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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. Source


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. Source


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. Source


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. Source


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. Source

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