• 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:
    • da S. Volk, L. B.
    • Cogo, N. P.
    • Volk, L. B. da S.
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 33
  • Issue: 5
  • Year: 2009
  • Summary: This work was accomplished with the purpose of establishing quantitative relationships between the D 50 index of the size distribution of the soil-eroded sediments, the runoff velocity, the SR index of the tillage-induced soil surface roughness, and the mean weight diameter (MWD) of the soil aggregates, in a soil submitted to different forms of management. The study was developed in the field, at the Agricultural Experimentation Station of the Federal University of Rio Grande do Sul (EEA/UFRGS), in Eldorado do Sul (RS), Brazil, by applying simulated rainfall on an Ultisol with a sandy clay loam texture in the surface layer and 0.115 m m -1 average slope steepness. This soil had been put into agricultural use by different manners (continuous and discontinued cultivation), with different crop sequences (winter and summer, grass and legume crop species, planted in rows, using no-tillage), for a 7.5 year period (starting at the original condition of native pasture). Seven erosion tests were performed in the study, each one of them at 63.5 mm h -1 rainfall intensity and 1.5 h duration, using the rotating-boom rainfall simulator and 3.5*11.0 m experimental plots. The referred erosion tests were performed in the following soil surface physical conditions: (a) non-mobilized soil, with complete and no cover by crop residues, and (b) soil successively mobilized by the passage of a light disc-harrow (five times, one at a time), with no cover. It was observed that the crop sequences provided values of the MWD index significantly different each other, which reflected in significantly different values of the SR index and, as consequence, of the runoff velocity and the D 50 index, with the sequences with none or less time of discontinued cultivation (in the last period of the research) having produced the best results. In the non-mobilized, completely mulch-covered soil, with a firm and smooth surface, the mulch of crop residues was the dominant factor either in reducing the runoff velocity or in trapping the eventually detached soil particles of larger size, which led to very small values of the D 50 index. In the non-mobilized, uncovered soil, where runoff reached its highest velocities, the size of the eroded sediments was determined by the consolidation of the soil surface and by the values of the MWD index, being the smaller for the greater values of the two last variables mentioned. Yet in the soil successively mobilized by the one at a time passage of a light disc-harrow and bare, with a loose and rough surface, the roughness of the soil surface created by tillage was the dominant factor either in reducing the runoff velocity or in trapping the detached soil particles of larger size, which increased the percentage of eroded sediments
  • 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:
    • Teasdale, J. R.
    • Hanson, J. C.
    • Hima, B. L.
    • Cavigelli, M. A.
    • Conklin, A. E.
    • Lu, Y. C.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 24
  • Issue: 2
  • Year: 2009
  • Summary: We present the results from enterprise budget analyses for individual crops and for complete rotations with and without organic price premiums for five cropping systems at the US Department of Agriculture-Agricultural Research Service (USDA-ARS) Beltsville Farming Systems Project (FSP) from 2000 to 2005. The FSP is a long-term cropping systems trial established in 1996 to evaluate the sustainability of organic and conventional grain crop production. The five FSP cropping systems include a conventional, three-year no-till corn ( Zea mays L.)-rye ( Secale cereale L.) cover crop/soybean ( Glycine max (L.) Merr)-wheat ( Triticum aestivum L.)/soybean rotation (no-till (NT)), a conventional, three-year chisel-till corn-rye/soybean-wheat/soybean rotation (chisel tillage (CT)), a two-year organic hairy vetch ( Vicia villosa Roth)/corn-rye/soybean rotation (Org2), a three-year organic vetch/corn-rye/soybean-wheat rotation (Org3) and a four- to six-year organic corn-rye/soybean-wheat-red clover ( Trifolium pratense L.)/orchard grass ( Dactylis glomerata L.) or alfalfa ( Medicago sativa L.) rotation (Org4+). Economic returns were calculated for rotations present from 2000 to 2005, which included some slight changes in crop rotation sequences due to weather conditions and management changes; additional analyses were conducted for 2000 to 2002 when all crops described above were present in all organic rotations. Production costs were, in general, greatest for CT, while those for the organic systems were lower than or similar to those for NT for all crops. Present value of net returns for individual crops and for full rotations were greater and risks were lower for NT than for CT. When price premiums for organic crops were included in the analysis, cumulative present value of net returns for organic systems (US$3933 to 5446 ha -1, 2000 to 2005; US$2653 to 2869 ha -1, 2000 to 2002) were always substantially greater than for the conventional systems (US$1309 to 1909 ha -1, 2000 to 2005; US$634 to 869 ha -1, 2000 to 2002). With price premiums, Org2 had greater net returns but also greater variability of returns and economic risk across all years than all other systems, primarily because economic success of this short rotation was highly dependent on the success of soybean, the crop with the highest returns. Soybean yield variability was high due to the impact of weather on the success of weed control in the organic systems. The longer, more diverse Org4+ rotation had the lowest variability of returns among organic systems and lower economic risk than Org2. With no organic price premiums, economic returns for corn and soybean in the organic systems were generally lower than those for the conventional systems due to lower grain yields in the organic systems. An exception to this pattern is that returns for corn in Org4+ were equal to or greater than those in NT in four of six years due to both lower production costs and greater revenue than for Org2 and Org3. With no organic premiums, present value of net returns for the full rotations was greatest for NT in 4 of 6 years and greatest for Org4+ the other 2 years, when returns for hay crops were high. Returns for individual crops and for full rotations were, in general, among the lowest and economic risk was, in general, among the highest for Org2 and Org3. Results indicate that Org4+, the longest and most diverse rotation, had the most stable economic returns among organic systems but that short-term returns could be greatest with Org2.
  • 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:
    • Buschman, L. L.
    • French, B. W.
    • Currie, R. S.
    • Davis, H. N.
  • Source: Southwestern Entomologist
  • Volume: 34
  • Issue: 1
  • Year: 2009
  • Summary: This study examined how land management practices can affect the abundance of several arthropods commonly found in agriculture. This work was done in plots that had been subjected to three successive years of an agronomic experiment that evaluated the effects of a wheat, Triticum aestivum L., cover crop or no cover crop on weed and water management. After the third growing season, pitfall traps were installed and arthropods were collected and identified. At one location, carabids (Coleoptera: Carabidae) were identified to genus. Four of the genera ( Amara, Anisodactylus, Harpalus, and Calathus) were more common under no-till conditions. Only one genus ( Stenolophus) was more common in tilled plots. Five genera ( Amara, Bradycellus, Scarites, Stenolophus, and Calathus) were more common in plots with a history of more weeds caused by less herbicide use. Carabids were not more abundant in plots with fewer weeds after herbicides had been applied. Past presence of a winter cover crop never reduced carabid numbers, but significantly increased members of two genera ( Harpalus and Poecilus). As a group, carabids at one location were more common in plots without a history of a cover crop. At another location, more carabids were in tilled than nontilled plots. Crickets (Orthoptera: Gryllidae) were more common under no-till conditions. At all locations, wolf spiders (Araneae: Lycosidae) were more common in plots with no tillage and a previous cover crop. Results suggested that surface residues affected carabids, wolf spiders, and crickets.
  • 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.