19602015
  • Authors:
    • Liu, We.
    • Meng, P.
    • Zhang, J.
    • Lu, S.
  • Source: Journal of Food Agriculture & Environment
  • Volume: 10
  • Issue: 2 part 3
  • Year: 2012
  • Summary: Agroforestry systems have unique advantages over conventional agricultural land in the carbon (C) balance. In this study, soil respiration under a tree intercropping system, an orchard and an agricultural land in north China were quantified during the growing season of March-November 2010. In the tree intercropping system, eight-year-old walnut ( Juglans regia L.) was intercropped with an annual wheat ( Triticum aestivum L.) - mung bean ( Vigna radiata L.) rotation. In the orchard and cropland, the eight-year-old walnut and wheat-mung bean rotation were grown as a mono practice, respectively. During the study period, the overall soil respiration rate was 1.89, 1.63 and 2.05 mol m 2 s 1 for the walnut intercropping, walnut orchard and cropland systems, respectively. Thus, there was a reduction in soil respiration when the cropland was converted to walnut intercropping and walnut orchard in north China. The higher soil CO 2 emission in the cropland result from the higher soil organic carbon and soil temperature. The van't Hoff model described the soil respiration as a function of soil temperature in the walnut intercropping system with R 2>0.78. Moreover, the temperature sensitivity of soil respiration (Q 10) was determined in the walnut intercropping system. The Q 10 values were similar in the walnut intercropping system and walnut orchard at 2.33 and 2.28, respectively, and significantly greater than for cropland (1.59). The result suggests that the walnut intercropping system had a higher sensitivity of soil respiration to temperature change than agricultural land. Compared with cropland, the slightly lower soil organic carbon in the walnut intercropping system may due to the short-term agroforestry practice, while in general the soil organic matter requires long term of turnover interactions. There was no significant difference in the walnut basal diameter and tree height between orchard and intercropping systems, showing that walnut growth was not affected by the introduction of the crop. Our results suggest that walnut intercropping could be practiced above conventional agriculture and produced less soil CO 2 emissions.
  • Authors:
    • Xu, L.
    • Li, W.
    • Ning, W.
    • Qiu, C.
    • Liao, K.
    • Ma, Y.
  • Source: Xinjiang Agricultural Sciences
  • Volume: 49
  • Issue: 1
  • Year: 2012
  • Summary: Objective: In order to know the environmental temperature and humidity daily variation regularity in apricot-wheat intercropping zone. Method: Temperature and humidity recorder (EI-USB-2), and portable tester soil temperature and humidity (Stevens POGO) were used to detect the change of air temperature, land surface temperature and relative humidity in apricot-wheat intercropping zone and apricot monoculture zone were observed. Result: The results showed that, the temperature and humidity change lies both in intercropping zone and monoculture zone. There was a positive correlation between the temperature, land surface temperature and PAR, but a negative correlation between relative humidity and PAR. The average temperature and land surface temperature in intercropping zone decreased 4.53°C and 0.7°C, respectively; The average temperature and land surface relative humidity increased 4.90% and 3.93% respectively in intercropping zone. Conclusion: To some extent, intercropping has a significant function of reducing temperature decrease and humidity in the orchard.
  • Authors:
    • Ercoli, L.
    • Masoni, A.
    • Mariotti, M.
    • Arduini, I.
  • Source: Grass and Forage Science
  • Volume: 67
  • Issue: 2
  • Year: 2012
  • Summary: Intercropping (IC) cereals and legumes could be an option for obtaining forage suitable for ensiling and enabling reduced N fertilization. Two experiments were performed in central Italy with durum wheat ( Triticum durum Desf.) and field bean ( Vicia faba L. var. minor) grown for forage production in IC and as sole crops (SC) with different N rates (20 and 50 kg ha -1) and row ratios (1:1 and 2:1 cereal/legume). The aims were to assess (i) whether IC is a feasible option to reduce N fertilization; (ii) the best combination of practices to obtain forage suitable for ensiling; and (iii) competition/facilitation effects exerted by field bean on durum wheat. Results showed IC allowed fertilizer-N reduction and led to improved forage yield with better quality, compared with SC. Land equivalent ratio indicated a high efficiency of the IC, by up to 26% with respect to SC. Field bean was the dominant species of IC, but N fertilization reduced its competitive ability and enhanced that of wheat. In the intercrop fertilized with 50 kg N ha -1, the proportion of the wheat in the herbage (0.34-0.41 of the total dry matter) was sufficient for ensiling of the forage mass. Field bean exerted both competition and facilitation effects on the cereal. N uptake of durum wheat was greater under IC with beans than as wheat SC.
  • Authors:
    • Quideau, S.
    • Pswarayi, A.
    • Nelson, A. G.
    • Frick, B.
    • Spaner, D.
  • Source: Agronomy Journal
  • Volume: 104
  • Issue: 3
  • Year: 2012
  • Summary: To investigate intercropping as a management strategy to increase crop productivity and weed suppression in organic systems, spring wheat ( Triticum aestivum L.), barley ( Hordeum vulgare L.), canola ( Brassica napus L.) and field pea ( Pisum sativum L.) monocultures were compared with two-, three-, and four-crop intercrops containing wheat at two organic and one conventional site in 2006 and 2007, central Alberta, Canada. We measured crop and weed biomass, grain yield, and crop competitiveness against weeds from a replacement design in a completely randomized block experiment. Pea and canola monocrops on organic sites yielded the least of all crop treatments. Conventional crop treatments generally yielded higher than organic treatments. Few land equivalent ratios (LERs) on organic sites were significantly >1.0. Some wheat intercrops without barley showed overyielding (LER >1.0) potential. Most of the significant LERs were from three- and four-crop intercrops. More than 50% of the intercrops on organic sites significantly suppressed weeds (based on relative weed biomass) and most of these intercrops had barley in the mixture. Barley as a sole crop and in intercrops suppressed weeds better than all other intercrops and sole crops. The wheat-canola intercrop exhibited the best weed suppression of the two-crop intercrops on organic and conventional sites. The crop densities used in this study may have contributed to the extremely low pea and canola monocrop yields as well as low LERs. Due to this, our findings should be regarded as showing trends and potential from intercrops only. We therefore recommend further studies to establish ideal densities for the intercrops used.
  • Authors:
    • Asselt, E.
    • Eitzinger, J.
    • Brisson, N.
    • Siebert, S.
    • Ewert, F.
    • Trnka, M.
    • Borjesson, T.
    • Peltonen-Sainio, P.
    • Skjelvag, A.
    • Rotter, R.
    • Palosuo, T.
    • Elsgaard, L.
    • Borgesen, C.
    • Olesen, J.
    • Oberforster, M.
    • Fels-Klerx, H.
  • Source: Food Additives and Contaminants Part A-Chemistry Analysis Control Exposure & Risk Assessment
  • Volume: 29
  • Issue: 10
  • Year: 2012
  • Summary: The phenological development of cereal crops from emergence through flowering to maturity is largely controlled by temperature, but also affected by day length and potential physiological stresses. Responses may vary between species and varieties. Climate change will affect the timing of cereal crop development, but exact changes will also depend on changes in varieties as affected by plant breeding and variety choices. This study aimed to assess changes in timing of major phenological stages of cereal crops in Northern and Central Europe under climate change. Records on dates of sowing, flowering, and maturity of wheat, oats and maize were collected from field experiments conducted during the period 1985-2009. Data for spring wheat and spring oats covered latitudes from 46 to 64°N, winter wheat from 46 to 61°N, and maize from 47 to 58°N. The number of observations (site-year-variety combinations) varied with phenological phase, but exceeded 2190, 227, 2076 and 1506 for winter wheat, spring wheat, spring oats and maize, respectively. The data were used to fit simple crop development models, assuming that the duration of the period until flowering depends on temperature and day length for wheat and oats, and on temperature for maize, and that the duration of the period from flowering to maturity in all species depends on temperature only. Species-specific base temperatures were used. Sowing date of spring cereals was estimated using a threshold temperature for the mean air temperature during 10 days prior to sowing. The mean estimated temperature thresholds for sowing were 6.1, 7.1 and 10.1°C for oats, wheat and maize, respectively. For spring oats and wheat the temperature threshold increased with latitude. The effective temperature sums required for both flowering and maturity increased with increasing mean annual temperature of the location, indicating that varieties are well adapted to given conditions. The responses of wheat and oats were largest for the period from flowering to maturity. Changes in timing of cereal phenology by 2040 were assessed for two climate model projections according to the observed dependencies on temperature and day length. The results showed advancements of sowing date of spring cereals by 1-3 weeks depending on climate model and region within Europe. The changes were largest in Northern Europe. Timing of flowering and maturity were projected to advance by 1-3 weeks. The changes were largest for grain maize and smallest for winter wheat, and they were generally largest in the western and northern part of the domain. There were considerable differences in predicted timing of sowing, flowering and maturity between the two climate model projections applied.
  • Authors:
    • Gaillard, B.
    • Foissy, D.
    • Dorvillez, D.
    • Carrouee, B.
    • Boucheny, P.
    • Biarnes, V.
    • Bedoussac, L.
    • Baranger, E.
    • Al-Rifai, M.
    • Naudin, C.
    • Corre-Hellou, G.
    • Makowski, D.
    • Bazot, M.
    • Pelzer, E.
    • Guichard, L.
    • Mansard, M.
    • Omon, B.
    • Prieur, L.
    • Yvergniaux, M.
    • Justes, E.
    • Jeuffroy, M.
  • Source: European Journal of Agronomy
  • Volume: 40
  • Year: 2012
  • Summary: Intensive agriculture ensures high yields but can cause serious environmental damages. The optimal use of soil and atmospheric sources of nitrogen in cereal-legume mixtures may allow farmers to maintain high production levels and good quality with low external N inputs, and could potentially decrease environmental impacts, particularly through a more efficient energy use. These potential advantages are presented in an overall assessment of cereal-legume systems, accounting for the agronomic, environmental, energetic, and economic performances. Based on a low-input experimental field network including 16 site-years, we found that yields of pea-wheat intercrops (about 4.5 Mg ha -1 whatever the amount of applied fertiliser) were higher than sole pea and close to conventionally managed wheat yields (5.4 Mg ha -1 on average), the intercrop requiring less than half of the nitrogen fertiliser per ton of grain compared to the sole wheat. The land equivalent ratio and a statistical analysis based on the Price's equation showed that the crop mixture was more efficient than sole crops particularly under unfertilised situations. The estimated amount of energy consumed per ton of harvested grains was two to three times higher with conventionally managed wheat than with pea-wheat mixtures (fertilised or not). The intercrops allowed (i) maintaining wheat grain protein concentration and gross margin compared to wheat sole crop and (ii) increased the contribution of N 2 fixation to total N accumulation of pea crop in the mixture compared to pea sole crop. They also led to a reduction of (i) pesticide use compared to sole crops and (ii) soil mineral nitrogen after harvest compared to pea sole crop. Our results demonstrate that pea-wheat intercropping is a promising way to produce cereal grains in an efficient, economically sustainable and environmentally friendly way.
  • Authors:
    • Konopatzki, M. R. S.
    • Lima, G. P. de
    • Nobrega, L. H. P.
    • Pickler, E. P.
    • Pacheco, F. P.
  • Source: Engenharia na Agricultura
  • Volume: 20
  • Issue: 1
  • Year: 2012
  • Summary: The increased mechanization, without adequate management, contributes to changes in soil structure, which facilitate erosive processes and soil degradation. The cover crops help protect soil surface, enhance physical, chemical, biological and productive potential of a soil and minimize degradation. This trial was done to analyze the influence of winter cover crop on the soil density, water content, macro and microporosity of soil cultivated to soybean and corn under no-tillage system. The experiment was conducted in a field with 24 plots, having six treatments of cover crops (forage turnip, pearl millet, oilseed rape, black oat, wheat and fallow) with four replications. After cover crop management, twelve plots were planted with corn and the other twelve with soybeans. It was observed that the soil under corn had better macroporosity, porosity and density compared to the soil cultivated to soybean. The crop cover with forage turnip increased soil macroporosity. However, cover crops did not influence water content, density, microporosity and porosity.
  • Authors:
    • Michelsen, O.
    • Henriksen, T. M.
    • Korsaeth, A.
    • Roer, A. G.
    • Stromman, A. H.
  • Source: Agricultural Systems
  • Volume: 111
  • Year: 2012
  • Summary: This study assesses the environmental impacts from production of 1 kg barley, oat and spring wheat, in central southeast Norway by means of life cycle assessment. The results were given for twelve impact categories, selected based on relevance to the system. These categories are climate change, fossil depletion, freshwater ecotoxicity, freshwater eutrophication, human toxicity, marine ecotoxicity, marine eutrophication, ozone depletion, particulate matter formation, photochemical oxidant formation, terrestrial acidification and terrestrial ecotoxicity. The assessment covers processes from cradle to farm gate, including all farm activities related to grain cultivation, as well as the production and acquisition of machinery, equipments and buildings, diesel and oil, fertilizer, lime, seeds and pesticides. In order to reveal the importance of system boundaries, factors that are included in this study and often excluded in other studies, such as machinery manufacturing, buildings, pesticide production and use, humus mineralization and NO X loss from use of mineral fertilizer were systematically individually omitted. The sensitivity of the LCA results to several selected parameters governing greenhouse gas emissions and climate change (CC) was evaluated by varying the parameters50% of the default value. The assessment gave a CC impact of 0.79, 0.77 and 0.74 kg CO 2-eq for production of 1 kg barley, oat and spring wheat, respectively. The choice of system boundaries were found to have great impact on the results, and CC impact was reduced by more than 40% when factors that are not commonly reported in literature were excluded. This clearly demonstrates the need of comprehensive documentation of system boundaries in order to perform meaningful comparisons of environmental impact caused by grain production under different conditions. The sensitivity analysis revealed that most of the impact categories were not particularly sensitive to the parameters selected. A 50% change in the emission factor for N 2O emissions from N inputs had highest effect on CC with 11-13%. The highest overall impacts were found for the fraction of mineral fertilizer volatilized as NH 3 and NO X , with 32-53% change in photochemical oxidant and particular matter formation, and terrestrial acidification impact categories.
  • Authors:
    • Wu, L.
    • Li, F.
    • Zhu, O.
    • Sun, Z.
  • Source: Journal of Resources and Ecology
  • Volume: 3
  • Issue: 1
  • Year: 2012
  • Summary: The major function of clover in a winter wheat-white clover intercropping system is to supply nitrogen (N) for the wheat. A field experiment was conducted at Yucheng Comprehensive Station of the Chinese Academy of Sciences, to evaluate the effect of cutting white clover on N fixation and the transfer of fixed N to the associated winter wheat. A method of 15N natural abundance was used to determine the nitrogen dynamics in the intercropping system. The results showed that the amount of N transferred from the clover to the wheat, throughout the growing season, varied between 34.4 and 57.5 kg ha -1. Compared to leaving the clover standing, cutting the clover increased the amount of N that accumulated in the soil and also resulted in reduced N concentrations in the leaves and stems of the wheat. Using the cut clover as mulch between wheat rows led to decreased N concentrations in the wheat plants' leaves and stems. The present study provides preliminary information on the amount of N transferred from clover to wheat in an intercropping system.
  • Authors:
    • Calegari, A.
    • Santos, D.
    • Tiecher, T.
  • Source: Soil & Tillage Research
  • Volume: 124
  • Year: 2012
  • Summary: Organic phosphorus (P) is an important source of phosphate for plants both in natural environments and in cultivated soils. Growing plants with high P recycling capacity may increase the importance of organic forms in phosphate availability mainly in undisturbed soils. The aim of this study was to evaluate the effect of long period of cultivation of different winter species under different soil management systems in the distribution of soil organic P forms, in the P content stored into the soil microbial biomass (SMB) and in the acid phosphatase enzyme activity. The experiment was established in 1986 with six winter treatments (blue lupine, hairy vetch, oat, radish, wheat and fallow) implanted in a Rhodic Hapludox in southern Brazil, under no-tillage system (NT) and conventional tillage system (CT). The crops were cultivated with rational use of chemical phosphate fertilizer, according to plant needs and soil type maintaining high levels of soil organic carbon leading to P organic form accumulation. Growing crops during the winter period in highly weathered subtropical soil increases the importance of microbial interactions in the P cycle, especially in the NT, where a large amount of crop residues is annually added to the soil surface, increasing soil organic P level, P content stored into the SMB and acid phosphatase enzyme activity.