• Authors:
    • Caesar-TonThat, T.
    • Sainju, U. M.
    • Wright, S. F.
    • Shelver, W. L.
    • Kolberg, R. L.
    • West, M.
  • Source: Biology and Fertility of Soils
  • Volume: 47
  • Issue: 2
  • Year: 2011
  • Summary: Little is known about the long-term tillage and cropping management effects on the microbiologically derived factors that influence macroaggregates in semi-arid soil. We tested the hypothesis that differences in macro-aggregation are due to changes in soil structure related to management treatment-induced microbiological changes. In an experiment, microbiological factors consisting of aggregate stability, glomalin, russuloid basidiomycete fungi, uronic acids, total organic C (TOC), and total N (TN) were quantified in macroaggregate-size classes ranging from 4.75 to 0.25 mm, collected at 0-5 cm depth for the following treatments: (1) 12th year of fallow phase after 11 years of conventional- and no-tilled spring wheat-fallow (CTF and NTF), (2) 12th year of lentil phase after 11 years of conventional- and no-tilled spring wheat-lentil (CTL and NTL), (3) 12 years no-tilled continuous spring wheat (NTCW), and (4) 16 years uncultivated pasture (P) used as a baseline treatment. Immunoreactive easily extractable glomalin concentration was five to six times greater under P, NTCW, or NTL in the 2.00-1.00- and 1.00-0.50-mm macroaggregate-size classes than the other treatments and these results corroborated well with the results from aggregate stability assays. Russuloid basidiomycetes were highest in all NTCW macroaggregate-size classes, suggesting that annual input of lignin-containing wheat residues may influence the growth and survival of these fungi. Uronic acid amounts were highest in P but did not differ among the other treatments. In all macroaggregate-size classes, TOC content was greater in NTCW compared to CTF, and TN was about three times higher in NTL than NTF or CTF. In conclusion, 12 years of NTCW management in semi-arid soil has resulted in higher macroaggregate stability, glomalin concentration, russuloid basidiomycete populations, and TOC in macroaggregates compared to alternate-year fallow. Lentil can be used to replace fallow in dryland wheat rotation under no-till to enhance TN content and improve soil macro-aggregation.
  • Authors:
    • Calonego, J. C.
    • Rosolem, C. A.
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 35
  • Issue: 3
  • Year: 2011
  • Summary: Soil water availability to plants is affected by soil compaction and other variables. The Least Limiting Water Range (LLWR) comprises soil physical variables affecting root growth and soil water availability, and can be managed by either mechanical or biological methods. There is evidence that effects of crop rotations could last longer than chiseling, so the objective of this study was to assess the effect of soil chiseling or growing cover crops under no-till (NT) on the LLWR. Crop rotations involving triticale (X Triticosecale) and sunflower (Helianthus annuus) in the fall-winter associated with millet (Pennisetum glaucum), sorghum (Sorghum bicolor) and sunn hemp (Crotalariajuncea) as cover crops preceding soybean (Glycine max) were repeated for three consecutive years. In the treatment with chiseling (performed. only in the first year), the area was left fallow between the fall-winter and summer crops. The experiment was carried out in Botucatu, Sao Paulo State, Brazil, from 2003 to 2006 on a Typic Rhodudalf. The LLWR was determined in soil samples taken from the layers 0-20 cm and 20-40 cm, after chemical desiccation of the cover crops in December of the first and third year of the experiment. Chiseling decreases soil bulk density in the 0-20 cm soil layer, increasing the LLWR magnitude by lowering the soil water content at which penetration resistance reaches 2.0 MPa; this effect is present up to the third year after chiseling and can reach to a depth of 0.40 in. Crop rotations involving sunflower + sunn hemp, triticale + millet and triticale + sunn hemp for three years prevented soil bulk density from exceeding the critical soil bulk density in the 0-0.20 in layer. This effect was observed to a depth of 0.40 m after three years of chiseling under crop rotations involving forage sorghum. Hence, chiseling and some crop rotations under no tillage are effective in increasing soil quality assessed by the LLWR.
  • Authors:
    • Campos-Magana, S. G.
    • Cadena-Zapata, M.
  • Source: Campos-Magana, SG
  • Volume: 42
  • Issue: 4
  • Year: 2011
  • Summary: A five year field experiment was conducted to assess the interaction between soil tillage levels, maize-sorghum-legume rotation and two levels of chemical fertilization at the rain feed tropical region of southeast Mexico. The purpose of this research work was to asses this interaction over the variation of some soil quality indices and the effect on the productivity of the soil-grain yield. The treatments for soil tillage were zero till and the intensive traditional soil tillage of the region. Crop rotations employed were five years maize (mmmmm), five years sorghum (sssss), two rotations; (smsms) and (msmsm) and two intercropping of legumes (f)-cereals, (fsfsf) and (fmsmf). Ninety two and 136 units of nitrogen were the two levels of fertilization and were applied only to the cereals. The evaluated soil index in the first and fifth year were organic matter (mo), water infiltration rate (ir), aggregate stability (as), ph, biomass microbiana (mb), nitrogen soluble nitrogen, soil density (sd), soil depth (sd), electrical conductivity (ec) and availability of nutrients. In general terms, the best grain yield for both sorghum and maize were obtained with the no till treatment although no big differences were observed between them. The five year sorghum mean yield under no till with fertilization levels 1 and 2 were 3.6 and 4.5 Mg/ha, whereas, with conventional tillage these were just 3.1 and 4.1 Mg/ha, respectively. The grain yield of maize with level 2 of nitrogen, with zero and traditional till were 5.1 and 4.6 Mg/ha; however, with nitrogen level 1 there were no apparent advantages of the first treatment (3.8 Mg/ha in both cases). The type of crop rotation and soil tillage level mainly affected the chemical soil index at 0 to 5 cm depth. However, no effect occurred with the way of handling crop residues and with the levels of chemical fertilization. The main values of electrical conductivity were attributed to an increase in the solubility of some elements. It was also observed that, under no till, there was an increase of the levels of soluble carbon.
  • Authors:
    • Cociu, A. I.
    • Alionte, E.
  • Source: Analele Institutului National de Cercetare-Dezvoltare Agricola Fundulea
  • Volume: 79
  • Issue: 2
  • Year: 2011
  • Summary: Grain yields of winter wheat (Triticum aestivum L.), maize ( Zea mays L.), and soybean [ Glycine max. (L.) Merr], in rotation were significantly influenced by soil deep loosening and tillage system, depending on water supply (irrigation application). Scientific literature regarding the influence of these agronomic factors on the yield quality of the respective three crops, in rotation, is quite limited. For this study, a field experiment was carried out at Fundulea, which is located in the eastern part of the Danube Plain, on a cambic chernozem soil type. One of the main objectives was to determine how the grain yield quality of winter wheat, maize and soybean is influenced by different reduced tillage systems, in comparison with the traditional (conventional) one, as well as by the direct seeding in non-worked ground, or in strip till, with and without soil deep loosing, under different irrigations. Regarding the maize, the water provisioning * tillage system interaction was very significant (P0.05). Under the three water provisions applied, protein content had values between 40.0%, recorded when the normal irrigation rate was used, at no till system, and 41.5%, recorded for the dry conditions, also at no till system. The 1,000 kernel weight varied between 120 g, registered for the dry conditions at no till variant, and 159 g, registered for normal irrigation rate, also at no till system. The results of this research do not make evident a certain tendency of protein content, but show clearly that the fat content increases concomitantly with grain yield growing. As concerns the winter wheat crop, the water provisioning * tillage system interaction was not significant (P>0.05). Protein content was comprised between 13.2%, registered when the normal irrigation rate was applied at no till system variant, and 15.7%, under dry conditions, at the traditional tillage system. The minimum value of 1,000 kernel weight was 37 g, recorded for dry conditions at chisel tillage variant, and the highest value, of 47 g, was obtained when normal irrigation rate was applied to no till variant.
  • Authors:
    • Costa, M. S. S. de M.
    • Pivetta, L. A.
    • Steiner, F.
    • Costa, L. A. de M.
    • Castoldi, G.
    • Gobbi, F. C.
  • Source: Revista Brasileira de Ciencias Agrarias
  • Volume: 6
  • Issue: 4
  • Year: 2011
  • Summary: Crop systems and fertilization sources can affect the chemical properties of the soil and, consequently, its fertility. With the aim of evaluating the effect of such management practices, soil samples collected at 0.0-0.10; 0.10-0.20; and 0.20-0.40 m in depth were collected and analyzed in the second year of an experiment installed in 2006 in a Rhodic Hapludox under no-till farming, located in the Agronomic Experimental Station of UNIOESTE, in the city of Marechal Candido Rondon, Parana, Brazil. The experiment consisted of two crop systems (with and without rotation of cover crops) and three fertilization sources (mineral, organic and mineral+organic). The organic and mineral+organic fertilizations consisted of the application of animal manure alone and animal manure mixed with mineral fertilizer, respectively. The values of pH, exchangeable potassium (K +) and cation exchange capacity (CEC) were not affected by the different crop systems, related to the application of different fertilization sources. However, they did influence the organic matter contents (OM), potential acidity (H ++Al 3+), exchangeable aluminum (Al 3+), phosphorus (P), calcium (Ca 2+), magnesium (Mg 2+), and the bases sum and saturation (V%). The organic and mineral+organic fertilizations, with animal manure promoted the highest increase in soil Ca and Mg.
  • Authors:
    • de Campos, B. -H. C.
    • Carneiro Amado, T. J.
    • Bayer, C.
    • da Silveira Nicoloso, R.
    • Fiorin, J. E.
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 35
  • Issue: 3
  • Year: 2011
  • Summary: Soil organic matter (SOM) plays a crucial role in soil quality and can act as an atmospheric C-CO2 sink under conservationist management systems. This study aimed to evaluate the long-term effects (19 years) of tillage (CT-conventional tillage and NT-no tillage) and crop rotations (R0-monoculture system, R1-winter crop rotation, and R2- intensive crop rotation) on total, particulate and mineral-associated organic carbon (C) stocks of an originally degraded Red Oxisol in Cruz Alta, RS, Southern Brazil. The climate is humid subtropical Cfa 2a (Koppen classification), the mean annual precipitation 1,774 mm and mean annual temperature 19.2 degrees C. The plots were divided into four segments, of which each was sampled in the layers 0-0.05, 0.05-0.10, 0.10-0.20, and 0.20-0.30 m. Sampling was performed manually by opening small trenches. The SOM pools were determined by physical fractionation. Soil C stocks had a linear relationship with annual crop C inputs, regardless of the tillage systems. Thus, soil disturbance had a minor effect on SOM turnover. In the 0-0.30 m layer, soil C sequestration ranged from 0 to 0.51 Mg ha(-1) yr(-1), using the CT R0 treatment as base-line; crop rotation systems had more influence on soil stock C than tillage systems. The mean C sequestration rate of the cropping systems was 0.13 Mg ha(-1) y(-1) higher in NT than CT. This result was associated to the higher C input by crops due to the improvement in soil quality under long-term no-tillage. The particulate C fraction was a sensitive indicator of soil management quality, while mineral-associated organic C was the main pool of atmospheric C fixed in this clayey Oxisol. The C retention in this stable SOM fraction accounts for 81 and 89% of total C sequestration in the treatments NT R1 and NT R2, respectively, in relation to the same cropping systems under CT. The highest C management index was observed in NT R2, confirming the capacity of this soil management practice to improve the soil C stock qualitatively in relation to CT R0. The results highlighted the diversification of crop rotation with cover crops as a crucial strategy for atmospheric C-CO2 sequestration and SOM quality improvement in highly weathered subtropical Oxisols.
  • Authors:
    • Diaz-Rossello, R.
    • Duran, H.
  • Source: Agrociencia
  • Volume: 15
  • Issue: 2
  • Year: 2011
  • Summary: Pastoral dairy farming systems in Uruguay exhibit an accelerated process of intensification with major changes in soil management during the last four decades. However, the production systems were always based on the same concept of sustainable rotations of annual forage crops and perennial grasses sown in association with legumes. The soil organic carbon (OC) in the plots of the Dairy Experimental Farm at La Estanzuela was monitored since 1974 up to 2010. Those records quantify the effect on OC dynamics of four production systems with different soil management carried out in long periods. This information is extremely relevant considering that survey studies showed that commercial dairy farming systems followed the same general pathway of technical changes. The extreme modification in tillage, animal stocking rate and feed imported to the farm determined two contrasting periods in the OC dynamics. Heavy losses of OC were estimated at an average of 0.89 Mg ha -1 year -1 during a first period of 17 years. This tendency was reversed for the following 18 years when OC increased at 0.94 Mg ha -1 year -1. Three major management factors are discussed to explain the fast build up of OC: the progressive tillage reduction, improvements in pasture and forage crop productivity and imported feed coming into the system. The large OC and N gains in semi-confinement paddocks are discussed as an opportunity to capitalize the high nutrient availability in the soil for crop production.
  • Authors:
    • dos Santos, N. Z.
    • Dieckow, J.
    • Bayer, C.
    • Molin, R.
    • Favaretto, N.
    • Pauletti, V.
    • Piva, J. T.
  • Source: Soil & Tillage Research
  • Volume: 111
  • Issue: 2
  • Year: 2011
  • Summary: To improve C sequestration in no-till soils requires further development of crop rotations with high phytomass-C additions. The objectives of this study were (i) to assess long-term (17 years) contributions of cover crop- or forage-based no-till rotations and their related shoot and root additions to the accumulation of C in bulk and in physical fractions of a subtropical Ferralsol (20-cm depth); and (ii) infer if these rotations promote C sequestration and reach an eventual C saturation level in the soil. A wheat (Triticum aestivum L., winter crop)-soybean (Glycine max (L.) Merr, summer crop) succession was the baseline system. The soil under alfalfa (Medicago sativa L, hay forage) intercropped every three years with maize (Zea mays L., summer crop) had the highest C accumulation (0.44 Mg C ha(-1) year(-1)). The bi-annual rotation of ryegrass (Lolium multiflorum Lam., hay winter forage)-maize-ryegrass-soybean had a soil C sequestration of 0.32 Mg C ha(-1) year(-1). Among the two bi-annual cover crop-based rotations, the vetch (Vicia villosa Roth, winter cover crop)-maize-wheat-soybean rotation added 7.58 Mg C ha(-1) year(-1) as shoot plus root and sequestered 0.28 Mg C ha(-1) year(-1). The counterpart grass-based rotation of oat (Avena strigosa Schreb., winter cover crop)-maize-wheat-soybean sequestered only 0.16 Mg C ha(-1) year(-1), although adding 13% more C (8.56 Mg ha(-1) year(-1)). The vetch legume-based rotation, with a relative conversion factor (RCF) of 0.147, was more efficient in converting biomass C into sequestered soil C than oat grass-based rotation (RCF = 0.057). Soil C stocks showed a close relationship (R(2) = 0.72-0.98, P < 0.10) with root C addition, a poor relationship with total C addition and no relationship with shoot C addition. This suggests a more effective role of root than shoot additions in C accumulation in this no-till soil. Most of the C accumulation took place in the mineral-associated organic matter (71-95%, in the 0-5 cm layer) compared to the particulate organic matter. The asymptotic relationship between root C addition and C stocks in bulk soil and in mineral-associated fraction supports the idea of C saturation. In conclusion, forages or legume cover crops contribute to C sequestration in no-till tropical Ferrasols, and most of this contribution is from roots and stored in the mineral-associated fraction. This combination of soil and rotations can reach an eventual soil C saturation.
  • Authors:
    • Feng, G.
    • Sharratt, B.
    • Young, F.
  • Source: Journal of Soil and Water Conservation
  • Volume: 66
  • Issue: 4
  • Year: 2011
  • Summary: In the low precipitation zone (<0.3 m [11.8 in] annual precipitation) of the Inland Pacific Northwest, no-tillage continuous spring cereal and no-tillage spring cereal-chemical fallow rotations are being examined as alternatives to the traditional winter wheat-summer fallow rotation for soil conservation. There is limited information, however, regarding the long-term effects of no-tillage cropping systems on soil hydraulic properties in this semiarid region. The objective of this study was therefore to characterize infiltration, water retention, saturated hydraulic conductivity and bulk density of a silt loam that had been subject to various tillage and crop rotations in east-central Washington. Treatments examined included no-tillage spring barley-spring wheat (NTSB-SW), no-tillage spring wheat-chemical fallow (NTSW-ChF), and traditional winter wheat-summer fallow (WW-SF). Soil properties were measured in spring and late summer 2006 due to the vulnerability of the soil to rapidly dry and erode during these seasons. Saturated hydraulic conductivity was determined by the falling-head method, infiltration was measured using a double-ring infiltrometer, and water retention characteristics was assessed by examining the temporal variation of in situ soil water content. NTSB-SW resulted in higher infiltration and saturated hydraulic conductivity, lower bulk density, and larger and/or more continuous pores in the upper soil profile (<0.1 in [<3.9 in] depth) than WW-SF and NTSW-ChE Infiltration and saturated hydraulic conductivity were lower for chemical fallow than for traditional fallow in spring whereas hydraulic conductivity was lower for summer fallow than chemical fallow in late summer. Soil hydrologic properties appeared more favorable for no-tillage continuous spring cereal rotations. These results arc useful for soil and water management and conservation planning in the low precipitation zone of the Inland Pacific Northwest.
  • Authors:
    • Fernandez, M. R.
    • Ulrich, D.
    • Brandt, S. A.
    • Zentner, R. P.
    • Wang, H.
    • Thomas, A. G.
    • Olfert, O.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 3
  • Year: 2011
  • Summary: The impact of cropping system management on root and crown rot of spring wheat ( Triticum aestivum L.) was examined on a Dark Brown Chernozem (Typic Boroll) soil in the Canadian Prairies. This systems approach tried to reflect the most common practices of organic and conventional producers in this region. The study consisted of a factorial combination of three input levels (high, with tillage, fertilizer and pesticides; reduced [RED], with conservation tillage, targeted fertilizer and weed control; and organic [ORG] with tillage and N-fixing legumes); and three levels of cropping diversity (low diversity with wheat and summerfallow or legume green manure fallow; diversified using annual grain crops; and diversified using annual grain crops and perennial forages). All rotations were 6 yr long. Subcrown internodes and crowns/lower culms of wheat plants were scored for discoloration, and fungi in discolored tissue were identified and quantified. Overall, input level had a greater impact on disease levels and fungal frequency than cropping diversity. Discoloration severity was lowest in the RED systems, which was attributed to lower percentage isolation of Cochliobolus sativus, the most common pathogen. Fusarium species varied with input level. The pathogens F. avenaceum and F. culmorum were most associated with RED and/or least associated with ORG systems, whereas the weak pathogen/saprophyte F. equiseti was most associated with ORG systems. Thus, ORG management helped to reduce populations of F. avenaceum and F. culmorum, two of the most important Fusarium pathogens in the Canadian Prairies.