• Authors:
    • Bagwan, N.
  • Source: International Journal of Plant Protection
  • Volume: 3
  • Issue: 2
  • Year: 2010
  • Summary: Crop root exudates of 20 crops like groundnut, soybean, pigeonpea, green gram, black gram, chickpea, pea, cowpea, mustard, cotton, castor, sunflower, safflower, sesamum, sorghum, pearl millet, maize, wheat, onion, and garlic were used in this study. Large variations of inhibitory effect of root exudates on S. rolfsii were observed. Low concentrations of root exudates (5% and 10%) had no effect on inhibition of mycelial growth and germination of sclerotia while, at high concentration (20%) inhibited the mycelial growth and germination of sclerotia. Mycelial growth, dry mycelium weight and sclerotial germination were recorded lowest in root exudates of sunflower, maize, pearl millet, sorghum, safflower, garlic, and onion. Mycelial growth, dry mycelium weight and sclerotial germination was recorded highest in root exudates of soybean, groundnut, green gram, black gram, pigeonpea, chickpea, pea and cowpea. It was observed that the root exudates of maize, sunflower and pearl millet showed a highest percentage of inhibition of mycelial growth and sclerotial germination. Another interesting of thing was observed that root exudates of groundnut, soybean and pea stimulate the mycelial growth and germination of sclerotia as compared to control. The results of this study suggested that the intercropping or crop rotation of safflower, maize, pearl millet, sorghum, sunflower, garlic, and onion with groundnut may be useful for the management of stem rot of groundnut and also for reduction of soil population of S. rolfsii in groundnut field. Similarly intercropping or crop rotation of soybean, green gram, black gram, chickpea, pea and cowpea with groundnut should be avoided. Based on these findings, it is hypothesized that root exudates of some crops contain antifungal compounds, while other stimulate the growth of fungal pathogens. Cultivation of safflower, maize, pearl millet and sorghum with groundnut could lead to a reduction in the occurrence of stem rot disease, especially when chemical control is not effective and economically costly. However, further investigation is necessary for isolation and identification of antifungal compounds in root exudates related to host-pathogen interaction.
  • Authors:
    • Mal'tsev, N.
    • Tsybikov, B.
    • Korshunov, V.
    • Batudaev, A.
  • Source: Russian Agricultural Sciences
  • Volume: 36
  • Issue: 6
  • Year: 2010
  • Summary: The performance of the following rotation systems with various types of fallow was evaluated at the steppe zone of Transbaikalia, Russia, during 1997-2007: clean fallow [fallow without ground cover]-wheat-oat-oat for biomass (T1); fallow with yellow sweet clover [ Melilotus officinalis]-wheat-clean fallow-yellow sweet clover (T2); fallow with yellow sweet clover-wheat-clean fallow-wheat + yellow sweet clover (T3); fallow with yellow sweet clover-wheat-oat-oat + yellow sweet clover for biomass (T4); fallow with oilseed radish-wheat-oat-oat for biomass (T5); oat for biomass-wheat-oat-oat for biomass (T6); and wheat-wheat-oat-clean fallow (T7). Spring wheat yields and productivity values recorded for fallow with yellow sweet clover (T2, T3 and T4) were as high as those registered for clean fallow (T1). The highest profitability values were obtained with T2 (172.0%) and T4 (170.0%).
  • Authors:
    • Bedoussac, L.
    • Justes, E.
  • Source: Plant and Soil
  • Volume: 330
  • Issue: 1/2
  • Year: 2010
  • Summary: In a previous paper [Bedoussac L, Justes E ( 2009) Plant Soil, doi: 10.1007/s11104-009-0082-2], we showed that intercropping of durum wheat and winter pea increased the yield and protein concentration of durum wheat when early N availability was less than 120 kg N ha -1. The aim of the present work was to understand these results by analysing intercrop species dynamics for growth, light and N acquisition. A 2-year field experiment was carried out in southwest France with different fertilizer-N levels in order to compare wheat ( Triticum turgidum L.) and pea ( Pisum sativum L.) grown as sole crops and as an intercrop in a row substitutive design. The advantages of intercropping in low N conditions were due mainly to: (1) better light use (up to 10%), thanks to species dynamic complementarity for leaf area index and height; (2) growth complementarity over time (higher growth rate of wheat until pea flowering and then of pea until wheat flowering); and (3) dynamic complementary N acquisition associated with better wheat N status throughout growth. Disadvantages, underlining poorer complementarity within the intercrop stand, were observed with ample available N in early growth. This induced higher cereal growth during winter, which led to increase interspecies competition by reducing pea light absorption and, consequently, its biomass production.
  • Authors:
    • Bedoussac, L.
    • Justes, E.
  • Source: PLANT AND SOIL
  • Volume: 330
  • Issue: 1/2
  • Year: 2010
  • Summary: Grain protein concentration of durum wheat is often too low, particularly in low-N-input systems. The aim of our study was to test whether a durum wheat-winter pea intercrop can improve relative yield and durum wheat grain protein concentration in low-N-input systems. A 2-year field experiment was carried out in SW France with different fertilizer-N levels to compare wheat ( Triticum turgidum L., cv. Nefer) and pea (winter pea, Pisum sativum L., cv. Lucy) grown as sole crops or intercrops in a row-substitutive design. Without N fertilization or when N was applied late (N available until pea flowering less than about 120 kg N ha -1), intercrops were up to 19% more efficient than sole crops for yield and up to 32% for accumulated N, but were less efficient with large fertilizer N applications. Wheat grain protein concentration was significantly higher in intercrops than in sole crops (14% on average) because more N was remobilized into wheat grain due to: (i) fewer ears per square metre in intercrops and (ii) a similar amount of available soil N as in sole crops due to the high pea N 2 fixation rate in intercrops (88% compared to 58% in sole crops).
  • Authors:
    • Yaduraju, N. T.
    • Das, T. K.
    • Tadesse, B.
  • Source: Weed Biology and Management
  • Volume: 10
  • Issue: 3
  • Year: 2010
  • Summary: Parthenium is widely distributed across the uncropped areas of the tropics. It has slowly encroached into many crops and causes considerable yield loss. It heavily infests sorghum, which is widely cultivated by the resource-poor farmers in Africa and Asia. Its interference and management in sorghum in these cropping systems is not well understood. Therefore, this experiment was undertaken to determine the appropriate parthenium management techniques to use in sorghum crops. All the studied weeds, in combination with parthenium, offered greater competition to sorghum than parthenium alone. Similarly, under a composite stand of weeds, parthenium was inferior in competitiveness to the other weeds until 60 days after sowing (DAS); by 90 DAS, it could accumulate a higher dry weight due to its consistent growth. A pre-emergence treatment of atrazine (0.75 kg ha -1) with wheat straw mulch (5.0 t ha -1) brought about a consistent and significant reduction in the parthenium growth and, consequently, increased the sorghum yield by 90.8%. Cowpea intercropping with and without pendimethalin (1.0 kg ha -1) as a pre-emergence treatment could not control parthenium between 0 and 60 DAS, but could reduce the parthenium growth during the later period of 60-90 DAS, which resulted in a significant increase in sorghum growth. These intercropping treatments increased the sorghum grain yield by 156.2% and 142.4%, respectively, over the unweeded control and by 18.5% and 12.1%, respectively, over the weed-free control. These treatments also promoted a higher uptake of N, P, and K by the sorghum crop. Thus, cowpea intercropping was the most effective method for parthenium management vis-a-vis sorghum yield improvement, followed by cowpea intercropping with pendimethalin and then by atrazine as a pre-emergence treatment with wheat straw mulch.
  • Authors:
    • Hinsinger, P.
    • Souche, G.
    • Justes, E.
    • Colomb, B.
    • Betencourt, E.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world
  • Year: 2010
  • Summary: We need to aim for ecological intensification of agroecosystems, in order to cover an increasing global food demand while decreasing agricultural inputs such as fertilisers is required to maintain ecosystem services. Increasing the efficiency of nutrients to plants while decreasing nutrient inputs means that better exploration and exploitation of soil resources must be achieved in agroecosystems. This paper focusses on intercropping, which proved efficient to increase agroecosystem productivity, via better exploitation of soil resources. We studied the underlying processes of acquisition of soil phosphorus (P) by plants in cereal/legume agroecosystems, with a particular focus on rhizosphere processes. The working hypothesis is that the two intercropped species may access different P pools, the legume being responsible for greater changes in P availability in the rhizosphere, as a consequence of root-induced acidification resulting from nitrogen fixation. We sampled the rhizosphere of field-grown plants at two stages of growth of durum wheat and pea/faba bean along a gradient of soil P availability. Available P increased in the rhizosphere, especially for the legumes, and more so when intercropped. This was possibly due to the increased proportion of nitrogen fixation in the intercropped legumes, thereby resulting in inter-species facilitation for P acquisition.
  • Authors:
    • Molnar, L. J.
    • Blackshaw, R. E.
    • Moyer, J. R.
  • Source: Canadian Journal of Plant Science
  • Volume: 90
  • Issue: 4
  • Year: 2010
  • Summary: Farmers on the Canadian prairies are interested in including legume cover crops in their cropping systems to reduce fertilizer inputs and improve farm sustainability. A field study was conducted to determine the merits of establishing alfalfa ( Medicago sativa L.), red clover ( Trifolium pratense L.) or Austrian winter pea ( Pisum sativum L.) cover crops in fall or in spring with winter wheat ( Triticum aestivum L.). Spring-planted legumes emerged well within the winter wheat crop, but their growth was limited under these semi-arid conditions. Fall-planted red clover had low plant densities following winter in two of three experiments and fall-planted winter pea reduced winter wheat yield by 23 to 37% compared with the no cover crop control. In contrast, fall-planted alfalfa exhibited good winterhardiness, provided some weed suppression without reducing winter wheat yield, caused only a slight reduction in soil water content, and contributed an extra 18 to 20 kg ha -1 of available soil N at the time of seeding the following spring crop. Additionally, fall-planted alfalfa increased the yield of succeeding canola ( Brassica napus L.) in unfertilized plots in two of three experiments. Further research is warranted to better understand the agronomic and economic benefits of alfalfa-winter wheat intercrops under a wider range of environmental conditions.
  • Authors:
    • Sarma, K. K.
    • Debnath, M. C.
    • Borah, B. K.
    • Das, B.
  • Source: Insect Environment
  • Volume: 15
  • Issue: 4
  • Year: 2010
  • Summary: Gram pod borer, Helicoverpa armigera Hubner is the most important pest on chickpea. The present study was undertaken to study the effect of different intercrops on the incidence of gram pod borer on chickpea. The experiment was conducted at Regional Agricultural Research Station, Shillongani, Nagaon (North-east India) in rabi season, 2007-2008. Seven crops were used as intercrops viz., linseed, marigold, wheat, mustard, fennel, coriander and garlic. The chickpea variety, PantG-186 was sown in 5 x 4m size plots and the ratio with intercrop was 4:1, except the sole crop which was used as check. Each intercrop was replicated thrice in RBD. Recommended package of practices were followed. For observation of larvae, ten plants were selected randomly from each plot and their count was recorded weekly. Similarly, for pod damage, ten plants randomly selected were uprooted at harvest and per cent pod damage was assessed by counting all the pods.
  • Authors:
    • Alda, L.
    • Baluta, D.
    • Manea, D.
    • Alda, S.
    • Lazureanu, A.
    • Caciu, G.
    • Circiu, L.
  • Source: Journal of Horticulture, Forestry and Biotechnology
  • Volume: 14
  • Issue: 2
  • Year: 2010
  • Summary: The research was conducted in 2008-2009 and followed the influence of six plants run on the cover of plants with weeds plants culture and production of winter wheat. Predominant weeds were Veronica hederifolia, Viola arvensis, Polygonum Convolvulus, Convolvulus arvensis and Stellaria media. The degree of reduction of weeds, depending on pre-plant fluctuated between 17,84 and 28%, 43% in 2008 and between 20.49% and 29.58% in 2009. Production is directly proportional to the absolute level of covering plants with weeds plants, beings from 38.05 q/ha and 43.26 q/ha in 2008 and between 44.72 q/ha and 52.08 q/ha in 2009.
  • Authors:
    • Wang, J.
    • Jolliffe, P.
    • Kimmins, J.
    • Cao, F.
  • Source: Agroforestry Systems
  • Volume: 79
  • Issue: 3
  • Year: 2010
  • Summary: Ginkgo ( Ginkgo biloba L.) is a multi-value deciduous tree species grown for the production of nuts, timber and foliage for medicinal products. Understanding the ecological and biological basis for Ginkgo agroforestry systems is essential for the design of optimum Ginkgo-crop species combinations. We established two greenhouse replacement series to examine interactions between Ginkgo and wheat ( Triticum aestivum L.); and Ginkgo and broad bean ( Vicia faba L.). The results showed that crop species were more competitive than Ginkgo at low Ginkgo density, but less competitive than Ginkgo at high Ginkgo density. Ginkgo: wheat ratio 5:1 and Ginkgo: broad bean ratio 5:1 had relative yield total (RYT) and relative land output (RLO) values of more than one and the largest total land output (TLO) values in respective mixtures. Therefore, these two ratios might be considered optimum Ginkgo: crop ratio for enhancing the combined biomass of the Ginkgo and crop in respective mixtures. Broad bean and wheat were more competitive than Ginkgo, which was less affected by wheat than by broad bean. However, there were compensatory interactions between Ginkgo and wheat, and Ginkgo and broad bean. There was significant belowground competition for soil N between Ginkgo and the two crop species in the Ginkgo/crop mixtures. The two mixtures outperformed monocultures of the individual species when comparing the mixtures with the crop monoculture system.