• Authors:
    • Krogstad, T.
    • Bechmann, M.
    • Aronsson, H.
    • Ulen, B.
    • Øygarden, L.
    • Stenberg, M.
  • Source: Soil Use and Management
  • Volume: 26
  • Issue: 2
  • Year: 2010
  • Summary: In Scandinavia high losses of soil and particulate-bound phosphorus (PP) have been shown to occur from tine-cultivated and mouldboard-ploughed soils in clay soil areas, especially in relatively warm, wet winters. The omission in the autumn of primary tillage (not ploughing) and the maintenance of a continuous crop cover are generally used to control soil erosion. In Norway, ploughing and shallow cultivation of sloping fields in spring instead of ploughing in autumn have been shown to reduce particle transport by up to 89% on highly erodible soils. Particle erosion from clay soils can be reduced by 79% by direct drilling in spring compared with autumn ploughing. Field experiments in Scandinavia with ploughless tillage of clay loams and clay soils compared to conventional autumn ploughing usually show reductions in total P losses of 10-80% by both surface and subsurface runoff (lateral movements to drains). However, the effects of not ploughing during the autumn on losses of dissolved reactive P (DRP) are frequently negative, since the DRP losses without ploughing compared to conventional ploughing have increased up to fourfold in field experiments. In addition, a comprehensive Norwegian field experiment at a site with high erosion risk has shown that the proportion of DRP compared to total P was twice as high in runoff water after direct drilling compared to ploughing. Therefore, erosion control measures should be further evaluated for fields with an erosion risk since reduction in PP losses may be low and DRP losses still high. Ploughless tillage systems have potential side-effects, including an increased need for pesticides to control weeds [e.g. Elytrigia repens (L.) Desv. ex Nevski] and plant diseases (e.g. Fusarium spp.) harboured by crop residues on the soil surface. Overall, soil tillage systems should be appraised for their positive and negative environmental effects before they are widely used for all types of soil, management practice, climate and landscape.
  • Authors:
    • Demuzere, M.
    • Gillijns, K.
    • Diels, J.
    • Govers, G.
    • Van den Putte, A.
  • Source: European Journal of Agronomy
  • Volume: 33
  • Issue: 3
  • Year: 2010
  • Summary: Many strategies exist to combat soil degradation through erosion and compaction on agricultural fields. One of these strategies is conservation agriculture (CA). Reduced or no-tillage techniques, together with crop residue management and crop rotation are the pillars of CA. The term reduced tillage covers a range of tillage practices but it never involves inverting the soil. In this way, soil disturbance is minimised and crop residues are left on the soil. Studies in many European countries have shown that CA can indeed be very effective in combating soil erosion. However, soil and water conservation do not appear as main drivers in farmers' decisions to shift or not to CA. Economic factors tend to be more important, but there are a lot of uncertainties on this domain. Studies show that production costs are mostly reduced, mainly by reduced fuel costs. Although many European studies have investigated the effect of reduced soil tillage on crop yields, a lot of uncertainties still exist. Most of the studies only cover a small range of field experiments, in one region. We present a meta-regression analysis (47 European studies, 563 observations) that compares crop yields under conventional tillage (CT), reduced tillage (RT) and no-tillage (NT) techniques. We analysed the possible influence on the relative yield ((RT or NT)/CT) of crop type, tillage depth, crop rotation, climate, CT yield and length of application of RT or NT. Our analysis shows that, while the introduction of conservation tillage in Europe may indeed have some negative effect on yields, these effects can be expected to be limited: the overall average reduction we found was ca. 4.5%. NT reduces crop yield on average with 8.5%. However, RT leads to a reduction in crop yields for maize and winter cereals only. By applying a linear mixed model, the importance of tillage depth and crop type as classification effects could be confirmed. Surprisingly, no-tillage did perform worse under drier climatic conditions. Negative effects such as an increased prevalence of pests and a lower quality of seed placement seem to outweigh possible gains due to increased water availability. On clay and sandy soils, however, this negative effect of no-tillage is counteracted, and all conservation tillage techniques perform better under drier climatic conditions. Another important finding is that, in cereals only rotations, relative yields under conservation tillage tend to decrease with time. Our analysis shows that conservation tillage is certainly a viable option for European agriculture from the viewpoint of agricultural productivity. Potential negative effects on agricultural productivity can be strongly reduced by applying sufficiently deep tillage and using a crop rotation including crops other than cereals. (C) 2010 Elsevier B.V. All rights reserved.
  • Authors:
    • Satkus, A.
    • Velykis, A.
  • Source: Zemdirbyste-Agriculture
  • Volume: 97
  • Issue: 2
  • Year: 2010
  • Summary: Experiments were carried out during 2007-2009 at the Joniskelis Experimental Station of the Lithuanian Institute of Agriculture on a clay loam Endocalcari-Endohypogleyic Cambisol (CMg-n-w-can). The study was designed to assess the effects of shallow ploughing and ploughless tillage as well as its combinations with other agronomic practices incorporation of lime sludge, cover crops (mixture of white mustard and oilseed radish) for green manure and mulch, improving soil condition and environment protection on the spread of weeds in a field pea crop and field pea productivity. It was found that when the post-sowing period was dry, reduced tillage of clay loam soil resulted in a higher weed incidence as well as a reduction in field pea yield, especially when leaving a cover crop for mulch during winter without tillage in autumn, as compared to deep ploughing. Under such conditions and due to reduced tillage, the spread of Galium aparine L. and Chenopodium album L. was wider, and in the cases of low field pea crop density as well as poor competition abilities, the mass of weeds increased. When the moisture was sufficient for field pea to emerge during post-sowing period, the spread of annual weeds was lower due to reduced tillage. Incorporation of lime sludge together with ploughless tillage helped to prevent the spread of weeds and reduction of field pea yield and was more favourable compared to ploughing.
  • Authors:
    • Rosolem, C. A.
    • Calonego, J. C.
  • Source: European Journal of Agronomy
  • Volume: 33
  • Issue: 3
  • Year: 2010
  • Summary: Compacted subsoil layers result in shallow root systems hindering the absorption of water and nutrients by plants. Disruption of soil compacted layers can be promoted by mechanical and/or biological methods, using plants with strong root systems. The immediate and medium term effects of mechanical chiseling and crop rotations on soybean root growth and yield were evaluated during four years in Brazil. Triticale (X Triticosecale Wittmack) and sunflower (Helianthus annuus L) were grown in the autumn-winter (April-August). In the next spring (September-October/early November), designated plots were chiseled down to 0.25 m or planted to millet (Pennisetum glaucum L), sorghum (Sorghum bicolor (L.) Moench) and sunn hemp (Crotalaria juncea L.), grown as cover crops, preceding soybean (Glycine max (L.) Merrill). Chiseling was done only in the first year, and these plots were left fallow during the spring (September-October/early November) for the rest of the experiment. Chiseling resulted in lower soil penetration resistance and higher soybean yields in the first year. However, in the following years soybean root growth in depth was increased under rotation with triticale and pearl millet due to the presence of biopores and a decrease in soil penetration resistance. Soybean yields tended to decrease over the years in plots that were chiseled when compared with plots under crop rotation. Chiseling can be replaced by crop rotations involving species with aggressive root systems in order to alleviate deleterious effects of soil compaction on soybean yields in tropical soils. This effect is gradual, thus crop rotation will be fully effective in remediating soil compaction in a 3- to 4-year term. (C) 2010 Elsevier B.V. All rights reserved.
  • Authors:
    • Constantin, N.
    • Zaharia, G. V.
    • Cociu, A. I.
  • Source: Romanian Agricultural Research
  • Issue: 27
  • Year: 2010
  • Summary: The increase of water use efficiency is very important, especially in water-limited conditions. The research project, carried out on cambic chernozem soil at Fundulea, in 2008 and 2009, had as the main objective the evaluation of contribution of the deep sub-soiling, done before the implementation of this experiment, and of certain tillage systems on over-winter soil water storage, water use efficiency (WUE) and water use as well as on the yield of winter wheat ( Triticum aestivum L.), maize ( Zea mays L.) and soybean [ Glycine max. (L) Merr.], in rotation. The following tillage systems were studied: (1) traditional, with moldboard plough (TS); (2) cizel plough tillage (CS); (3) disc/sweep tillage (DS); (4) strip till, only for row crops (ST); and no till (NT). The over-winter soil water storage estimation was based on calculation of the coefficient of rainfall accumulation during winter (CA), and of capacity of soil water conservation (CC). In the case of maize after wheat, CA was 0.6 on plots with deep sub-soiling, 0.6 on plots without deep sub-soiling, 0.6 with TS, 0.6 with CS, 0.7 with DS, 0.7 with ST, and 0.7 with NT. CC was 85% on plots with deep sub-soiling, 85% on plots without deep subsoiling, 82% with TS, 0.84% with CS, 86% with DS, 86% with ST, and 86% with NT. For soybean after maize, CA was 0.5 on plots with deep sub-soiling, 0.6 on plots without deep sub-soiling, 0.5 with TS, 0.5 with CS, 0.5 with DS, 0.6 with ST, and 0.6 with NT. CC was 77% on plots with deep sub-soiling, 79% on plots without deep sub-soiling, 72% with TS, 78% with CS, 78% with DS, 78% with ST, and 79% with NT. Water use and water use efficiency showed non significant differences for all crops under this study on both plots with deep sub-soiling and without deep sub-soiling, suggesting that the yield differences were not significantly determined by water supply. The water use average for wheat was: 380 mm with TS, 377 mm with CS, 395 mm with DS, and 382 mm with NT. For maize, water use was 339 mm with TS, 345 mm with CS, 343 mm with DS, 341 mm with ST and 343 mm with NT. For soybean, water use was 320 mm with TS, 315 mm with CS, 317 mm with DS, 314 mm with ST and 319 mm with NT. Water use efficiency from precipitations was given for wheat, maize and soyabean. Yield increases due to deep sub-soiling were: 0.1% for wheat 1.5% for maize, and 7.3% for soybean. The average yields recorded were: For wheat 4948 kg ha -1 with TS. 4536 kg ha -1 with CS, 4814 kg ha -1 with DS, 5048 kg ha -1 with NT. For maize 8743 kg ha -1 with TS, 8954 kg ha -1 with CS, 8792 kg ha -1 with DS, 7940 kg ha -1 with ST and 9052 kg ha -1 with NT. For soybean 2098 kg ha -1 with TS, 1812 kg ha -1 with CS, 1846 kg ha -1 with DS, 1798 kg ha -1 with ST and 1941 kg ha -1 with NT. The highest yields were obtained with NT for wheat and maize. WUE was strongly correlated with yield, and had the highest values far wheat and maize with NT. In the case of soybean, we consider that a significant yield increase can be obtained with an efficient weed control and soil protection with adequate amounts of residues from the previous crop.
  • Authors:
    • Țărau, D.
    • Borza, I.
    • Dicu, D.
  • Source: Research Journal of Agricultural Science
  • Volume: 42
  • Issue: 3
  • Year: 2010
  • Summary: Studies were conducted on a cambic cernosiom, with a medium content of clay, dominant in the Prodagro West Arad agro-centre and representative for a large surface in the Banat-Crisana Plain, on the Arad cadasiral territory, Romania. The experimental factors considered include: soil work system; foliar phyto-sanitary treatment; classical system; and no-till system. From the geomorphological point of view, the perimeter on which the experiments are located belongs to the large physical-geographic unity called the Vinga High Plain. Relief present itself as a succession of high plain, almost even, with altitudes between 95-200 m, separated by wide valleys, rather deep, collected quite in exclusivity by Berecsau river (and less by Mires river). The zone between the rivers are well individuated in 5 steps layed in fan shape: Seceani (180 m), Alios (160 m), Vinga (150 m), Calacea (130 m), Satchinez (100 m) realized by Mires river at different geological moments an partly tectonically influenced. Hydrographically, the perimeter where the experiment is placed belongs to the hydrographic basin of Mires river which flows at approximately 2-3 km north from this. The pedophreatic levels are at 5.1-10 m depth (they do not interfere in the pedogenesis processes) in flat areas and between 1.5-3.0 m depth in the valleys. For wheat, the production was between 3613-4817 kg/ha, the highest production of 4817 kg/ha, being registered in the no-till system, treated and the lowest of 3613 kg/ha in the no-till system . For maize the obtained production had values of 3658-5680 kg/ha, the highest production of 5680 kg/ha, being registered in classic system treated and the lowest of 3658 kg/ha in no-till system untreated.
  • Authors:
    • Rosa Becker, A.
    • Camilo Bedano, J.
    • Dominguez, A.
  • Source: Soil & Tillage Research
  • Volume: 110
  • Issue: 1
  • Year: 2010
  • Summary: No-till (NT) has been recognized as a management system of low environmental impact when applied in combination with crop residue mulch and rotations involving cover crops. It has been suggested, however, that, if these conditions are not met, NT may result in physical, chemical and biological soil degradation. This study evaluates the effect of NT on the litter decomposition process and on soil macrofauna communities and how changes in soil physical, chemical, and physicochemical properties affect litter decomposition and soil macrofauna. We hypothesised (1) that macrofaunal abundance, richness and diversity would be lower in NT soils than in natural grasslands; (2) that this would be a consequence of unfavourable physical and chemical soil conditions and high inputs of agrochemicals; and (3) that these changes in macrofauna would influence soil functioning, reducing litter decomposition rate. The study was conducted during winter and spring 2007 on Typic Haplustolls from southern Cordoba, Argentina (32 degrees 41' and 32 degrees 50'S; 63 degrees 58' and 63 degrees 44'W). Macrofauna was sampled twice in NT and in natural grasslands (NA) - as a reference situation - by extracting five soil monoliths of 25 cm x 25 cm x 30 cm at each plot. Soil properties were measured using standard methods. The decomposition rate was determined by the litterbag method, using a 2 mm and a 10 mm size meshes to evaluate litter decomposition mediated by macrofauna. NT greatly reduced richness (from 33 species in NA to 12 species in NT) and abundance (from 1870 ind/m(2) in NA to 475 ind/m(2) in NT) of macroinvertebrates, confirming our first hypothesis. Changes in macrofauna community under NT were mainly explained by high compaction and low organic matter content, confirming our second hypothesis. The reduction in earthworm abundance may also be explained by the influence of the intense use of toxic agrochemicals. No-till increased surface horizon bulk density (from 1.22 to 1.33 g/cm(3)) and decreased organic matter content (from 3.51% to 2.58%) and pH (from 6.74 to 6.01) compared with NA. The litter decomposition rate was lower in NT, confirming our third hypothesis, and it was correlated with low earthworms abundance and activity. We conclude that in our study area the capacity of soils under NT to maintain ecosystem functions would be at risk. (C) 2010 Elsevier B.V. All rights reserved.
  • Authors:
    • Hu, C. S.
    • Ren, T. S.
    • Du, Z. L.
  • Source: Soil Science Society of America Journal
  • Volume: 74
  • Issue: 1
  • Year: 2010
  • Summary: Little information is available about their influences of conservation tillage on the distribution and storage of soil organic C (SOC) and total N in soil profiles in the North China Plain. We investigated the changes in SOC and total N as related to the shift from conventional to conservation tillage using a long-term field experiment with a winter wheat ( Triticum aestivum L.)-corn ( Zea mays L.) double cropping system. The experiment included four tillage treatments for winter wheat: moldboard plow without corn residue return (MP-R), moldboard plow with corn residue return (MP+R), rotary tillage (RT), and no-till (NT). Compared with the MP-R treatment, returning crop residue to the soil (MP+R, RT, and NT) increased SOC and total N in the 0- to 30-cm soil layer, but no distinct changes in SOC and total N concentration were observed among the four treatments at soil depths >30 cm. Compared with the MP+R treatment, the RT and NT treatments increased SOC and total N concentration significantly in the 0- to 10-cm layer but decreased SOC and total N concentration in the 10- to 20-cm layers. As a consequence, soil profile SOC and total N storage did not vary among the MP+R, RT, and NT treatments. Thus under the experimental conditions, conservation tillage (RT and NT) increased SOC and total N contents in the upper soil layers, but did not increase SOC and total N storage over conventional tillage (MP+R) in the soil profile.
  • Authors:
    • Ferreira, A. C. de B.
    • Lamas, F. M.
  • Source: Revista Ceres
  • Volume: 57
  • Issue: 6
  • Year: 2010
  • Summary: The objective of this work was to evaluate the production, persistence and the effect of different cover crops on weed control and cotton yield in no-tillage system. The treatments included: Pennisetum glaucum; Brachiaria ruziziensis; Sorghum bicolor; Eleusine coracana; Crotalaria juncea; Crotalaria spectabilis; Avena strigosa; Raphanus sativus; P. glaucum+ C. juncea; P. glaucum+ C. spectabilis; B. ruziziensis+ C. juncea; B. ruziziensis+ C. spectabilis; S. bicolor+ C. juncea; S. bicolor+ C. spectabilis; E. coracana+ C. juncea; E. coracana+ C. spectabilis; A. strigosa+ R. sativus; P. glaucum+ R. sativus; fallow. The cover crops were sown in late summer, after soybean harvest. The cotton cultivar BRS 269-Buriti was sown nine months later. The experiment was carried out in a randomized complete block design with four replications. Dry matter of B. ruziziensis, B. ruziziensis+ C. juncea, B. ruziziensis+ C. spectabilis and P. glaucum+ R. sativus was above 6.8 t ha -1 The dry matter produced by B. ruziziensis provided sufficient soil cover during the cotton cycle. Residues of B. ruziziensis, B. ruziziensis+ C. juncea and B. ruziziensis+ C. spectabilis reduced weed incidence until the time of cotton sowing, lasting until the initial stages of cotton development. The use of both R. sativus and A. strigosa, alone or in mixtures, resulted in reduced yield of cotton fiber.
  • Authors:
    • Bayer, C.
    • Vieira, R. C. B.
    • Fontoura, S. M. V.
    • Ernani, P. R.
    • Moraes, R. P. de
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 34
  • Issue: 6
  • Year: 2010
  • Summary: Little is known about the agronomic effectiveness of phosphate rocks in high-yielding crop rotation systems under no-till in the Center-South of the state of Parana, Brazil. This field study was undertaken to compare the effectiveness of rock phosphates and soluble P fertilizers to increase the yield of several annual crops grown in two consecutive triennial crop-rotation cycles under no-tillage. The experiment was carried out in an Oxisol, in Guarapuava, PR, from 2000 until 2006. Two phosphate rocks (PR - Gafsa and Arad) and a soluble P fertilizer (TSP - triple superphosphate) were broadcast over the soil surface at rates of 0, 40, 80 and 160 kg ha -1 P 2O 5, at the beginning of the first and the second rotation cycle of the triennial crops (oat, maize, wheat, soybean, barley and soybean). With exception of barley, crop yields were not affected in the first rotation cycle by any phosphate fertilizer regardless of type and rate, probably due to the high P contents available in the soil (8.7 mg dm -3 in the 0-10 cm layer). In the second rotation cycle, when soil available P was 4.1 mg dm -3; P application at oat sowing increased the yield of summer crops by 11% and of winter crops by 20%. The yield increment was lowest for maize (8%) and highest for barley (44%). In this cycle, TSP resulted in higher yield than PR, though only for winter crops (oat, wheat and barley), in a mean of 11%, with no difference between Gafsa and Arad. Water soluble fertilizer (TSP) was more efficient than phosphate rocks in soils under no-till system both in the short and long term. Nevertheless, it is not necessary to apply phosphates for high yields in soils with high available P contents under no-till, except for species with high P requirement, e.g., barley.