• Authors:
    • Mullinix, B. G.,Jr.
    • Keeling, J. W.
    • Bordovsky, J. P.
    • Wheeler, T. A.
    • Woodward, J. E.
  • Source: Plant Disease
  • Volume: 96
  • Issue: 7
  • Year: 2012
  • Summary: A field experiment was conducted under center-pivot irrigation in four wedges, with one wedge in continuous cotton (CC) and three wedges in a rotation (ROT) with 2 years cotton and 1 year in sorghum. Three irrigation rates (base = 1.0B, 1.5B, and 0.5B) were applied during 2007 to 2009 on a susceptible (ST) and partially resistant (PR) cultivar. Nitrogen applied during the season was proportional to irrigation rate. In the ROT wedges, 0.5B, 1.0B, and 1.5B irrigation and nitrogen rates averaged 1, 3, and 9% incidence of wilt, respectively. Disease incidence in the CC wedge averaged 6, 18, and 34% wilt incidence for 0.5B, 1.0B, and 1.5B irrigation and nitrogen rates. In the ROT wedges, the ST cultivar returned $143/ha more than the PR cultivars at the 0.5B irrigation and nitrogen rate whereas, at the 1.0B and 1.5B rates, the PR cultivars averaged $121 and $350/ha more than the ST cultivar. There was no significant irrigation and nitrogen or cultivar effect in the CC wedge on net value; however, trends were similar to the ROT wedge. Overall, ROT returned $285/ha more than CC, PR cultivars returned $123/ha more than the ST cultivar, and 1.0B returned $271 and $296/ha more than 0.5B and 1.5B rates, respectively. Microsclerotia density of V. dahliae averaged 2/cm(3) of soil in the ROT wedges and 23/cm(3) of soil in the CC wedge. Crop rotation, avoiding excessive irrigation, and using a partially resistant cultivar all reduced incidence of Verticillium wilt and improved net returns.
  • Authors:
    • Bakshawain, A. A.
    • Abusuwar, A. O.
  • Source: African Journal of Microbiology Research
  • Volume: 6
  • Issue: 14
  • Year: 2012
  • Summary: A field experiment was carried out during 2009/2010 and 2010/2011 seasons at Hada Al-Sham experimental Farm of King A/Aziz University in Jeddah, Saudi Arabia. The objective was to evaluate the effect of some chemical fertilizers on productivity and nutritive value of Sorghum Sudanense Var. Panar intercropped with Cowpea ( Vigna unguiculata L. Walp) in an adverse condition of soil and irrigation water. The chemical fertilizers applied were 50 kg/ha of urea (46%N), 50 kg/ha of triple superphosphate (46% P), 50 kg/ha of KNO 3, 50 kg/ha of NPK (20:20:40) and a control for check. Sudan grass and Cowpea were sown as sole crops and as a mixture. Treatments were laid out in a split plot design with the fertilizer treatments in the main plots and the intercropping treatments in the subplots. Parameters measured were plant height and nutritive value for the Sudan grass, fresh and dry yields and the land equivalent ratio (LER). The chemical fertilizers had no significant (P≤0.05) effect on productivity but significantly improved forage quality. Intercropping of Sudan grass and Cowpea significantly (P≤0.05) increased forage productivity and improved forage quality and land equivalent ratio (LER). Cowpea was not a good competitor as it disappeared following the first cut in the first season.
  • Authors:
    • Begue, A.
    • Dubreuil, V.
    • Meirelles, M.
    • Arvor, D.
    • Shimabukuro, Y. E.
  • Source: Applied Geography
  • Volume: 32
  • Issue: 2
  • Year: 2012
  • Summary: The Amazonian state of Mato Grosso is the main production area for soybeans in Brazil and contains 31.3% of the national production as of 2009. The rapid evolution of the agricultural systems in this area shows that the region is experiencing a rapid agricultural transition. In this paper, we broke down this transition process into three steps: crop expansion, agricultural intensification and ecological intensification. We used remote sensing products to develop and compute satellite-derived indices describing the main agricultural dynamics during the cropping years from 2000-2001 to 2006-2007. Our results indicated that Mato Grosso is continuing to expand its agricultural sector, with a 43% increase in the net cropped area during the study period. Although this expansion mainly occurred in the cerrado ecoregion until the early 2000s, the forest ecoregion is experiencing expansion at this time. We observed that 65% of the crop expansion in Mato Grosso from 2000 to 2006 occurred in this ecoregion. However, we did not identify this crop expansion as the major driver of deforestation in Mato Grosso because only 12.6% of the cleared areas were directly converted into croplands. Agricultural intensification also evolved rapidly, as the proportion of the net cropped area cultivated with double cropping systems harvesting two successive commercial crops (i.e., soybean and corn or soybean and cotton) increased from 6% to 30% during the study period. Finally, we found that ecological intensification occurred because the region's farmers planted a non-commercial crop (i.e., millet or sorghum) after the soybean harvest to prevent soil erosion, improve soil quality, break pest cycles, maintain soil moisture and set the conditions for high-quality no-tillage operations. In 2006-2007, 62% of the net cropped area was permanently covered by crops during the entire rainy season. This practice allowed the farmers to diversify their production, as shown by the positive evolution of the Area Diversity Index. Future scholars can use the method proposed in this paper to improve their understanding of the forces driving the agricultural dynamics in Mato Grosso.
  • Authors:
    • Tchoundjeu, Z.
    • Kalinganire, A.
    • Coe, R.
    • Sileshi, G. W.
    • Bayala, J.
    • Sinclair, F.
    • Garrity, D.
  • Source: Journal of Arid Environments
  • Volume: 78
  • Year: 2012
  • Summary: To address the decline in crop productivity in the drylands of West Africa, many initiatives have focused on combating soil degradation. Various practices including (1) parkland trees associated with crops, (2) coppicing trees, (3) green manure, (4) mulching. (5) crop rotation and intercropping, and (6) traditional soil/water conservation have been tested. The present study attempts to provide a comprehensive, quantitative synthesis of existing reports on the effect of conservation agriculture (CA) practices on crop yield response in Burkina Faso, Mali, Niger and Senegal. Out of a total of 155 reports found, 63 fulfilled all the appropriate criteria to be included in the meta-analysis of the effect of various conservation agriculture practices on the yield response of maize, millet and sorghum. The study revealed significant variability in cereal yield response (and hence risk) with all the practices examined. Despite the variability, the mean effects of the six CA practices on crop yield were more positive than negative except with parkland trees. However, for this last practice, species like Faidherbia albida exerts more positive impact on crop yield. Yield increases relative to the control were higher with green manure and mulching than with coppicing trees and parklands. Increases in yield in the six CA practices were higher on low to medium productivity sites for maize, millet and sorghum. Coppicing trees and rotations improved yields when the rainfall is >800 mm whereas the opposite happens with parkland and soil-water conservation measures. Mulching performed better when the rainfall is
  • Authors:
    • Obi,M. E.
    • Obalum, S. E.
    • Wakatsuki, T.
    • Amalu, U. C.
  • Source: Experimental Agriculture
  • Volume: 47
  • Issue: 1
  • Year: 2011
  • Summary: Over a decade after the forest-savanna transition zone of Nigeria was deemed suitable for production of sorghum (Sorghum bicolor), no research has been undertaken on the crop's tillage requirements in the southeastern part of the zone. This study evaluated the effects of tillage-mulch practices on soil moisture, water use (WU), grain yield and water use efficiency (WUE) of the crop in a Typic Paleustult (sandy loam) at Nsukka during 2006 and 2007 growing seasons. In a split-plot design, no-till (NT) and conventional tillage (CT) treatments were left bare (B) or covered with mulch (M) at 5 Mg ha(-1). The ensuing treatments (NTB, NTM, CTB, and CTM) represented four tillage methods, which were replicated four times in a randomized complete block. In the monitored root. zone, NTB and CTM significantly (p <= 0.05) enhanced the soil moisture status over NTM and CTB, but the main effects of the tillage and the mulch factors were not significant. The crop WU was uninfluenced by the treatments throughout the study Although the grain yield showed higher values with NT than with CT, the differences were significant (p <= 0.05) only in 2007 that was marked with erratic rainfall and relatively low mean yield. Mulch significantly (p <= 0.05) enhanced the grain yield in 2006, with greater effect in CT than NT On average, the mulch plots out-yielded their bare counterparts by about 26%. The tillage x mulch interaction was significant (p <= 0.01), and showed higher grain yields in NTB, NTM and CTM than in CTB. In the year-weighted average, yield increments in NTB, NTM and CTM over CTB were 53, 53 and 67% respectively, a pointer to the relevance of mulch with the CT but not the NT. Relative WU showed that the crop's water demand was met under all treatments. Hence, the yield reduction in the CTB was not due to water shortage. The WUE varied among the treatments in the same pattern as grain yield. In summary, NTB and CTM proved superior to NTM only in soil moisture status but to CTB in all measured parameters. From a socio-economic viewpoint, however, NTB would be preferable to CTM for growing sorghum in this area.
  • Authors:
    • Wakatsuki, T.
    • Obi, M.
    • Okpara, I.
    • Obalum, S.
  • Source: Tropical and Subtropical Agroecosystems
  • Volume: 14
  • Issue: 2
  • Year: 2011
  • Summary: A key indicator of soil quality as organic carbon needs to be enhanced in the highly weathered soils predominant in southeastern Nigeria through appropriate tillage-mulch practices and cropping systems. We subjected a degraded Typic Paleustult (sandy loam) at Nsukka to no-till (NT) and conventional tillage (CT) and bare fallow (B) and mulch cover (M). This was duplicated with one sole-cropped to sorghum and the other to soybean as separate crop treatments during 2006 and 2007 growing seasons. The CT resulted in higher available P (P av) (under soybean) and cation exchange capacity (CEC) (under both crops) than the NT. Mulch gave lower P av under sorghum and vice versa under soybean. Exchangeable Ca was lowered while exchangeable acidity was enhanced with mulch under soybean. Overall, soil organic carbon and exchangeable Mg, Na and acidity were enhanced under soybean relative to sorghum; the reverse was the case for P av. However, the soil's CEC indicated comparable values in both cropping systems. Our results suggest that cropping 'CT with M' soil to soybean could be a promising agronomic combination for enhancing the SOC and fertility status of the soil.
  • Authors:
    • Strickland, G. L.
    • Epplin, F. M.
    • Varner, B. T.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 5
  • Year: 2011
  • Summary: The majority of cropland in the Southwest Oklahoma Agricultural Statistics District is tilled and seeded to continuous monoculture winter wheat (Triticum aestivum L.). This study was conducted to determine the expected yield and expected net returns of wheat, cotton (Gossypium hirsutum L.), and grain sorghum [Sorghum bicolor (L.) Moench], under two production systems, no-till (NT) and tilled (TL), and to determine the most risk-efficient system. The effect of tillage was investigated over 6 yr at Altus, OK, on a Hollister silty clay loam (fine, smectitic, thermic Typic Haplusterts) soil. Wheat and cotton yields were not different between tillage systems. Sorghum NT yielded significantly more than TL sorghum (P <= 0.05). Wheat NT produced the greatest expected net return to land, labor, overhead, and management ($217 ha(-1) yr(-1)). Tilled grain sorghum was the least profitable system (-$42 ha(-1) yr(-1)). Wheat NT required additional expenditures for herbicides ($15 ha(-1)), less for machinery fuel, lube, and repairs ($22 ha(-1)), and less ($23 ha(-1)) for machinery fixed costs. Net returns were slightly greater ($18 ha(-1)) for NT wheat than for TL wheat. However, since NT wheat yields were more variable, TL wheat may be preferred by risk-averse producers. Estimated machinery labor savings from switching from TL to NT wheat were 0.588 h ha(-1) or 609 h yr(-1) for a 1036 ha farm. The decision to switch from TL to NT wheat depends on risk preferences, and on the potential to use saved labor productively elsewhere, or to farm more land.
  • Authors:
    • Orr, W.
    • Cooper, J.
    • Chataway, R.
    • Cowan, R.
  • Source: Animal Production Science
  • Volume: 51
  • Issue: 10
  • Year: 2011
  • Summary: Dairy farms located in the subtropical cereal belt of Australia rely on winter and summer cereal crops, rather than pastures, for their forage base. Crops are mostly established in tilled seedbeds and the system is vulnerable to fertility decline and water erosion, particularly over summer fallows. Field studies were conducted over 5 years on contrasting soil types, a Vertosol and Sodosol, in the 650-mm annual-rainfall zone to evaluate the benefits of a modified cropping program on forage productivity and the soil-resource base. Growing forage sorghum as a double-crop with oats increased total mean annual production over that of winter sole-crop systems by 40% and 100% on the Vertosol and Sodosol sites respectively. However, mean annual winter crop yield was halved and overall forage quality was lower. Ninety per cent of the variation in winter crop yield was attributable to fallow and in-crop rainfall. Replacing forage sorghum with the annual legume lablab reduced fertiliser nitrogen (N) requirements and increased forage N concentration, but reduced overall annual yield. Compared with sole-cropped oats, double-cropping reduced the risk of erosion by extending the duration of soil water deficits and increasing the time ground was under plant cover. When grown as a sole-crop, well fertilised forage sorghum achieved a mean annual cumulative yield of 9.64 and 6.05 t DM/ha on the Vertosol and Sodosol, respectively, being about twice that of sole-cropped oats. Forage sorghum established using zero-tillage practices and fertilised at 175 kg N/ha.crop achieved a significantly higher yield and forage N concentration than did the industry-standard forage sorghum (conventional tillage and 55 kg N/ha.crop) on the Vertosol but not on the Sodosol. On the Vertosol, mean annual yield increased from 5.65 to 9.64 t DM/ha (33 kg DM/kg N fertiliser applied above the base rate); the difference in the response between the two sites was attributed to soil type and fertiliser history. Changing both tillage practices and N-fertiliser rate had no affect on fallow water-storage efficiency but did improve fallow ground cover. When forage sorghum, grown as a sole crop, was replaced with lablab in 3 of the 5 years, overall forage N concentration increased significantly, and on the Vertosol, yield and soil nitrate-N reserves also increased significantly relative to industry-standard sorghum. All forage systems maintained or increased the concentration of soil nitrate-N (0-1.2-m soil layer) over the course of the study. Relative to sole-crop oats, alternative forage systems were generally beneficial to the concentration of surface-soil (0-0.1 m) organic carbon and systems that included sorghum showed most promise for increasing soil organic carbon concentration. We conclude that an emphasis on double- or summer sole-cropping rather than winter sole-cropping will advantage both farm productivity and the soil-resource base.
  • Authors:
    • Urashima, A.
    • Silva, C.
  • Source: Journal of Phytopathology
  • Volume: 159
  • Issue: 11/12
  • Year: 2011
  • Summary: Blast caused by Magnaporthe grisea ( Pyricularia grisea) is a disease that occurs in many important gramineous plants in Brazil such as rice, wheat, triticale and barley. In 2005, the presence of this disease was reported on black oat ( Avena strigosa) at different locations of Parana state. Due to little information of M. grisea that is infecting this host, this work aimed to characterize it at molecular, sexual and pathogenic level. DNA analysis showed that M. grisea from black oat formed a homogenous and genetic distinct group of its own, different from other hosts, including rice, wheat, triticale and barley. Isolate 15720 was an exception, because it was similar to wheat isolate. There was no sexual compatibility between M. grisea from oat and other tested hosts. In pathogenic terms, isolates of M. grisea from oat infected triticale, wheat, rye, millet, barley, sorghum and rice; cross-inoculation was positive with wheat, triticale, rice and barley.
  • Authors:
    • Gamar, Y.
    • Abdalla, H.
  • Source: International Journal of AgriScience
  • Volume: 1
  • Issue: 3
  • Year: 2011
  • Summary: Sorghum ( Sorghum bicolor (L.) Moench) is the most important cereal crop in Sudan in terms of consumption and total acreage under production. However recent climatic changes, have affected productivity. Cultivation has been constrained by the detrimental effect of drought which has often caused food shortages resulting in famine. Almost 90% of the total sorghum cropped area is rain-fed, and 60% of that is in drought prone soil conditions. A series of experiments were conducted to develop elite early maturing and combinable open pollinated varieties with good grain quality. Seven superior pure lines from an adapted drought tolerant land race commercial Arf'a' Gadamak (CAG,) were selected and tested under irrigation for three seasons at Gezira Research Station (GRS). Based on high yield potential and early maturity, AG-17 line was selected and advanced together with AG-8, AG-15, Wad Ahmed and CAG as checks for multi-location testing under intermediate and high rainfall areas (400-900/mm). Eight specific rain-fed environments were chosen as sites for standard variety trials, over three seasons (2006 to 2009). Results revealed that lines AG-17 flowered 12 days earlier by 50%, than Wad Ahmed. This early maturity coupled with very high yield potential, highlights drought tolerance making it an adaptable and stable crop across a wide range of rainfall environments. Like the released sorghum variety AG-8, the AG-17 line has exceptionally high protein content, 23% and 33% more than the checks, CAG and Wad Ahmed, respectively. This line also possesses the best grain quality, white, large and preferred by the market in addition to other attractive, physical grain characteristics. It was also evident that this line has high bread (kisra) making qualities.