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Liu C.,Gansu Provincial Key Laboratory of Arid Land Crop Science | Liu C.,Gansu Agricultural University | Zhang R.,Gansu Agricultural University
PIC 2014 - Proceedings of 2014 IEEE International Conference on Progress in Informatics and Computing | Year: 2014

This paper presents a modified fruit fly optimization algorithm(FOA). The proposed modified FOA establishes a balanced tradeoff between exploration and exploitation, and thus overcomes original FOA's drawbacks of premature convergence and easy trapping in a local optima. In the proposed modified FOA, firstly, the whole population performs a global search; Secondly, the whole population are sequenced in descending order by the individual fitness value; Thirdly, every n consecutive individuals are divided into a meme group, then every meme group iteratively performs a deep search around the local optima; Finally, all the meme groups are mixed, and then the above process is implemented iteratively until meeting the end conditions. The modified FOA efficiently avoids relapsing into local optima and improves convergence precision. Finally, our modified algorithm was validated against the original by testing on six standard benchmark functions, and comparisons show that the performance of the proposed modified FOA is much better than original FOA. © 2014 IEEE. Source


Zhang S.,Gansu Agricultural University | Zhang S.,Key Laboratory of Grassland Ecosystems | Zhang S.,Pratacultural Engineering Laboratory of Gansu Province | Zhang S.,Sino Us Centers For Grazingland Ecosystems Sustainability | And 6 more authors.
BioControl | Year: 2014

Trichoderma longibrachiatum can be used for the control of Heterodera avenae in crops, but the effectiveness and possible mechanisms are unknown. Here we determined the efficacy and the mechanism responsible for the nematode control in spring wheat (Triticum aestivum L.). Wheat seedlings inoculated with T. longibrachiatum at the concentrations from 1.5 × 104 to 1.5 × 108 spores ml-1 significantly increased plant height, root length, and plant biomass; decreased H. avenae infection in both rhizospheric soil and roots; and enhanced chlorophyll content, root activity, and the specific activities of resistance-related enzymes (peroxidase, polyphenol oxidase and phenylalanine ammonia lyase), compared to the control. Those reactions occurred soon after T. longibrachiatum inoculation and the effect reached the maximum 7-9 days after inoculation. Promoting competitive plant growth and inducing enzyme-trigged resistance serve as the main mechanism responsible for T. longibrachiatum against H. avenae. T. longibrachiatum can be considered an effective biocontrol agent against H. avenae in wheat. © 2014 International Organization for Biological Control (IOBC). Source


Mu Y.,Gansu Provincial Key Laboratory of Arid Land Crop Science | Chai Q.,Gansu Provincial Key Laboratory of Arid Land Crop Science | Chai Q.,Gansu Agricultural University | Yu A.,Gansu Agricultural University | And 4 more authors.
Crop Science | Year: 2013

Intercropping is shown to have yield advantages over sole cropping, but it is unknown how much yield increase is due to belowground interspecies interactions. This study determined land equivalent ratio (LER) and water use efficiency (WUE) of spring wheat (Triticum aestivum L.)/ maize (Zea mays L.) intercropping and quantified the magnitude of yield increases due to belowground interspecies interactions. Field experiments, conducted at Wuwei (37°96′N, 102°64′E) in 2008 to 2010, included sole wheat (W), sole maize (M), wheat/maize intercropping with no root-barrier (W/M), with a plastic sheet barrier (PW/M), or with a nylon mesh barrier (NW/M), vertically placed to one meter deep between the intercrops. Wheat/maize intercropping increased grain yields by 46% in 2008, 26% in 2009, and 64% in 2010, and improved WUE by 49, 30, and 20% in the respective years, compared with the corresponding sole cropping. The LER values ranged from 1.24 to 1.60 for W/M, suggesting that the grain yield of intercropping per hectare is equivalent to the yield that sole wheat or sole maize would produce on 1.24 and 1.60 ha. The W/M system had total yield of 10.6, 11.1, and 16.9 t ha-1 in 2008, 2009, and 2010, respectively; they were 20, 14, and 15% greater compared with the PW/M system; belowground interspecies interactions contributed 32% of the increased yield in 2008, 29% in 2009, and 40% in 2010. With the large, positive belowground interspecies interactions, wheat/ maize intercropping is shown to be a promising farming practice for improving crop productivity and WUE in arid irrigation areas. © © Crop Science Society of America All rights reserved. Source


Zhang S.,Gansu Agricultural University | Zhang S.,Key Laboratory of Grassland Ecosystems | Zhang S.,Pratacultural Engineering Laboratory of Gansu Province | Zhang S.,Sino Us Centers For Grazingland Ecosystems Sustainability | And 10 more authors.
Biological Control | Year: 2014

Heterodera avenae is a devastating plant pathogen that causes significant yield losses in many crops, but there is a lack of scientific information whether this pathogen can be controlled effectively using biocontrol agents. Here we determined the parasitic and lethal effects of Trichoderma longibrachiatum against H. avenae and the possible mechanism involved in this action. Both in vitro and greenhouse experiments were conducted. In vitro, T. longibrachiatum at the concentrations of 1.5×104 to 1.5×108spores per ml had a strong parasitic and lethal effect on the cysts of H. avenae, with the concentration of 1.5×108spores per ml having >90% parasitism 18days after treatments. In greenhouse, T. longibrachiatum inoculation decreased H. avenae infection in wheat (Triticum aestivum) significantly. Observations with microscopes revealed that after mutual recognition with cysts, the spore of T. longibrachiatum germinated with a large number of hyphae, and reproduced rapidly on the surface of cysts. Meanwhile, the cysts surface became uneven, with some cysts producing vacuoles, and the others splitting. Finally the cysts were dissolved by the metabolite of T. longibrachiatum. Chitinase activity increased in the culture filtrates of T. longibrachiatum and reached the maximum 4days after inoculation in the medium supplemented with colloidal chitin (1.02U/minperml) and nematode cysts (0.78U/minperml). The parasitism and inhibition of cysts through the increased extracellular chitinase activity serves as the main mechanism with which T. longibrachiatum against H. avenae. In conclusion, T. longibrachiatum has a great potential to be used as a biocontrol agent against H. avenae. © 2014 Elsevier Inc. Source


Hu F.,Gansu Provincial Key Laboratory of Arid Land Crop Science | Hu F.,Gansu Agricultural University | Gan Y.,Gansu Provincial Key Laboratory of Arid Land Crop Science | Gan Y.,Agriculture and Agri Food Canada | And 10 more authors.
European Journal of Agronomy | Year: 2016

In arid and populated areas or countries, water shortage and heavy carbon emissions are threatening agricultural sustainability with food security severely, and becoming a major issue. It is unclear whether improved farming systems can be developed to tackle those issues through a sustainable agriculture. Here three farming practices that have proven to be essential and successful, which were: (a) crop intensification through strip intercropping, (b) water harvesting through conservation tillage; and (c) carbon sequestration through improved crop residue management options, were integrated in one cropping system. We hypothesize that the integrated system allows the increase of crop yields with improved water use efficiency, while reducing carbon emissions from farming. The hypothesis was tested in field experiments at Hexi Corridor (37°96'N, 102°64'E) in northwest China. We found that the integrated system increased soil moisture (mm) by 7.4% before sowing, 10.3% during the wheat-maize co-growth period, 8.3% after wheat harvest, and 9.2% after maize harvest, compared to the conventional sole cropping systems. The wheat/maize intercrops increased net primary production by 68% and net ecosystem production by 72%; and when combined with straw mulching on the soil surface, it decreased carbon emissions by 16%, compared to the monoculture maize without mulch. The wheat/maize intercrops used more water but increased grain yields by 142% over the monoculture wheat and by 23% over the monoculture maize, thus, enhancing water use efficiency by an average of 26%. We conclude that integrating strip intercropping, conservation tillage as well as straw mulching in one cropping system can significantly boost crop yields, improve the use efficiency of the limited water resources in arid areas, while, lowering the carbon emissions from farming. The integrated system may be considered in the development of strategies for alleviating food security issues currently experienced in the environment-damaged and water-shortage areas. © 2015 Elsevier B.V.. Source

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