• Authors:
    • Meca, A. V.
    • Popescu, N.
  • Source: Annals of the University of Craiova - Agriculture, Montanology, Cadastre Series
  • Volume: 40
  • Issue: 2
  • Year: 2010
  • Summary: Within our country conditions the wheat, rye, barley, oilseed rape and pea-oat fodder are sown in autumn. They may be grown after crops that are harvested during summer or perennial crops or pastures that are included is crop rotation schemes. In the conditions of our country, crops that are harvested during the summer are: pea-oat fodder, pea, early potato, barley and wheat. After harvesting these crops, there must be done, immediately, the summer plowing because the soil is still moist, resulting a good quality plowing. Any delay conducts to diminishing the yields. Usually, the summer plow is made at 18-20 cm depth. Deeper plow are not necessary on most soil types from our country. Twenty cm deeper plow is need only on clayey soil that easily compacts, when the soil is highly infested by weeds, covered by high straw or when in the last year there was made a shallow plow. Summer plow, no matter the depth must be done along with harrow after plow. During the fall, till drilling, the soil has to be harrowed in order to destroy weeds and to maintain soil loosened.
  • Authors:
    • Arriaga, F. J.
    • Rogers, H. H.
    • Runion, G. B.
    • Prior, S. A.
  • Source: Journal of Environmental Quality
  • Volume: 39
  • Issue: 2
  • Year: 2010
  • Summary: Increasing atmospheric CO(2) concentration has led to concerns about potential effects on production agriculture. In the fall of 1997, a study was initiated to compare the response of two crop management systems (conventional tillage and no-tillage) to elevated CO(2). The study used a split-plot design replicated three times with two management systems as main plots and two atmospheric CO(2) levels (ambient and twice ambient) as split plots using open-top chambers on a Decatur silt learn soil (clayey, kaolinitic, thermic Rhodic Paleudults). The conventional system was a grain sorghum [Sorghum bicolor (L.) Moench.] and soybean (Glycine max (L.) Merr.] rotation with winter fallow and spring tillage practices. In the no-tillage system, sorghum and soybean were rotated, and three cover crops were used [crimson clover (Trifolium incarnatum L.), sunn hemp (Crotalaria juncea L.), and wheat (Triticum aestivum L.)]. Over multiple growing seasons, the effect of management and CO(2) concentration on leaf-level gas exchange during row crop (soybean in 1999, 2001, and 2003; sorghum in 2000, 2002, and 2004) reproductive growth were evaluated. Treatment effects were fairly consistent across years. In general, higher photosynthetic races were observed under CO(2) enrichment (more so with soybean) regardless of residue management practice. Elevated CO(2) led to decreases in stomatal conductance and transpiration, which resulted in increased water use efficiency. The effects of management system on gas exchange measurements were infrequently significant, as were interactions of CO(2) and management. These results Suggest that better soil moisture conservation and high rates of photosynthesis can occur in both tillage systems in CO(2)-enriched environments during reproductive growth.
  • Authors:
    • Belina, K.
    • Baumgartner, K.
    • Steenwerth, K.
    • Veilleux, L.
  • Source: Weed Science
  • Volume: 58
  • Issue: 3
  • Year: 2010
  • Summary: This research compared effects of the weed control practice, soil cultivation, and the conventional practice, glyphosate application on weed seedbank, in a vineyard system. The experiment was conducted in a commercial wine-grape vineyard in the Napa Valley of northern California from 2003 to 2005. The annual treatments were "winter-spring glyphosate," "spring cultivation," "fall-spring cultivation," and "fall cultivation-spring glyphosate," and were applied "in-row," under the vine. Composition of the weed seedbank collected in 2002 before treatment establishment did not differ among treatments. After 3 yr of weed treatments, detrended correspondence analysis indicated that the composition of spring cultivation and winter-spring glyphosate tended to differ from each other, but the remaining two treatments showed little differentiation. As determined by linear discriminant analysis, the specific weed species were associated with seedbanks of certain treatments. These were Carolina geranium, annual bluegrass, brome grasses, California burclover, and scarlet pimpernel, which do not pose problems with regard to physical aspects of grape production. Although 'Zorro' rattail fescue was ubiquitous among treatments, its distribution between depths in the cultivated treatments indicated that tillage provided some homogenization of seedbank along the vertical soil profile. The seedlings from the seedbank study were not congruent with those measured aboveground in the field, suggesting that both treatment and microclimatic effects in the field may have influenced germination, and thus, aboveground composition.
  • Authors:
    • Thierfelder, C.
    • Wall, P. C.
  • Source: Experimental Agriculture
  • Volume: 46
  • Issue: 3
  • Year: 2010
  • Summary: Conservation agriculture (CA) systems are based on minimal soil disturbance, crop residue retention and crop rotation. Although the capacity of rotations to break pest and disease cycles is generally recognized, other benefits of crop rotations in CA systems are seldom acknowledged and little understood. We monitored different conventional and CA cropping systems over the period from 2005 to 2009 in a multi-seasonal trial in Monze, southern Zambia. Both monocropped maize and different maize rotations including cotton and the green manure cover crop sunnhemp (Crotalaria juncea) were compared under CA conditions, with the aim of elucidating the effects of crop rotations on soil quality soil moisture relations and maize productivity. Infiltration, a sensitive indicator of soil quality, was significantly lower on conventionally ploughed plots in all cropping seasons compared to CA plots. Higher water infiltration rate led to greater soil moisture content in CA maize treatments seeded alter cotton. Earthworm populations, total carbon and aggregate stability were also significantly higher on CA plots. improvements in soil quality resulted in higher rainfall use efficiency and higher maize grain yield on CA plots especially those in a two- or three-year rotation. lit the 2007/08 and 2008/2009 season, highest yields were obtained from direct-seeded maize after sunnhemp, which yielded 74% and 136% more than maize in the conventionally ploughed control treatment with a continuous maize crop. Even in a two-year rotation (maize-cotton), without a legume green manure cover crop, 47% and 38% higher maize yields were recorded compared to maize in the conventionally ploughed control in the two years, respectively This suggests that there are positive effects from crop rotations even in the absence of disease and pest problems. The overall profitability of each system will, however, depend on markets and prices, which will guide the farmer's decision on which, Wally, rotation to choose,
  • 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:
    • van Rensburg, L. D.
  • Source: South African Journal of Plant and Soil
  • Volume: 27
  • Issue: 1
  • Year: 2010
  • Summary: This is the third soil physics review to be published in South African Journal of Plant and Soil. In the previous reviews the focus was broad and covered almost every aspect of the subject, providing a comprehensive list of contributions in soil physics. For the 25th year anniversary celebration of South African Journal of Plant and Soil, I have chosen to narrow the scope and focus on advances in soil physics in relation to irrigation and dryland agriculture. From a bio-physical viewpoint, South African researchers have made a major contribution to the body of scientific knowledge about irrigation and its application, expressed mainly in the form of irrigation or crop models such as PUTU, SWB and BEWAB. Attention was also given to modern ways of irrigation scheduling based on continuous soil water monitoring. Several irrigation scheduling service providers have adapted their businesses accordingly, with the result that South Africa is probably the leading country in Africa with respect to soil water monitoring and associated communication technology. In contrast, the review has shown that at farm and irrigation scheme level, salt management requires urgent attention. This is necessary as a precautionary measure to protect our natural resources. In the second part of the review the contribution of soil physics in relation to tillage practices is explored, and in particular how these have modified the field water balance components in order to enhance yield and rain water productivity. Based on the results of field experiments, new relationships were established, viz, rainfall and maize yield; water storage and yield; runoff and surface coverage by crop residue mulches; tillage depth, texture and yield relationships. Lastly, the review also showed how the water balance on clay and duplex soils in semi-arid zones can be modified through in-field rainwater harvesting to increase their rain water productivity. This technology has enhanced the livelihoods of many communal families who have applied the technique in their homesteads.
  • 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:
    • Nobrega, L. H. P.
    • Smanhotto, A.
    • Sampaio, S. C.
    • Caovilla, F. A.
    • Queiroz, M. M. F. de
    • Gomes, B. M.
  • Source: Revista Brasileira de Engenharia Agricola e Ambiental
  • Volume: 14
  • Issue: 7
  • Year: 2010
  • Summary: In this work the distribution was evaluated "in situ" of phosphorus (P), organic matter (MO), potassium (K), calcium (Ca), magnesium (Mg), cation exchange capacity (CEC), aluminum (Al), sum of bases (S), base saturation (V) and pH of a soil cultivated with soybean and irrigated with swine wastewater in the 0, 25, 50 and 75% levels. The factorial scheme was constituted by the 20, 40 and 60 cm soil depths and four wastewater levels with five repetitions. The results showed that significant difference occurred only for P, K and CEC in the soil profile. However, in all parameters, the 60 cm soil depth showed that the concentrations levels are similar to before the application of treatments.
  • 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.