• Authors:
    • Lajeunesse, J.
    • Pageau, D.
    • Reid, J. F.
    • Collin, J.
    • Vanasse, A.
    • Lanoie, N.
    • Durand, J.
  • Source: CROP SCIENCE
  • Volume: 50
  • Issue: 5
  • Year: 2010
  • Summary: Naked oat ( Avena sativa L.) grown in Quebec, Canada, produces an average of 10% covered grains. The objectives of this study were to evaluate the effects of environment, herbicide, and genotype on the proportion of covered grains, to study the relation between the presence of awns and the proportion of covered grains, and to determine the location of covered grains on the plant (tiller) and on the panicle. Eight oat lines were evaluated over 2 yr at four experimental sites. Each line was treated with bromoxynil/MCPA, dicamba/MCPA, or thifensulfuron methyl/tribenuron methyl applied at Zadoks 12-13 and compared to a hand-weeded check. The highest percentages of covered grains, 5.5 and 6.9%, were found at different sites in 2006 and 2007. The application of dicamba/MCPA increased the percentage of covered grains in the lines normally producing a higher proportion of covered grains, but low producing lines were less affected. Minor differences were found among the other weed control treatments. No relation was found between the presence of awns and the proportion of naked grains. Covered grains were mostly produced on the main stem and their position on the panicle depended on genotype and weed control treatment.
  • Authors:
    • Li, L.
    • Chen, W.
    • Sun, J.
    • Hu, H.
    • Yu, C.
    • Li, Q.
  • Source: Plant Nutrition and Fertilizer Science
  • Volume: 16
  • Issue: 4
  • Year: 2010
  • Summary: In a field micro-plot experiment in China of three intercropping systems (barley/maize, wheat/maize, faba bean/maize) and their corresponding sole cropping systems, nitrogen (N) was applied at N 0 and 225 kg/ha, and N absorption and use efficiency and its accumulation on the soil profile were investigated. The competitive ability of crops for nutrients was closely related to the concentration and accumulation of mineral nitrogen in the root zone of the plants. Accumulation of mineral nitrogen under barley or wheat strips intercropped with maize decreased by 203-282 or 107-171 kg/ha in the 0-100 cm soil profile, respectively, compared with faba bean intercropped with maize. Accumulation of mineral nitrogen under maize strips intercropped with barley or wheat was reduced by 93-120 or 56-87 kg/ha compared with maize intercropped with faba bean, respectively. Crop types, interspecific competition and soil condition affected accumulation of mineral nitrogen in the soil profile. Interspecific interaction increased nitrogen recovery efficiency for barley and wheat intercropped with maize and decreased that for maize intercropped with barley and wheat. Nitrogen use efficiency was the highest in the no-N treatment for competitive intercropping systems (barley/maize or wheat/maize). Nitrogen harvest index was reduced in barley and wheat with N fertilizer application, but increased in maize and not changed in faba bean. It is concluded that competition between crops, soil fertility status, fertilizer rate and cultural measures should be considered carefully in order to achieve intercropping advantage when associated crops are chosen. Complement systems of legumes/cereals are recommended for low soil fertility and competitive systems of cereals/cereals for high soil fertility.
  • Authors:
    • Lithourgidis, A.
    • Dordas, C.
  • Source: Crop Science
  • Volume: 50
  • Issue: 5
  • Year: 2010
  • Summary: Annual cool-season grain legumes like faba bean ( Vicia faba L.) grown in mixtures with winter cereals such as wheat ( Triticum aestivum L.), barley ( Hordeum vulgare L.), or rye ( Secale cereale L.) may offer advantages over cereal-alone crops grown for forage production. A 2-yr field study was conducted to evaluate the effects of intercropping faba bean with each of the above cereals in three seeding ratios (i.e., 75:25, 50:50, and 75:25) on growth rate, plant height, chlorophyll content, forage yield, and N uptake. Growth rate of faba bean and cereals was lower in the mixtures than in the monocultures, especially in the faba bean-barley mixtures because of the strong competitive ability of barley. Chlorophyll content was lower in faba bean compared with the cereals, and there was no difference among seeding ratios. Plant height of faba bean was higher in the intercrops compared with its monocrop at 3 wk after tillering (WAT), whereas at 6 WAT, the trend was different since faba bean plants in the monocrop were higher than in the intercrops. Rye monocrop and rye-faba bean intercrops provided the greatest forage yield. Although the three intercrops of faba bean with rye had lower crude protein (CP) content than the faba bean monocrop, they provided the highest CP yields per hectare because of their higher forage yield than the faba bean monocrop.
  • Authors:
    • Liu Qian
    • Zhang TingWei
    • Liu ChangZhong
  • Source: Guizhou Agricultural Sciences
  • Issue: 6
  • Year: 2010
  • Summary: The results from studying the effect of inter-cropping of wheat with different crops on occurrence quantity of wheat aphid at flowering and filling stage of wheat showed that the aphid occurrence quantity of inter-cropping of wheat with maize or Helianthus annuus or soybean significantly lower than wheat single cultivation, there was significantly difference in aphid occurrence quantity among three inter-cropping patterns and the aphid occurrence quantity of wheat/maize inter-cropping pattern was the lowest, followed by wheat/ Helianthus annuus inter-cropping pattern.
  • Authors:
    • Duan, Z.
    • Dong, Y.
    • Tang, L.
    • Zheng, Y.
    • Zhao, P.
    • Lu, Y.
  • Source: Journal of Triticeae Crops
  • Volume: 30
  • Issue: 2
  • Year: 2010
  • Summary: Field and pot experiments were carried out in China to investigate the effects of intercropping wheat with faba bean on manganese uptake by wheat plants grown under a paddy-upland rotation system. Samples of wheat plants and rhizosphere soil were taken at the tillering, stem elongation, heading, milking and ripening stages of wheat for various determinations. Exchangeable manganese (NH 4OAC-Mn) in the soil rhizosphere of intercropping wheat was significantly higher than that of continuous cropping. NH 4OAC-Mn content of row 1 (IW1) and row 3 (IW3) of intercropping wheat increased by 21.09% and 7.78% in the field experiment and by 37.63% in the pot experiment, respectively. However, manganese absorption of wheat intercropping showed no advantage at the stem elongation stage before heading. After heading, faba bean intercropped with wheat promoted the absorption of manganese in wheat. Manganese accumulation in the above-ground parts of wheat in IW1 and IW3 increased by 39.30% and 29.06% at the heading stage, by 51.50% and 65.30% at the milking stage and by 36.17% and 13.86% at the ripening stage in the field experiment, respectively. In the pot experiment, manganese accumulation in the above-ground intercropping wheat increased by 107.46, 36.07, 26.67, and 20.92%, respectively, at the tillering, stem elongation, milking and ripening stages. However, NH 4OAC-Mn content in rhizosphere soil of intercropping showed no accumulation. In conclusion, intercropping faba bean with wheat increased manganese available in the rhizosphere soil before heading and its uptake by the above-ground parts of the wheat plants, especially leaves and spike, at the milking stage.
  • Authors:
    • Jing, Q.
    • Dai, T.
    • Wollenweber, B.
    • Jiang, D.
    • Mu, H.
    • Cao, W.
  • Source: Journal of Agronomy and Crop Science
  • Volume: 196
  • Issue: 1
  • Year: 2010
  • Summary: Low radiation reduces wheat grain yield in tree-crop intercropping systems in the major wheat planting area of China. Here, two winter wheat ( Triticum aestivum L) cultivars, Yangmai 158 (shading tolerant) and Yangmai 11 (shading sensitive), were shaded from jointing to maturity to evaluate the impact of low radiation on crop growth, photosynthesis and yield. Grain yield losses and leaf area index (LAI) reduction were less than the reduction in solar radiation under both shading treatment in both cultivars. Compared with the control (S0), grain yield only reduced 6.4% and 9.9% under 22% shading treatment (S1), while 16.2% and 25.8% under 33% shading (S2) in Yangmai 158 and Yangmai 11 respectively. The reduction in LAI was 6.0% and 9.2% (S1), and 18.2% and 22.2% (S2) in Yangmai 158 and Yangmai 11 respectively. However, decline in canopy apparent photosynthetic rate (CAP) was 15.0-22.9% (S1) and 29.5-49.6% (S2), which was consistent with the reduction in radiation. The reduction in LAI was partially compensated by increases in the fraction of the top and bottom leaf area to the total leaf area, which facilitated to intercept more solar radiation by the canopy. The decrease in photosynthetic rate ( Pn) of flag leaf was partially compensated by the increase in Pn of the third leaf from the top. In addition, an inconsistency between the low Pn and the high Chl content in flag leaf was observed at 30 DAA. This could be explained that more excitation energy was dispersed via the non-photochemical approaches in the photosystem II (PSII) of flag leaf after long-term shading.
  • Authors:
    • Crozat, Y.
    • Pineau, S.
    • Corre-Hellou, G.
    • Naudin, C.
    • Jeuffroy, M. H.
  • Source: Field Crops Research
  • Volume: 119
  • Issue: 1
  • Year: 2010
  • Summary: Cereal-legume intercrops are a promising way to combine high productivity and several ecological benefits in temperate agro-ecosystems. However, the proportion of each species in the mixture at harvest is highly variable. The aim of this study was to test whether the timing of small application of N fertilizer is an effective way of influencing the dynamic interactions between species during crop growth and affecting the percentage of each species in the biomass of the mixture without greatly disturbing N 2 fixation. The influence of timing of nitrogen fertilization in pea-wheat intercrops was studied as regards (i) the dynamics of crop growth, (ii) nitrogen acquisition of each species, (iii) the inhibition and recovery of symbiotic N 2 fixation (SNF) after N application and (iv) final performance (yield, % of wheat, grain protein content). This was assessed in winter pea-wheat ( Pisum sativum L.- Triticum aestivum L.) intercrops in 2007 and 2008 at two locations in France. Whatever the stage of application, N fertilizer tended to increase wheat growth and to decrease pea growth. N fertilization (applied once at different dates from tillering to the end of stem elongation) delayed the decrease in the contribution of wheat to total biomass and maintained the competitive ability of wheat over pea for longer than in unfertilized intercrops. N acquisition dynamics and N sharing between the two species were modified by N fertilization and its timing. Crop conditions at the time of N application (growth and phenology of each species, and their proportions in the intercrop biomass) greatly influenced intercrop response to N fertilization. Partitioning between species of soil and fertilizer N was correlated with the proportion of wheat in the total intercrop biomass observed at the date of N application. Short-term inhibition of nitrates on SNF was shown during the few days after N application, whatever its date. SNF recovery after N applications was observed only until pea flowering, but was prematurely stopped by N fertilization after this stage. The effect of N fertilization on the amount of fixed N 2 at harvest was correlated with pea biomass. N fertilization affects N 2 fixation mainly by affecting crop growth rather than %Ndfa in pea-wheat intercrops. In conclusion, N fertilization could be used as a tool to enhance the contribution of wheat in the intercrop biomass but may reduce the amount of fixed N 2 in the intercrop by decreasing pea biomass.
  • Authors:
    • Gill, R. I. S.
    • Baljit, S.
    • Navneet, K.
  • Source: Indian Journal of Agronomy
  • Volume: 55
  • Issue: 1
  • Year: 2010
  • Summary: Field experiments were done to standardize the agronomic practices of wheat grown in association with poplar ( Populus deltoides Bartr.) plantation at Ludhiana, Punjab. The study was conducted under block plantation of poplar (Clone G-48) grown at a spacing of 5*4 m, (accommodating 500 trees/ha) at the age of 2, 3 and 4 years in 2004, 2005 and 2006, respectively. The soil of the site was low in available N and medium in available P. Three seed rates (100, 125 and 150 kg/ha) and combinations of 3 N (125, 187.5 and 250 kg N/ha) and 2 P levels (27 and 40.5 kg P/ha) were evaluated to find out the optimum fertilizer and seed requirement of wheat (cv. PBW 343) intercropped with poplar. The height and diameter of trees increased from 10.4-15.1 m and 10.4-16.5 cm, respectively in the span of 2 years (2004-06). Wheat yield under poplar reduced with the increase in tree age. However, the crop under poplar responded positively to higher fertilizer and seed rates. The yield of sole wheat was significantly higher when compared with intercropped wheat. Among 3 seed rates, 25% additional seed rate (125 kg/ha) over recommended to sole wheat significantly increased (6%) the grain yield of wheat under poplar plantation. Among different fertilizer levels, grain yield of wheat was significantly higher (3.93 tonne/ha) at 50% additional N than recommended to sole wheat with recommended P i.e. at 187.5 kg N and 27 kg P/ha. N and P uptake by wheat was higher in sole wheat than under poplar. Additional application of seed and nutrients over the recommended levels significantly increased their uptake. The benefit cost ratio in poplar plantation were highest with the application of 150 kg/ha seed and 187.5+27 kg N+P/ha to wheat.
  • Authors:
    • Meinhardt, C. G.
    • Nelson, K. A.
    • Smoot, R. L.
  • Source: International Journal of Agronomy
  • Volume: 2010
  • Year: 2010
  • Summary: Field research (2003-2005) evaluated the effect of wheat row spacing (19 and 38 cm) and cultivar on double-cropped (DC) soybean response, 38-cm wheat on relay-intercrop (RI) response, and wheat cultivar selection on gross margins of these cropping systems. Narrow-row wheat increased grain yield 460 kg ha -1, light interception (LI) 7%, and leaf area index (LAI) 0.5 compared to wide rows, but did not affect DC soybean yield. High yielding wheat (P25R37) with greater LI and LAI produced lower (330 kg ha -1) soybean yields in an RI system than a low yielding cultivar (Ernie). Gross margins were $267 ha -1 greater when P25R37 was RI with H431 Intellicoat (ITC) soybean compared to Ernie. Gross margins were similar for monocrop H431 non-coated (NC) or ITC soybean, P25R37 in 19- or 38-cm rows with DC H431 NC soybean, and P25R37 in 38-cm rows with RI H431 ITC soybean in the absence of an early fall frost.
  • Authors:
    • Burdick, B.
    • Smoot, R.
    • Nelson, K.
  • Source: Crop Management
  • Issue: July
  • Year: 2010
  • Summary: Soybean seeded [ Glycine max (L.) Merr.] early into standing wheat ( Triticum aestivum L.) using relay intercropping (RI) and seed-coat technology may reduce mechanical damage and soybean interference to wheat. Field research at Novelty from 2003 to 2005 and Albany in 2004 evaluated effects of seed coat technology on wheat and soybean response, and gross profits of RI soybean using seed coat technology compared with selected full season (FS) wheat or soybean and double crop (DC) wheat-soybean. Wheat grain yield in the absence of soybean was 10 bu/acre greater in narrow (7.5-inch) than wide (15-inch) rows. Relay intercropped Intellicoat (ITC) treated 5143 soybean delayed germination and increased 15-inch wheat grain yields 8 bu/acre compared to non-coated (NC) 5143. At Novelty, RI 5143 ITC yield was similar in all three years and 7 bu/acre greater at Albany than 5143 NC. In 2005, dry conditions in mid- to late June reduced RI stands and yields compared to DC soybean at Novelty. Double-cropped 5143 NC soybean had greater gross profits than RI 5143 ITC when wheat and soybean prices were high. However, RI 5143 ITC gross profits were greater when soybean prices were high and wheat prices were low. The RI system using ITC maintained soybean yields and did not reduce wheat yields due to mechanical damage or soybean interference compared to non-coated or fungicide-only coating.