• Authors:
    • Ren, Z.
    • Xie, M.
    • Gu, M.
    • Zhang, X.
    • Huang, S.
    • Wu, J.
    • Ju, Y.
    • Zhong, W.
    • Wang, W.
  • Source: Southwest China Journal of Agricultural Sciences
  • Volume: 23
  • Issue: 5
  • Year: 2010
  • Summary: Anthocyanin of color potato was important as its nutritional value, but very little research had been conducted on the influence of cultivation techniques on anthocyanin content of potatoes. In this paper, orthogonal experimental design L 9(3 4) was used to investigate the effect of fertilizers and planting densities on anthocyanin content of color potatoes In different cultivation conditions. The results showed that to obtain the highest anthocyanin content in Ziyun No. 1, optimal cultivation techniques were as follow: at the condition of intercropping with orchard in the shallow valley, optimal average per hectare consumption of fertilizer nutrients was pure P 2O 5 100 kg, the most cost-effective plant density was 50 000 plants/hm 2, with 2 per mil spray concentration of KH 2PO 4; at the condition of individual cropping in the shallow valley, optimal average per hectare consumption of fertilizer nutrients was pure P 2O 5 75 kg, the most cost-effective plant density was 60 000 plants/hm 2, with a 3 per mil spray concentration of KH 2PO 4; at the condition of individual cropping in deep valley between low mountains areas, optimal average per hectare consumption of fertilizer nutrients was pure P 2O 5 100 kg, the most cost-effective plant density was 60 000 plant/hm 2, with 3 per mil spray concentration of KH 2PO 4.
  • Authors:
    • Wang, L.
    • Anjum, S.
    • Xue, L.
    • Zhang, Y,
    • Hu, X,
    • Wang, G.
    • Zou, C.
  • Source: Zhongguo Shengtai Nongye Xuebao / Chinese Journal of Eco-Agriculture
  • Volume: 18
  • Issue: 3
  • Year: 2010
  • Summary: Under the "wheat/maize/sweet potato" tri-crop intercropping system in the southwest China, we researched into the effects of different straw mulching treatments on root morphology, physiological characteristics of transplanted maize at seedling stage. Taking local traditional farming (T) as CK, the other two treatments were straw mulching (TS) and straw mulching plus decomposition catalysts (TSD). The entire experiment lasted for two years. Results show that straw mulching moderately increases root length and root surface area, while significantly increasing root length within 1.0-2.5 mm diameter compared with T treatment. However, there is no significant difference between TSD and TS treatments. Significantly increases in maize seedling root vigor by respectively 19.12%, 27.46%, in root-shoot ratio by 36.72%, 37.50%, and in root biomass by 62.53%, 69.42% are noted under TS and TSD treatments for 2008. Compared with T, the above indicators increase respectively by 17.86% and 25.83%, 31.54% and 33.08%, 65.69% and 77.37% for 2009. Meanwhile, straw mulching enhances soil moisture and nutrient supply. Straw mulching conservation tillage enhances root development and other physiological characteristics under maize intercropping system at seedling stage by changing farmland environment. Straw mulching with decomposition catalysts even performs better.
  • Authors:
    • Maraseni, T. N.
    • Cockfield, G.
    • Maroulis, J.
  • Source: Journal of Environmental Science and Health, Part B: Pesticides, Food Contaminants, and Agricultural Wastes
  • Volume: 45
  • Issue: 6
  • Year: 2010
  • Authors:
    • Dejoux, J. F.
    • Aubinet, M.
    • Bernhofer, C.
    • Bodson, B.
    • Buchmann, N.
    • Carrara, A.
    • Cellier, P.
    • Di Tommasi, P.
    • Elbers, J. A.
    • Eugster, W.
    • Gruenwald, T.
    • Jacobs, C. M. J.
    • Jans, W. W. P.
    • Jones, M.
    • Kutsch, W.
    • Lanigan, G.
    • Magliulo, E.
    • Marloie, O.
    • Moors, E. J.
    • Moureaux, C.
    • Olioso, A.
    • Osborne, B.
    • Sanz, M. J.
    • Saunders, M.
    • Smith, P.
    • Soegaard, H.
    • Wattenbach, M.
    • Ceschia, E.
    • Beziat, P.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 139
  • Issue: 3
  • Year: 2010
  • Summary: The greenhouse gas budgets of 15 European crop sites covering a large climatic gradient and corresponding to 41 site-years were estimated. The sites included a wide range of management practices (organic and/or mineral fertilisation, tillage or ploughing, with or without straw removal, with or without irrigation, etc.) and were cultivated with 15 representative crop species common to Europe. At all sites, carbon inputs (organic fertilisation and seeds), carbon exports (harvest or fire) and net ecosystem production (NEP), measured with the eddy covariance technique, were calculated. The variability of the different terms and their relative contributions to the net ecosystem carbon budget (NECB) were analysed for all site-years, and the effect of management on NECB was assessed. To account for greenhouse gas (GHG) fluxes that were not directly measured on site, we estimated the emissions caused by field operations (EFO) for each site using emission factors from the literature. The EFO were added to the NECB to calculate the total GHG budget (GHGB) for a range of cropping systems and management regimes. N2O emissions were calculated following the IPCC (2007) guidelines, and CH4 emissions were estimated from the literature for the rice crop site only. At the other sites, CH4 emissions/oxidation were assumed to be negligible compared to other contributions to the net GHGB. Finally, we evaluated crop efficiencies (CE) in relation to global warming potential as the ratio of C exported from the field (yield) to the total GHGB. On average, NEP was negative (-284 +/- 228 gC m(-2) year(-1)), and most cropping systems behaved as atmospheric sinks, with sink strength generally increasing with the number of days of active vegetation. The NECB was, on average, 138 +/- 239 gC m(-2) year(-1), corresponding to an annual loss of about 2.6 +/- 4.5% of the soil organic C content, but with high uncertainty. Management strongly influenced the NECB, with organic fertilisation tending to lower the ecosystem carbon budget. On average, emissions caused by fertilisers (manufacturing, packaging, transport, storage and associated N2O emissions) represented close to 76% of EFO. The operation of machinery (use and maintenance) and the use of pesticides represented 9.7 and 1.6% of EFO, respectively. On average, the NEP (through uptake of CO2) represented 88% of the negative radiative forcing, and exported C represented 88% of the positive radiative forcing of a mean total GHGB of 203 +/- 253 gC-eq m(-2) year(-1). Finally, CE differed considerably among crops and according to management practices within a single crop. Because the CE was highly variable, it is not suitable at this stage for use as an emission factor for management recommendations, and more studies are needed to assess the effects of management on crop efficiency.
  • Authors:
    • van Groenigen, K. J.
    • van Kessel, C.
    • Oenema, O.
    • Velthof, G. L.
    • van Groenigen, J. W.
  • Source: European Journal of Soil Science
  • Volume: 61
  • Issue: 6
  • Year: 2010
  • Summary: Agricultural soils are the main anthropogenic source of nitrous oxide (N2O), largely because of nitrogen (N) fertilizer use. Commonly, N2O emissions are expressed as a function of N application rate. This suggests that smaller fertilizer applications always lead to smaller N2O emissions. Here we argue that, because of global demand for agricultural products, agronomic conditions should be included when assessing N2O emissions. Expressing N2O emissions in relation to crop productivity (expressed as above-ground N uptake: "yield-scaled N2O emissions") can express the N2O efficiency of a cropping system. We show how conventional relationships between N application rate, N uptake and N2O emissions can result in minimal yield-scaled N2O emissions at intermediate fertilizer-N rates. Key findings of a meta-analysis on yield-scaled N2O emissions by non-leguminous annual crops (19 independent studies and 147 data points) revealed that yield-scaled N2O emissions were smallest (8.4 g N2O-N kg-1N uptake) at application rates of approximately 180-190 kg Nha-1 and increased sharply after that (26.8 g N2O-N kg-1 N uptake at 301 kg N ha-1). If the above-ground N surplus was equal to or smaller than zero, yield-scaled N2O emissions remained stable and relatively small. At an N surplus of 90 kg N ha-1 yield-scaled emissions increased threefold. Furthermore, a negative relation between N use efficiency and yield-scaled N2O emissions was found. Therefore, we argue that agricultural management practices to reduce N2O emissions should focus on optimizing fertilizer-N use efficiency under median rates of N input, rather than on minimizing N application rates.
  • Authors:
    • Ogle, S.
    • Del Grosso, S.
    • Delgado, J.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 86
  • Issue: 3
  • Year: 2010
  • Summary: It is difficult to quantify nitrogen (N) losses from agricultural systems; however, we can use 15N isotopic techniques to conduct site-specific studies to increase our knowledge about N management and fate. Our manuscript analyzes two reviews of selected 15N isotopic studies conducted to monitor N fate. The mechanistic foci of these studies include crop residue exchange and N fate in farming systems. Analysis of the data presented in these studies supports the claim that the average N losses are greater from inorganic N fertilizer inputs than organic crop residue N inputs. Additionally we conducted unique DAYCENT simulations of the effects of crop residue on nitrous oxide (N2O-N) emissions and nitrate (NO3-N) leaching. The simulation evaluations support the crop residue 15N exchange studies and show lower leaching and N2O-N emissions from crop residue sources when compared to N fertilizer. The 15N data suggest that the N in the crop residue pool must be recycled, and that this is a slower and more protected pool when compared to the readily available fertilizer. The results suggest that the Intergovernmental Panel on Climate Change (IPCC) methodology should be reevaluated to determine whether the direct and indirect N2O-N emission coefficients need to be lowered to reflect fewer N2O-N emissions from high C/N crop residue N inputs. The data suggest that accounting for nutrient cycling has implications for public policy associated with the United Nations Framework Convention on Climate Change (UNFCCC) and mitigation of N2O-N emissions from agricultural soils. Additional crop residue exchange studies, field N2O-N and NO3-N leaching and support model evaluations are needed across different worldwide agroecosystems.
  • Authors:
    • Dolan, M. S.
    • Wilson, M. L.
    • McNearney, M.
    • Rosen, C. J.
    • Venterea, R. T.
    • Hyatt, C. R.
  • Source: Soil Science Society of America Journal
  • Volume: 74
  • Issue: 2
  • Year: 2010
  • Summary: Irrigated potato (Solanum tuberosum L.) production requires large inputs of N, and therefore has high potential for N loss including emissions of N2O. Two strategies for reducing N loss include split applications of conventional fertilizers, and single applications of polymer-coated urea (PCU), both of which aim to better match the timing of N availability with plant demand. The objective of this 3-yr study was to compare N2O emissions and potato yields following a conventional split application (CSA) using multiple additions of soluble fertilizers with single preplant applications of two different PCUs (PCU-1 and PCU-2) in a loamy sand in Minnesota. Each treatment received 270 kg of fertilizer N ha-1 per season. An unfertilized control treatment was included in 2 of 3 yr. Tuber yields did not vary among fertilizer treatments, but N2O emissions were significantly higher with CSA than PCU-1. During 3 consecutive yr, mean growing season emissions were 1.36, 0.83, and 1.13 kg N2O-N ha-1 with CSA, PCU-1, and PCU-2, respectively, compared with emissions of 0.79 and 0.42 kg N2O-N ha-1 in the control. The PCU-1 released N more slowly during in situ incubation than PCU-2, although differences in N2O emitted by the two PCUs were not generally significant. Fertilizer-induced emissions were relatively low, ranging from 0.10 to 0.15% of applied N with PCU-1 up to 0.25 to 0.49% with CSA. These results show that N application strategies utilizing PCUs can maintain yields, reduce costs associated with split applications, and also reduce N2O emissions.
  • Authors:
    • Rajat, P.
    • Singh, N.
    • Amitava, K.
  • Source: Journal of Entomological Research (New Delhi)
  • Volume: 34
  • Issue: 2
  • Year: 2010
  • Summary: The field study on effect of intercropping on population dynamics of major insect pests and vectors of potato revealed that all the treatments viz., T 2=Potato+recommended pesticide schedule of the area, T 3=Potato+Onion in alternative rows (1:1), and T 4=Potato+Garlic in alternative rows (1:1) were statistically superior and significant over control (T 1). Potato along with recommended pesticide schedule was the most effective treatment in reducing the population of cutworm, various defoliators, epilachna beetle, aphid, whitefly and other pests as well as damage caused by the pests.
  • Authors:
    • Animesh, S.
  • Source: APANews
  • Issue: 37
  • Year: 2010
  • Summary: The cultivation of vegetables under Dendrocalamus asper plantation in Jharkhand, India, is briefly described. The five-year old plantation was intercropped with potatoes, tomatoes, ginger and pea. The yield of potatoes, ginger and tomatoes decreased when cultivated in a bamboo plantation as compared to the data from the monoculture plantation. The performances of pea and ginger were found satisfactory.
  • Authors:
    • Sun, Y.
    • Zhao, Y.
    • Wu, P.
    • Cui, H.
    • Chen, Z.
  • Source: Soil & Tillage Research
  • Volume: 110
  • Issue: 2
  • Year: 2010
  • Summary: Wind erosion near soil surface is one of the major causes of farmland degradation and desertification in arid and semiarid areas. Intercropping wheat and potato can effectively reduce wind erosion, soil desertification and degradation. In this paper, a quantitative research on effective resistance width to wind erosion for the wheat and potato intercropping farmland was performed using several 8-channel wind speed samplers and a movable wind tunnel. As can be seen from the test results, the effective width to control wind erosion for conventional tillage strips on wheat and potato intercropping farmland was lower than or equal to 5 m as the wind speed at 2 m height was 6-7 m.s -1. Moreover, the effective width to control wind erosion of conservation tillage strips on wheat and potato intercropping farmland should be greater than or equal to 5.5 m. Therefore, wheat and potato intercropping with suitable strip width is a cropping mode that not only protects farmland soil from wind erosion to the utmost but also satisfies the requirements of regional planting structure.