• Authors:
    • Halvorson, A. D.
    • Nielsen, D. C.
    • Reule, C. A.
  • Source: Agronomy Journal
  • Volume: 96
  • Issue: 4
  • Year: 2004
  • Summary: No-till (NT) production systems, especially winter wheat (Triticum aestivum L.)-summer crop-fallow, have increased in the central Great Plains, but few N fertility studies have been conducted with these systems. Therefore, winter wheat (W) response to N fertilization in two NT dryland crop rotations, wheat-corn (Zea mays L.)-fallow (WCF) and wheat-sorghum (Sorghum bicolor L.)-fallow (WSF), on a Platner loam (fine, smectitic, mesic Aridic Palleustoll) was evaluated for 9 yr. Five N rates, 0, 28, 56, 84, and 112 kg N ha(-1), were applied to each rotation crop. Wheat biomass and grain yield response to N fertilization varied with year but not with crop rotation, increasing with N application each year, with maximum yields being obtained with 84 kg N ha(-1) over all years. Based on grain N removal, N fertilizer use efficiency (NFUE) varied with N rate and year, averaging 86, 69, 56, and 46% for the 28, 56, 84, and 112 kg ha(-1) N rates, respectively. Grain protein increased with increasing N rate. Precipitation use efficiency (PUE) increased with N addition, leveling off above 56 kg N ha(-1). A soil plus fertilizer N level of 124 to 156 kg N ha(-1) was sufficient to optimize winter wheat yields in most years in both rotations. Application of more than 84 kg N ha(-1) on this Platner loam soil, with a gravel layer below 120 cm soil depth, would more than likely increase the amount of NO3-N available for leaching and ground water contamination. Wheat growers in the central Great Plains need to apply N to optimize dryland wheat yields and improve grain quality, but need to avoid over-fertilization with N to minimize NO3-N leaching potential.
  • Authors:
    • Mosier, A. R.
    • Burke, I. C.
    • Kaye, J. P.
    • Guerschman, J. P.
  • Source: Ecological Applications
  • Volume: 14
  • Issue: 4
  • Year: 2004
  • Summary: Land-use change is an important driver of soil-atmosphere gas exchange, but current greenhouse-gas budgets lack data from urban lands. Field comparisons of urban and non-urban ecosystems are required to predict the consequences of global urban-land expansion for greenhouse-gas budgets. In a rapidly urbanizing region of the U.S. Great Plains, we measured soil-atmosphere exchange of methane (CH 4) and nitrous oxide (N 2O) for one year in replicated ( n=3) urban lawn, native shortgrass steppe, dryland wheat-fallow, and flood-irrigated corn ecosystems. All soils were net sinks for atmospheric CH 4, but uptake by urban, corn, and wheat-fallow soils was half that of native grasslands (-0.300.04 g C.m -2.yr -1 [mean1 Se]). Urban (0.240.03 g N.m -2.yr -1) and corn (0.200.02 g N.m -2.yr -1) soils emitted 10 times more N 2O to the atmosphere than native grassland and wheat-fallow soils. Using remotely sensed land-cover data we calculated an upper bound for the contribution of lawns to regional soil-atmosphere gas fluxes. Urban lawns occupied 6.4% of a 1578-km 2 study region, but contribute up to 5% and 30% of the regional soil CH 4 consumption and N 2O emission, respectively, from land-use types that we sampled. Lawns that cover small portions of the landscape may contribute significantly to regional soil-atmosphere gas exchange.
  • Authors:
    • Figueroa-Viramontes, R.
    • Vazquez-Vazquez, C.
    • Salazar-Sosa, E.
    • Lopez-Martinez, J. D.
    • Berumen-Padilla, S.
    • Martinez-Rubin, E.
  • Source: Agrofaz: publicación semestral de investigación científica, ISSN 1665-8892, Vol. 3, Nº. 1, 2003 or Phyton REVISTA INTERNACIONAL DE BOTÁNICA EXPERIMENTAL INTERNATIONAL JOURNAL OF EXPERIMENTAL BOTANY
  • Volume: 2004
  • Year: 2004
  • Summary: Taking into consideration that potential evapotranspiration normally exceeds the growing season rainfall and that a water shortage can occur unless a reserve of soil water is stored before the crop is planted, it can be concluded that the amount of stored soil water at sowing time is a critical factor in the success of dryland cropping systems. The main aim of this investigation was to know if interaction chi 2 test is a valuable tool, when taking into account stored soil (0-60 cm depth) water at sowing time and maize grain yield, in making decision for sowing or not sowing at a given time. Data on the amount of soil water at sowing time and maize grain yield from four experiments carried out during 2001 and 2002 at the Ejido Francisco Villa, Lerdo, Durango, Mexico were used to run the interaction chi 2 tests. For a minimum maize yield of 1000 kg ha -1, the following level of stored soil water was defined as critical: 8.34 cm for cv. 'Blanco Hualauises' and cv. 'H-412'. The interaction chi 2 test is a good tool to determine soil water critical levels at the sowing time of maize to ensure success in the present dryland cropping system.
  • Authors:
    • Zamfir, M. C.
    • Mitu, D.
  • Source: Analele ale Institutului de Cercetări pentru Cereale şi Plante Tehnice Fundulea
  • Volume: 71
  • Year: 2004
  • Summary: In 2001-03 at ARDS Teleorman, Romania, 14 maize hybrids were studied for their response to drought during the first part (2002) and second part (2001) of summer, and to prolonged drought (2003) under irrigated and dryland conditions. Paltin, Campion, Rapsodia, Danubiu, Faur and Olt performed well under irrigated and dryland conditions. Partizan, Orizont, Vultur, Octavian and Granit were sensitive to drought. During the dry years, the disparity in flowering (days) and the frequency of sterile plants resulted in a significant reduction in kernel yield. Prolonged drought throughout the growth period resulted in higher yield losses (76-77%) compared with partial drought experienced in the second part of summer (62-65%) or in the first part of maize growth (26-30%).
  • Authors:
    • Johnson, J. J.
    • Doerge, T. A.
    • Shanahan, J. F.
    • Vigil, M. F.
  • Source: Precision Agriculture
  • Volume: 5
  • Issue: 3
  • Year: 2004
  • Summary: The goal of this research was to determine the potential for use of site-specific management of corn hybrids and plant densities in dryland landscapes of the Great Plains by determining (1) within-field yield variation, (2) yield response of different hybrids and plant densities to variability, and (3) landscape attributes associated with yield variation. This work was conducted on three adjacent fields in eastern Colorado during the 1997, -98, and -99 seasons. Treatments consisted of a combination of two hybrids (early and late maturity) and four plant densities (24 692, 37 037, 49 382 and 61 727 plants ha -1) seeded in replicated long strips. At maturity, yield was measured with a yield-mapping combine. Nine landscape attributes including elevation, slope, soil brightness (SB) (red, green, and blue bands of image), EC a (shallow and deep readings), pH, and soil organic matter (SOM) were also assessed. An analysis of treatment yields and landscape data, to assess for spatial dependency, along with semi variance analysis, and block kriging were used to produce kriged layers (10 m grids). Linear correlation and multiple linear regression analysis were used to determine associations between kriged average yields and landscape attributes. Yield monitor data revealed considerable variability in the three fields, with average yields ranging from 5.43 to 6.39 Mg ha -1 and CVs ranging from 20% to 29%. Hybrids responded similarly to field variation while plant densities responded differentially. Economically optimum plant densities changed by around 5000 plants ha -1 between high and low-yielding field areas, producing a potential savings in seed costs of $6.25 ha -1. Variability in yield across the three landscapes was highly associated with landscape attributes, especially elevation and SB, with various combinations of landscape attributes accounting for 47%, 95%, and 76% of the spatial variability in grain yields for the 1997, -98, and -99 sites, respectively. Our results suggest site-specific management of plant densities may be feasible.
  • Authors:
    • Taylor, J. R. N.
    • Somani, R. B.
  • Source: Alternative uses of sorghum and pearl millet in Asia. Proceedings of an expert meeting, ICRISAT, Patancheru, Andhra Pradesh, India, 1-4 July, 2003; CFC Technical Paper No.34
  • Year: 2004
  • Summary: Adaptation to poor habitats, poor resource base and production and consumption by poorer sections of the society have made sorghum crop an indispensable component of dryland agriculture. It is a drought hardy crop, can withstand waterlogging and thus excels over maize; it is also ecologically sound and environment friendly, demanding little pesticide use for crop management. Notwithstanding the moderate contribution of sorghum to the national food basket, this crop offers enormous advantages such as early maturity, wide adaptation, ease of cultivation and good nutritive value of both grain and fodder. With the green revolution and availability of fine cereals in remote places, proper disposition by value addition and establishing food, feed, beverages, sugars and alcohol industries will not only generate employment potential but also improve the regional economy. Sorghum is a valuable food grain for many of the world's most food insecure people. Much of Africa and India is characterized by semi-arid tropical climatic conditions. Sorghum is undoubtedly and uniquely adapted in the Afro-Asian regions. Sorghum in Africa and Asia is processed into a very wide variety of nutritive food products. Documentation, standardization, popularization and commercial exploitation of traditional products need attention. A large number of accessions are available. Proper selection for the requirements of the end users is necessary. Use of new biotechnological tools such as anti-sense gene technology to incorporate desired traits is now possible. Continuing focused fundamental and applied research is essential to unleash sorghum's capacity to be the cornerstone in food, feed, fuel and fibre sectors in Afro-Asian countries. Sorghum types of both continents are different; in Africa it is 'milo' based whereas in the Indian subcontinent it is 'caudatum' type. More attention on dehulling and debranning of red sorghum and mold resistance in white sorghum is anticipated. The future for sweet sorghum or high energy sorghum is also bright. Combined efforts of research institutions, private seed sector, industry and the government are necessary for its commercial exploitation. So far, there is a concept of developing an agro-based industry. However, we now have to think of industry-based agriculture.
  • Authors:
    • Varlev, I.
  • Source: Bulgarian Journal of Agricultural Science
  • Volume: 10
  • Issue: 1
  • Year: 2004
  • Summary: Long-term data (13-18 years) from 15 experimental farms were used to evaluate quantitatively the risk of maize cultivation on drylands in different regions of Bulgaria. Results established that the risk of maize cultivation on drylands in north Bulgaria seldom surpasses 10% of the years. Losses in south Bulgaria cover 20-70% of the years. Only on soils of high water-holding capacity is the risk close to 20%.
  • Authors:
    • Sharma, R. D.
    • Corrêa, J. C.
  • Source: Pesquisa Agropecuária Brasileira
  • Volume: 39
  • Issue: 1
  • Year: 2004
  • Summary: An experiment was carried out on a heavy red yellow latosol to evaluate crop rotation on herbaceous cotton ( Gossypium hirsutum) yields in no-till system under rainfed Savannah conditions. The treatments were: soyabean-millet ( Pennisetum glaucum)-soyabean-millet-cotton; soyabean-amaranth ( Amaranthus hypochondriacus)-soyabean-forage radish-soyabean-cotton; soyabean-grain sorghum ( Sorghum vulgare [ S. bicolor])-soyabean-grain sorghum-cotton; soyabean-black rye ( Avena strigosa [ A. nuda])-soyabean-black rye-cotton and soyabean-soyabean-cotton. The highest cotton seed yield and best weed control were recorded in the sequence soyabean-millet-soyabean-millet-cotton.
  • Authors:
    • Nelson, L. A.
    • Baltensperger, D. D.
    • Eskridge, K. M.
    • Russell, W. K.
    • Guillen-Portal, F. R.
    • D'Croz-Mason, N. E.
    • Johnson, B. E.
  • Source: Crop Science
  • Volume: 44
  • Issue: 5
  • Year: 2004
  • Summary: Dryland maize ( Zea mays L.) production in the U.S. western High Plains is hampered by variable yields because of substantial environmental variation in this region. This study was conducted to determine the degree to which the ranking of superior maize hybrids for dryland production in the western High Plains was predictable from performance of the same hybrids in highly productive, irrigated environments in the same region. Forty-five maize hybrids were evaluated for grain yield performance under different water regimes in western Nebraska, eastern Wyoming, and northeastern Colorado in 1998 and 1999. The value of genotypic variance was by far larger in fully irrigated test environments (0.70) than in nonirrigated test environments (0.01-0.17). The genotypic mean repeatability in fully irrigated test environments (0.63) compared with that in nonirrigated test environments (0.18-0.69, respectively), and it showed correspondence with yield performance. The genetic correlation between fully and nonirrigated environments (0.72) was lower than that observed between all-nonirrigated environments (0.78-1.02). Thus, the proportion of direct advance in the former case (0.63) was generally lower than in the latter (0.41-0.97). However, an environmental similarity ratio (ESR) derived from crossover interaction indicated that water-contrasting environments were as similar (ESR=0.53) as nonirrigated environments (ESR=0.49) in ranking the maize hybrids. Selective identification of maize hybrids in irrigated environments for production under nonirrigated environments in the western High Plains might be a useful surrogate to direct selection in the latter environments.
  • Authors:
    • Sherrod,L. A.
    • Shaver,T. M.
    • Peterson,G. A.
  • Source: Geoderma
  • Volume: 116
  • Issue: 1-2
  • Year: 2003
  • Summary: Great Plains dryland agriculture is a risky venture because of large annual fluctuations in precipitation and high evaporation potentials. Water capture is limited by low water infiltration rates because many of our soils have relatively small aggregate size distributions, which limit infiltration, and are also susceptible to crusting and sealing. No-till management has permitted cropping intensification, which via improved water storage, has increased crop residue returned to the soil, decreased surface bulk density, and increased surface soil porosity. Our objective was to quantify the relationship between crop residue biomass generated by cropping system intensification and the physical properties of the surface soil (0-2.5-cm depth). This study was conducted within an existing long-term dryland experiment consisting of three sites in eastern Colorado that transect an evapotranspiration gradient. Each site transects a soil catena with three distinct soils arranged along a slope gradient. Only soils at the summit and toe slopes were sampled for this study. Soils are Argiustolls and Ustochrepts. Three no-till cropping systems, Wheat-Fallow (WF), Wheat-Corn-Fallow (WCF), and Continuous Cropping (CC), were sampled in the summer of 1998 after the cropping systems had been in place for 12 years. Bulk density, effective porosity, aggregate size distribution, sorptivity, and soil aggregate organic C content were measured at the surface 2.5 cm of the soil in each cropping system at the two soil positions at each site. Bulk density was reduced by 0.01 g cm(-3) for each 1000 kg ha(-1) of residue addition over the 12-year period. Each 1000 kg ha(-1) of residue addition increased effective porosity by 0.3%. Increases in macroaggregation were associated with linear increases in the C content of the aggregates; each g kg(-1) of organic C in the macroaggregates increased the proportion of macroaggregates by 4.4%. Implementation of no-till intensive cropping systems under this semiarid environment increased, residue biomass, which has ultimately increased effective porosity, and thus water capture potential was increased.