-
[show abstract]
[hide abstract]
ABSTRACT: BACKGROUND: The disproportionate distribution of arable land and water resources has become a bottleneck for guaranteeing food security in China. Virtual water and virtual water trade theory have provided a potential solution to improve water resources management in agriculture and alleviate water crises in water-scarce regions. The present study evaluates the green and blue virtual water content of wheat, maize and rice at the regional scale in China. It then assesses the water-saving benefits of virtual water flows related to the transfer of the three crops between regions. RESULTS: The national average virtual water content of wheat, maize and rice were 1071 m(3) per ton (50.98% green water, 49.02% blue water ), 830 m(3) per ton (76.27% green water, 23.73% blue water) and 1294 m(3) per ton (61.90% green water, 38.10% blue water), respectively. With the regional transfer of wheat, maize and rice, virtual water flows reached 30.08 Gm(3) (59.91% green water, 40.09% blue water). Meanwhile, China saved 11.47 Gm(3) green water, while it consumed 7.84 Gm(3) more blue water than with a no-grain transfer scenario in 2009. CONCLUSION: In order to guarantee food security in China, the government should improve water productivity (reduce virtual water content of crops) during the grain production process. Meanwhile, under the preconditions of economic feasibility and land-water resources availability, China should guarantee the grain-sown area in southern regions for taking full advantage of green water resources and to alleviate the pressure on water resources. © 2012 Society of Chemical Industry.
Journal of the Science of Food and Agriculture 09/2012; · 1.44 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Based on the multi-disciplinary researches, and in terms of the transformation efficiency of surface water to soil water, availability of cropland soil water, crop canopy structure, total irrigation volume needed on a given area, and crop yield, this paper discussed the water-saving mechanisms of intercropping system in improving cropland water use efficiency. Intercropping system could promote the full use of cropland water by plant roots, increase the water storage in root zone, reduce the inter-row evaporation and control excessive transpiration, and create a special microclimate advantageous to the plant growth and development. In addition, intercropping system could optimize source-sink relationship, provide a sound foundation for intensively utilizing resources temporally and spatially, and increase the crop yield per unit area greatly without increase of water consumption, so as to promote the crop water use efficiency effectively.
Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 05/2012; 23(5):1400-6.
-
[show abstract]
[hide abstract]
ABSTRACT: A field experiment was conducted at the Yuzhou Experimental Base of Henan Province to study the effects of different application rates (0, 30, 60, and 90 kg x hm(-2)) of water-retaining agent (WRA) on the root physiological characteristics, biomass, and grain yield of two winter wheat cultivars Zhengmai-9694 and Aikang-58, aimed to probe into the action mechanisms of WRA on the root system of winter wheat at its different growth stages. The application of WRA decreased the root membrane permeability and soluble sugar content, and increased the root vigor. After the application of WRA, the Zhengmai-9694 at its different growth stages had a greater decrement of root membrane permeability, compared with Aikang-58. In all treatments except 90 kg x hm(-2) of WRA, the root vigor of Aikang-58 was obviously higher than that of Zhengmai-9694. At booting and grain-filling stages, the root soluble sugar content of Zhengmai-9694 decreased much more than that of Aikang-58. In the whole growth period of the two cultivars, their root membrane permeability and soluble sugar content were the lowest in treatment 60 kg x hm(-2) of WRA, and no significant differences were observed between treatments 60 and 90 kg x hm(-2) of WRA. The root vigor of Zhengmai-9694 increased remarkably with the increasing rate of WRA application, while that of Aikang-58 was the highest in treatment 60 kg x hm(-2) of WRA. The application of WRA also increased root biomass, and at jointing and booting stages, the root biomass of Aikang-58 was much higher than that of Zhengmai-9694. However, at grain-filling stage, the biomass of Aikang-58 in treatments 60 and 90 kg x hm(-2) of WRA was lower than that of Zhengmai-9694. Treatment 60 kg x hm(-2) of WRA had the highest grain yield of the two cultivars. It was concluded that WRA had more significant effects on Zhengmai-9694 than on Aikang-58, and applying 60 kg x hm(-2) of WRA could obtain the best effect.
Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 01/2011; 22(1):73-8.
-
[show abstract]
[hide abstract]
ABSTRACT: The effects of water-retaining agent (60 kg x hm(-2)) and nitrogen fertilizer (0, 225, and 450 kg x hm(-2)) on the leaf photosynthetic characteristics, chlorophyll content, and water utilization of winter wheat at jointing and grain-filling stages were studied under field conditions. In all treatments, the net photosynthetic rate, stomata conductance, intercellular CO2 concentration, water use efficiency, and chlorophyll content were greater at grain-filling stage than at jointing stage. Under nitrogen fertilization but without water-retaining agent application, the water use efficiency (WUE) of single leaf at jointing stage increased with increasing nitrogen fertilization rate, while the net photosynthetic rate, stomata conductance, intercellular CO2 concentration, and transpiration rate decreased after an initial increase. The chlorophyll content was the highest under 225 kg x hm(-2) nitrogen fertilization. In the treatments of water-retaining agent application, the intercellular CO2 con- centration decreased with increasing nitrogen application rate, but the net photosynthetic rate, transpiration rate, and WUE increased. The application of water-retaining agent or its combination with nitrogen fertilization increased the chlorophyll content, but excessive nitrogen fertilization had lesser effects. At grain-filling stage, applying nitrogen fertilizer alone significantly increased the net photosynthetic rate and WUE, but decreased the stomata conductance, intercellular CO2 concentration, and transpiration rate. The chlorophyll content increased with increasing nitrogen application rate. After applying water-retaining agent and with the increase of nitrogen fertilization rate, the photosynthetic rate and WUE decreased after an initial increase, while the intercellular CO2 concentration and transpiration rate were in adverse but still lower than those without water-retaining agent application. The stomata conductance increased with increasing nitrogen fertilization rate. The chlorophyll content increased significantly under the application of water-retaining agent, but somewhat decreased under the combined application of water-retaining agent and nitrogen fertilizer. The application of both water-retaining agent and nitrogen fertilizer increased the 1000 grain mass, grain yield, and water production efficiency of winter wheat significantly, with the best effect in the treatment of water-retaining agent with 225 kg x hm(-2) nitrogen fertilization.
Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 01/2011; 22(1):79-85.
