• Authors:
    • Klimek, S.
    • Steinmann, H-H
    • Ulber, L.
    • Isselstein, J.
  • Source: Weed Research
  • Volume: 49
  • Issue: 5
  • Year: 2009
  • Summary: Weed species diversity may benefit from organic farming due to enhanced temporal diversification of crop species in a rotation and omission of herbicide applications. However, in intensively managed conventional systems, little evidence exists as to what extent diversified crop rotations contribute to higher weed species richness. Using an on-farm approach, the effect of crop rotation (organic, conventional diverse (CD) and conventional simple (CS) crop rotations) and weed control (with vs. without) on weed species richness, cover, community composition and crop biomass, was analysed in 24 winter wheat fields. Weed species with beneficial functions for invertebrates and birds were analysed separately. Weed species richness was higher in the organic crop rotation, but did not differ between CD and CS crop rotations. Weed control treatment reduced species richness in both conventional rotations, but not in the organic one. Redundancy analyses revealed that crop rotation intensity accounted for the largest part of the explained variation in weed species composition. Results from the study indicate that the maintenance of weed species richness and conservation of species with important ecological functions requires not only temporal diversification of crop species in the rotation, but also an adjustment of weed control strategies.
  • Authors:
    • Zudilin, S. N.
  • Source: Kormoproizvodstvo
  • Issue: 2
  • Year: 2009
  • Summary: Productivity of fodder crop rotation was studied in the Samara Region, Russia in 1993-2004. The fodder crop rotation consisted of 7 following combinations: (1) rape and radish; (2) winter wheat; (3) pea; (4) maize; (5) vetch and oat; (6) pea and barley and (7) goat's-rue. The most productive crop was goat's-rue which showed green mass yield of 20.27 t/ha. Rape, maize, vetch and oat mix had green mass yield of 19.78, 20.11 and 16.42 t/ha, respectively. Winter wheat and pea produced 2.4 and 1.18 t/ha of grain, respectively. Application of mineral fertilizers increased yield by 25-40%. Detailed data are presented in 2 tables.
  • Authors:
    • Hedtcke, J. L.
    • Posner, J. L.
    • Chavas, J. P.
  • Source: Agronomy Journal
  • Volume: 101
  • Issue: 2
  • Year: 2009
  • Summary: This article, the second in a series looking at the Wisconsin Integrated Cropping Systems Trial (WICST), reports on the profitability of six conventional and organic systems, with a focus on net returns and associated risk exposure. Several pricing scenarios were compared to evaluate the impact of government programs and organic price premiums. When net return estimates are made using only neighboring elevator prices (no government programs or organic price premiums), we found that the no-till corn-soybean system [ Zea mays L. and Glycine max (L.) Merr.] was the most profitable grain system, and management intensive rotational grazing (MIRG) the most profitable forage system. When government programs and organic price premiums are included, returns increased by 85 to 110% for the organic grain system corn-soybean-wheat+red clover ( Triticum aestivum L.+ Trifolium pratense L.) and 35 to 40% for the organic forage system [companion seeded alfalfa with oat+field pea ( Medicago sativa L., Avena sativa L., and Pisum sativum L.), hay, and then corn]. This places both organic systems with higher returns than any of the Midwestern standards of no-till corn-soybean, continuous corn, or intensive alfalfa production. Also, the results indicate how risk exposure varied across systems. Interestingly, taking risk into consideration did not drastically affect the ranking among those systems. Our analysis shows that, under the market scenarios that prevailed between 1993 and 2006, intensive rotational grazing and organic grain and forage systems were the most profitable systems on highly productive land in southern Wisconsin.
  • Authors:
    • Madar, R.
    • Cosma, C.
    • Vuşcan, A.
    • Samuel, A. D.
    • Jurcă, A.
    • Ciobanu, G.
    • Domuta, C.
    • Ciobanu, C.
    • Albu, R.
    • Şandor, M.
  • Source: Bulletin of the University of Agricultural Sciences & Veterinary Medicine Cluj-Napoca
  • Volume: 66
  • Issue: 1
  • Year: 2009
  • Summary: The paper based on the research carried out during 2005-2008 in the long term trial placed in 1990 on the preluvosoil from Oradea. The monoculture of maize, maize-wheat and maize-soybean-wheat crop rotations were studied in unirrigated and irrigated conditions. The crop rotation of six years (oat+clover-clover-maize-wheat-maize-sunflower) was studied in unirrigated conditions. The research emphasized that the monoculture is the most responsible for the pest multiplication. In maize monoculture the larvae number on the roots was ranged between 4.91-8.23 and root attack degree in IOWA scale (with marks from 1 to 6 in which maximum attack is 6), had values between 3.84 and 5.62 and the frequent of attacked plants with the symptom "goose neck" ranged between 16,4% and 31.2% and larval aggressiveness being higher in the case of favorable soil moisture in irrigated condition. The maize rotation with other plants interrupts the biologic pest cycle. The results obtained emphasize that later maize sowing alongside by the utilizing of lower plant thickness level contribute to prevention of pest multiplication, while earlier sowing at high thickness favor the larvae developing.
  • Authors:
    • Mermillod, G.
    • Bohren, C.
    • Wirth, J.
    • Delabays, N.
    • de Joffrey, J. -P
  • Source: Revue Suisse d'Agriculture
  • Volume: 41
  • Issue: 6
  • Year: 2009
  • Summary: Allelopathy, the interaction between plants mediated by chemicals, is drawing growing interest the last few years, especially in agriculture. This phenomenon Could be helpful to optimise weed management in cultivated fields, for instance through allelopathic cultivars breeding, laying of allelopathic ground covers or insertion of allelopathic crops in the rotation scheme. This approach is welcome, particularly with present need of alternatives to chemical weed control. Nevertheless, allelopathy still remains controversial, mainly because it is often difficult to unambiguously distinguish it experimentally from competition effects. This paper presents a synthesis of our results with Artemisia annua, producing artemisinin, a molecule with very potent phytotoxic propel-ties. The mose of action of artemisinin could be demonstrated under lab, greenhouse and field conditions, whereby confirming the reality of allelopathic phenomenon. Preliminary results are also presented concerning the putative role played by this molecule in natural conditions. Lastly, ongoing works using others species, aimed at providing a practical use of allelopathy for weed management of cultivated fields, is briefly described.
  • Authors:
    • Tarau, D.
    • Borza, I.
    • Dicu, D.
  • Source: Research Journal of Agricultural Science
  • Volume: 41
  • Issue: 2
  • Year: 2009
  • Summary: This study was conducted on a cambic chernozem in the Banat-Crisana Plain (Romania) to determine the quantitative and qualitative influence of tillage and fertilizer modifications made on the agroecosystem level on wheat, maize and soyabeans. The treatments include with and without deep soil working, conventional and no-tillage, and with (P1, N 80P 80K 80; P2, N 160P 80K 80) and without fertilizer application. Wheat was sown in 17 October 2007 and harvested in 28 June 2008. Maize was sown in 20 April 2008 and harvested in 27 Septerm 2008. Soyabean was sown 22 April 2008 and harvested in 11 October 2008. The field under the no-till system was maintained with more weeding than the conventional tillage. In terms of the evolution of soil humidity, more uniform values were obtained in the soil profile of the no-till system, while a low increase in soil water content was observed in the fields with deep working of soil. For wheat, the highest yield (4579 kg/ha) was obtained from the no-till system without deep working of the soil with P2 treatment, while the lowest yield (3475 kg/ha) was obtained from the conventional tillage system with deep soil working without fertilizer. For maize, the highest yield (5749 kg/ha) was obtained under the no-till system without deep working of soil with P2 treatment, while the lowest yield (3415 kg/ha) in classic system with deep work of soil without fertilizer. For soyabeans, the highest yield (1988 kg/ha) was obtained from the conventional tillage system without deep working of soil with P2 treatment, while the lowest (880 kg/ha) was obtained from the no-till system with deep working of soil without fertilizer treatment.
  • Authors:
    • Sabau, N. C.
    • Domuta, C.
    • Borza, I.
    • Bandici, G.
    • Samuel, A.
    • Ciobanu, C.
    • Ardelean ,I.
    • Ciobanu, G.
    • Sandor, M.
    • Domuta, C.
    • Brejea, R.
    • Vuscan, A.
  • Source: Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Agriculture
  • Volume: 66
  • Issue: 1
  • Year: 2009
  • Summary: Field studies were conducted in Oradea, Romania, from 2003 to 2008, in a long term trial placed in 1990 on preluvosoils. The climate indicator de Martonne aridity index (IdM) was used for quantification of the correlation between climate and wheat yield in unirrigated and irrigated conditions and a new class called arid was used for climate index characterization. Maintaining the soil water reserve on 0-50 cm depth between easily available water content and field capacity using the irrigation determined the increase of the IdM values for period IV-VI with 79% in 2003, 73% in 2004, 36% in 2005, 16% in 2006, 162% in 2007 and with 131% in 2008. Using the irrigation and the improvement of the microclimate conditions determined to obtain the yield gains, showed very significant results every year and every crop rotation studied, both in unirrigated and irrigated conditions. The smallest wheat yields were obtained in monocrop and the biggest in the wheat-maize-soyabean rotation. In the all 3 rotations, the direct links statistically assured were registered between the values of the IdM and yields in unirrigated and irrigated wheat. These correlations sustained the need of the irrigation in wheat from Crisurilor Plain. Correlation between the IdM was stronger in the wheat-maize-soyabean rotation compared to the wheat-maize rotation and with wheat monocrop. As a consequence, rotation of wheat-maize-soyabean was recommended because the climate and microclimate conditions were better used.
  • Authors:
    • Bara, C.
    • Sabau, N. C.
    • Domuta, C.
    • Borza, I.
    • Bara, V.
    • Samuel, A.
    • Ardelean, I.
    • Bara, L.
    • Ciobanu, G.
    • Sandor, M.
    • Domuta, C.
    • Brejea, R.
    • Vuscan, A.
  • Source: Analele Universităţii din Oradea, Fascicula: Protecţia Mediului
  • Volume: 14
  • Year: 2009
  • Summary: The paper is based on the research carried out during 2003-2008 in a long term trial placed in 1990 on the preluvosoil from Oradea. Climate indicator "de Martonne aridity index" (IdM) was used for quantification the correlation between climate and wheat yield in unirrigated and irrigated conditions and new class called "arid" was purposed for climate index characterization. Maintaining the soil water reserve on 0-50 cm depth between easily available water content and field capacity using the irrigation determined the increase of the IdM values for period IV-VI with 79% in 2003, 73% in 2004, 36% in 2005, 16% in 2006, 162% in 2007 and with 131% in 2008; using the irrigation and the improvement of the microclimate conditions determined to obtain the yield gains, very significant every year and every crop rotation studied; both in unirrigated conditions and in irrigated conditions, the smallest yields wheat were obtained in monocrop and the biggest in the wheat-maize-soybean crop rotation; in the all three crop rotation, the direct links statistically assured were registered between the values of the De Martonne aridity index and yields in unirrigated and irrigated wheat. These correlations sustain the need of the irrigation in wheat from Crisurilor Plain; correlation between De Martonne aridity index is stronger (R 2=0.7361 xx) in the wheat-maize-soybean crop rotation in comparison with wheat-maize crop rotation (R 2=0.6215 x) and with wheat monocrop (R 2=0.6105 x). As consequence, crop rotation of wheat-maize-soybean is recomanded because the climate and microclimate conditions are better use.
  • Authors:
    • Swanton, C. J.
    • Tardif, F.
    • Hamill, A. S.
    • Sikkema, P. H.
    • Gulden, R. H.
  • Source: Weed Science
  • Volume: 57
  • Issue: 6
  • Year: 2009
  • Summary: Glyphosate-resistant (GR) crops have been adopted rapidly since their commercial introduction, and with the increase in commercially available crops resistant to glyphosate, continuous use of the same herbicide mode of action is now possible in some crop rotations. A 6-yr study was initiated to investigate the effects of conventional herbicides compared with continuous use of gyphosate in GR or Roundup Ready corn and GR soybean in a corn-soybean and a corn-soybean-winter wheat rotation. Individual experiments were fully phased and established at three locations under conventional tillage (CT) and at two locations under no-tillage (NT). Results indicated that midseason weed ground cover was lower when weeds were controlled with glyphosate; however, in most cases, this did not result in improved corn or soybean yields. Within locations, species richness, which strongly influenced other diversity indicators, was most affected by the herbicide treatments. Including winter wheat in the crop rotation had little effect on corn and soybean weed ground cover, density, and community structure and only affected soybean yield. Moreover, no effects of herbicide system used in previous corn and soybean were observed in winter wheat, with the exception of species diversity in NT, where species diversity tended to be greater when weeds in previous corn and soybean were treated with conventional herbicides. After 6 yr, the effects of continuous use of GR crops in rotation were similar to those reported in previous Studies; however, continued monitoring and longer-term investigations of these systems are necessary to detect the early stages of development of herbicide-resistant biotypes.
  • Authors:
    • Doka, L. F.
    • Vad, A.
  • Source: Cereal Research Communications
  • Volume: 37
  • Issue: Suppl. 1
  • Year: 2009
  • Summary: Effects of crop-rotation, fertilization and irrigation on the yield of maize has been studied in different cropyears characterized by different water supply (2007 year=dry; 2008 year=optimum) on chernozem soil. Our scientific results proved that in water stress cropyear (2007) the maximum yields of maize were 4316 kg ha -1 (monoculture), 7706 kg ha -1 (biculture), 7998 kg ha -1 (triculture) in non irrigated circumstances and 8586 kg ha -1, 10 970 kg ha -1, 10 679 kg ha -1 in irrigated treatment, respectively. In dry cropyear (2007) the yield-surpluses of irrigation were 4270 kg ha -1 (mono), 3264 kg ha -1 (bi), 2681 kg ha -1 (tri), respectively. In optimum water supply cropyear (2008) the maximum yields of maize were 13 729-13 787 (mono), 14 137-14 152 kg ha -1 (bi), 13 987-14 180 kg ha -1 (tri) so there was no crop-rotation effect. In water stress cropyear (2007) fertilization caused yield depression in non irrigated treatment (control=2685 kg ha -1; N 240+PK=2487 kg ha -1). Our scientific results proved that the effects of abiotic stress could be strongly reduced by using the optimum crop models in maize production. We obtained 8,6-11,0 t ha -1 maximum yields of maize in water stress cropyear and 13,7-14,2 t ha -1 in optimum cropyear on chernozem soil with using appropriate agrotechnical elements.