• Authors:
    • Spera, S.
    • Fontaneli, R.
    • Santos, H.
    • Maldaner, G.
  • Source: PESQUISA AGROPECUARIA BRASILEIRA
  • Volume: 46
  • Issue: 10
  • Year: 2011
  • Summary: The objective of this work was to assess energy conversion and balance of integrated crop-livestock production systems, under no-tillage. The experiment was carried out from 2001 to 2008. From 2001 to 2002, the following systems were evaluated: 1, wheat/soybean, and black oat pasture+common vetch/corn; 2, wheat/soybean, and black oat pasture+common vetch+ryegrass/corn; 3, wheat/soybean and black oat pasture+common vetch/millet pasture; 4, wheat/soybean and black oat pasture+common vetch+rygrass/millet pasture; 5, wheat/soybean, white oat/soybean, and black oat pasture+common vetch/millet pasture; 6, wheat/soybean, white oat/soybean, and black oat pasture+common vetch+rygrass/millet pasture. From 2003 to 2008, the following systems were evaluated: 1, wheat/soybean, and common vetch/corn; 2, wheat/soybean, and black oat pasture/corn; 3, wheat/soybean, and black oat pasture/soybean; 4, wheat/soybean, and field pea/corn; 5, wheat/soybean, common vetch/soybean, and double purpose triticale/soybean; and 6, wheat/soybean, double purpose white oat/soybean, and double purpose wheat/soybean. Corn showed highest returned energy in comparison to the other grain crops, and to winter and summer annual pastures. Of the winter cover crops and green manure species evaluated, field pea was the most efficient in energy conversion. Systems 1, 2, and 4, from 2003 to 2008, had the most efficient energy balance.
  • Authors:
    • Costa, O.
    • Ziech, M.
    • Nornberg, J.
    • Bermudes, R.
    • Viegas, J.
    • Skonieski, F.
    • Meinerz, G.
  • Source: REVISTA BRASILEIRA DE ZOOTECNIA-BRAZILIAN JOURNAL OF ANIMAL SCIENCE
  • Volume: 40
  • Issue: 3
  • Year: 2011
  • Summary: The objective of this work was to evaluate the influence of species intercropped with ryegrass on the botanical and structural composition and the nutritional values of pastures in an agroecological transition system. It was evaluated ryegrass ( Lolium multiflorum Lam.) intercropped with black oats ( Avena strigosa Schreb.), white clover ( Trifolium repens L.) and forage peanut ( Arachis pintoi Krapov. & Gregory). It was used a complete random design with three treatments and three repetitions. The first grazing was done 21 days after emergence of the plants on the pastures with ryegrass and black oats and ryegrass and forage peanuts and 28 days after emergence on the pasture of ryegrass+white clover. The second grazing, on the pasture with ryegras+black oats, occurred 30 days after the first one, whereas on the other pastures, grazing occurred 37 days later. The rates of dry matter (DM) accumulation, from the beginning of period of exclusion until maximal production of dry matter were: 77.7; 75.0 and 71.3 kg/ha/day of DM for the pastures intercropped with white clover, forage peanut and black cover, respectively. Leaf/culm ratio until second grazing, was high on all pastures. Reduction on contents of crude protein according to exclusion days on ryegrass+black oat pasture is lower than on pastures of ryegrass intercropped with white clover or forage peanut.
  • Authors:
    • Macak, M.
    • Smatana, J.
  • Source: Acta Fytotechnica et Zootechnica
  • Volume: 14
  • Issue: 2
  • Year: 2011
  • Summary: The research of crop rotation pattern and field homogenization was carrying out during 2000-2010 at company Agrokarpaty Plavnica Ltd in Slovakia. The average temperature of the site during growing period is 14.9degreesC and a sum of precipitation 438 mm. The fields are situated at 300-450 m above the see level. Total acreage of arable land is 380 ha. Share of medicinal plants varied from 85 ha to 145 ha during evaluated period. The main growing medicinal and spices plants are as follows: Galega officinalis L, Medicago sativa L, Hypericum perforation L, Mentha piperita L, Melissa officinalis L, Calendula officinalis L, Fagopyrum esculentum Moench, Carum carvi L., Achilea milefolium L, Agrimonia eupatoria L, Matricaria recutita L, Plantago lanceolata L, Malva mauritiana L. As a forecrop red clover ( Trifolium pratense L), winter wheat ( Triticum aestivum L), spring barley ( Hordeum sativum L.) and oat ( Avena sativa L.) have been growing. The management practices of "Agrokarpaty Plavnica" are in full compliance with the good agricultural practices (GAP). The high priority is maintenance of soil fertility and sustain of nutrients, mainly nitrogen. The green manure, cover crop, growing of legumes and compost from own productions are used. Two steps for designing have been suggested (i) Field consolidation and homogenisation of field for crop rotations area, (ii) Proposal of crop rotation pattern. The interested area is characterized by low production potential of 8 classes of soil production categories. We have proposed new cropping pattern of 14 fields with total acreage of 180.11 ha with average field 12.87 ha. Share of medicinal and spices plants is 68.27%, share of red clover 14.29% and spring cereals 17.46%. The design of propose crop rotation allows to use organic manure mainly before medicinal plants growing for leaves drug, and incorporation of cover crops for maintenance of soil fertility. Supposed crop rotation pattern complies with basic principles of crop rotation and sustainable agriculture.
  • Authors:
    • Topp, C.
    • Walker, R.
    • Rees, R.
    • Edwards, A.
    • Baddeley, J.
    • Watson, C.
  • Source: Organic Agriculture
  • Volume: 1
  • Issue: 3
  • Year: 2011
  • Summary: The ability to maintain crop yield and quality in systems based on nitrogen (N) fixed by legumes rather than from synthetic N fertilisers is fundamental to the long-term viability of organic farming. This paper reports crop yield and nitrogen uptake parameters for the first spring oat crop after grass/clover ley in organically managed ley/arable rotations to indicate the amount of fertility built-up during the ley period. The trial site, at Tulloch in North East Scotland, underwent two complete cycles of 6-year ley/arable rotations with different lengths of grazed ley (3 or 4 years). Trials were sufficiently replicated so that each course of the rotation was present in every year. The rotation containing 3 years of ley was also compared with a similar rotation at a nearby site (Woodside) with lower rainfall and soil fertility over one and a half rotational cycles. Grain yields were consistently higher at Tulloch (5.1 tha -1 compared with 4.5 tha -1 at Woodside) and were unaffected by the length of ley. However, grain N percentage was higher following the 4-year ley (1.38% compared with 1.30% following the 3-year ley). While yields were maintained between the first and second cycles of all the rotations, grain N percentage declined. Annual grain yields of the organically grown oats at Tulloch were not significantly different from National List/Recommended List yields in NE Scotland for oats receiving 100 kg N ha -1. Results suggest that these particular rotation designs were suitable for maintaining acceptable grain yields under organic management conditions.
  • Authors:
    • Alvaro-Fuentes, J.
    • Paustian, K.
  • Source: Plant and Soil
  • Volume: 338
  • Issue: 1/2
  • Year: 2011
  • Summary: Climate change is projected to significantly impact vegetation and soils of managed ecosystems. In this study we used the ecosystem Century model together with climatic outputs from different atmosphere-ocean general circulation models (AOGCM) to study the effects of climate change and management on soil organic carbon (SOC) dynamics in semiarid Mediterranean conditions and to identify which management practices have the greatest potential to increase SOC in these areas. Five climate scenarios and seven management scenarios were modeled from 2010 to 2100. Differences in SOC sequestration were greater among management systems than among climate change scenarios. Management scenarios under continuous cropping yielded greater C inputs and SOC gain than scenarios under cereal-fallow rotation. The shift from rainfed conditions to irrigation also resulted in an increase of C inputs but a decrease in the SOC sequestered during the 2010-2100 period. The effects of precipitation and temperature change on SOC dynamics were different depending on the management system applied. Consequently, the relative response to climate and management depended on the net result of the influences on C inputs and decomposition. Under climate change, the adoption of certain management practices in semiarid Mediterranean agroecosystems could be critical in maximizing SOC sequestration and thus reducing CO 2 concentration in the atmosphere.
  • Authors:
    • O'Donovan, J.
    • Harker, K.
    • Clayton, G.
    • Brandt, R.
    • Hao, X.
    • Blackshaw, R.
    • Johnson, E.
    • Vera, C.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 1
  • Year: 2011
  • Summary: Nitrogen fertilizer is a major input cost in canola ( Brassica napus L.) production and farmers are interested in improving N use efficiencies. A multi-site study in western Canada was conducted to determine the merits of polymer-coated urea (Environmentally Smart Nitrogen, ESN) compared with urea on weed management and yield of hybrid and open-pollinated (OP) canola. Treatments included a hybrid and OP canola cultivar, ESN and urea, 100 and 150% of soil test N fertilizer rates, and 50 and 100% of registered in-crop herbicide rates. Canola was grown in rotation with barley ( Hordeum vulgare L.) in a no-till system and both crops of the rotation were present each year. Fertilizer and herbicide rate treatments were applied to the same plots in four consecutive years to determine annual and cumulative effects. Hybrid compared with OP canola reduced weed tissue N concentration in 40% of the cases and reduced weed biomass in 80% of the cases. Additionally, weed tissue N concentration was lower with ESN than with urea in 70% of the cases, indicating that crop-weed competition for soil N might be reduced if ESN were used. Canola yield was greater for the hybrid cultivar in 15 of 20 site-years. Both cultivars expressed a positive yield response to the 150% N fertilizer rate in 10 of 20 site-years. This yield response occurred in three additional site-years with hybrid canola, indicating that hybrid cultivars have a higher N demand under favorable growing conditions. Canola yield was similar with ESN and urea in 14 of 20 site-years. The ESN compared with urea increased canola yield in 4 site-years and in one additional site-year for hybrid canola, indicating that ESN may be advantageous in some situations. Canola seed oil concentration was similar with ESN and urea in 19 of 20 site-years. Information gained in this study will be used to develop improved fertilization strategies for canola production on the semiarid Canadian prairies.
  • Authors:
    • Askegaard, M.
    • Olesen, J. E.
    • Kristensen, K.
    • Rasmussen, I. A.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 142
  • Issue: 3-4
  • Year: 2011
  • Summary: Two main challenges facing organic arable farming are the supply of nitrogen (N) to the crop and the control of perennial weeds. Nitrate leaching from different organic arable crop rotations was investigated over three consecutive four-year crop rotations in a field experiment at three locations in Denmark (12 years in total). The experimental treatments were: (i) crop rotation, (ii) catch crop and (iii) animal manure. Nitrate leaching was estimated from measured soil nitrate concentration in ceramic suction cells and modelled drainage. There were significant effects on annual N leaching of location (coarse sand > loamy sand > sandy loam) and catch crops (without > with). Including a grass-clover green manure on 25% of the area did not increase N leaching compared with crop rotations without green manure. Also the application of animal manure did not influence N leaching, probably because even in the manured treatments the application rate was lower than crop demand. The results identify management of crop and soil during autumn as the main determinant of N leaching. Nitrate leaching was lowest for a catch crop soil cover during autumn and winter (avg. 20 kg N ha -1), a soil cover of weeds/volunteers had on avg. 30 kg N ha -1, and the largest N leaching losses were found after stubble cultivation (avg. 55 kg N ha -1). The N leaching losses increased with increasing number of autumn soil cultivations.
  • Authors:
    • Jitareanu, G.
    • Bucur, D.
    • Ailincai, D.
    • Ailincai, C.
  • Source: Cercetări Agronomice în Moldova
  • Volume: 44
  • Issue: 3
  • Year: 2011
  • Summary: The goal of the experiments carried out at the Podu-Iloaiei Agricultural Research Station, Iași County, was the study of water runoff and soil losses, caused by erosion, in different crops and the influence of water and soil erosion on the losses of organic matter and mineral elements from soil. The results on water runoff and soil losses in different crops from the Moldavian Plateau have shown that in the last seven years, of the total amount of 608.4 mm rainfall, 387.5 mm (63.7%) produced water runoff, which was between 8.5 mm in perennial grasses, in the second year of vegetation, and 34.9 - 36.8 mm, in maize and sunflower crops. The annual soil losses due to erosion, recorded at the same period, were between 0.190 t/ha/year in perennial grasses, and 4.079 - 4.451 t/ha/year in maize and sunflower crops. Erosion has affected soil fertility by removing once with eroded soil, high amounts of organic carbon and mineral elements, which reached 10.71 - 11.26 kg/ha nitrogen, 0.56 – 0.64 kg/ha phosphorus and 0.98 - 1.11 kg/ha potassium, in maize and sunflower crops. The crop structure, which determined the diminution in mean soil losses by erosion until 1.383 t/ha included 20 % straw cereals, 20% annual legumes, 20% row crops and 40 % perennial grasses and legumes. On land with a slope of 16%, lowering the percentage of weeding plants from 60% to 20% has reduced the amount of eroded soil by 49%.
  • Authors:
    • Blanco-Canqui, H.
    • Mikha, M. M.
    • Presley, D. R.
    • Claassen, M. M.
  • Source: Soil Science Society of America Journal
  • Volume: 75
  • Issue: 4
  • Year: 2011
  • Summary: Inclusion of cover crops (CCs) may be a potential strategy to boost no-till performance by improving soil physical properties. To assess this potential, we utilized a winter wheat ( Triticum aestivum L.)-grain sorghum [ Sorghum bicolor (L.) Moench] rotation, four N rates, and a hairy vetch (HV; Vicia villosa Roth) CC after wheat during the first rotation cycles, which was replaced in subsequent cycles with sunn hemp (SH; Crotalaria juncea L.) and late-maturing soybean [LMS; Glycine max (L.) Merr.] CCs in no-till on a silt loam. At the end of 15 yr, we studied the cumulative impacts of CCs on soil physical properties and assessed relationships between soil properties and soil organic C (SOC) concentration. Across N rates, SH reduced near-surface bulk density (rho b) by 4% and increased cumulative infiltration by three times relative to no-CC plots. Without N application, SH and LMS reduced Proctor maximum rho b, a parameter of soil compactibility, by 5%, indicating that soils under CCs may be less susceptible to compaction. Cover crops also increased mean weight diameter of aggregates (MWDA) by 80% in the 0- to 7.5-cm depth. The SOC concentration was 30% greater for SH and 20% greater for LMS than for no-CC plots in the 0- to 7.5-cm depth. The CC-induced increase in SOC concentration was negatively correlated with Proctor maximum rho b and positively with MWDA and cumulative infiltration. Overall, addition of CCs to no-till systems improved soil physical properties, and the CC-induced change in SOC concentration was correlated with soil physical properties.
  • Authors:
    • Janzen, H. H.
    • Ellert, B. H.
    • McKenzie, R. H.
    • Bremer, E.
  • Source: Soil Science Society of America Journal
  • Volume: 75
  • Issue: 4
  • Year: 2011
  • Summary: Agroecosystems provide a range of benefits that are strongly influenced by cropping practice. Crop productivity and C, N, and greenhouse gas (GHG) balances were evaluated in an 18-yr cropping system study on an Aridic Haplustoll in the northern Great Plains. Application of synthetic fertilizers consistently increased crop yield and soil organic carbon (SOC), with greatest impact in perennial grass and continuous wheat ( Triticum aestivum L.) rotations and least impact in rotations with fallow or annual legumes. Based on N balance, N inputs other than fertilizer were 16 to 30 kg N ha -1 yr -1 in rotations without legumes and 62 kg N ha -1 yr -1 in a legume-wheat (LW) rotation, while losses of synthetic fertilizer N were 32% in annual crop rotations and 3% in perennial grass. Due to large gains in SOC, perennial grass reduced atmospheric GHG by 20 to 29 Mg CO 2 equivalent (eq.) ha -1 during the 18 yr of this study. For annual crop rotations, seed yield ranged from 1.2 to 2.5 Mg ha -1 yr -1, protein yield from 0.20 to 0.41 Mg ha -1 yr -1, and GHG intensity from 0 to 0.5 Mg CO 2 eq. Mg -1 seed. Fertilized continuous wheat had the highest crop productivity and lowest net GHG intensity, while an annual LW rotation had the highest protein productivity and among the lowest GHG intensities (0.2 Mg CO 2 eq. Mg -1 seed). Further evaluation at broader temporal and spatial scales is necessary to account for future changes in SOC and differences in use of crop products.