• Authors:
    • Suyker, A. E.
    • Verma, S. B.
  • Source: Agricultural and Forest Meteorology
  • Volume: 149
  • Issue: 3/4
  • Year: 2009
  • Summary: We have been making year-round measurements of mass and energy exchange in three cropping systems: (a) irrigated continuous maize, (b) irrigated maize-soybean rotation, and (c) rainfed maize-soybean rotation in eastern Nebraska since 2001. In this paper, we present results on evapotranspiration (ET) of these crops for the first 5 years of our study. Growing season ET in the irrigated and rainfed maize averaged 548 and 482 mm, respectively. In irrigated and rainfed soybean, the average growing season ET was 452 and 431 mm, respectively. On average, the maize ET was higher than the soybean ET by 18% for irrigated crops and by 11% for rainfed crops. The mid-season crop coefficient Kc (=ET/ET 0 and ET 0 is the reference ET) for irrigated maize was 1.030.07. For rainfed maize, significant dry-down conditions prevailed and mid-season Kc was 0.840.20. For irrigated soybean, the mid-season Kc was 0.980.02. The mid-season dry down in rainfed soybean years was not severe and the Kc (0.900.13) was only slightly lower than the values for the irrigated fields. Non-growing season evaporation ranged from 100 to 172 mm and contributed about 16-28% of the annual ET in irrigated/rainfed maize and 24-26% in irrigated/rainfed soybean. The amount of surface mulch biomass explained 71% of the variability in non-growing season evaporation totals. Water use efficiency (or biomass transpiration efficiency), defined as the ratio of total plant biomass ( YDM) to growing season transpiration ( T) was 5.200.34 and 5.220.36 g kg -1, respectively for irrigated and rainfed maize crops. Similarly, the biomass transpiration efficiency for irrigated and rainfed soybean crops was 3.210.35 and 2.960.30 g kg -1. Thus, the respective biomass transpiration efficiency of these crops was nearly constant regardless of rainfall and irrigation.
  • Authors:
    • Gao, L.
    • Chen, Q.
    • Liu, J.
    • Zhang, X.
    • Tian, Y.
  • Source: Scientia Horticulturae
  • Volume: 123
  • Issue: 2
  • Year: 2009
  • Summary: The increased use of rotation, grafting, and soil sterilization has been documented to increase crop yield in intensive vegetable production systems in China. It is believed that these practices can promote changes in the rhizosphere that enhance early growth of plants. A 2-year greenhouse experiment on tomato double-cropping systems was conducted to investigate the effects of different agricultural treatments on microbial properties of rhizosphere soils and tomato fruit yield. The treatments included planting of welsh onion as a cover crop in the summer fallow (SF) period (CW), rotating vegetable chrysanthemum and tomato (CT), planting graft-tomato instead of auto-root tomato (GT), sterilizing soil with calcium cyanamide in the SF period (TC), and fallowing in the SF period (Control). Microbial population was analyzed by dilution plating. In general, microbial populations were higher in CT, CT and TC than in control. Fungal population was higher in TC whereas a high number of bacteria were found in CT. Soil microbial biomass C and N, total microbial population, organic C and total N showed significant positive correlations (P
  • Authors:
    • Todorova, R.
  • Source: Rasteniev'dni Nauki
  • Volume: 46
  • Issue: 4
  • Year: 2009
  • Summary: As a result of long research work on genetic improvement of soybean, new varieties have been developed and rich germplasm has been obtained. Classic breeding methods of hybridization and experimental mutagenesis were used. Our studies were directed to obtaining of varieties with high productive potential and resistance to biotic and abiotic stress, as well as to increase of crude protein and crude fat content. The candidate variety Rosa was presented for testing in the system of EAVTFISC (Executive Agency for Variety Testing, Field Inspection and Seed Control). In our competition variety trials it possessed high productive potential under irrigated and nonirrigated conditions and showed resistance to the diseases of bacteriosis and mildew.
  • 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:
    • He, J.
    • Wang, X. Y.
    • Gao, H. W.
    • Li, H. W.
    • Yao, Z. L.
  • Source: Soil Research
  • Volume: 47
  • Issue: 8
  • Year: 2009
  • Summary: The furrow opening configuration used by no-till seeders can have a major effect on crop emergence in conservation tillage systems. This is particularly important in annual double-cropping regions (winter wheat and summer maize) of northern China where large volumes of residue remain on the soil surface after maize harvesting. This problem has been investigated using 3 different opening configurations for no-till wheat seeding near Beijing in 2004-05 and 2005-06, and assessing performance in terms of soil disturbance, residue cover index, soil cone index, fuel consumption, winter wheat emergence, plant growth, and subsequent yield. In this cropping system, the single-disc opening configuration significantly decreased mean soil disturbance and increased residue cover index compared with the combined strip-chop and strip-till opening configurations, but winter wheat emergence was 6-9% less, probably due to greater levels of residue cover and greater seed zone soil cone index. Winter wheat growth after seeding in combined strip-chop and strip-till seeded plots was faster than that in single-disc seeded plots and mean yield was greater. The most suitable furrow opening configuration in heavy residue cover conditions appeared to be the strip-chop one, which can provide similar crop performance with marginally better fuel economy than the strip-till opening configuration. These results should be seen as preliminary, but they are still valuable for the design and selection of no-till wheat seeders for double cropping in this region of China.
  • 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.