• Authors:
    • Sheffield, K. J.
    • Abuzar, M.
    • Whitfield, D. M.
    • O'Connell, M. G.
    • McClymont, L.
    • McAllister, A. T.
  • Source: Acta Horticulturae
  • Issue: 889
  • Year: 2011
  • Summary: SEBAL-METRIC estimates of evapotranspiration (ET) were derived from Landsat-5 imagery of Sunraysia Irrigation Region of Victoria, Australia. Paired estimates of ET and vegetation cover, NDVI, were derived from an image taken mid-season on 5 January 2009. NDVI and ET were attributed to land use based on data provided by SunRISE21 Inc. Relationships between ET, scaled by field measured reference tall crop evapotranspiration, ET r, and NDVI for the dominant almond, citrus and grape crops showed that the evaporation ratio (ET/ET r) was strongly related to NDVI. These findings suggest that SEBAL-METRIC satellite remote sensing approaches offer an affordable and robust method for the deviation of NDVI-based block-customised estimates of crop coefficient (K c) for almond, citrus and grape crops.
  • Authors:
    • Christie, K. M.
    • Rawnsley, R. P.
    • Eckard, R. J.
  • Source: Animal Feed Science and Technology
  • Volume: 166-167
  • Year: 2011
  • Authors:
    • Eckard, R. J.
    • Cullen, B. R.
  • Source: Animal Feed Science and Technology
  • Volume: 166-167
  • Year: 2011
  • Authors:
    • Grace, P.
    • Barton, L.
    • Chen, D.
    • Eckard, R.
    • Kelly, K.
    • Officer, S.
    • Scheer, C.
    • Schwenke, G.
    • Wang, W.
  • Source: Soil Solutions for a Changing World
  • Year: 2011
  • Authors:
    • Al-Mohammadi, F.
    • Al-Zu'bi, Y.
  • Source: Journal of Agricultural Science and Technology
  • Volume: 13
  • Issue: 2
  • Year: 2011
  • Summary: This research was conducted under greenhouse conditions to evaluate the optimum combination of irrigation and fertilizer levels to attain the best yield and quality of tomato crop. The experiment was conducted by using a split-plot design with three replicates. Irrigation levels were applied to the main plots and fertilizer levels to the sub-plots. For each experimental unit, the irrigation levels were W1=8 mm/day, W2=7 mm/day, W3=6 mm/day, and W4=5 mm/day. Fertilizers treatments varied during the growing season. For the period after transplanting till flowering, the treatments consisted of weekly applications of F1=(N1, P1, K1, respectively, 9.8, 6.13, 7.35 g/plot), F2=(N2, P1, K1, respectively,14.7, 6.13, 7.35 g/plot), F3=(N2, P2, K1, respectively, 14.7, 9.19, 7.35 g/plot), and F4=(N2, P2, K2, respectively, 14.7, 9.19, 11.0 g/plot). Fertilizer levels were increased as the plants developed during the growing season. Plant height and the number of flowers per tomato plant were measured during the growing season and at harvesting time. Random samples of tomato leaves and fruits were taken from each experimental plot to determine the percentage of dry matter, total nitrogen, phosphorus, and potassium contents of fruits and leaves. Total yield during harvesting period and average fruit weight were also measured. Results indicated that irrigation and fertilizer levels had significant effects on the number of flowers per plant and W1F2 combination was significantly the most effective treatment compared to the other treatments. Plant height was not affected significantly by any treatment. The total yield significantly increased in W3F1 treatment. Average fruit weight was significantly higher in W2F3 as compared to the other treatments. The percentage of dry matter was significantly affected by the treatment W3F3 in both leaves and fruits. Total leaf contests of nitrogen, phosphorus, and potassium significantly increased in W2F4 treatment. Total nitrogen content in tomato fruits did not show any significant difference among different treatments, whereas fruit phosphorus and potassium contents significantly increased in W2F3 and W4F4 treatments.
  • Authors:
    • Cociu, A. I.
    • Alionte, E.
  • Source: Analele Institutului National de Cercetare-Dezvoltare Agricola Fundulea
  • Volume: 79
  • Issue: 2
  • Year: 2011
  • Summary: Grain yields of winter wheat (Triticum aestivum L.), maize ( Zea mays L.), and soybean [ Glycine max. (L.) Merr], in rotation were significantly influenced by soil deep loosening and tillage system, depending on water supply (irrigation application). Scientific literature regarding the influence of these agronomic factors on the yield quality of the respective three crops, in rotation, is quite limited. For this study, a field experiment was carried out at Fundulea, which is located in the eastern part of the Danube Plain, on a cambic chernozem soil type. One of the main objectives was to determine how the grain yield quality of winter wheat, maize and soybean is influenced by different reduced tillage systems, in comparison with the traditional (conventional) one, as well as by the direct seeding in non-worked ground, or in strip till, with and without soil deep loosing, under different irrigations. Regarding the maize, the water provisioning * tillage system interaction was very significant (P0.05). Under the three water provisions applied, protein content had values between 40.0%, recorded when the normal irrigation rate was used, at no till system, and 41.5%, recorded for the dry conditions, also at no till system. The 1,000 kernel weight varied between 120 g, registered for the dry conditions at no till variant, and 159 g, registered for normal irrigation rate, also at no till system. The results of this research do not make evident a certain tendency of protein content, but show clearly that the fat content increases concomitantly with grain yield growing. As concerns the winter wheat crop, the water provisioning * tillage system interaction was not significant (P>0.05). Protein content was comprised between 13.2%, registered when the normal irrigation rate was applied at no till system variant, and 15.7%, under dry conditions, at the traditional tillage system. The minimum value of 1,000 kernel weight was 37 g, recorded for dry conditions at chisel tillage variant, and the highest value, of 47 g, was obtained when normal irrigation rate was applied to no till variant.
  • Authors:
    • Bustamante, M. M. da C.
    • Cruvinel, E. B. F.
    • Kozovits, A. R.
    • Zepp, R. G.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 144
  • Issue: 1
  • Year: 2011
  • Summary: In the last 40 years, a large area of savanna vegetation in Central Brazil (Cerrado) has been converted to agriculture, with intensive use of fertilizers, irrigation and management practices. Currently, the Cerrado is the main region for beef and grain production in Brazil. However, the consequences of these agricultural practices on NO, N 2O and CO 2 emissions from soil to atmosphere are still poorly investigated. The objectives of this study were to quantify soil emissions of NO-N, N 2O-N and CO 2-C in different no-till cultivation systems in comparison with native savanna vegetation. The agricultural areas included: (a) the maize and Brachiaria ruzizienses intercropping system followed by irrigated bean in rotation; (b) soybean followed by natural fallow; and (c) cotton planting over B. ruzizienses straw. The study was performed from August 2003 to October 2005 and fluxes were measured before and after planting, after fertilizations, during the growing season, before and after harvesting. NO-N fluxes in the soybean field were similar to those measured in the native vegetation. In the cornfield, higher NO-N fluxes were measured before planting than after planting and pulses were observed after broadcast fertilizations. During Brachiaria cultivation NO-N fluxes were lower than in native vegetation. In the irrigated area (bean cultivation), NO-N fluxes were also significantly higher after broadcast fertilizations. Most of the soil N 2O-N fluxes measured under cultivated and native vegetation were very low (<0.6 ng N 2O-N cm -2 h -1) except during bean cultivation when N 2O-N fluxes increased after the first and second broadcast fertilization with irrigation and during nodule senescence in the soybean field. Soil respiration values from the soybean field were similar to those in native vegetation. The CO 2-C fluxes during cultivation of maize and irrigated bean were twice as high as in the native vegetation. During bean cultivation with irrigation, an increase in CO 2-C fluxes was observed after broadcast fertilization followed by a decrease after the harvest. Significantly lower soil C stocks (0-30 cm depth) were determined under no-tillage agricultural systems in comparison with the stocks under savanna vegetation. Fertilizer-induced emission factors of N oxides calculated from the data were lower than those indicated by the IPCC as default.
  • Authors:
    • Fourie, J.
    • Joubert, M.
    • Freitag, K.
  • Source: SA Fruit Journal
  • Volume: 10
  • Issue: 1
  • Year: 2011
  • Summary: Five soil management practices applied in a micro-sprinkler irrigated 'Pink Lady' (Cripps Pink/M7) orchard established on a loam soil near Grabouw were evaluated from October 2003 to March 2010. Dry matter production by the cover crops at the end of September was higher under integrated soil management (IP) than under organic soil management (Organic) during 2004, 2007 and 2008, with the same trend being observed during 2005, 2006, and 2009. Cover crops in the IP and Organic treatments suppressed the winter growing weeds significantly over all seasons compared to treatments in which no cover crop was sown and weeds were slashed during the growing season of the trees (Weeds (IP) and Weeds (Organic) treatments). Except for September 2004, a similar result was achieved where a full surface straw mulch was packed out annually during October, followed by hand weeding during the growing season of the trees (Straw Mulch (Organic) treatment). Summer growing weeds were controlled effectively by the Cover Crop (IP) and Straw Mulch (Organic) treatments. Weeds (IP) and Weeds (Organic) caused broad leaf weeds to disappear and perennial grasses to dominate the weed spectrum. Although not as drastic, a similar trend developed in the Cover Crop (Organic) treatment. In contrast, annual weed species became dominant where Cover Crop (IP) was applied. All soil cultivation practices caused changes in the weed spectrum, with species dominance shifting with time. This aspect of weed control should be studied more extensively in future.
  • Authors:
    • Jantalia, C. P.
    • Halvorson, A. D.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 5
  • Year: 2011
  • Summary: Converting to no-till (NT) production can affect N requirements for optimizing corn ( Zea mays L.) yields while enhancing soil organic carbon (SOC) and N levels. Nitrogen fertilization impacts on irrigated, NT continuous-corn grain, stalk, cob, and stover yields, stover C and N uptake, and C/N ratios were evaluated for 11 yr on a clay loam soil. Changes in SOC and total soil nitrogen (TSN) were also monitored. Grain, stalk, cob, and stover yields increased with increasing N rate, as did N and C uptake. The C/N ratio of stalk residue declined with increasing N rate, but cob C/N ratio was not affected, with an average stover C/N ratio of 68 at the highest N rate. Nitrogen fertilization increased SOC and TSN levels with average SOC and TSN mass rate gains with N application of 0.388, 0.321, and 0.160 Mg SOC ha -1 yr -1 and 0.063, 0.091, and 0.140 Mg TSN ha -1 yr -1 in the 0- to 7.6-, 0- to 15.2-, and 0- to 30.4-cm soil depths, respectively. The SOC and TSN mass rate changes were lower without N application. Increases in TSN appeared to be more rapid than SOC, resulting in a decline in the soil C/N ratio with time. Under irrigated, NT continuous corn production, N fertilization optimized grain and residue yields, with the enhanced benefit of increased SOC and TSN levels in the semiarid central Great Plains. Removal of cobs or partial stover residue as a cellulosic feedstock for ethanol production appears possible without negative effects on soil quality under irrigated, NT corn production.
  • Authors:
    • Avval, S. H. M.
    • Rafiee, S.
    • Jafari, A.
    • Mohammadi, A.
  • Source: Journal of Agricultural Technology
  • Volume: 7
  • Issue: 3
  • Year: 2011
  • Summary: The energy consumption in different operations of soybean, canola and sunflower productions in Golestan province of Iran was investigated. This study also focused sketches the environmental footprints of energy use in oilseed production. For these purpose Inquiries on 319 oilseed farms were conducted in 2009/10 production period. The results revealed that soybean gave the highest operational energy input (22235 MJ ha -1); while, total operational energy for canola and sunflower was relatively low as 8317 and 6013 MJ ha -1, respectively. Irrigation operation consumed the highest share of total operational energy in soybean and sunflower productions; it was mainly in the form of electricity energy; however, in canola production, the tillage operation was the most intensive energy consumer, followed by harvesting practice. From this study it was found that increasing energy use efficiency of water pumping systems by good repair and maintenance and employing improved tillage and harvesting practices, such as low till agriculture, could be the pathways to make oilseed productions more environmental friendly and thus reduce their environmental footprints.