• Authors:
    • Németh, T.
    • Kismányoky, A.
    • Lehoczkya, É.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 40
  • Issue: 1/6
  • Year: 2009
  • Summary: The study was carried out in 2006 in Keszthely, on the soil tillage portion of a long-term experiment. In this experiment, a combination of three cultivation methods [no-till drill, disk tillage, conventional tillage (plowed)] and five nitrogen (N) rates (N 0: 0, N 1: 120, N 2:180, N 3: 240, and N 4: 300 kg N ha -1) were assessed. The trial was arranged in a split-plot design with four replications, and it was carried out during the first occurrence of maize in winter wheat-winter wheat-maize-maize rotation. Maize was sown on 10 May 2006; the weed survey was carried out using Balazs-Ujvarosi coenological method on 5 June 2006, after which weed control was implemented. Maize biomass of plants at the three to four leaf stage was determined at the same time. Sixteen weed species were identified in the no-till treatment, and 14 each in the in the conventional and the disk tillage treatments. Cultivation systems had a profound effect on the weediness of maize, with the lowest weediness occurring in the conventional tillage treatment. There was a strong interaction between N application and weed biomass that favored increased yield of maize over all cultivation treatments at higher N rates. The N content of weeds decreased as follows: conventional tillage < disc tillage < no-till.
  • Authors:
    • Rizzo, I.
    • Sarandón, S. J.
    • Sisterna, M. N.
    • Lori, G. A.
    • Chidichimo, H.
  • Source: Crop Protection
  • Volume: 28
  • Issue: 6
  • Year: 2009
  • Summary: Fusarium head blight (FHB) is a destructive disease of the world's wheat-growing areas. In Argentina, the area under reduced tillage has increased due to soil erosion that threatened productivity. The effect of conventional and no tillage systems on FHB combined with other agronomic practices such as nitrogen fertilization, and the influence of the environmental conditions was analysed under natural infection on different cultivars. Wheat trials were conducted in three consecutive years; maize was the previous crop in the first and wheat the previous crop in the subsequent two years of the study. The experimental design was a split plot, with tillage treatments (conventional tillage and no-till) as the main plots. Fertilizer treatments were applied as a range of urea concentrations. Fusarium head blight was observed in all three experimental years. Differences of disease expression among trials were associated with the environmental factors prevailing during the experiments. In the first year, with moderate weather conditions, the only interactions for FHB incidence were between no-till and urea split doses. Seedling emergence, seed health, thousand kernel weight and deoxynivalenol (DON) concentration did not differ suggesting that the fertilizers and genotypes did not affect disease susceptibility. Climatic conditions prevailing in the second year were more conducive to disease development and severe FHB infection was observed. Tillage and fertilization treatments did not affect the variables analysed. Only cultivars showed significant differences and DON values were high. In the third year, unfavourable conditions for disease development resulted in low disease levels and no effect or interaction among variables was observed. The results obtained would suggest that favourable weather conditions are likely to be more important than tillage practice and fertilizer treatments. Since soil conservation practices have been widely adopted in most areas of Argentina, an integrated used of all the available strategies should be considered to decrease FHB damage.
  • Authors:
    • Raper, R. L.
    • Reddy, K. C.
    • Nyakatawa, E. Z.
    • Reddy, S. S.
    • Reeves, D. W.
    • Lemunyon, J. L.
  • Source: Field Crops Research
  • Volume: 114
  • Issue: 2
  • Year: 2009
  • Summary: Long-term field experiments are needed to fully realize positive and negative impacts of conservation tillage and poultry litter application. A study was initiated on a Decatur silt loam soil at the Tennessee Valley Research and Extension Center, Belle Mina, AL, USA in 1996 to evaluate cotton (Gossypium hirsutum L.) performance with long-term poultry litter (PL) application under different tillages and to Study the build up of phosphorus (P) With application of PL. Treatments include incomplete factorial combinations of three tillage systems [conventional till (CT), mulch till (MT), and no-till (NT)], two cropping systems [cotton-fallow and cotton-winter rye (Secale cereale L.)], and two nitrogen sources and rates [100 kg N ha(-1) from ammonium nitrate (AN), and 100 and 200 kg N ha(-1) from poultry litter (PL)]. Cotton was rotated with corn (Zea mays L.) every third year. Results from 2003 to 2008 showed that all tillages gave similar cotton lint yields with AN at 100 kg N ha(-1). Application of PL at 100 kg N ha(-1) in NT plots resulted in 12 and 11% yield reductions compared to that of CT and MT, respectively. However, NT plots with higher quantity of PL (200 kg N ha(-1)) gave similar yields to CT and MT at 100 kg N ha(-1). During corn years, higher residual fertility of PL, in terms of grain yields, was observed in NT plots compared to CT and MT. Long-term PL application (100 kg N ha(-1) year(-1)) helped to maintain original soil pH in CT and MT while AN application decreased soil pH. In NT plots, PL at 100 kg N ha(-1) was not sufficient to maintain original soil pH, but 200 kg N ha(-1) maintained original pH. Although not-significant, elevated P levels were observed in all tillages compared to original P levels which indicates possibility of P build up in future with further application of PL. Application of PL at double rate (200 kg N ha(-1)) in NT plots resulted in significant build up of P. Results indicate that NT gives similar yields to CT when received AN. but needs higher rate of PL application to achieve similar yields to CT. (C) 2009 Elsevier B,V. All rights reserved.
  • Authors:
    • Sandor, M.
    • Domuta, C.
    • Samuel, A. D.
    • Vuscan, A.
  • Source: Research Journal of Agricultural Science
  • Volume: 41
  • Issue: 2
  • Year: 2009
  • Summary: Agricultural practices that reduce soil degradation and improve agricultural sustainability are needed particularly for preluvosoil. No-tillage planting causes minimal soil disturbance and combined with crop rotation may hold potential to meet these goals. Soil enzyme activities can provide information on how soil management affects the soil potential to perform processes, such as decomposition and nutrient cycling. Soil enzyme activities (actual and potential dehydrogenase, catalase, acid and alkaline phosphatase) were determined in the 0-20-, 20-40- and 40-60-cm layers of a preluvosoil submitted to a complex tillage (no-till and conventional tillage) and crop rotation (2- and 6-crop rotations) experiment. Each activity in both non-tilled and conventionally tilled soil under all crops of both rotations decreased with increasing sampling depth. No-till - in comparison with conventional tillage - resulted in significantly higher soil enzymatic activities in the 0-20- and in significantly lower activities in the deeper layers. The soil under maize or wheat was more enzyme-active in the 6- than in the 2-crop rotation. In the 2-crop rotation, higher enzymatic activities were recorded under wheat than under maize. The enzymatic indicators of soil quality were calculated from the values of enzymatic activities determined in the plots of the 6-crop rotation. The results obtained show that the different hierarchies of the six plots as registered in 2008 may be related to the different nature of crops and kind of fertilisers. This means that by determination of enzymatic activities, valuable information can be obtained regarding fertility status of soils.
  • Authors:
    • Wall, P. C.
    • Thierfelder, C.
  • Source: Soil & Tillage Research
  • Volume: 105
  • Issue: 2
  • Year: 2009
  • Summary: The adoption of conservation agriculture (CA), based on minimal soil movement, permanent soil cover with crop residues or growing plants and crop rotation has advanced rapidly in the Americas and Australia over the last three decades. One of the immediate benefits of CA in dryland agriculture is improved rainfall-use efficiency through increased water infiltration and decreased evaporation from the soil surface, with associated decreases in runoff and soil erosion. This paper focuses on the effect of CA techniques on soil moisture relations in two researcher-managed trials in Zambia and Zimbabwe. In 2005/2006 and 2006/2007, we found significantly higher water infiltration on both sites on CA fields compared to conventionally ploughed fields. At Henderson Research Station, Zimbabwe, on a sandy soil, a direct seeded CA treatments had a 49% and 45% greater infiltration rate than the conventionally tilled plots after a simulated rainfall in both seasons. At Monze Farmer Training Centre, Zambia, on a finer-textured soil, the same treatment had 57% and 87% greater infiltration rate than the conventionally tilled control treatment in both seasons. Treatments that included reduced tillage and surface residue retention had less water runoff and erosion on runoff plots at Henderson Research Station, Zimbabwe. On average, soil moisture was higher throughout the season in most CA treatments than in the conventionally tilled plots. However, the full potential of CA in mitigating drought was not evident as there was no significant drought period in either season. Results suggest that CA has the potential to increase the productivity of rainfall water and therefore reduce the risk of crop failure, as was apparent at the Monze Farmer Training Centre, Zambia, in 2005/2006 when a period of moisture stress at tassling affected CA treatments less than the conventionally tilled treatment. (C) 2009 Elsevier B.V. All rights reserved.
  • 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:
    • 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:
    • Kuzyakov, Y.
    • Fan, M.
    • Li, H.
    • Gong, Y.
    • Hou, R.
    • Chen, H.
  • Source: Soil & Tillage Research
  • Volume: 106
  • Issue: 1
  • Year: 2009
  • Summary: The Loess Plateau in northwest China is one of the most eroded landscapes in the world, and it is urgent that alternative practices be evaluated to control soil erosion. Our objective was to determine how three different tillage practices for monoculture of winter wheat (Triticum aestivum L) affected soil organic carbon (SOC) and N content after 11 years. Conventional tillage with residue removal (CT), shallow tillage with residue cover (ST), and no-tillage with residue cover (NT) were investigated. Carbon and N in various aggregate-size classes and various labile organic C fractions in the 0-15- and 15-30-cm soil layers were evaluated. The ST and NT treatments had 14.2 and 13.7% higher SOC stocks and 14.1 and 3.7% higher total N(N(t))stocks than CT in the upper 15 cm, respectively. Labile C fractions: particulate organic C (POC), permanganate oxidizable C (KMnO(4)-C), hot-water extractable C (HWC), microbial biomass C (MBC) and dissolved organic C (DOC) were all significantly higher in NT and ST than in CT in the upper 15 cm. KMnO(4)-C, POC and HWC were the most sensitive fractions to tillage changes. The portion of 0.25-2 mm aggregates, mean weight diameter (MWD) and geometric mean diameter (GMD) of aggregates from ST and NT treatments were larger than from CT at both 0-15- and 15-30-cm soil depths. The ST and NT treatments had significantly higher SOC and Nt in the 0.25-2 mm fraction at both depths and significantly higher N, content in the upper 15 cm. Positive significant correlations were observed between SOC, labile organic C fractions, MWD, GMD, and macroaggregate (0.25-2 mm) C within the upper 15 cm. We conclude that both variants of conservation tillage (NT and ST) increase SOC stock in the rainfed farming areas of northern China and are therefore more sustainable practices than those currently being used. (C) 2009 Elsevier B.V. All rights reserved.
  • Authors:
    • Miyao, G.
    • Jackson, J.
    • Mitchell, J. P.
    • Horwath, W. R.
    • Doane, T. A.
    • Brittan, K.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 85
  • Issue: 3
  • Year: 2009
  • Summary: In spite of potential benefits and positive assessments of reducing primary tillage operations, only a small part of irrigated row crops is currently managed using reduced tillage, for reasons that include concerns about its agronomic suitability for certain crop rotations. Three years of a tomato/corn rotation under standard and no-tillage management were used to understand the fate of a fertilizer and cover crop nitrogen (N) application. Uptake of both inputs was reduced under no-tillage during the year of application, in this case a tomato crop. As a result, more input N was retained in the soil in this system. The initial challenge of reduced tomato yields diminished as no-tillage management remained in place and the soil N reservoir developed. Corn production was not affected by tillage treatment. Inclusion of a legume cover crop increased the amount of fertilizer N retained in the soil over time, more so under no-tillage than under standard tillage, emphasizing the benefit of cover crops in reducing the amount of fertilizer required to maintain productivity. While acceptance of reduced tillage ultimately depends on economic performance, the results of this study support its agronomic viability for irrigated row crops.
  • Authors:
    • Ralisch, R.
    • Nakashima, P.
    • Gasparetto, N. V. L.
    • Domingos, M. M. M.
    • Tavares Filho, J.
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 33
  • Issue: 6
  • Year: 2009
  • Summary: Structural changes caused by management systems to soil can result in compaction and may change crop root development. With the aim to evaluate the effects of the farming systems on the soil structure by qualitative (cultural profile) and quantitative (soil density) methodologies, a field study was carried out in Maringa, state of Parana, Brazil (23degrees29′S, 51degrees59′W). A conventional tillage system with crop succession of corn ( Zea mays L.) and soybean ( Glycine max) and a no-till system with crop rotation of wheat ( Triticum spp.), corn ( Zea mays L.), common bean ( Phaseolus vulgaris), black oats ( Avena strigosa), and soybean ( Glycine max) established for more than 20 years were evaluated. An area under natural forest near the experimental field was evaluated as reference. After the description of the cultural (soil) profile, deformed samples were collected from the homogeneous soil volumes: two samples under forest, two samples in the no-till system and three samples in the conventional system. The physical and morphologic analyses of the soil structures of the layers 0-20 and 20-40 cm showed: (a) the two different tillage system promoted distinct depths of anthropic horizons; (b) the soil structure affected root distribution; (c) soil compaction under conventional system occurred in vertical and horizontal directions (d) soil structure was best under the no-till system; (e) the cultural profile methodology is efficient in soil morphology evaluations.