• Authors:
    • Huang, B.-X.
    • Christie, P.
    • Oenema, O.
    • Gao, B.
    • Ju, X.-T.
    • Su, F.
    • Hu, X.-K.
    • Jiang, R.-F.
    • Zhang, F.-S.
  • Source: Environmental Pollution
  • Volume: 176
  • Year: 2013
  • Summary: Here, we report on a two-years field experiment aimed at the quantification of the emissions of nitrous oxide (N2O) and methane (CH4) from the dominant wheat maize double cropping system in North China Plain. The experiment had 6 different fertilization strategies, including a control treatment, recommended fertilization, with and without straw and manure applications, and nitrification inhibitor and slow release urea. Application of N fertilizer slightly decreased CH4 uptake by soil. Direct N2O emissions derived from recommended urea application was 0.39% of the annual urea-N input. Both straw and manure had relatively low N2O emissions factors. Slow release urea had a relatively high emission factor. Addition of nitrification inhibitor reduced N2O emission by 55%. We conclude that use of nitrification inhibitors is a promising strategy for N2O mitigation for the intensive wheat maize double cropping systems.
  • Authors:
    • Gao, W.
    • Sui, P.
    • Chen, Y.
    • Huang, J.
  • Source: Science of The Total Environment
  • Volume: 456-457
  • Year: 2013
  • Summary: The net greenhouse gas balance (NGHGB), estimated by combining direct and indirect greenhouse gas (GHG) emissions, can reveal whether an agricultural system is a sink or source of GHGs. Currently, two types of methods, referred to here as crop-based and soil-based approaches, are widely used to estimate the NGHGB of agricultural systems on annual and seasonal crop timescales. However, the two approaches may produce contradictory results, and few studies have tested which approach is more reliable. In this study, we examined the two approaches using experimental data from an intercropping trial with straw removal and a tillage trial with straw return. The results of the two approaches provided different views of the two trials. In the intercropping trial, NGHGB estimated by the crop-based approach indicated that monocultured maize (M) was a source of GHGs (-1315 kg CO2-eq ha(-1)), whereas maize-soybean intercropping (MS) was a sink (107 kg CO2-eq ha(-1)). When estimated by the soil-based approach, both cropping systems were sources (-3410 for M and -2638 kg CO2-eg ha(-1) for MS). In the tillage trial, mouldboard ploughing (MP) and rotary tillage (RT) mitigated GHG emissions by 22,451 and 21,500 kg CO2-eq ha(-1), respectively, as estimated by the crop-based approach. However, by the soil-based approach, both tillage methods were sources of GHGs: -3533 for MP and -2241 kg CO2-eq ha(-1) for RT. The crop-based approach calculates a GHG sink on the basis of the returned crop biomass (and other organic matter input) and estimates considerably more GHG mitigation potential than that calculated from the variations in soil organic carbon storage by the soil-based approach. These results indicate that the crop-based approach estimates higher GHG mitigation benefits compared to the soil-based approach and may overestimate the potential of GHG mitigation in agricultural systems.
  • Authors:
    • Jamont,Marie
    • Piva,Guillaume
    • Fustec,Joelle
  • Source: Plant and Soil
  • Volume: 371
  • Issue: 1-2
  • Year: 2013
  • Summary: Legume-brassica intercrops may help to reduce N fertilizer input. We tested whether (i) intercropping with faba bean can improve N status of rapeseed, and (ii) root complementarity and/or N transfer is involved in such performance. Pre-germinated rapeseed and faba bean were grown either together or in monospecific rhizotrons (2 plants per rhizotron). Root growth was recorded. N rhizodeposition of the crops and N transferred between species were assessed using a N-15 stem-labelling method. Intercropped rapeseeds accumulated 20 % higher amounts of N per plant than monocultures. Up to 32 days after sowing, root distribution in the rhizotrons was favourable to physical sharing of the soil N: 64 % of faba bean root length was located in the upper part, as 70 % was in the lower part for rapeseed. At late flowering of the faba bean (52 days after sowing), N rhizodeposition of the two crops were similar and reached 8 to 9 % of the plant N. N transferred from the faba bean to the rapeseed was similar to that transferred from the rapeseed to the faba bean. Niche complementarity benefits more intercropped rapeseed than net N fluxes between species in the early growth.
  • Authors:
    • da Silva, P. B.
    • Wendling, B.
    • Cardoso, M. M.
    • Kondo, M. K.
    • Brant Albuquerque, C. J.
  • Source: Bioscience Journal
  • Volume: 28
  • Issue: 1
  • Year: 2012
  • Summary: The objective of this work was evaluated the physical attributes of soil and the main agronomic characteristics of sorghum for grain in no-tillage under different vegetation cover. The experiment was conducted during two growing seasons. In the first years were sown seven grass species in intercropping with sorghum for pasture establishment and the sorghum single defining the eight treatments. In the second season, when direct sowing of sorghum, forages available in the trial were previously desiccated for no-till sorghum. The areas representing the tillage had been barred again. In relation to soil physical properties, experiments were conducted under a randomized block design in factorial 8 (treatments) x 3 (depths) with four replications. Data related to the agronomic characteristics of the sorghum experiment was conducted in a randomized block design with four replications. It concluded with the work that the various forages used in the formation of vegetation for no-tillage affects both soil physical properties such as grain yield of sorghum.
  • Authors:
    • Tortosa, F.
    • Villafuerte, R.
    • Barrio, I.
  • Source: Wildlife Biology
  • Volume: 18
  • Issue: 1
  • Year: 2012
  • Summary: Damage caused by wildlife foraging can lead to significant agricultural losses and the problem can be further complicated if the damage-inducing animal is a valuable resource in its own right. Provision of alternative food sources such as cover crops might be a means of reducing the damage which appears to be linked to scarcity of alternative foods in intensively-managed agroecosystems. Cover crops may provide other benefits to agroecosystems, i.e. preventing soil erosion but can potentially have some undesired consequences, i.e. water competition with the cash crop. In our study, we tested the effectiveness of cover crops in reducing the damage caused by foraging European rabbit Oryctolagus cuniculus to vineyards in a semi-arid agroecosystem in southern Spain. Experimental treatments consisted of a combination of the presence/absence of sown cover crops (70% oat Avena sativa and 30% garden vetch Vicia sativa) with/without rabbit exclusion. In the 2009 growing season, we assessed rabbit-induced damage using a browsing index on vine shoots, rabbit use of plots was estimated based on faecal pellet counts and grapevine yield was measured at harvest. Rabbits ate the cover crops, and rabbit use was highest in the plots sown with the oat and vetch cover crop. However, the effect of the presence of the cover crop on the amount of damage caused by rabbits was limited and, moreover, the presence of the cover crop had a negative effect on grapevine yield. Exclosure fences effectively reduced rabbit damage by keeping rabbit densities close to zero, but even a low rabbit number (~1 rabbit/ha) can cause significant damage. Although cover crops provided rabbitswith an alternative food source, they acted as attractants for rabbits and were not effective in reducing the damage caused to vineyards by higher rabbit numbers. Therefore, adding cover crops might not be an effective measure in controlling rabbit-induced damage in semi-arid wine-growing regions.
  • Authors:
    • Desclaux, D.
    • Colomb, B.
    • Duputel, M.
    • Betencourt, E.
    • Hinsinger, P.
  • Source: Soil Biology & Biochemistry
  • Volume: 46
  • Year: 2012
  • Summary: Cereal-legume intercropping can promote plant growth (i.e. facilitation) through an increase in the amount of phosphorus (P) taken up, especially in low P soils. The aim of this study was to test the hypothesis that these positive interactions are supported by rhizosphere processes that increase P availability, such as root-induced pH changes. In neutral and alkaline soils legumes are assumed to increase inorganic P availability by rhizosphere acidification due to N 2 fixation which benefit to the intercropped cereal. Growth, P uptake, changes in inorganic P availability and pH in the rhizosphere of intercropped species were thus investigated in a greenhouse pot experiment with durum wheat and chickpea either grown alone or intercropped. We used a neutral soil from a P fertilizer long-term field trial exhibiting either low (-P) or high (+P) P availability. Phosphorus availability was increased in the rhizosphere of both species, especially when intercropped in -P. Such increase was associated with alkalization. Rhizosphere pH changes could not fully explain the observed changes of P availability though. Low rates of N 2 fixation may explain why no rhizosphere acidification was observed. Increases in P availability did not lead to enhanced P uptake but growth promotion was observed for durum wheat intercropped with chickpea in -P soil. Our hypothesis of an increase in inorganic P availability in intercropping as a consequence of root-induced acidification by the legume was not validated, and we suggested that root-induced alkalization was involved instead, as well as other root-induced processes. Thus, the cereal through rhizosphere alkalization may also enhance P uptake and growth of the intercropped legume. Facilitation can thus occur in both ways.
  • Authors:
    • Wang, J.
    • Kimmins, J.
    • Cao, F.
  • Source: Agroforestry Systems
  • Volume: 84
  • Issue: 3
  • Year: 2012
  • Summary: Intercropping Ginkgo and crop species in southern China is receiving increasing attention because it offers potential advantages for resource utilization, higher economic income to farmers and increased sustainability in crop production, We carried out a 2-year field intercropping system composed of Ginkgo with wheat, broad bean, and rapeseed, respectively, to determine the competitive interactions between the different species, and productivity and the economic yield of each intercropping system. The density of Ginkgo and crop species was varied systematically in a two-way density matrix composed of three monoculture densities and nine intercropping of all possible pairwise combinations of monoculture densities. Intercropping systems were assessed on the basis of several intercropping indices such as land equivalent ratio, relative crowding coefficient, relative competition intensity and vector competition analysis. The results showed that the combined biomass production of the component crop species was significantly greater in the Ginkgo/crop mixtures than in monocultures crops (Ginkgo, broad bean, wheat, and rapeseed). Ginkgo:rapeseed ratio 24:12, Ginkgo:bread bean ratio 24:5, and Ginkgo:wheat ratio 24:200 had the best total biomass production. Ginkgo:rapeseed (and broad bean) ratio 24:5 and Ginkgo:wheat ratio 24:200 in respective Ginkgo/crop mixtures had the maximum economic yield. Vector competition analysis showed that Ginkgo/rapeseed mixture exhibited an antagonistic interaction type and therefore is not suitable for intercropping. Ginkgo/broad bean mixture demonstrated the most beneficial effects among the three intercropping systems.
  • Authors:
    • Valaci, F.
    • Andrade, L.
    • Fonseca, G.
    • Andrade, M.
    • Carvalho, G.
    • Carvalho, W.
    • Oliveira, D.
  • Source: Revista Brasileira de Biociencias
  • Volume: 10
  • Issue: 1
  • Year: 2012
  • Summary: This study aimed at evaluating the allelopathic effect of species used as cover crops in no-tillage system on common bean crop. It was conducted in the greenhouse and at the Seed Analysis Laboratory in the Agricultural Department of the Federal University of Lavras, Brazil. The cover crop species used in the experiment were sunn hemp, jack bean, pigeon pea, black oat, sorghum and millet, with and without intercropping, with their straws collected at the early grain filling stage. The aqueous extracts of 5% and 10% (w/v) obtained from those straws were placed in plastic boxes (Gerbox-type) containing common bean seeds. The straws were also laid on the substrate surface sown with common bean in plastic pots and installed in the greenhouse for chemical and physical effects evaluation of the cover crops. Considering most of the variables studied, it was not verified any damage by either using of mulch or by applying allelopathic extracts. When used as mulch or when applied as aqueous extracts, residues from the intercropping between sunn hemp and sorghum positively affected the common bean plant, benefiting its initial growth.
  • Authors:
    • Li, B.
    • Qiao, B.
    • Zhang, C.
    • Chang, J.
  • Source: Journal of Fruit Science
  • Volume: 29
  • Issue: 2
  • Year: 2012
  • Summary: To improve ecological efficiency of Chinese jujube orchard and to further dig out its productive potentiality, comparative tests between intercropping wheat with Chinese jujube and single-cropping wheat were conducted. The results showed that intercropping wheat with Chinese jujube could obviously decrease dry-hot winds in wheat field; Bulk density and temperature of the soil were decreased, and the total porosity, capillary porosity, capillary moisture capacity and moisture capacity were apparently improved ( P
  • Authors:
    • Chapagain, T.
    • Riseman, A.
  • Source: American Journal of Plant Sciences
  • Volume: 3
  • Issue: 5
  • Year: 2012
  • Summary: A cultivar trial, including commercial and heirloom cultivars of major cereals and grain legumes was conducted in Vancouver, BC, under low input organic conditions. We assessed 19 wheat (6 commercial and 13 heirloom), 17 barley (8 commercial and 9 heirloom), 5 pea, 5 favabean, 5 kidneybean, 2 lentil, and 2 soyabean cultivars for plant performance metrics, and their potential in a small grain:legume intercropping system. Heirloom wheat cultivars showed notable response in a number of parameters including late maturity, taller plants, greatest number of spikes per m 2, longest spike, highest number of seed per spike, greater seed weight to volume ratio, and resistance to stripe rust compared with commercial cultivars. For the heirloom-type, 6 of 14 wheat cultivars, ( i.e., "Reward", "Glenn", "Cerebs", "Red Bobs", "Sounders" and "Black Bearded") produced yields comparable to the commercial cultivars ( i.e., nearly 5 t/h or higher). Also, heirloom cultivars typically contained higher protein levels most suitable for baking and blending purposes with "Einkorn" displaying the highest level (16.2%). Heirloom and commercial barley cultivars did not differ significantly with respect to plant height, spike length, and seed weight to volume ratio. However, a number of heirloom cultivars (e.g., "Jet", "Dolma", "Andie" and "Himalayan") displayed greater responses on earliness, number of spikes per m 2, grain yield, protein content and seed weight to volume ratio. Pea and lentil yielded lower than the national average under trial conditions. However, heirloom peas "Corgi", "De Grace", "Snowbird", and "Golden" were earlier compared to the commercial cultivar "Reward". All kidney bean cultivars yielded ~3 t/h with the highest yield from "Red Kidney" (3.8 t/h). Fava and soyabean appeared as promising crops as the cultivars produced good growth and yields. Neither lentil ("Crimson" and "Essex") produced satisfactory responses though they had excellent vegetative growth and flowered. Therefore, significant variation was observed including several heirloom cultivars displayed great potential in terms of yield, protein content, and disease resistance and that specific cultivars were better suited for an intercropping system.