• Authors:
    • Wang, G.
    • Thorp, K. R.
    • Norton, R.
    • Gutierrez, M.
  • Source: Crop Science
  • Volume: 52
  • Issue: 2
  • Year: 2012
  • Summary: Canopy reflectance plays an increasingly important role in crop management and yield prediction at large scale. The relationship of four spectral reflectance indices with cotton (Gossypium hirsutum L.) biomass, leaf area index (LAI), and crop yield were investigated using three cotton varieties and five N rates in the irrigated low desert in Arizona during the 2009 and 2010 growing seasons. Biomass, LAI, and canopy reflectance indices (normalized difference vegetation index [NDVI], simple ratio [SR], near-infrared index [NIR] and ratio vegetation index [RVI]) were determined at different growth stages. The commonly used NDVI and the other three canopy reflectance indices explained over 87% variation in cotton biomass (all R-2 > 0.87) and LAI (R-2 > 0.93). Indices SR, NIR, and RVI all had higher coefficients of determination (R-2) compared to NDVI because these indices were not saturated at late growth stages. There was no significant relationship between lint yield and the spectral indices measured at early growth stages. However, the spectral indices determined at peak bloom showed significant correlations with lint yield. Indices SR, NIR, and RVI explained 56, 60, and 58% of variations in cotton lint yield, respectively, while NDVI only explained 47% of variation in lint yield. This study suggests canopy reflectance indices can be used to predict cotton lint yield at peak bloom and the accuracy of yield prediction can be significantly improved when SR, NIR, and RVI are used.
  • Authors:
    • Yasir, I.
    • Ghazanfar, M. U.
    • Zafar, I.
    • Khan, M. A.
    • Hamid, M. I.
    • Naeem, A.
  • Source: Pakistan Journal of Phytopathology
  • Volume: 24
  • Issue: 1
  • Year: 2012
  • Summary: Bacterial blight (BL), caused by Xanthomonas campestris pv. malvacearum (Smith) Dye, is a common disease affecting the growth, development and yield of cotton ( Gossypium hirsutum L.) in Pakistan. Field trial was conducted for a season to determine the influence of environmental conditions representing heavy and low rainfall periods, wind speed and direction on disease incidence by growing 101 commercial varieties. However, out of 101 varieties, a total of 68 varieties were moderately susceptible response while 8 were susceptible to bacterial blight disease. A total of 25 varieties were moderately resistant to bacterial blight disease. No variety was resistant to bacterial blight disease. Except radiation and wind speed, overall correlation of maximum and minimum air temperature, relative humidity, rainfall and pan evaporation with bacterial blight disease severity was statistically significant. The poor correlation of wind speed with disease severity may also be due to frequency and amount of air currents received in a certain adjoining areas of Faisalabad district of Pakistan and its indirect role to create humid conditions. Similarly relative humidity is different at different levels of crop canopy and largely depends upon the amount of moisture resulted due to rain showers and irrigation.
  • Authors:
    • Finlay, L. A.
    • Weaver, T. B.
    • Hulugalle, N. R.
    • Lonergan, P.
  • Source: Soil Research
  • Volume: 50
  • Issue: 4
  • Year: 2012
  • Summary: Comparative studies of soil quality and energy use in two- and three-crop rotations in irrigated cotton ( Gossypium hirsutum L.) based cropping systems under varying stubble management practices in Australian Vertosols are sparse. Our primary objective was to quantify selected soil quality indices (salinity, sodicity, exchangeable cations, nitrate-N, pH), crop yields, and greenhouse gas emissions in four irrigated cotton-based cropping systems sown on permanent beds in a Vertosol with subsoil sodicity near Narrabri in north-western New South Wales. A secondary objective was to evaluate the efficacy of sowing vetch in rotation with cotton over a long period on the incidence of black root-rot in cotton seedlings. Results: presented in this report pertain to the period June 2005-May 2011. The experimental treatments were: cotton-cotton; cotton-vetch ( Vicia benghalensis L.); cotton-wheat ( Triticum aestivum L.), where wheat stubble was incorporated; and cotton-wheat-vetch, where wheat stubble was retained as in-situ mulch. Vetch was terminated during or just before flowering by a combination of mowing and contact herbicides, and the residues were retained as in-situ mulch. Soil pH, electrical conductivity (EC 1:5), Cl -, NO 3--N, exchangeable cations, exchangeable sodium percentage (ESP), electrochemical stability index (=EC 1:5/ESP), and EC 1:5/ESC (exchangeable sodium concentration) were evaluated in samples taken from the 0-1.2 m depth before sowing cotton during late September or early October of each year. Incidence of black root-rot was assessed 6 weeks after sowing cotton. Compared with sowing cotton every year, including wheat in cotton-based cropping systems improved cotton yield and reduced soil quality decline, emissions of carbon dioxide equivalents (CO 2-e) per unit area, and CO 2-e emissions per unit of cotton yield. Including vetch in the rotation was of negligible benefit in terms of yield and CO2-e emissions per unit of yield. The rate of soil quality decline was unaffected by including vetch in a cotton-wheat rotation but was accelerated when included in a cotton-cotton sequence. Among all cropping systems, soil quality was best with cotton-wheat and cotton-wheat-vetch but poorest with cotton-vetch. Although CO2-e emissions associated with growing 1ha of cotton could be reduced by 9% by growing vetch because of substituting fixed atmospheric N for N fertiliser derived from fossil fuels, this advantage was partly negated by the emissions from farming operations associated with growing a vetch crop. Relative to a two-crop rotation (one cotton-one rotation crop), negligible benefits in terms of yield, soil quality, greenhouse gas emissions, and black root-rot control accrued from a three-crop rotation (one cotton-two rotation crops). Incidence of black root-rot increased as the number of cotton crops sown increased. In addition to the cropping systems, soil quality indices and yield were significantly influenced by irrigation water quality and climate.
  • Authors:
    • Abraham, S.
    • Babar, S.
    • Singh, J.
    • Majumdar, G.
    • Venugopalan, M. V.
  • Source: Better Crops with Plant Food
  • Volume: 96
  • Issue: 2
  • Year: 2012
  • Summary: Despite large tracts of irrigated cotton, rainfed systems remain the most important option for improving cotton production in India. Within rainfed fields, the potential effects of adopting high plant population with adequate NPK fertilizer management offer a good opportunity to increase crop productivity.
  • Authors:
    • Liu, H.
    • Liu, S.
    • Jiang, H.
  • Source: Chinese Journal Geophysics
  • Volume: 55
  • Issue: 2
  • Year: 2012
  • Summary: This study uses turbulence, net radiation and soil data from International Energy Balance Experiment (EBEX-2000) to study the characteristics of sensible and latent heat flux under thermal internal boundary layer which is induced by heterogeneous irrigation. Energy balance closure on irrigated days was compared with that on non-irrigated days. Schotanus correction and Webb correction were applied when calculating turbulence heat fluxes and their influences were also analyzed. During this research, eddy covariance method is used. Results indicate that turbulence heat fluxes in the surface layer are affected by thermal internal boundary layer resulted from heterogeneous irrigation, this interaction leads to a decrease of sensible heat flux and a oscillation of latent heat flux. This phenomenon is more significant at 8.7 m than that at 2.7 m. The existence of thermal internal boundary layer induced by heterogeneous irrigation result in a decreased energy balance ratio of 0.65; while with no internal thermal boundary layer, the energy balance ratio is close to 0.70. Schotanus correction results in a significant diminution of sensible heat flux in this experiment. The daily average of Schotanus correction reach up to -8 W/m(2), almost 4% of the net radiation. The daily average of Webb correction to latent heat flux is about 2 W/m(2), having slight influence on energy balance closure.
  • Authors:
    • Naidu, M. V. S.
    • Kailaimannan, R.
    • Venkaiah, K.
  • Source: Madras Agricultural Journal
  • Volume: 99
  • Issue: 4/6
  • Year: 2012
  • Summary: Some important physico-chemical parameters of irrigation water of guava orchards in Prakasam district were evaluated for the criteria of the irrigation water quality. Thirty water samples were collected from three different mandals of the Prakasam district. The present study revealed that pH was neutral to moderately alkaline, Electrical Conductivity (EC) was high, Sodium Adsorption Ratio (SAR) was low to medium and Residual Sodium Carbonate (RSC) was good to marginal. So, initiative must be taken to reduce salt accumulation in the soil through drainage and adopting the highly salt tolerant crops like cotton, mustard and tamarind for the better utilization of the land.
  • Authors:
    • Diker, K.
    • Sezen, S.
    • Tekin, S.
    • Unlu, M.
    • Onder, S.
    • Kanber, R.
  • Source: Turkish Journal of Agriculture and Forestry
  • Volume: 36
  • Issue: 1
  • Year: 2012
  • Summary: In this study, the water saving and conservation potential of various furrow irrigation management techniques for irrigated cotton were compared. Conventional every-furrow irrigation with open-end furrows (EFO) and blocked-end furrows (EFB), and alternate every-other-furrow management with open-end furrows (AFO) and blocked-end furrows (AFB), were considered. Considerable seasonal water savings were obtained with AFO and AFB flows, on average from 717 mm to 906 mm, respectively, when compared to EFO. Alternate furrows showed the ability to reduce tailwater runoff considerably. When compared with EFO, water use was reduced by 9063 m(3) ha(-1) (60%) using AFB and 7167 m(3) ha(-1) (48%) using AFO, with decreases in yield of 765 kg ha(-1) (27%) and 492 kg ha(-1) (17%), respectively. Similarly, average water use efficiencies were 0.36 kg m(-3) for AFB and 0.31 kg m(-3) for AFO, compared to 0.20 kg m(-3) for EFO. Results showed the possibility of applying alternate-flow furrow management techniques for water conservation in cotton irrigation. Additionally, the alternate furrow method could also be considered as a deficit irrigation approach in the Harran Plain.
  • Authors:
    • Liu, S.
    • Jiang, S.
    • Hu, W.
    • Wan, S.
    • Wang, R.
    • Kang, Y.
  • Source: Agricultural Water Management
  • Volume: 109
  • Year: 2012
  • Summary: Due to the mismanagement of water and fertilizer application, cotton cultivation in Xinjiang Northwest China is faced with the problems of soil deterioration and groundwater table ascension. This study was conducted to evaluate the effects of different levels of water applied through drip irrigation on cotton yield and water use in an arid region of Northwest China. The experiment included five water treatments in which the soil matric potential (SMP) at a depth of 20 cm was controlled higher than -10 kPa (S1), -20 kPa (S2), -30 kPa (S3), -40 kPa (S4), and -50 kPa (S5) after cotton was established. The results revealed that the highest cotton evapotranspiration (ETc) was achieved under S1 (-10 kPa) treatment and the ETc, deep percolation and the ratio of deep percolation with irrigation water all increased with increasing SMP threshold. After three years experiment, no salt accumulation in surface soil layer was found under our irrigation schedule. The highest seed cotton yield was obtained when the SMP threshold was controlled above -30 kPa in 2008, and -20 kPa in 2009 and 2010. Moreover, the highest yield obtained after 3 years was 42% higher than the average yield achieved by local farmers in the area. Additionally, the water use value (WUE and IWUE) tended to increase as the SMP threshold decreased in 2009 and 2010. Considering the cotton yield and the impact of irrigation on the underground water table, an SMP higher than -20 kPa at 20 cm can be used as an indicator for cotton drip irrigation scheduling and agronomic practices in this area to help alleviate the dangerous increase in the water table while increasing the cotton seed yield. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Al-Ain, F.
    • Al-Chammaa, M.
    • Khalifa, K.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 43
  • Issue: 16
  • Year: 2012
  • Summary: A field experiment was carried out to study the effect of different rates of potassium (K) fertilizer [0, 50, 100, and 150 potassium oxide (K2O) ha(-1)] in the presence of increased supply of nitrogen (N) (120, 180, and 240 kg N ha(-1)) on cotton (Gossypium hirsutum L.) yield and the N and K use efficiencies using the N-15 isotopic dilution technique. Potassium fertilizer increased cotton yield, which was significant and more pronounced with the application of N in the high level (N3). The greatest cotton yield (6442 kg ha(-1)) was obtained in N2K3 treatment with an increase of 14% over the control. In addition, K fertilizer significantly increased N uptake efficiency in the N2 and N3 treatments. The greatest N uptake efficiency (98%) was in N2K3 treatment. The greatest K uptake efficiency (42%) was occurred in N3K1 treatment. In conclusion, the use of K fertilizer could be useful when growing cotton in soils of moderate to high N content to improve N uptake efficiency and consequently increase cotton yield.
  • Authors:
    • Rathore, P.
    • Singh, H.
    • Singh, K.
    • Gumber, R. K.
  • Source: Journal of Cotton Research and Development
  • Volume: 26
  • Issue: 1
  • Year: 2012
  • Summary: A field experiment was conducted at PAU, Regional Research Station, Faridkot during kharif 2009 and 2010 to evaluate the performance of two arboreum varieties (FDK 124 and LD 694 as check) under two plant geometries (67.5*45 and 67.5*60 cm) and three nutrient levels (i.e. 56.25, 22.5 kg NP/ha; 75, 30 kg NP/ha and 93.75, 37.5 kg NP/ha). New variety FDK 124 yielded 24.5 per cent significantly higher seed cotton yield (2814 kg/ha) as compared to LD 694 (2260 kg/ha) due to significantly more number of bolls. Pooled data further indicated that significantly higher seed cotton yield was recorded under closer geometry of 67.5*45 cm (2613 kg/ha) than wider plant geometry of 67.5*60 cm (2460 kg/ha). Though, yield attributing parameters such as bolls/plant were statistically improved in wider as compared to closer spacing but it could not compensate yield due to significantly higher plant population in the later case. Among nutrient levels, similar seed cotton yield was recorded with application of 93.75, 37.5 kg NP/ha (2688 kg/ha) and 75, 30 Kg NP/ha (2587 kg/ha) but both were significantly better than that of 56.25, 22.5 kg NP/ha (2335 kg/ha). So, 75, 30 kg NP/ha and plant geometry of 67.5*45 cm seemed to be ideal for new variety FDK 124 for realizing higher productivity under the specific agro climatic conditions of Faridkot.