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Zhang Y.-C.,Hebei Academy of Agriculture and Forestry Science | Li R.-N.,Hebei Academy of Agriculture and Forestry Science | Wang L.-Y.,Hebei Academy of Agriculture and Forestry Science | Zhai C.-X.,Hebei Academy of Agriculture and Forestry Science | And 8 more authors.
Communications in Soil Science and Plant Analysis | Year: 2010

Phosphorus (P) accumulation is a common phenomenon in greenhouse soil for vegetables. Excessive P accumulation in soil usually decreases the yield and quality of vegetables as well as potentially polluting water environments. Ninety-eight tomato and 48 cucumber greenhouses were investigated in the eight main vegetable production areas of Hebei Province, China. Soil Olsen-P, the electrical conductivity (EC), the pH value, the organic matter of the soil, and the cropping years of these green-houses were investigated and analyzed in order to better understand the status of soil P accumulation and positively find effective ways to solve the excessive phosphate accumulation problem. The investigation showed that the ratio was above 70% for all of the greenhouses where the soil Olsen-P exceeded 90 mg·kg-1 (upper bound of soil Olsen-P optimum value in greenhouse) in the 0-20 cm surface soil in the investigated green-houses. There was a significant positive correlation between the soil Olsen-P content and the soil EC, between the soil Olsen-P and the cropping years, and the Olsen-P had a significant negative correlation with the soil pH value. It is concluded that supplying phosphate fertilizer excessively induced the soil EC to ascend and the pH value to descend, which increases the possibility of the soil secondary salinization and soil degeneration. The significant positive correlation between the soil organic content and the soil Olsen-P contents suggests that supplying organic fertilizer might mobilize soil residual phosphate. This also provides a good way to solve the problem of soil P accumulation. In order to further explore the threshold content of soil Olsen-P demanded by tomato and cucumber under the high soil Olsen-P condition, two tomato green-houses (T1, T2) in Dingzhou and two cucumber greenhouses (C1, C2) in Wuqiang were researched. All of the greenhouses had ranges of soil Olsen-P content that were between 150 and 300 mg·kg-1, which far exceeded the 90 mg·kg-1 ideal. The P fertilizer application rates showed positive correlations with the soil Olsen-P contents and EC values in cucumber and tomato greenhouses in the current season. Analyzing T1 and T2 results showed that tomato was sensitive to the high soil Olsen-P contents ranging from 230.64 to 729.42 mg kg-1 at the seedling stage (15 days after transplanting; DAT) and from 199.41 to 531.42 mg kg-1 at the fruiting stage (90 DAT), because the yields correlated negatively with soil Olsen-P contents at each growth stage. It is suggested that the maximum soil Olsen-P threshold content for tomato should be lower than 230 mg·kg-1 at the seedling stage and lower than 199 mg·kg-1 at the fruiting stage. But cucumber yield did not change significantly as soil Olsen-P content rose from 248.75 to 927.62 mg kg-1, 212.40 to 554.07 mg kg-1, 184.48 to 455.90 mg kg-1, and 128.42 to 400.96 mg kg-1 at the seedling stage (15 DAT), early fruiting stage (50 DAT), middle fruiting stage (140 DAT), and late fruiting stage (235 DAT), respectively, suggesting that the maximal soil Olsen-P threshold content was lower than 249, 212, 185, and 128 mg·kg-1 at each growth stage, respectively. The relationship between fruit qualities and soil Olsen-P contents at each growth stage was not evident. Activities of soil alkaline phosphatase (ALP) decreased as soil Olsen-P supply was raised in T1, T2, and C1 at the seedling stage. It is concluded that in an excess soil Olsen-P condition tomato yield decreases strongly as soil ALP activity decreases, whereas ALP activity has little direct effect on cucumber yield. © Taylor & Francis Group, LLC. Source

Guan D.-W.,Chinese Academy of Sciences | Guan D.-W.,Key Laboratory of Plant Nutrition and Nutrient Cycling | Ma M.-C.,Chinese Academy of Sciences | Ma Z.-Y.,Chinese Academy of Sciences | And 8 more authors.
Journal of Integrative Agriculture | Year: 2012

The symbiotic matching for nodulation of Bradyrhizobium japonicum strains is a synergy of multi-proteins and plays a key role in symbiotic nitrogen fixation in nature. Studies on mechanism of symbiotic matching are significant in both theory and practice. In this paper, B. japonicum USDA110-A with high symbiotic matching with high-oil content soybean cultivar Suinong 20 and B. japonicum 2178 with low symbiotic matching were selected for proteomic to reveal mechanism of different symbiotic nodulation. The results showed that the amount and categories of proteins identified in this test were different when the two strains were treated by symbiotic nodulation. There were 10 up-regulated proteins and 5 down-regulated proteins with significant difference for B. japonicum USDA110-A. Proteins associated with nodulation and metabolism of energy and material, which were propitious to symbiotic nodulation, were all up-regulated, such as PHDPS synthase, metal-dependent phosphohydrolase, glycosyl transferase family. In contrast, only 5 up-regulated and 7 down-regulated differential proteins were detected in B. japonicum 2178. Molecular chaperones and defensive proteins, which influence the folding of nascent polypeptide chains and the active of azotase were down-regulated. To a certain extent, the different responses of B. japonicum to daidzein were one of the most important reasons that cause varieties in symbiotic matching ability. © 2012 Chinese Academy of Agricultural Sciences. Source

Mei P.-P.,Key Laboratory of Plant Soil Interactions | Mei P.-P.,Key Laboratory of Plant Nutrition and Nutrient Cycling | Mei P.-P.,China Agricultural University | Gui L.-G.,Ningxia Academy of Agriculture and Forestry science | And 10 more authors.
Field Crops Research | Year: 2012

Development of reclaimed desert soils using intercropping systems and inoculation with rhizobia is a potentially important strategy for utilizing phosphorus-deficient soils and extending the arable land area. Two years of field experiments with different rates of P fertilizer (0 and 120kgP 2O 5ha -1 in 2008 and 0, 60, and 120kgP 2O 5ha -1 in 2009) were carried out to study the influence of fertilizer P application on the productivity and phosphorus utilization of a Rhizobium-inoculated maize (Zea mays L.)/faba bean (Vicia faba L.) intercropping system in the reclaimed desert soil. Average grain yields of intercropped faba bean and maize increased by 30-197% and 0-31%, respectively (and increased more with zero fertilizer P application) compared with sole crops. Intercropped faba bean showed higher root nodulation and P accumulation but little response to P application regardless of cropping system. The apparent P recovery of the intercropping system was 297.0% greater (P<0.001) than that of sole cropping systems (weighted means) and was highest at the intermediate P application rate on average. Moderate fertilizer P application enhanced productivity and nodulation of the intercropping system in a reclaimed desert soil and P deficiency was ameliorated to some extent. The results indicate that Rhizobium-inoculated maize/faba bean intercropping may be an efficient cropping system for reclaimed desert soils. © 2012 Elsevier B.V. Source

Fan M.,China Agricultural University | Fan M.,Key Laboratory of Plant Nutrition and Nutrient Cycling | Fan M.,Key Laboratory of Plant Soil Interactions | Shen J.,China Agricultural University | And 15 more authors.
Journal of Experimental Botany | Year: 2012

In recent years, agricultural growth in China has accelerated remarkably, but most of this growth has been driven by increased yield per unit area rather than by expansion of the cultivated area. Looking towards 2030, to meet the demand for grain and to feed a growing population on the available arable land, it is suggested that annual crop production should be increased to around 580 Mt and that yield should increase by at least 2% annually. Crop production will become more difficult with climate change, resource scarcity (e.g. land, water, energy, and nutrients) and environmental degradation (e.g. declining soil quality, increased greenhouse gas emissions, and surface water eutrophication). To pursue the fastest and most practical route to improved yield, the near-term strategy is application and extension of existing agricultural technologies. This would lead to substantial improvement in crop and soil management practices, which are currently suboptimal. Two pivotal components are required if we are to follow new trajectories. First, the disciplines of soil management and agronomy need to be given increased emphasis in research and teaching, as part of a grand food security challenge. Second, continued genetic improvement in crop varieties will be vital. However, our view is that the biggest gains from improved technology will come most immediately from combinations of improved crops and improved agronomical practices. The objectives of this paper are to summarize the historical trend of crop production in China and to examine the main constraints to the further increase of crop productivity. The paper provides a perspective on the challenge faced by science and technology in agriculture which must be met both in terms of increased crop productivity but also in increased resource use efficiency and the protection of environmental quality. © 2011 The Author(s). Source

Li J.,Chinese Academy of Agricultural Sciences | Li J.,Key Laboratory of Plant Nutrition and Nutrient Cycling | Xiao W.-L.,Chinese Academy of Agricultural Sciences | Xiao W.-L.,Key Laboratory of Plant Nutrition and Nutrient Cycling | And 9 more authors.
Agricultural Sciences in China | Year: 2011

Competitiveness for nodulation of Bradyrhizobium japonicum strains plays a key role in symbiotic nitrogen fixation. In order to reveal the difference in competitiveness, B. japonicum 4534 with high competitiveness and B. japonicum 4222 with low competitiveness for nodulation were analyzed by proteomic technique. The results showed that differential proteins were fewer when two strains were treated with just daidzein. Only 24 and 10 differential proteins were detected with an up-regulated rate of 58 and 40% in B. japonicum 4534 and B. japonicum 4222, respectively. However, more differential proteins were detected upon treatment with daidzein and mutual extracellular materials simultaneously. There were 78 differential proteins detected in B. japonicum 4534 with 43 being up-regulated and 35 being down-regulated. These differential proteins, such as metabolism-related proteins, transporters, transcription-related proteins, translation-related proteins, and flagellin, were found to be associated with nodulation process. 25 up-regulated and 22 down-regulated proteins were detected in B. japonicum 4222. Some of these proteins were not related to nodulation. More differential proteins associated with nodulation in B. japonicum 4534 may be the reason for its high competitiveness. The results can provide a guide to the selection and inoculation of effective strains and are significant to biological nitrogen fixation. © 2011 Chinese Academy of Agricultural Sciences. Source

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