• Authors:
    • Ferguson, R. B.
    • Liska, A. J.
    • Wortmann, C. S.
    • Lyon, D. J.
    • Klein, R. N.
    • Dweikat, I.
  • Source: Agronomy Journal
  • Volume: 102
  • Issue: 1
  • Year: 2010
  • Summary: Sweet sorghum [SS; Sorghum bicolor (L.) Moench] is a potential biofuel crop for the Great Plains. Sweet sorghum was compared with corn [ Zea mays (L.)] and grain sorghum for potential ethanol yield, energy use efficiency, and greenhouse gas (GHG) emissions at seven dryland site-years in Nebraska. Seasonal rainfall ranged from approximately 340 to 660 mm. Soils were deep with medium texture at all site-years. The effects of seeding rate, N rate, and cultivar on SS performance were evaluated. Sweet sorghum sugar yield was not affected by seeding rate and N application at six of seven site-years, but yield was increased by 19% at one site-year. Calculated ethanol yield and net energy yield were 33 and 21% more, respectively, with the grain crops compared with SS, but mean net energy yield of an earlier-maturing SS cultivar was comparable with the grain crops. The mean ratio of energy produced in ethanol per total energy invested was 23% less for grain crops compared with SS. Mean life cycle GHG emissions were 53% and 66 to 69% less compared with gasoline for SS and grain crops, respectively. Very efficient use of the ethanol coproducts was assumed for the grain crops while SS bagasse was assumed to be returned to the field. At least one SS cultivar is competitive with grain crops for some biofuel criteria, but SS is not competitive with grain crops for total or net liquid transportation fuel produced per hectare.
  • Authors:
    • Li, S.
    • Chen, X.
    • Liu, Y.
    • Zhu, L.
    • Xu, H.
  • Source: Scientia Agricultura Sinica
  • Volume: 43
  • Issue: 14
  • Year: 2010
  • Summary: Objective: A field experiment was carried out on typical Hap-Ustic Isohumisol soil on dry highland of loess plateau to study the absorption and translocation of nitrogen in different farmland water management patterns under the same N fertilizer rate, therefore, the result would have good application values in guiding high yield cultivation of maize. Method: Four field water management practices, including supplementary irrigation, rain-fed, corn straw mulching and plastic film mulching, were adopted in spring maize Xianyu 335. The amount and proportion of N from different management practices at 6 growing stages (seedling, jointing, tasseling, blister, dough and maturity) were measured. Result: The experimental results showed that with the growing stage increasing, N absorption increased. After tasseling stage, with the center of growth changing the absorption quantity of organs absorbing N was changed. In every growing stage the N amount in supplementary irrigation treatment was higher than other three treatments, followed by plastic film mulching treatment, rain-fed treatment and corn straw mulching treatment. In supplementary irrigation treatment, the amount of organs N translocation was 235.5 kg.hm -2, higher than other three treatments, followed by 225.3 kg.hm -2 in plastic film mulching treatment; straw mulching treatment was higher than rain-fed treatment, but the difference was not significant. Supplementary irrigation treatment and plastic film mulching treatment were significantly higher than other two treatments. Conclusion: Under the conditions of this experiment, in dry highland of loess plateau area, different farmland water management patterns had significantly effects on spring maize nitrogen absorption, distribution and translocation. The management patterns which can increase the yield, the water utilization efficiency and the nitrogen utilization efficiency can also increase the N absorption and the grain N content. Supplementary irrigation treatment and plastic film mulching treatment were better treatments in this experiment. As for the comprehensive water saving and rainfall use efficiency, the recommended management practice should be the plastic film mulching treatment based on the results of this experiment.
  • Authors:
    • Zhang, X.
    • Shi, F.
    • Li, B.
    • Xue, Y.
    • Yang, Z.
  • Source: Journal of Henan Agricultural Sciences
  • Issue: 10
  • Year: 2010
  • Summary: By using field monitoring methods, the village, the water consumption of winter wheat grown Zhangcun town of Huixian county, Henan province were determined. Water consumption can reach 216.3-345.2 mm at the yield level of 4 500-6 000 kg/ha. The water consumption percentage constitution of different growing period was 25.9%-36.9% between seeding and reviving stages, 22.0%-31.1% between reviving and heading stages, and 31.9%-52.2% between heading and maturation. The variation was great among different years. When the yield level of corn was 6 750-7 500 kg/ha, water consumption 299.6-462 mm which account for 81.3%-97.4% of precipitation during the period of the year. The water consumption percentage constitution of different growing period was 17.1%-17.3% between seeding and jointing stages, 34.5%-39.1% between jointing and trumpet stages, and 43.6%-48.4% between trumpet and maturation stages. For both wheat and corn, the water consumption density increased dramatically after jointing stage. The jointing and seed filling stages were two important periods for wheat water consumption. The trumpet stage was important for corn. In the dry-land hilly areas of middle and north Henan province at the current situation, natural precipitation can generally meet the water demand of autumn grain crops, while for summer grain crops, it is inadequate. So the emphases of water-saving irrigation should be on the summer grain crops.
  • Authors:
    • Sharaiha, R.
    • Adamu, M.
  • Source: World Journal of Agricultural Sciences
  • Volume: 6
  • Issue: 6
  • Year: 2010
  • Summary: Mixed cropping of barley and durum wheat has been the practice of smallholder farmers in some drylands of Ethiopia even though the reasons for this successful cropping system were not well understood. Therefore, four planting densities, five intercrop proportions and three irrigation water levels were studied in a split-split plot arrangement in RCBD with three replications to determine the competition levels and resource use of barley and wheat mixed cropping under different growth stages. Barley was more competitive at early stages, while wheat dominated towards the reproductive stage. Intra- and inter-specific competition was decreased with increasing irrigation water levels but it was increased with increasing planting densities. Intraspecific competition was increased with increasing barley ratio in the cropping systems at all irrigation water levels, planting densities and harvesting stages. Fast growing nature of barley at early growth stages helps the intercropping system in that barley can capture belowground and areal resources faster, while wheat grows slowly and demands less resource at earlier growth stages. At later stages when wheat becomes dominant and resource demanding, early maturity of barley leaves more space for wheat to satisfy its resource demand. Thus niche differentiation index was consistently more than one in all growth stages and irrigation water levels. Therefore, mixed cropping of these two crop species helps combine important characters in a cropping system so as to enhance productivity through complementary resource uses in drylands.
  • Authors:
    • Prasad, V.
    • Staggenborg, S.
    • Assefa, Y.
  • Source: Crop Management
  • Issue: November
  • Year: 2010
  • Summary: Because sorghum is a drought-tolerant crop, it is often preferred by producers in cases of expected water stress. The objectives of this review were to summarize the water requirements, effect of water stress, and hybrid variation in drought tolerance of grain sorghum, and to suggest possible solutions that could help narrow the gap between potential and actual dryland sorghum yield. We reviewed more than 70 reports in peer-reviewed journals, extension publications, books, and websites. Grain sorghum tolerates and avoids drought more than many other cereal crops, but the drought response of sorghum does not come without a yield loss. Water stress at the vegetative stage alone can reduce yield more than 36%, and water stress at the reproductive stage can reduce yield more than 55%. Eighty percent of sorghum production in the world is under dryland conditions. We deduced that by focusing on techniques that can improve water availability in sorghum growing season alone, we can double the current dryland sorghum yield with the existing genetic potential. Results of this review suggest the existence of genotypic variation in drought tolerance among sorghum hybrids due to possible physiological differences or vice versa. We concluded by presenting possible management options to reduce the effects of water stress in dryland conditions and suggesting possible areas of research.
  • Authors:
    • Riffkin, P.
    • MacEwan, R.
    • Clough, A.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Symposium 4.2.1 Soil, energy and food security
  • Year: 2010
  • Summary: Dryland cropping in the high rainfall zone (HRZ) of southern Australia has the potential to produce high yields of cereals, canola and pulses. However, actual yields often fall well short of the estimated potential. A survey of grain growers in the HRZ was conducted to gain a greater understanding of the factors which may prevent growers from achieving potential yields. The survey was developed in consultation with growers, soil scientists and agronomists and distributed nationally through an industry magazine. The survey captured grower perceptions of soil and crop management using multiple choice questions and free comment sections. This paper documents the section of the survey pertaining to soils. In this survey, growers throughout the HRZ provided common responses regarding their use of some forms of tillage, trafficking, chemical soil amelioration techniques and physical soil engineering techniques. Different responses were evident depending upon region and farm size for issues such as the use of conventional tillage, raised beds and lime. The perceived success of various types of soil management options is also discussed. This information is valuable for those who wish to identify which regions or grower audiences should be targeted for research and extension in soil management.
  • Authors:
    • Chen, D.
    • Dixit, P.
  • Source: Computers and Electronics in Agriculture
  • Volume: 74
  • Issue: 2
  • Year: 2010
  • Summary: High levels of subsoil salinity limit the growth and yield of dryland cereals in the Victorian southern Mallee, Australia. Currently available crop simulation models of wheat production perform poorly in this region, presumably due to their inability to account for subsoil limitations, mainly salinity. The objective of this work was to modify a spatially referenced Water and Nitrogen Management Model (WNMM) to account for the spatial pattern of subsoil salinity, by adjusting crop water uptake, in order to explain the spatial variation in wheat yield in this area. Measurements of above-ground biomass and yield of wheat, and the profile of soil salinity (0-80 cm) were made at 40 locations across an 88 ha paddock (35.78°S, 142.98°E) in the Victorian southern Mallee. The S-shaped water stress response function for crop water uptake proposed by van Genuchten (1987) was explored to modify the WNMM by adjusting the water uptake due to salinity, which significantly improved yield simulation over the original WNMM. The improvement in the model's ability to simulate wheat yield indicates that the subsoil salinity limits crop performance in the area. The incorporation of a salinity function in spatial crop models offers potential for simulating yield across a landscape and thus practicing precision agriculture provided salinity impact is considered dynamically.
  • Authors:
    • Hao, M.
    • Fan, J.
    • Malhi, S.
  • Source: Canadian Journal of Soil Science
  • Volume: 90
  • Issue: 3
  • Year: 2010
  • Summary: Nitrate (NO 3-) leaching and water contamination have become a worldwide concern. In this review, some examples are presented to show the extent and magnitude of NO 3- accumulation in the soil profiles and its potential effects on contamination of ground water and surface water under dryland farming in northern China. Climatic and management factors affecting NO 3- leaching are also discussed. In northern China, rainfall is relatively sparse, but the high intensity of precipitation and porous soils play an important role in the accumulation of NO 3N in soil and its subsequent leaching in the soil profile. There is a risk of nitrate accumulation and leaching when high rates of fertilizer N are applied to improve crop yields, and it becomes even worse when conventional land use is changed from cereal crops to vegetable crops and fruit orchards. Under such conditions, shallow ground water might be polluted by NO 3-. This suggests that more attention should be paid to prevent this problem by using best management practices, especially by controlling the amount of N fertilizer input, balanced fertilization, split N application, inclusion of crops with deep taproots in the rotation and minimizing summer fallow (especially tilled) frequency.
  • Authors:
    • Garcia-Ruiz, J. M.
  • Source: Catena
  • Volume: 81
  • Issue: 1
  • Year: 2010
  • Summary: Soil erosion is a key factor in Mediterranean environments, and is not only closely related to geoecological factors (lithology, topography, and climatology) but also to land-use and plant cover changes. The long history of human activity in Spain explains the development of erosion landscapes and sedimentary structures (recent alluvial plains, alluvial fans, deltas and flat valleys infilled of sediment). For example, the expansion of cereal agriculture and transhumant livestock between the 16th and 19th centuries resulted in episodes of extensive soil erosion. During the 20th century farmland abandonment prevailed in mountain areas, resulting in a reduction of soil erosion due to vegetation recolonization whereas sheet-wash erosion, piping and gullying affected abandoned fields in semi-arid environments. The EU Agrarian Policy and the strengthening of national and international markets encouraged the expansion of almond and olive orchards into marginal lands, including steep, stony hill slopes. Vineyards also expanded to steep slopes, sometimes on new unstable bench terraces, thus leading to increased soil erosion particularly during intense rainstorms. The expansion of irrigated areas, partially on salty and poorly structured soils, resulted in piping development and salinization of effluents and the fluvial network. The trend towards larger fields and farms in both dry farming and irrigated systems has resulted in a relaxation of soil conservation practices.
  • Authors:
    • Wallwork, H.
    • Tester, M.
    • Hassan, M.
    • Lott, G.
    • Verbyla, A. P.
    • Oldach, K.
    • Genc, Y.
    • McDonald, G. K.
  • Source: Theoretical and Applied Genetics
  • Volume: 121
  • Issue: 5
  • Year: 2010
  • Summary: Worldwide, dryland salinity is a major limitation to crop production. Breeding for salinity tolerance could be an effective way of improving yield and yield stability on saline-sodic soils of dryland agriculture. However, this requires a good understanding of inheritance of this quantitative trait. In the present study, a doubled-haploid bread wheat population (Berkut/Krichauff) was grown in supported hydroponics to identify quantitative trait loci (QTL) associated with salinity tolerance traits commonly reported in the literature (leaf symptoms, tiller number, seedling biomass, chlorophyll content, and shoot Na + and K + concentrations), understand the relationships amongst these traits, and determine their genetic value for marker-assisted selection. There was considerable segregation within the population for all traits measured. With a genetic map of 527 SSR-, DArT- and gene-based markers, a total of 40 QTL were detected for all seven traits. For the first time in a cereal species, a QTL interval for Na + exclusion ( wPt-3114-wmc170) was associated with an increase (10%) in seedling biomass. Of the five QTL identified for Na + exclusion, two were co-located with seedling biomass (2A and 6A). The 2A QTL appears to coincide with the previously reported Na + exclusion locus in durum wheat that hosts one active HKT1; 4 ( Nax1) and one inactive HKT1; 4 gene. Using these sequences as template for primer design enabled mapping of at least three HKT1; 4 genes onto chromosome 2AL in bread wheat, suggesting that bread wheat carries more HKT1; 4 gene family members than durum wheat. However, the combined effects of all Na + exclusion loci only accounted for 18% of the variation in seedling biomass under salinity stress indicating that there were other mechanisms of salinity tolerance operative at the seedling stage in this population. Na + and K + accumulation appear under separate genetic control. The molecular markers wmc170 (2A) and cfd080 (6A) are expected to facilitate breeding for salinity tolerance in bread wheat, the latter being associated with seedling vigour.