• Authors:
    • Ma, C. L.
    • Wang, P.
    • Guo, P.
    • Peng, H. Y.
    • Chen, L .S.
    • Yang, L. T.
  • Source: Scientia Horticulturae
  • Volume: 133
  • Year: 2012
  • Summary: 'Sour pummelo' ( Citrus grandis) seedlings were irrigated for 18 weeks with nutrient solution containing 0 (-Al) and 1.2 mM (+Al) AlCl 3.6H 2O * 0, 10 and 500 M sodium nitroprusside (SNP), a nitric oxide (NO) donor. Leaf malate content did not significantly change in response to SNP with or without aluminum (Al) except for an increase under 1.2 mM Al+10 M SNP, while leaf citrate content decreased with increasing SNP supply. Root malate content kept unchanging with or without Al except for an increase under 500 M SNP in the absence of Al, while SNP-treated roots had a higher or similar citrate content. Al decreased or did not affect malate content in roots and leaves, and citrate content in roots, but increased leaf citrate content. Al-treated roots and leaves displayed lower or similar activities of acid-metabolizing enzymes [phospho enolpyruvate carboxylase (PEPC), NAD-malate dehydrogenase (NAD-MDH), NADP-malic enzyme (NADP-ME), citrate synthase (CS), aconitase (ACO), NADP-isocitrate dehydrogenase (NADP-IDH), phospho enolpyruvate phosphatase (PEPP) and pyruvate kinase (PK)] except that they had higher or similar activities of NADP-ME and PK and Al-treated leaves had a higher or similar activity of PEPP. In conclusion, the OA metabolism in leaves and roots is differently affected by NO and Al interactions.
  • Authors:
    • Zhang, Z
    • Sui, X.
    • Wang, S.
    • Zhang, L.
    • Gao, L.
    • Zhang, L.
  • Source: Scientia Horticulturae
  • Volume: 138
  • Year: 2012
  • Summary: Water and nitrogen in soil have a great effect on growth and productivity of cucumber (Cucumis sativus L.), which is widely cultivated with high economic benefit in solar greenhouse in North China. To understand the effects of alternate furrow irrigation (AFI) and nitrogen levels on migration of water and nitrogen in soil, accumulation of nitrate-nitrogen (NO3--N) and root growth of cucumber in the solar greenhouse, cucumber variety Jinyu No. 5 was fertilized with different amounts of nitrogen [no nitrogen (CK2), optimal nitrogen (AINo), conventional nitrogen (AINc)] under AFI. Conventional furrow irrigation and conventional nitrogen were used as the control (CK1). The results indicated that soil NO3--N content, electrical conductivity values in the 0-20 cm, 20-40 cm and 40-60 cm layers, and soil residual NO3--N content at the end of the two growing seasons were all increased as the nitrogen fertilizer increased under AFI, especially in the top layer of soil (0-20 cm). However, compared with conventional furrow irrigation, AFI with optimized fertilizer led to increases of root length, root biomass yield, root-shoot ratio of the cucumber crop and economic coefficient (K). AFI also greatly improved both biomass and economic yield water use efficiency. Altogether, AFI with optimized fertilizer (AINo) was a good irrigation practice in the solar greenhouse for increasing the use efficiency of both water and fertilizer, reducing salinity accumulation in the top soil, and maintaining economic yield of cucumber crop. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Desneux, N.
    • Han, P.
    • Niu, C. Y.
    • Zhou, X. W.
  • Source: Journal of Economic Entomology
  • Volume: 105
  • Issue: 4
  • Year: 2012
  • Summary: The Chinese citrus fruit fly, Bactrocera minax (Enderlein) is a univoltine Tephritidae pest that infests Citrus species. Field trials were conducted in 2010 to determine the potential use of a lure based on enzymatical-hydrolyzed beer yeast as liquid bait (hereafter named H-protein bait) for B. minax in the Hubei province, China. In a citrus orchard, we compared the attractiveness among aqueous solutions of H-protein bait, GF-120 fruit fly bait, sugar-vinegar-wine mixture, torula yeast, and Jufeng attractant when used in traps and in spot sprays, that is, lures used in combination with the insecticide trichlorphon. The H-protein bait was the most attractive lure in traps, ensnaring significantly more adults than sugar-vinegar-wine mixture, torula yeast, and Jufeng attractant, in decreasing efficiency order. In spot sprays those with H-protein bait killed significantly more female and male flies within 40 min than those with sugar-vinegar-wine mixture, GF-120, Jufeng attractant, and the control. In addition, the total number of flies killed by H-protein bait during the spot spray duration was higher than other treatments. Our results demonstrated that the H-protein bait may be a useful tool in citrus orchards in China to monitor B. minax populations as well as to manage this pest when used in spot sprays.
  • Authors:
    • Luo,Y.
    • Zhou,C.
  • Source: Journal of Food, Agriculture and Environment
  • Volume: 10
  • Issue: 2
  • Year: 2012
  • Summary: Panzhuang Irrigation District is one of the Yellow River irrigation areas. The spatial and temporal distribution of water resources is severely uneven in the upper, middle and lower reaches of the irrigation district. In order to solve this problem, it is necessary to study the differences of crop water consumption (evapotranspiration-ET), irrigation amount, soil water and water use efficiency (WUE) of winter wheat, summer maize and cotton which are the main crops in the irrigation district. This paper improved calculating methods of the capillary rise and percolation of the established model. The model was then applied to the upper, middle and lower reaches of the irrigation district. Conclusions by the model simulation were as follows: (I) The model could simulate the dynamics of water balance components of wheat-maize and cotton relatively accurately in the irrigation district. (II) Winter wheat and summer maize (wheat-maize) had the highest ET in the upper reaches, followed by the middle reaches and then the lower reaches. There was almost no difference for cotton ET in the upper, middle and lower reaches. (III) Irrigation amount of wheat-maize was 225-300 mm in the upstream, 300 mm in the middle reaches, and 500 mm in the downstream. Cotton irrigation quantity was 60-150 mm in the upper and middle reaches, and 60-390 mm in the lower reaches. (IV) Soil water basically showed a decreasing trend in growth periods of wheat-maize and cotton in the middle and lower reaches, its recharge was primarily from irrigation of wheat. Combined with other references, there was a trend of soil drying in the North China Plain. (V) Mean values of water use efficiency (WUE) of winter wheat, summer maize and cotton were highest in the middle reaches and lowest in the upstream and downstream.
  • Authors:
    • Li, J.
    • Xu, Y.
    • Yang, J.
    • Liu, J.
    • Wang, J.
    • Zhou, S.
  • Source: Hydrological Processes
  • Volume: 26
  • Issue: 8
  • Year: 2012
  • Summary: Eddy covariance flux measurements were performed at a cotton crop site of an oasis in northern Xinjiang, northwest China from 2008 to 2010 in order to study ecosystem evapotranspiration (ET). The soil surface area was approximately 80% covered by plastic film mulch and a cotton crop was grown with a mean population density of around 24 plants m-2 under drip irrigation. The total annual ET was measured to be 560 mm, which was 350 mm more than the average annual mean precipitation for the time period 19632006. Due to the low vapor pressure deficit associated with low temperatures, the ET was low from November to March. The ET totaled 538 mm during the cotton crop growing season, generally from early-April through mid-October. Mean daily ecosystem ET was 1.41.6 mm day-1 in April and May, 3.44.7 mm day-1 from June through August, 1.82.3 mm day-1 in September and 0.70.8 mm day-1 in October. The diurnal variations of ET in all months were consistent with those of net radiation, although the leaf area index (LAI) and climate conditions changed substantially. Soil water content was not a limiting factor for ET during the period from April through September, as the crop was regularly irrigated. Therefore, ET was mainly controlled by the available energy in April and May, and by leaf area from June through September. Due to a complete lack of irrigation, ET was constrained by soil water in October. These results of ET variability are helpful for improved allocation of water resources and agricultural water use practices in the region. Copyright (c) 2011 John Wiley & Sons, Ltd.
  • Authors:
    • Hu, H.
    • Tian, S.
    • Zhong, W.
    • Li, Z.
    • Ning, T.
    • Wang, Y.
    • Zhang, Z.
  • Source: Scientia Agricultura Sinica
  • Volume: 44
  • Issue: 9
  • Year: 2011
  • Summary: Objective: The objective of this study was to understand the effects of normal urea and controlled release urea on grain filling rate, yield and water use efficiency of different maize cultivars under different tillage modes. Method: Three sets of treatments were arranged in a split-split plot design. The whole-plot treatment factor was the tillage mode, stubble ploughing or subsoiling after stubble ploughing. The subplot treatment factor was maize cultivars Zhengdan 958 and Denghai 3. The sub-subplot treatment factor was the nitrogen level, including applied with 225 kg N.hm -2 normal urea, applied with 225 kg N.hm -2 controlled release urea, and no nitrogen fertilizer used as control. Result: At the same tillage mode, nitrogen level and maize cultivars, the soil water content in 0-100 cm soil layer applied with controlled release urea was higher at pre-tasselling stage, while lower at maturity stage than those applied with normal urea. It indicated that treatment applied with controlled release urea could realize higher use of soil water through time and space, and as a result increased the gain filling rate and water use efficiency. Subsoiling after stubble ploughing could also increase the grain filling rate and water use efficiency. Compared with Zhengdan 958, Denghai 3 had higher grain filling rate, yield and water use efficiency. And these were positive coupling effects between urea type, subsoiling, and maize cultivars, which was benefit for higher yield in dryland farm. Conclusion: Higher use of soil water through time and space and higher grain filling rate were the important reasons for higher yield and water use efficiency. Using suitable maize cultivars and applying controlled release urea, with subsoiling after stubble ploughing, could make the good use of soil water, and realize the space-time coincide between soil water supply and crop needs, which will be the important measures to achieve higher grain yield and higher benefit in semi-humid region of China.
  • Authors:
    • Li, W.
    • He, R.
  • Source: Journal of Yunnan Agricultural University
  • Volume: 26
  • Issue: 4
  • Year: 2011
  • Summary: Jianghuai region is one of the major grain producing areas in China, where planting has high energy consumption. In addition, greenhouse gases displacement of planting is larger than ever, and the phenomenon of straw burned is extremely serious. To solve the problem, the multifunctional no-till wheat and paddy planter was designed with the technique of mechanized cultivation of energy-saving emission reduction. Combing with controlled traffic tillage and strip chopping anti-blocking mechanism, it could be used to returning corn stalks to the filed, fertilizing, seeding, covering and so on. The filed experiment indicates that the machine can decrease operating power consumption, and its steering ability is outstanding.
  • Authors:
    • Shi, X.
    • Shen, Y.
    • Zhang, X.
    • McLaughlin, N. B.
    • Fan, R.
    • Liang, A.
  • Source: Acta Agriculturae Scandinavica, Section B - Soil & Plant Science
  • Volume: 61
  • Issue: 6
  • Year: 2011
  • Summary: Soil aggregate-size distribution and soil aggregate stability are used to characterize soil structure. Quantifying the changes of structural stability of soil is an important element in assessing soil and crop management practices. A 5-year tillage experiment consisting of no till (NT), moldboard plow (MP) and ridge tillage (RT), was used to study soil water-stable aggregate size distribution, aggregate stability and aggregate-associated soil organic carbon (SOC) at four soil depths (0-5, 5-10, 10-20 and 20-30 cm) of a clay loam soil in northeast China. Nonlinear fractal dimension (D m) was used to characterize soil aggregate stability. No tillage led to a significantly greater aggregation for >1 mm aggregate and significant SOC changes in this fraction at 0-5 cm depth. There were significant positive relationships between SOC and >1 mm aggregate, SOC in each aggregate fraction, but there was no relationship between soil aggregate parameters (the proportion of soil aggregates, aggregate-associated SOC and soil stability) and soil bulk density. After 5 years, there was no difference in D m of soil aggregate size distribution among tillage treatments, which suggested that D m could not be used as an indicator to assess short-term effects of tillage practices on soil aggregation. In the short term, >1 mm soil aggregate was a better indicator to characterize the impacts of tillage practices on quality of a Chinese Mollisol, particularly in the near-surface layer of the soil.
  • Authors:
    • Yang, X.
    • Li, C.
    • Liu, L.
    • Liu, Z.
  • Source: Nongye Jixie Xuebao = Transactions of the Chinese Society for Agricultural Machinery
  • Volume: 42
  • Issue: 2
  • Year: 2011
  • Summary: The 2BMG-24Q pneumatic no-till wheat planter was designed. Seeds were transported into seeder pipes with high-speed air current to perform precision metering. The wavy disc coulters were used to cut stubble for sowing, and the double disc coulters were used to open furrow for fertilizing. The test results showed that the quanlification percent of seed depth and fertilizer depth were 88.3% and 85.2%, respectively.
  • Authors:
    • Ma, E.
    • Ma, J.
    • Xu, H.
    • Cai, Z.
    • Yagi, K.
  • Source: Acta Pedologica Sinica
  • Volume: 48
  • Issue: 5
  • Year: 2011
  • Summary: To study effect of timing of topdressing on N 2O emission from wheat fields during the period from the jointing stage till the maturing stage of wheat, a field experiment was conducted to have three topdressing schedules (top-dressing before rain, topdressing during rain and topdressing after rain) in jointing-maturing stage of wheat from 2007 to 2008. Results show that N 2O emission was 37%-67% and 22%-46% less in fields topdressed after rain, than in fields topdressed before rain and during rain, respectively. No significant difference was observed between the treatments in wheat grain yield ( p>0.05). Soil water content was the key factor affecting N 2O emission during that wheat growing season. Topdressing after rain when soil was wet is an appropriate topdressing method, which may decrease N 2O emission significantly in the wheat-growing season with no adverse effect on wheat yield.