• Authors:
    • Humphreys, E.
    • Yadvinder-Singh
    • Eberbach, P. L.
    • Katupitiya, A.
    • Kukal, S. S.
    • Balwinder-Singh
  • Source: Field Crops Research
  • Volume: 121
  • Issue: 2
  • Year: 2011
  • Summary: Intensive cultivation of rice and wheat in north-west India has resulted in air pollution from rice straw burning, soil degradation and declining groundwater resources. The retention of rice residues as a surface mulch could be beneficial for moisture conservation and yield, and for hence water productivity, in addition to reducing air pollution and loss of soil organic matter. Two field experiments were conducted in Punjab, India, to study the effects of rice straw mulch and irrigation scheduling on wheat growth, yield, water use and water productivity during 2006-2008. Mulching increased soil water content and this led to significant improvement in crop growth and yield determining attributes where water was limiting, but this only resulted in significant grain yield increase in two instances. There was no effect of irrigation treatment in the first year because of well-distributed rains. In the second year, yield decreased with decrease and delay in the number of irrigations between crown root initiation and grain filling. With soil matric potential (SMP)-based irrigation scheduling, the irrigation amount was reduced by 75 mm each year with mulch in comparison with no mulch, while maintaining grain yield. Total crop water use (ET) was not significantly affected by mulch in either year, but was significantly affected by irrigation treatment in the second year. Mulch had a positive or neutral effect on grain water productivity with respect to ET (WP ET) and irrigation (WP I ). Maximum WP I occurred in the treatment which received the least irrigation, but this was also the lowest yielding treatment. The current irrigation scheduling guidelines based on cumulative pan evaporation (CPE) resulted in sub-optimal irrigation (loss of yield) in one of the two years, and higher irrigation input and lower WP I of the mulched treatment in comparison with SMP-based irrigation scheduling. The results from this and other studies suggest that farmers in Punjab greatly over-irrigate wheat. Further field and modelling studies are needed to extrapolate the findings to a wider range of seasonal and site conditions, and to develop simple tools and guidelines to assist farmers to better schedule irrigation to wheat.
  • Authors:
    • Schwartz, R. C.
    • MacDonald, J. C.
    • Tolk, J. A.
    • Baumhardt, R. L.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 3
  • Year: 2011
  • Summary: Cattle (Bos taurus) grazing intensifies production of the dryland wheat (Triticum aestivum L.)-sorghum [Sorghum bicolor (L.) Moench]-fallow (WSF) rotation in the U. S. Southern High Plains. Stubble-mulch (SM) tillage controls weeds and counteracts soil compaction. No-till (NT) increases soil water at planting and dryland crop yields, but added grazing effects are unknown. Our objectives were to quantify dryland winter wheat and sorghum yield responses to grazing and tillage practices. At the USDA-ARS Conservation and Production Research Laboratory, Bushland, TX, we established all WSF rotation phases in triplicate ungrazed and grazed paddocks beginning 1999 on a Pullman clay loam (fine, mixed, superactive, thermic Torrertic Paleustoll) using SM tillage. During spring 2004, NT or SM tillage were superimposed within grazing main plots. Cattle gain, soil water aft er fallow, and crop yield were compared during 2005 to 2009 using a split-plot randomized complete block design. Cattle, stocked at 1.8 Mg ha(-1), grazed sorghum stover and growing wheat an average of 29 d for a mean gain of 147 kg ha(-1). Soil water at planting was unaffected by grazing, but increased from 14 to 28 mm with NT. Although grazing seldom reduced yield of wheat or sorghum, NT in ungrazed plots increased crop yields sufficiently (0.96-2.6 Mg ha(-1)) in 2008 and 2009 to off set any value added by grazing. We conclude that cumulative grazing effects in NT plots reduced soil water storage and depressed yield. We recommend post-wheat-harvest SM tillage to disrupt soil compaction and restore grazed soil productivity.
  • Authors:
    • Ortega-Farias, S.
    • Selles, G.
  • Source: ISHS Acta Horticulturae
  • Issue: 889
  • Year: 2011
  • Summary: These proceedings contain 79 papers on irrigation systems for horticultural crops. Specific topics covered include the following: improvement of water use for agriculture at catchment level under drought conditions; impact of climatic change on irrigated fruit tree production; effects of the irrigation regime and partial root zone drying on grape cv. Vermentino in Sardinia, Italy; effects of canopy exposure changes on plant water status in grape cv. Syrah; water use by drip-irrigated early-season peach trees; soil water content variations as water stress indicator in peach trees; reduction in the number of fruits in peach (T204) due to postharvest deficit irrigation; effects of irrigation management and N fertilizer on the yield and quality of apple cv. Gala; canopy temperature as an indicator of water status in citrus trees; effects of root anatomy on sap flow rate in avocado trees; influence of rootstock on the response of avocado cv. Hass to flooding stress; methods of selection for drought tolerance in potato; and drip irrigation for the establishment of strawberry transplants in southern California.
  • Authors:
    • Evett, S. R.
    • O'Shaughnessy, S. A.
    • Colaizzi, P. D.
    • Howell, T. A.
  • Source: Agricultural Water Management
  • Volume: 98
  • Issue: 10
  • Year: 2011
  • Summary: The use of digital infrared thermography and thermometry to investigate early crop water stress offers a producer improved management tools to avoid yield declines or to deal with variability in crop water status. This study used canopy temperature data to investigate whether an empirical crop water stress index could be used to monitor spatial and temporal crop water stress. Different irrigation treatment amounts (100%, 67%, 33%, and 0% of full replenishment of soil water to field capacity to a depth of 1.5 m) were applied by a center pivot system to soybean ( Glycine max L.) in 2004 and 2005, and to cotton ( Gossypium hirsutum L.) in 2007 and 2008. Canopy temperature data from infrared thermography were used to benchmark the relationship between an empirical crop water stress index (CWSI e) and leaf water potential (Psi L) across a block of eight treatment plots (of two replications). There was a significant negative linear correlation between midday Psi L measurements and the CWSI e after soil water differences due to irrigation treatments were well established and during the absence of heavy rainfall. Average seasonal CWSI e values calculated for each plot from temperature measurements made by infrared thermometer thermocouples mounted on a center pivot lateral were inversely related to crop water use with r2 values >0.89 and 0.55 for soybean and cotton, respectively. There was also a significant inverse relationship between the CWSI e and soybean yields in 2004 ( r2=0.88) and 2005 ( r2=0.83), and cotton in 2007 ( r2=0.78). The correlations were not significant in 2008 for cotton. Contour plots of the CWSI e may be used as maps to indicate the spatial variability of within-field crop water stress. These maps may be useful for irrigation scheduling or identifying areas within a field where water stress may impact crop water use and yield.
  • Authors:
    • Rypowski, K.
    • Cortes, M.
    • Osorio, A.
    • Burgos, M.
  • Source: Acta Horticulturae
  • Issue: 889
  • Year: 2011
  • Summary: Six tests were done to evaluate the application of irrigation rates in Limari River Valley (3036′ South Latitude 7112′ West Longitude and 218 m of altitude) in avocado and mandarin tree orchards during two agricultural seasons. Assessments were made in volumes of water applied, discharge of the drippers and irrigation frequency used. Also, the water stored in the soil profile was monitored by moisture direct sampling with drill, performed deeply and transversely to the drip lines and plantation rows. In the cases studied it was possible to appreciate a wide variety of situations regarding water stored in the profile. In the vast majority of cases, excess water conditions were found, both in the root zone and below it. In very few cases, the moisture in the root zone of trees reached levels close to permanent wilting percentage (PWP). This would reflect poor efficiency in the implementation and management of irrigation water through drip irrigation, regardless of the uniformity coefficient (UC) of drippers. This situation becomes much more problematic in those soils which present high percentages of clay; creating low aeration conditions for root development. It is also possible to observe an important deviation from moisture profiles to the lower or steeper sectors of the plantation system; generating drier soil or less humid conditions in higher zones, with a big impact on root development. When calculating the relation between the water stored in the root zone versus the total water available in the profile, results between 44 and 73% were obtained, values that reflect inefficient irrigation conditions. These results were corroborated by the high variation coefficients (VC) in the moisture content in the profile, with values higher than 19.00% and with maximum value equal to 43.64% VC.
  • Authors:
    • Hachum, A. Y.
    • Farahani, H. J.
    • Oweis, T. Y.
  • Source: Agricultural Water Management
  • Volume: 98
  • Issue: 8
  • Year: 2011
  • Summary: Cotton ( Gossypium hirsutum L.) is the most important industrial and summer cash crop in Syria and many other countries in the arid areas but there are concerns about future production levels, given the high water requirements and the decline in water availability. Most farmers in Syria aim to maximize yield per unit of land regardless of the quantity of water applied. Water losses can be reduced and water productivity (yield per unit of water consumed) improved by applying deficit irrigation, but this requires a better understanding of crop response to various levels of water stress. This paper presents results from a 3-year study (2004-2006) conducted in northern Syria to quantify cotton yield response to different levels of water and fertilizer. The experiment included four irrigation levels and three levels of nitrogen (N) fertilizer under drip irrigation. The overall mean cotton (lint plus seed, or lintseed) yield was 2502 kg ha -1, ranging from 1520 kg ha -1 under 40% irrigation to 3460 kg ha -1 under 100% irrigation. Mean water productivity (WP ET) was 0.36 kg lintseed per m 3 of crop actual evapotranspiration (ET c), ranging from 0.32 kg m -3 under 40% irrigation to 0.39 kg m -3 under the 100% treatment. Results suggest that deficit irrigation does not improve biological water productivity of drip-irrigated cotton. Water and fertilizer levels (especially the former) have significant effects on yield, crop growth and WP ET. Water, but not N level, has a highly significant effect on crop ET c. The study provides production functions relating cotton yield to ET c as well as soil water content at planting. These functions are useful for irrigation optimization and for forecasting the impact of water rationing and drought on regional water budgets and agricultural economies. The WP ET values obtained in this study compare well with those reported from the southwestern USA, Argentina and other developed cotton producing regions. Most importantly, these WP ET values are double the current values in Syria, suggesting that improved irrigation water and system management can improve WP ET, and thus enhance conservation and sustainability in this water-scarce region.
  • Authors:
    • Fernández-Trujillo, J. P.
    • Provencio, A. B.
    • Martínez-López, J.A.
    • Pérez-Reverte, R.
    • Pérez-Pastor, A.
    • Domingo, R.
    • Robles, J. M.
    • Pagán, E.
  • Source: Acta Horticulturae
  • Issue: 892
  • Year: 2011
  • Summary: The quality of 'Fortune' mandarin fruit ( Citrus clementine Hort. Ex. Tanaka * C. reticulate Blanco) subjected to four different drip irrigation treatments was studied at harvest and after a subsequent storage period of 50 days at 5degreesC plus a shelf-life period of 8 days at 20degreesC. Irrigation treatments consisted of a control (CTL) irrigated at 130% of crop evapotranspiration (ETc) throughout the season, and three regulated deficit irrigation (RDI) regimes. These treatments were irrigated as a CTL except during the non critical periods, when different percentage of the control were applied: 50% during stage I and beginning of stage II in RDI 1 and RDI 2 treatments, and 80 and 200% during stage III in RDI 1 and RDI 2, respectively. RDI 3 was irrigated at 50% of RDI 1 during the water deficit periods. The electrical conductivity of the irrigation water averaged 4.23 dS m -1. RDI treatments promoted a water stress integral, derived from stem water potential at midday values, of 56, 46 and 114 MPa day for RDI 1, RDI 2 and RDI 3, respectively. Fruit at harvest from RDI1 and RDI 3 treatments showed around 15% higher total soluble solids and 11 and 19% higher levels of titratable acidity, respectively than CTL (13.8degreesBrix and 20.3 g L -1 citric acid). RDI fruits showed about 5-10% lower values of extractable juice than control. The storage period reduced fruit titratable acidity compared with harvest levels. Weight loss in control fruit reached 1.4 or 2.3% w/w at the end of cold storage or shelf-life, respectively, while in RDI treatments were reduced by 0.2-0.4% w/w. Overall, the effect of water stress on fruit quality were more pronounced at harvest than after the postharvest treatments. Under water scarcity conditions RDI1 showed acceptable fruit quality at harvest and increased storability of mandarin fruit, saving considerable amounts of water.
  • Authors:
    • Srivastava, A. K.
    • Panigrahi, P.
  • Source: Indian Journal of Soil Conservation
  • Volume: 39
  • Issue: 2
  • Year: 2011
  • Summary: A field experiment was conducted during 2006-08 to assess the response of deficit irrigation (DI) in 16 year old drip-irrigated Nagpur mandarin ( Citrus reticulata) trees budded on Rough lemon ( Citrus jambhiri L.) root stock at Nagpur, Maharashtra. The DI regimes imposed were at 30, 50, and 70% of Full irrigation (FI) and compared with FI (control). The annual increase in vegetative growth parameters (tree height and canopy volume) of trees under FI was found to be superior over DI treatments. The soil moisture status measured at 30 cm, 45 cm and 60 cm depths showed that the mean monthly soil moisture content was significantly affected at 30 cm depth, with highest magnitude (27.6-30.7%, v/v) under FI. Leaf nutrients (N, P, K, Fe, Mn, Cu, and Zn) analysis indicates that FI registered the maximum leaf N, K, and Fe, followed by 70% FI. The highest fruit yield (14.10 t ha -1) recorded under FI was at par with DI at 70% FI (13.35 t ha -1). More number and smaller size of fruits were recorded in FI as compared to DI at 70% FI. However, DI at 70% FI produced 36% higher water productivity with superior quality fruits (more fruit weight, higher TSS and lower acidity) over FI.
  • Authors:
    • Srivastava, A. K.
    • Panigrahi, P.
  • Source: Journal of Agricultural Engineering
  • Volume: 48
  • Issue: 3
  • Year: 2011
  • Summary: A field experiment was conducted during 2006-2008 to optimize the combined use of irrigation and fertilizers through drip irrigation for bearing Nagpur mandarin ( Citrus reticulate Blanco) plants at Nagpur, Maharashtra, India. The irrigation at 50% (I 1), 75% (I 2), and 100% (I 3) of daily class-A pan evaporation rate (Ep) along with 25% (F 1), 50% (F 2) and 75% (F 3) of recommended dose of fertilizers (RDF: 600 g N+100 g P 2O 5+200 g K 2O) were applied through drip emitters to 12 year old mandarin plants. For comparison, band placement of fertilizer (BPF) at 100% RDF under basin irrigation (BI) was taken as control. All the irrigation and fertilizer treatments (except I 1F 1) imposed through drip system produced higher plant growth and fruit yield, with better quality fruits over BI with BPF. The highest fruit yield (16.03 t.ha -1) with superior quality fruits (41.8% juice content, 10.2degreesBrix TSS and 0.82% acidity) was recorded under I 2F 3. Leaf nutrients (N, P, K, Fe, Cu, Zn and Mn) analysis indicated that I 2F 3 registered significantly higher leaf-N (2.15%) and K (1.87%), whereas I 3F 3 produced higher P (0.11%) and Fe (113.99 ppm) as compared with BI with BPF (1.98% N, 0.081% P, 1.64% K, and 93.52 ppm Fe). The study demonstrated that the application of optimum quantity of water and fertilizers (I 2F 3) through drip irrigation saved 50% and 25% of water and fertilizers, respectively, besides producing 60% higher fruit yield with better quality fruits over BI with BPF.
  • Authors:
    • Singh, A. K.
    • Srivastav, M.
    • Dubey, A. K.
    • Patel, S. K.
    • Dahuja, A.
    • Pandey, R. N.
  • Source: The Journal of Horticultural Science & Biotechnology
  • Volume: 86
  • Issue: 2
  • Year: 2011
  • Summary: Seven-month-old, uniform-sized seedlings of five citrus rootstocks [sour orange ( Citrus aurantiam), Attani-2 ( C. rugulosa), Troyer citrange ( C. sinensis * Poncirus trifoliata), billikhichlli ( C. reshni), and RLC-6 ( C. jambhiri)] were irrigated to 70% of field capacity with water containing 0, 50, 100, or 200 mM NaCl for 180 d. Growth, in terms of plant heights and the numbers of leaves, decreased with increasing levels of salinity in all five rootstocks. The decrease in plant height was greatest in the salt-susceptible Troyer citrange and billikhichlli at higher levels of salinity. However, in the salt-tolerant sour orange and Attani-2, NaCl caused only a slight decrease in plant height. Defoliation was maximum in the salt-susceptible Troyer citrange and billikhichlli. The maximum increases in superoxide dismutase (SOD) and peroxidase (POD) activities were found in the salt-susceptible Troyer citrange at higher levels of salinity. Leaf proline contents increased most in Attani-2, sour orange, and RLC-6 at higher levels of salinity. The concentration of Na + ions in leaf tissues increased to a maximum in Attani-2; while, in root tissues, RLC-6 and Troyer had the highest Na + ion contents. The maximum increase in leaf Cl-ion levels occurred in Troyer citrange, and the minimum was in RLC-6, at 200 mM NaCl. These data suggest that higher levels of proline accumulation and leaf abscission could be used as indicators for screening citrus rootstocks for resistance to NaCl stress. Sour orange and Attani-2 were able to exclude Cl-ions, whereas Troyer citrange appeared to exclude Na + ions at lower levels of NaCl. Further studies are required to observe the translocation of harmful and beneficial mineral elements to scion cultivars grafted onto sour orange and Attani-2 and grown under NaCl stress. Overall, salt-tolerance increased in the following order: Troyer