• Authors:
    • Li, S.
    • Zhao, M.
    • Zhen, X.
    • Zhou, J.
    • Wang, C.
  • Source: Journal of Northwest A & F University - Natural Science Edition
  • Volume: 36
  • Issue: 1
  • Year: 2008
  • Summary: An experiment was conducted to investigate the effects of cultivation methods and N rates on N accumulation, distribution and utilization efficiency of winter wheat on manual loessial soils under the winter wheat-summer maize cropping rotation system. The treatments comprised 4 different cultivation methods, i.e. control (C), supplementary irrigation (SI), straw mulching (SM) and furrow planting (FP), and 3 N rates, i.e. 0, 120 and 240 kg/hm 2. Compared with the other 3 cultivation methods, the N residue in leaf and stem of wheat after harvesting was lower in the SI cultivation method, so was the rate of N residue to total N accumulation in the crop. However, the rate of N residue in grain to the N accumulated in shoot was increased. As the application rates of N increased, the N accumulation in leaf, stem, glume and rachis, and grain of wheat was significantly increased. When the N application was increased from 120 to 240 kg/hm 2, the N accumulation in wheat leaf, stem, and glume and rachis was increased after harvesting. However, the N accumulation in grain did not increased significantly. The application of N did not show significant effect on the distribution of N in the different organs of wheat. As the application rates of N increased, the N recovery, agronomic efficiency and physiological efficiency decreased. Compared with the other cultivation methods, the N recovery, agronomic efficiency and physiological efficiency of the SI pattern were higher during the 2 continuous years; the changes in the N efficiency indices of the other 3 cultivation methods varied in different years.
  • Authors:
    • Xia, J.
    • Wu, D.
    • Yu, Q.
    • Wang, E.
  • Source: International Journal of Climatology
  • Volume: 28
  • Issue: 14
  • Year: 2008
  • Summary: The North China Plain (NCP) is the largest agricultural production area in China. The extensive use of groundwater for irrigation agriculture under variable climatic conditions has resulted in the rapid decline of the groundwater table especially in areas north of the Yellow River, leading to hydrological imbalance and unsustainable agricultural production. This article analyses the sustainable level of vegetation/crop water use under the NCP climate by mimicking the evapotranspiration of a natural forest ecosystem. Such a system would have a mean annual evapotranspiration ranging from 470 mm/year in the northern to 910 mm/year in the southern part of the plain, leading to a mean annual water excess (rainfall minus evapotranspiration) ranging from 21 to 124 mm/year. The natural forest ecosystem would use less water than the current wheat/maize double cropping system. To mimic the water use of the natural system, dryland farming has to be practiced, and wheat and maize crops would have a water deficit of 90-435 and 0-257 mm/year, respectively. Under average conditions, this would mean that all the areas north of the 36 degrees N line have to abandon winter wheat production. Stopping irrigation will lead to significantly lower wheat yields (average yield 0.8 t/ha in the north to 5.2 t/ha in the south) and increased variability in wheat and maize yield both interannually and spatially. Better management practices, such as opportunity cropping (what and when to crop depending on climate and soil conditions rather than a set annual cycle), better use of climate forecast information to direct decision making, are required in order to achieve maximum return in good years while minimizing cost in bad years. Analysis on rainfall and potential evapotranspiration (PET) from 1961 to 2000 shows that there has been an increasing trend in crop water deficit in the northern part, but a decreasing trend in the southern part of the plain. It remains to be further studied whether this reflects long-term climate change or only a part of the climate variability.
  • Authors:
    • Egbert, S. L.
    • Wardlow, B. D.
  • Source: Remote Sensing of Environment
  • Volume: 112
  • Issue: 3
  • Year: 2008
  • Summary: Improved and up-to-date land use/land cover (LULC) data sets that classify specific crop types and associated land use practices are needed over intensively cropped regions such as the U.S. Central Great Plains, to support science and policy applications focused on understanding the role and response of the agricultural sector to environmental change issues. The Moderate Resolution Imaging Spectroradiometer (MODIS) holds considerable promise for detailed, large-area crop-related LULC mapping in this region given its global coverage, unique combination of spatial, spectral, and temporal resolutions, and the cost-free status of its data. The objective of this research was to evaluate the applicability of time-series MODIS 250 m normalized difference vegetation index (NDVI) data for large-area crop-related LULC mapping over the U.S. Central Great Plains. A hierarchical crop mapping protocol, which applied a decision tree classifier to multi-temporal NDVI data collected over the growing season, was tested for the state of Kansas. The hierarchical classification approach produced a series of four crop-related LULC maps that progressively classified: (1) crop/non-crop, (2) general crop types (alfalfa, summer crops, winter wheat, and fallow), (3) specific summer crop types (corn, sorghum, and soybeans), and (4) irrigated/non-irrigated crops. A series of quantitative and qualitative assessments were made at the state and sub-state levels to evaluate the overall map quality and highlight areas of misclassification for each map. The series of MODIS NDVI-derived crop maps generally had classification accuracies greater than 80%. Overall accuracies ranged from 94% for the general crop map to 84% for the summer crop map. The state-level crop patterns classified in the maps were consistent with the general cropping patterns across Kansas. The classified crop areas were usually within 1-5% of the USDA reported crop area for most classes. Sub-state comparisons found the areal discrepancies for most classes to be relatively minor throughout the state. In eastern Kansas, some small cropland areas could not be resolved at MODIS' 250 m resolution and led to an underclassification of cropland in the crop/non-crop map, which was propagated to the subsequent crop classifications. Notable regional areal differences in crop area were also found for a few selected crop classes and locations that were related to climate factors (i.e., omission of marginal, dryland cropped areas and the underclassification of irrigated crops in western Kansas), localized precipitation patterns (overclassification of irrigated crops in northeast Kansas), and specific cropping practices (double cropping in southeast Kansas).
  • Authors:
    • Nayyar, A.
    • Bijay, S.
    • Humphreys, E.
    • Brar, N.
    • Yadvinder, S.
    • Timsina, J.
  • Source: ACIAR Proceedings Series
  • Issue: 127
  • Year: 2008
  • Summary: Rice-wheat (RW) is the dominant cropping system in north-western India and is of immense importance for national food security. However, the sustainability of the RW system is threatened by water shortage and nutrient mining. Permanent bed RW systems with crop residue retention have been proposed as a means of reducing irrigation water use, improving soil properties and reducing the cost of crop establishment. A field experiment was conducted over 4 years in Punjab, India, to compare conventional and permanent bed RW cropping systems, with and without retention of crop residues, in terms of crop performance and nitrogen use efficiency (NUE). Two methods of rice establishment (transplanting and dry seeding) were included on both beds and flats with four N application rates (0, 80, 120, 160 kg N/ha). Rice grain yield increased significantly as N rate increased up to 160 kg N/ha irrespective of method of rice establishment. Puddled transplanted rice (PTR) was always superior to all other establishment methods in terms of biomass, yield and NUE. At 120 kg N/ha, yield of transplanted rice on permanent beds (TRB) was 29% lower than yield of PTR, while yield of direct-seeded rice on permanent beds (DSRB) was even lower (44% lower than yield of TRB). Wheat straw mulch further reduced yield of DSRB by 26% on average, but there was no effect of mulching on yield of TRB. Dry-seeded rice on flats and beds was prone to severe iron deficiency and root nematode infestation. Yield of DSRB relative to yield of PTR declined as the beds aged but there was no trend in relative yield of TRB. Recovery of fertiliser 15N in the straw plus grain was 30% in PTR compared with 14% for TRB and 17% for DSRB. The majority (65-83%) of the crop N uptake was derived from the soil in all treatments despite the application of urea at 120 kg N/ha. Total N losses from the urea N applied to rice ranged from 52% to 60% in TRB and DSRB compared with 38% in PTR. Wheat yield increased with N rate up to 120 kg N/ha, with further significant response to 160 kg N/ha in 2 of the 4 years. Wheat grain yield on permanent beds after TRB and DSRB was 75-96% of that of conventionally tilled wheat (CTW), with no trend in relative yield over time as the beds aged. Grain yield of wheat was similar in CTW and direct-drilled ('zero-till') wheat (DDW) on the flat. The 15N recovery in the wheat plants in all flat and bed treatments was similar. Straw mulch had no effect on yield or NUE of wheat. Recoveries of applied N in the wheat plants (27-38%) and soil (45-59%) were much higher than in rice. Total fertiliser N losses were much lower in wheat (mean 14-21%) compared with rice (mean 38-60%). After eight crops, soil organic C, total N and available K were significantly higher with straw mulch compared with no mulch. Permanent beds for RW seem to have limited potential under the soil and climatic conditions of Punjab, India, with current technology, even with full residue retention for both crops. Further research on permanent raised beds should focus on selection of rice and wheat cultivars that are better suited to beds; soil health issues such as nematodes and iron deficiency; weed control; N, water and residue management; and machinery development and practices.
  • Authors:
    • [Anonymous]
  • Source: Muhle + Mischfutter
  • Volume: 145
  • Issue: 18
  • Year: 2008
  • Summary: The article describes harvest and yield details of the German cereals season 2008. All federal states of Germany are covered and all cereals including milling, feed, industrial and grain maize, but excluding silage and corn-cob-mix maize. In 2008, the total tonnage increased from 23% to 49 million tonnes. The highest yield increases, compared to the poor year 2007, were reported from the northern states, Mecklenburg-Vorpommern, Niedersachsen, Schleswig-Holstein and Nordrhein-Westfalen. Average winter wheat yields were 8.1 t/ha, winter barley 6.6 t/ha and triticale 6.0 t/ha. Spring barley was 4.9 t/ha and oats only 4.6 t/ha. Because of the large quantities, enough good quality milling wheat will be available. An outlook on the EU cereal harvest, the global and USA harvests in 2008 are given at the end of the paper.
  • Authors:
    • Ullrich, S.
    • Baik, B.
  • Source: Journal of Cereal Science
  • Volume: 48
  • Issue: 2
  • Year: 2008
  • Summary: Barley ( Hordeum vulgare vulgare L.) is an ancient cereal grain, which upon domestication has evolved from largely a food grain to a feed and malting grain. However, barley food use today remains important in some cultures around the world, particularly in Asia and northern Africa, and there is renewed interest throughout the world in barley food because of its nutritional value. This review covers basic and general information on barley food use and barley grain processing for food use, as well as an in-depth look at several major aspects/traits of interest for barley food use including kernel hardness and colour, grain starch, and beta-glucan contents. These traits are described in terms of their effects on processing and nutrition, as well as their inheritance and the prospects for barley improvement through breeding. Whereas, the aspects listed above have been studied relatively extensively in barley in terms of content, form, genetics, physiology, and in some cases nutritional quality, little is know about functional properties for processing and food product development. Renewed interest in barley for food uses largely centres around the effects of beta-glucans on lowering blood cholesterol levels and glycemic index. Wholegrain barley foods also appear to be associated with increased satiety and weight loss. There is great potential to utilise barley in a large number of cereal-based food products as a substitute partially or wholly for currently used cereal grains such as wheat ( Triticum aestivum), oat ( Avena sativa), rice ( Oryza sativa), and maize ( Zea mays).
  • Authors:
    • Baker, B.
  • Source: Proceedings of the 5th Organic Seed Growers Conference, Salem, Oregon, USA
  • Year: 2008
  • Summary: The market for organic seed poses a great opportunity for both organic producers who want to diversify into new crops as well as for seed producers who want to enter into the rapidly growing organic market. While organic standards in the United States require the use of organic seed, organic producers are not able to find organic seed in sufficient quantity and of suitable quality to meet their production needs. Because commercial availability must be evaluated as part of the certification process, the certifying agents play an important role in assessing both the supply and demand for organic seed. Certifying agents were surveyed to identify how they assess commercial availability, what information resources are used, and what crops and varieties are considered commercially unavailable. More research is needed to forecast organic seed demand and overcome production obstacles.
  • Authors:
    • Bleidere, M.
    • Malecka, S.
    • Belicka, I.
  • Source: Agronomijas Vestis
  • Issue: 10
  • Year: 2008
  • Summary: The aim of experiment was to evaluate and compare grain chemical composition (crude protein, starch, crude fat, crude fibre, crude ash and phosporus) of hulled and hulless cereals. The four hulless barley varieties and lines - 'Gainer' (Canada), 'KM-2084', (the Czech Republic), 'L-302' (Latvia), 'SW-1291' (Sweden), one hulled barley variety - 'Linga' (Latvia), hulless oat line 'L-28156' (Latvia), hulled variety 'Laima' (Latvia) and spring wheat variety 'Vinjett' (Sweden) were included in this study. Field experiments were carried out at the State Stende Cereal Breeding Institute in 2004-2006. All plots received 60 kg ha -1 nitrogen (N). On the average for all hulless varieties, the content of crude protein ranged from 129.7-171.0 g kg -1. The hulled variety 'Linga' contained 140.7 g kg -1 crude protein. The content of crude protein for hulless oat line was 170.9 g kg -1 and it was significantly higher than for covered oat variety (120.9 g kg -1), but spring wheat 'Vinjett' (133.3 g kg -1) took place between hulled barley and hulled oat. In 2006, hot summer temperatures increased the crude protein content in all cereal varieties. There were differences in starch content among cereals. Regarding to starch content the species were ranged in following order: wheat > hulless barley > hulled barley > hulless oat > hulled oat (668, 623-686, 598, 589, 454 g kg -1, respectively). The hulless line L-28156 showed the highest fat content - 91.7 g kg -1. This value exceeded 1.5 to 3.8 fold the content of fat found in hulled oat, hulled and hulless barley and spring wheat. The hulless barley, hulless oat and spring wheat had the lowest crude fibre content 18.3-24.3 g kg -1, 20.3 g kg -1 and 28.5 g kg -1, respectively. The hulled barley and oat contained from 2 to 5 fold more crude fibre than hulless types. Hulled varieties of barley and oat had higher crude ash content (23.0-25.2 g kg -1) than hulless type (17.6-22.2 g kg -1). The results of grain chemical composition suggest that the hulless varieties of barley and oats might awake interest for food and feed producers.
  • Authors:
    • Bellinder, R. R.
    • Brainard, D. C.
    • Hahn, R. R.
    • Shah, D. A.
  • Source: WEED SCIENCE
  • Volume: 56
  • Issue: 3
  • Year: 2008
  • Summary: Three major hypotheses were examined in this study: (1) the density of summer annual weeds is reduced in crop rotation systems that include winter wheat compared to those with strictly summer annual crops, (2) the integration of a red clover in cropping systems reduces weed seedbank densities, and (3) changes in weed seedbanks due to crop rotation system have greater impact on future crops that are managed with cultivation alone, compared to those managed with herbicides. To test these hypotheses, five 3-year rotation sequences were examined in central New York state, USA: continuous field maize (FC); field maize with red clover (FC+CL); field maize-oats-wheat (FC/O/W); sweetcorn-peas-wheat (SC/P/W), and SC/P/W with red clover (SC/P/W+CL). In the fourth year, sweetcorn, snap beans, and cabbage were planted in subplots with three levels of weed management as sub-subplots: cultivation alone, reduced-rate herbicides (1/2*), and full-rate herbicides (1*). The trial was carried out in two separate cycles, from 1997 to 2000 (cycle 1) and from 1998 to 2001 (cycle 2). Crop rotations with strictly summer annual crops (FC) did not result in consistently higher weed seedbank densities of summer annual weeds compared to rotations involving winter wheat (FC/O/W; SC/P/W; SC/P/W+CL). Integration of red clover in continuous field maize resulted in higher weed seedbanks (cycle 1) or emergence (cycle 2) of several summer annual weeds compared to field maize alone. In contrast, integration of red clover in the SC/P/W rotation led to a 96% reduction in seedbank density of winter annuals in cycle 1, although this effect was not detected in cycle 2. Observed changes in weed seedbank density and emergence due to crop rotation resulted in increased weed biomass in the final year in only one case (sweetcorn, cycle 2), and did not result in detectable differences in crop yields. In contrast, final year weed management had a strong effect on weed biomass and yield; cultivation alone resulted in yield losses for sweetcorn (32 to 34%) and cabbage (0 to 7%), but not snap beans compared to either 1/2* or 1* herbicides.
  • Authors:
    • Zanatta, J. A.
    • Bayer, C.
    • Costa, F. de S.
    • Mielniczuk, J.
  • Source: Revista Brasileira de Ciencia do Solo
  • Volume: 32
  • Issue: 1
  • Year: 2008
  • Summary: Carbon (C) addition through crop residues (residue-C), C dioxide emission (CO 2-C) and the soil C stock (soil-C) are components of the C cycle in the soil-plant-atmosphere system. This 18-year study was conducted to identify agricultural practices that could potentially increase C retention in the soil and lessen global warming trends. The three C pools (residue-C, CO 2-C and soil-C) under different tillage systems (CT-conventional tillage and NT-no tillage) and cropping systems (O/M-oat ( Avena strigosa [ Avena nuda])/maize ( Zea mays) and V/M-vetch ( Vicia sativa)/maize) were evaluated and the CO 2-C/[residue-C+soil-C] quotient was proposed as C retention index (CRI), where low values indicate a high capacity of the management system to keep C in the soil. The CO 2-C emissions were measured for 17 months (between November 2002 and March 2004), sampling of aboveground residues of cover crops and harvest indexes of maize were used to quantify C addition by cropping systems, and soil-C stocks (0-0.2 m) were evaluated in 2003. The soil temperature (0.05 m) and gravimetric water content (0-0.05, 0.05-0.1 and 0.1-0.2 m) were also monitored from May 2003 onwards. In comparison to 1985, the C balance was negative in the soil under CT (-0.31 t ha -1 year -1 for O/M and -0.10 t ha -1 year -1 for V/M). On the other hand, the C balance was positive in NT soil, but only under V/M (+0.15 t ha -1 year -1) due to the greater C addition by crop residues. The CO 2-C emission was related to the soil temperature (r>0.85). The total CO 2-C emission varied from 3.6 to 4.0 t ha -1 and was not affected by the soil management systems. However, the CRI allowed a clear discrimination of the soil management systems to keep C in the soil. The C retention potential increased in the following order: CT O/M