land management interventions for the policy-driven "Grain-for-Green" eco-restoration program in the Loess Plateau of China. The objective of this study was to characterize the relationships of four selected soil quality indicators to land use under vegetation restoration and topography for a small catchment (0·58km2) in the Loess Plateau. The major land uses established in the catchment are cropland, fallow (i.e., natural revegetation), grassland, and jujube orchard. The four soil quality indicators were soil organic carbon (SOC), soil total nitrogen (STN), soil total phosphorus (STP), and mean root zone soil water content during the wet season (MRZSWwet). SOC, STN, and MRZSWwet were significantly different (p<0·05) for different land uses. Grassland showed the highest values for these three properties, whereas cropland had relatively low values for SOC and STN. Land use had no effect on STP, although the lowest value was observed in grassland. Spatial analysis showed that various relations between soil quality indicators and topography (slope and elevation) were observed. These relations were generally weak for most of them, and they varied with land uses. Further analyses indicated that land uses, slope, and elevation had significant effects on the relations between different soil quality indicators. The results here should provide useful information for the further development of "Grain-for-Green" program. © 2012 John Wiley & Sons, Ltd.


Huang J.,National Engineering Research Center for Water Saving Irrigation at Yangling | Zhao X.,National Engineering Research Center for Water Saving Irrigation at Yangling | Wu P.,National Engineering Research Center for Water Saving Irrigation at Yangling
Journal of Soil and Water Conservation | Year: 2013

The effect of rainfall intensity, slope gradient, initial soil moisture, and vegetation cover on runoff intensity and its progress were investigated using simulated rainfall. Various surface treatments of soil packed into bins were examined, namely bare ground and plantings with purple medic (Medicago sativa L.), spring wheat (Triticum aestivum L.), or ryegrass (Lolium perenne L.). Five different rainfall intensities (0.5, 0.75, 1, 1.5, and 2 mm min-1 [0.02, 0.03, 0.04, 0.06, and 0.08 in min-1]) and four different slope gradients (5°, 10°, 15°, and 20°) were studied. The main results were as follows. (1) There was a positive linear relationship between mean runoff intensity and rainfall intensity, gradient, and initial soil moisture, while there was a negative exponential relationship between mean runoff intensity and vegetation cover. (2) The piecewise function approach was used to determine effective vegetation cover values; these were found to be 52%, 62%, and 73% for purple medic, spring wheat and ryegrass, respectively. (3) Runoff intensity increased with increasing rainfall duration; the relationship was logarithmic, and the time to stable runoff was proportional to gradient but inversely proportional to rainfall intensity and initial soil moisture. (4) The function describing the relationship between runoff intensity and rainfall duration was y = aeb/x (b < 0) for limited vegetation cover (<60%) and y = a + bln(x) for more dense vegetation cover (>60%). © 2013 Soil and Water Conservation Society. All rights reserved.


Li P.,Northwest University, China | Chen J.,University of Idaho | Wu P.,Northwest University, China | Wu P.,National Engineering Research Center for Water Saving Irrigation at Yangling
Crop Science | Year: 2012

Accurate field evaluation of yield-related physiological traits is critical for selecting high yield and drought resistance in wheat (Triticum aestivum L.). To characterize grain yield and three physiological traits for 30 spring wheat genotypes, field experiments with three irrigation regimes were conducted in 2009 and 2010 field seasons. Our study suggests that Feekes 11.2 is the optimal stage to evaluate flag leaf senescence (FLS) and canopy temperature (CT) when making selections for high grain yield and drought resistance among wheat genotypes. Flag leaf carbon isotope discrimination (CID) was positively correlated with grain yield, whereas FLS and CT were negatively correlated with grain yield. The three traits together explained 92% of the total phenotypic variation of grain yield. Selected genotypes were classified into four groups based on yield performance across irrigation regimes. High-yield genotypes IDO599, 'Alturas', and IDO702 produced high grain yield across different water conditions; drought-resistant genotypes 'Aga-wam', 'McNeal', and 'Alpowa' produced higher grain yield under the nonirrigated regime. High yield of those genotypes was contributed by good performance of physiological traits such as late FLS, great CID, or low CT or combinations of these traits. Preliminary results indicate that using physiological traits to estimate yield performance can be effective, and selecting suitable genotypes for different water environments may be crucial for improving yield productivity © Crop Science Society of America.

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