• Authors:
    • Rodrigues, L.
    • Lazarini, E.
    • Leal, A.
    • Muraishi, C.
    • Gomes Junior, F.
  • Source: Acta Scientiarum Agronomy
  • Volume: 27
  • Issue: 2
  • Year: 2005
  • Summary: This experiment aimed to verify the reaction of soyabean and maize cultures sown 38 days near or after chemical or mechanical handling of different soil coverings. The experiment was carried out at the experimental Station of Unesp, Ilha Solteira Campus, in the municipality of Selviria, state of Mato Grosso do Sul, Brazil, during the agricultural year of 2001/02. The covering cultures used were: rice, sorghum, Brachiaria decumbens [ Urochloa decumbens] and B. brizantha [ U. brizantha], millet [ Pennisetum glaucum] and Eleusine coracana. It was observed that the covering cultures showed good environment adaptation in dry mass production. The maize productivity was larger when the covering cultures handling was mechanically accomplished. The interval between handling and sowing of soyabean and maize culture is important only for rice or Brachiaria decumbens covering cultures; in this case, a 38-day previous handling is recommended. Maize yield was inferior when sown on sorghum residues.
  • Authors:
    • Schulte, M.
  • Source: Gesunde Pflanzen
  • Volume: 57
  • Issue: 2/3
  • Year: 2005
  • Summary: Herbicide-resistant varieties currently play a key role among the genetically modified arable crops soyabean, cotton, oilseed rape, and maize grown worldwide. Reasons for the quick increase in areas cultivated by herbicide-resistant crops are, among others, shortcomings of existing chemical weed control solutions in these crops and an increase in cultivation methods using minimum tillage techniques. As a countermove, the minimum or no-till cropping area increased significantly, due to the introduction of herbicide-resistance technology, particularly in soybeans. Decision criteria during the past 8 years for choosing adequate weed control systems using herbicide-resistant or conventional varieties were: varietal performance, superior crop tolerance and application timing flexibility, efficacy of post-emergent weed control measures in dry areas, controlled weed spectrum, and duration of activity including control of resistant weed biotypes. Due to restrictive labelling instructions and lack of authorization in main overseas export markets, including European liability and coexistence rules, sales restrictions are essential decision parameters for individual farms. The technical progress of herbicide-resistance technology is achieved in the short and medium term by further development of spraying sequences and tank mixtures towards ready-formulated mixtures of complementary herbicides with conventional residual mixture partners. To control and prevent the spread of new herbicide-resistant weed biotypes, complementary herbicides are combined with other modes of action. Further developments are combinations of various other transgenic traits with transgenic herbicide resistance and herbicide-resistant varieties of (worldwide) less important minor crops without satisfying conventional chemical weed control solutions. For long-term developments, plastid transformation techniques to prevent the unwanted dissemination of transgenic features could gain importance.
  • Authors:
    • Klepker, D.
    • Yamada, M.
    • Hitsuda, K.
  • Source: Agronomy Journal
  • Volume: 97
  • Issue: 1
  • Year: 2005
  • Summary: Sulfur deficiency symptoms are more often observed in crops at early stages of growth since S can be easily leached from the surface soil. The objectives of this study were to evaluate some of the popular rotation crops grown in Brazil for tolerance to low external S levels and to determine the critical tissue concentration for S deficiency during early stages of growth. Germinated seedlings of soybean [ Glycine max (L.) Merr.], rice ( Oryza sativa L.), maize ( Zea mays L.), field bean ( Phaseolus vulgaris L.), wheat ( Triticum aestivum L.), cotton ( Gossypium spp.), sorghum ( Sorghum bicolor L.), and sunflower ( Helianthus annuus L.) were transferred to water culture with 0.0 to 32.0 mg S L -1 and were grown for 29 d. The minimum S concentration required in nutrient solutions was 2.0 mg L -1 for sunflower; 1.0 mg L -1 for cotton, sorghum, wheat, and soybean; and 0.5 mg L -1 or less for field bean, rice, and maize. All crops achieved optimum growth at 2.0 mg S L -1. Critical shoot S concentration at early stages of growth was 0.8 g kg -1 in maize and soybean; 1.1 to 1.3 g kg -1 in cotton, sorghum, and rice; and 1.4 to 1.6 g kg -1 in wheat, sunflower, and field bean. Our results demonstrate that the tolerance to low external S (
  • Authors:
    • Shimi, P.
    • Kazemi, H.
  • Source: Iranian Journal of Weed Science
  • Volume: 1
  • Issue: 1
  • Year: 2005
  • Summary: An isolate of F. moniliforme [Gibberella moniliformis], a pathogen of winter wild oat (A. ludoviciana [A. sterilis var. ludoviciana]), was obtained from Tehran Province, Iran, in 1994. A host range test performed on wheat, barley, maize, rye, millet, crested wheatgrass, faba bean, red bean, green bean, sunflower, soyabean, oilseed rape, cotton, safflower, cucumber, water melon, berseem clover, and sainfoin, resulted in no symptom induction by the pathogen. However, winter wild oat, crested wheatgrass, johnsongrass and tomato showed susceptibility to the pathogen with 78, 24, 19 and 17% mortality, respectively. The results indicate that this pathogen could be considered as a potential biological agent for the control of winter wild oat.
  • Authors:
    • Cooke, F. T.,Jr.
    • Robinson, J. R. C.
    • Martin, S. W.
    • Parvin, D.
  • Source: Crop Management
  • Issue: April
  • Year: 2005
  • Summary: This study compared conventional, reduced tillage and no-till systems for cotton, maize, soyabean and sorghum in the Mississippi Delta. Most of the necessary parameters (e.g. yields, costs, equipment, field operations) were obtained from published budgets. The conventional systems typically involved subsoiling, discing, field cultivation, hipping and in-season cultivation. The reduced tillage systems substituted herbicides for heavy pre-plant soil preparation and in-season cultivation, while no-till systems substituted herbicides for all tillage operations. A whole-farm, mixed integer programming model was developed to determine the most profitable crop/tillage combinations at different acreage sizes, assess the actual economies of size (in dollars per acre) in row crop farming, determine the number of acres required to maximize economic viability, determine the best acreage size to minimize or optimize full-time labour, and evaluate profitability trade-offs, including farm programme eligibility, under different tillage systems.
  • Authors:
    • Zamfir, M. C.
    • Mitu, D.
  • Source: Probleme de agrofitotehnie teoretica si aplicata
  • Volume: 27
  • Issue: 2
  • Year: 2005
  • Summary: During 2001-03 in Teleorman, 14 Romanian maize hybrids (Campion, Rapsodia, Danubiu, Paltin, Olt, F. 376, Faur, Partizan, Octavian, Granit, F. 322, Milcov, Orizont and Vultur) were studied under different situations, such as irrigation and dryland, and under 3 types of drought during the maize vegetation: drought in the second part of summer (2001), drought in the first part of summer (2002), and long lasting drought (2003). Paltin, Campion, Rapsodia, Danubiu, Faur and Olt had a good behaviour under irrigated or dryland conditions, but Partizan, Orizont, Vultur, Octavian and Granit proved to be sensitive to drought. During dry years, the flowering delay (days) and the frequency of sterile plants had determined significant diminution of maize yield. The effects of drought on maize yield differed, depending on its type, intensity and way of action, under different stages of growth and development of the plants. Long lasting and pronounced drought over the whole period of maize vegetation resulted in the highest losses in yield (76-77%) compared to partial droughts during the second part of summer (62-65%) or during the first part of vegetation growth (26-30%). To reduce the negative effect of drought on maize, the cultivation of 2-3 hybrids with different earliness is recommended, which ensures a more efficient use of the distribution of rainfall during the maize vegetation as well as a reduced variation of harvest.
  • Authors:
    • Chivinge, O. A.
    • Rimawu, S.
    • Musambasi, D.
    • Mariga, I. K.
  • Source: Crop Research
  • Volume: 29
  • Issue: 1
  • Year: 2005
  • Summary: An on-farm field trial was conducted to assess the residual effects of 2 multi-purpose trees (Sesbania sesban and Sesbania macrantha) and 3 cowpea cultivars (IT 90K-59, IT 18 and Kavara) grown in Striga asiatica-infested fields for 2 consecutive seasons, 1998/99 and 1999/2000 summer seasons on maize grain yield and Striga asiatica density. A three-way maize hybrid, SC 501, was used as a test crop. At two of the sites, there were no significant differences in the number of emerged S. asiatica plants, while plots previously planted to maize/Kavara and S. sesban supported the least number of emerged S. asiatica plants at 8 and 10 weeks after crop emergence. Maize grain yield was statistically the same at Mungoriwo, while grain yield for the other two sites was lost because farmers bulked the trials before the researchers could take the records.
  • Authors:
    • Negrila, E.
    • Negrila, M.
  • Source: Probleme de Agrofitotehnie Teoretica si Aplicata
  • Volume: 27
  • Issue: 2
  • Year: 2005
  • Summary: Mineral fertilizer application on crops is one of the reliable ways of increasing soil productivity, improving the yield, quality and soil fertility. The nitrogen and phosphorus long-term fertilizer application in the cambic chernozem, under non-irrigated condition at the A.R.D.S. Teleorman, Romania, caused plants and soil modifications. The annual nitrogen and phosphorus (NP) fertilizer application (in 28 years) with moderate amounts and balanced ratios resulted in a yield increase of 12-17 kg wheat/1 kg NP, 7-11 kg maize/1 kg NP, 4-6 kg sunflower/1 kg NP, the smallest increase was during the drought years. The use of coefficient depends on crop and climatic evolution. The best nitrogen and phosphorus use efficiency was with wheat, followed by maize and sunflower. During the drought years, both elements use was reduced to half. It also had a positive influence on the crude protein content (4.08% for winter wheat and 3.76% for maize), on the other quality indices: technological flour indices, macro- and microelements. The P:Zn ratio of 57-100 also indicated a good ratio between the two elements which does not lead to occurrence of Zn deficiency. The values of N:S indicated some disorders in sulfur metabolism which can generate sulfur deficiency, especially in maize. The long-term fertilizer application (1977-2000) determined the improvement in soil fertility: maintenance of the humus content, the improvement of the mobile phosphorus content, of the saturation degree in alkali up to 83% and the reaction up to 5.9 pH, without mobile aluminium and Mn coming out. The absence of nitrogen and phosphorus fertilizers during 24 years led to soil fertility, yield and yield quality reduction.
  • Authors:
    • Peterson, G. A.
    • Westfall, D. G.
    • Ortega, R. A.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 36
  • Issue: 19/20
  • Year: 2005
  • Summary: In the West Central Great Plains of the United States, no-till management has allowed for increased cropping intensity under dryland conditions. This, in turn, has affected the carbon (C) and nitrogen (N) mineralization dynamics of these systems. In this region, moisture stress increases from north to south due to an increase in evapotranspiration (ET), resulting in a climatic gradient that affects cropping system management. The objectives of this study were to determine the interaction of cropping system intensification and climatic gradient (ET) on C and N mineralization and to determine if the presence or absence of crop residue on the soil surface affects C and net N mineralization. Two cropping systems, winter wheat-fallow (WF) ( Triticum aestivium L.) and winter wheat-corn (sorghum)-millet-fallow (WCMF) [ Zea mays (L.), Sorghum bicolor (L.) Moench, Panicum milaceum (L.)] were studied at three locations across this aforementioned ET gradient. The treatments had been in place for 8 yrs prior to sampling in the study. These results showed that the more intense cropping system (WCMF) had a higher laboratory C mineralization rate at two of the three locations, which the study concluded resulted from larger residue biomass additions and larger quantities of surface residue and soil residue at these locations (Soil residue is defined as recognizable crop residue in the soil that is retained on a 0.6 mm screen). However, no differences in N mineralization occurred. This is most likely due to more N immobilization under WCMF as compared to WF. Presence or absence of crop residue on the surface of undisturbed soil cores during incubation affected potential C and net N mineralization more than either cropping system or location. Soil cores with the surface residue intact mineralized as much as 270% more C than the same soils where the surface crop residue had been removed. In laboratory studies evaluating the relative differences in cropping systems effects on C and N mineralization, the retention of crop residue on the soil surface may more accurately access the cropping system effects.
  • Authors:
    • Spiridon, C.
    • Rotarescu, M.
    • Raranciuc, S.
    • Guran, M.
    • Popov, C.
    • Vasilescu, S.
    • Gogu, F.
  • Source: Probleme de Protectia Plantelor
  • Volume: 33
  • Issue: 1/2
  • Year: 2005
  • Summary: The paper presents the harmful organisms which attacked the field crops in 2004. It is emphasized the occurrence and spreading of the most important pathogens and harmful insects in cereals, grain legumes, industrial and fodder crops as well as their role on yield quality and quantity. In Romania, the most important issues of plant protection in 2004, by the economic impact and applied chemical measures were those determined by the following pathogens and harmful insects. The soil and seed pathogens were: Tilletia spp., Fusarium spp. in wheat; Ustilago nuda [ U. segetum var. nuda], Pyrenophora graminea in barley; Pythium spp., Fusarium spp. in maize; Sclerotinia sclerotiorum, Botrytis cinerea, Plasmopara helianthi [ Plasmopara halstedii], Orobanche cumana in sunflower; Fusarium spp., Pythium spp. in pea, beans and soyabean foliar and ear diseases were: Erysiphe spp., Septoria spp., Pyrenophora graminea, Puccinia spp., Fusarium spp. in wheat and barley; Ustilago maydis [ Ustilago zeae], Helminthosporium turcicum [ Setosphaeria turcica], Fusarium spp., Nigrospora oryzae [ Khuskia oryzae] in maize; Sclerotinia sclerotiorum, Botrytis cinerea, Alternaria spp., Phomopsis spp. in sunflower; Erysiphe spp., Septoria spp. in rape. The soil pests were: Zabrus tenebrioides, Agriotes spp. in spiked cereals; Tanymecus dilaticollis, Agriotes spp. in maize and sunflower; Delia platura in beans; Phyllotreta atra in rape and mustard; Aphthona euphorbiae in linseed; Sitona spp., Agriotes spp. in lucerne and clover. The pests which attack aerial part of plants and seeds were: Eurygaster integriceps, Lema melanopa [ Oulema melanopus], Anisoplia spp. in wheat, barley and oats; Ostrinia nubilalis, Diabrotica virgifera virgifera in maize; Thrips linarius in linseed; Athalia rosae, Meligethes aeneus, Brevicoryne brassicae in rape and mustard; Hypera variabilis [ Hypera postica], Semiothisa clathrata [ Chiasmia clathrata], Bruchophagus roddi, Subcoccinella 24- punctata in lucerne and clover. Based on evaluation of the attack potential of these harmful organisms in 2004, the potential for the future manifestation was also estimated.