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1.
Summary Irrigated winter barley (Hordeum vulgare L.) can be a profitable alternative to some low profit major crops in the Texas High Plains. A six-year evaluation of yield response related to total spring irrigation water, applied by surface methods (furrow), and seasonal precipitation resulted in a multivariate function explaining 74% of the yield variation. Predicted yields varied from a low of 3.69 Mg ha–1 to a maximum 6.18 Mg ha–1 with 0 and 389 mm, respectively, based on average monthly precipitation quantities. Precipitation is skewed to less than average in th semi-arid Texas High Plains. Using modal precipitation amounts of 40% of average precipitation, yield estimates were reduced to 2.29 Mg ha–1 with zero spring irrigation and to 5.63 Mg ha–1 at the peak with 450 mm. A second multivariate yield response function related to alternative timings of single and multiple spring irrigations explained 76% of the variation in yields. Among all combinations of 1, 2, 3, and 4 spring irrigations, irrigation water-use efficiency was estimated to be highest with one application at the boot stage of development. All other single and combinations of multiple irrigations resulted in lower water-use efficiencies. A comparison of enterprise budgets of four irrigation timing alternatives and levels of application indicated highest profit over variable costs, $ 287 ha–1, was attained by applying a total of 307 mm in three spring applications at the boot, head, and milk stages. A lower level of 217 mm applied at boot and milk stages was $ 12 ha–1 less profitable and a higher level of 425 mm was $ 24 ha–1 less profitable. When fixed costs of irrigation facilities, land, and machinery were considered, returns to management and risk were highest, $ 101 ha–1, with 217 mm. Using 40% of average precipitation, profits were reduced $ 65 ha–1 with 217 mm and $ 69 ha–1 with 307 mm spring irrigation levels.Respectively, agricultural economist, research scientist, and research associate, Texas Agr. Exp. Station, Amarillo, Texas; Emeritus Extension agronomist, Texas Agr. Ext. Service, Amarillo, Texas; agricultural engineer, Texas Agr. Exp. Station, Amarillo, Texas 相似文献
2.
Summary Four irrigation treatments: no irrigation; early irrigation (150 mm); late irrigation (150 mm); and early+late irrigation (275 mm), with 363 mm of rain; and four basic applications of nitrogen (0, 60, 120, 180 kg ha–1), with and without an additional nitrogen top dressing of 60 kg ha–1, were applied to autumn-sown wheat.For any given total nitrogen rate, there was no difference between the single and the split application.Grain yields ranged from 3040 kg ha–1 for the unirrigated, zero-nitrogen treatment to 6340 kg ha–1 for the two irrigations, 180 kg ha –1 N treatment. There was a strong interaction of irrigation and nitrogen on grain yields which was due mainly to the late irrigation: in the absence of the late irrigation the optimal nitrogen rate was 120 kg hat, followed by a marked decline in yield with additional nitrogen, whereas the application of the late irrigation shifted the optimum nitrogen rate to 180 kg ha–1. In the absence of the late irrigation, increasing the nitrogen rate from 0 to 240 kg ha –1 reduced kernel weight from 42 to 32 mg, whereas late irrigation largely prevented this decrease (42 to 39 mg). The reduction in kernel weight was evident even at the first nitrogen increments, in the range where grain yield was still increasing. Lack of nitrogen reduced soil moisture extraction during the grain filling stage, particularly from soil layers deeper than 60 cm.Stomatal aperture in the irrigated treatments was markedly larger in nitrogen-supplied than in nitrogen-deficient wheat, although the leaf hydration was similar; in the unirrigated treatment, the nitrogen-supplied plants had a lower hydration and smaller stomatal aperture than nitrogen-deficient plants.Contribution from the Agricultural Research Organization, Bet Dagan, Israel, No: 282-E, 1977 series 相似文献
3.
Experiments were conducted during the winter seasons of 1983–1984 and 1984–1985 to identify suitable irrigation regimes s for wheat grown after rice in soils with naturally fluctuating shallow water table (SWT) at a depth of 0.4 to 0.9 m and medium water table (MWT) at a depth of 0.8 to 1.3 m. Based on physiological stages, the crop was subjected to six irrigation regimes viz., rainfed (I0); irrigation only at crown root initiation (I1); at only crown root initiation and milk (I2); at crown root initiation, maximum tillering and milk (I3); at crown root initiation, maximum tillering, flowering and milk (I4); and at crown root initiation, maximum tillering, flowering milk and dough (I5). Tube-well water with an EC <0.4 dsm–1 was used for irrigation. Based on 166 mm effective precipitation during the cropping season, 1983–1984 was designated as a wet year and 1984–1985 with 51 mm as a dry year. The change in profile soil water content W (depletion) in the wet year was less (23%) under SWT and 10% under MWT as compared to the dry year. The ground water contribution (GWC) to evapotranspiration (ET) was 58% under SWT and 42% under MWT conditions in both the years. The GWC in the wet year was 20% under SWT and 23% under MWT. Of the total net water use (NWU), about 85% was ET and 15% drainage losses. The NWU was highest (641 and 586 mm) in I5 under SWT and MWT conditions, respectively, but not the yield (5069 kg ha–1). Compared to I5, NWU in I2 treatment decreased by 10% in the wet and 25% in the dry year. A similar trend was observed in the I3 treatment under MWT condition. However, there was no statistically significant difference between yields of the I1 to I5 treatments of either water table depth during the wet year. This was also true during the dry year for the I2 to I5 treatments. Under SWT, in I2, the grain yield was 5130 kg ha–1 and under I3 regime, 5200 kg ha–1. Under MWT in I3, the yield was 5188 kg ha–1 and under I4 regime, 5218 kg ha–1. Thus it appears that in the Tarai region where the water table remains shallow (<0.9 m) and medium (<1.3 m) for most of the wheat growing season applications of more than 120 and 180 mm irrigation under SWT and MWT conditions, respectively were not necessary. Irrigation given only at crown root initiation and milk stages under shallow water table conditions, and at crown root initiation, maximum tillering and milk stages under medium water table conditions, appears to be as effective as frequent irrigations. 相似文献
4.
Anil Kumar Singh Rojalin Tripathy Usha Kiran Chopra 《Agricultural Water Management》2008,95(7):776-786
Crop simulation models can provide an alternative, less time-consuming and inexpensive means of determining the optimum crop N and irrigation requirements under varied soil and climatic conditions. In this context, two dynamic mechanistic models (CERES (Crop Environment REsource Synthesis)-Wheat and CropSyst (Cropping Systems Simulation Model)) were validated for predicting growth and yield of wheat (Triticum aestivum L) under different nitrogen and water management conditions. Their potential as N and water management tool was evaluated for New Delhi representing semi-arid irrigated ecosystems in the Indo-Gangetic Plains. The field experiment was carried out on a silty clay loam soil at the Research Farm of the Indian Agricultural Research Institute, New Delhi, India during 2000–2001 to collect the input data for the calibration and validation of both the models on wheat crop (variety HD 2687). The models were evaluated for three water regimes [I4 (4 irrigations within the growing season), I3 (3 irrigations within the growing season) and I2 (2 irrigations within the growing season)] and five N treatments (N0, N60, N90, N120 and N150). Both the models were calibrated using data obtained from the treatments receiving maximum nitrogen and irrigations, i.e., N150 and I4 treatments. The models were then validated against other water and nitrogen treatments. For performance evaluation, in addition to coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE) and Wilmot's index of agreement (IoA) were estimated. Both CERES-Wheat and CropSyst provided very satisfactory estimates for the emergence, flowering and physiological maturity dates. For CERES-Wheat overall prediction (pooled result of the three water regimes) of grain yield was satisfactory with significant R2 values (0.88). The model, however, under estimated the biomass under all water regimes and N levels except for N0 level, under which biomass was overpredicted. CropSyst predicted yield and biomass of wheat more closely than CERES-Wheat. The combined RMSE for the three water regimes between predicted and observed grain yield was 0.36 Mg ha−1 for CropSyst as compared to 0.63 Mg ha−1 for CERES-Wheat. Similarly, RMSE between observed and predicted biomass by CropSyst was 1.27 Mg ha−1 as compared to 1.94 Mg ha−1 between observed and predicted biomass by CERES-Wheat. Wilmot's index of agreement (IoA) also indicated that CropSyst model is more appropriate than CERES-Wheat in predicting growth and yield of wheat under different N and irrigation application situations in this study. 相似文献
5.
Summary The effect of the soil water potential on pod yield of snap beans grown with a series of irrigation frequencies was studied over two seasons. The treatments were to furrow-irrigate either weekly or fortnightly during the preflowering period, and each treatment then received weekly or fortnightly irrigations to harvest. These treatments were compared with trickle irrigation applied daily in the first season and every second day in the second season. The irrigation frequencies during the pre-flowering period did not influence the pod yield. However, in the second season plants given the trickle irrigation treatment produced more early flowers and set pods earlier than those in the other treatments. Consequently the pods were harvested three days earlier from plants on this treatment.Pod yield was determined by the irrigation treatments applied after flowering. The highest yield was similar in each season (16.7 t ha–1) and was produced under trickle irrigation. Fortnightly irrigations during the pod-fill phase reduced yield by 56% in the first season and 41% in the second season when compared with trickle irrigation. The pod yield was reduced by 0.5 t ha–1 each day the soil water potential at 30 cm depth was less than –50 kPa. This relationship accounted for about 77% of the variation in pod yield. 相似文献
6.
High evaporative demand and limited precipitation restrict the yield of winter wheat (Triticum aestivum L.) grown in the Loess Plateau of China under semiarid climatic conditions. Grain yield can be improved by effective water management practices. A 13-year field experiment was conducted at the CERN Changwu Agro-ecological Experimental Station of the Loess Plateau to determine optimal irrigation strategies under limited water supply and to develop relationships among grain yield (Y), seasonal evapotranspiration (SET) and water-use efficiency (WUE). The experiment consisted of five irrigation treatments and three blocks. Measurements included grain yield, soil water content at various depth intervals in the 0–3,000 mm layer, irrigation amount, and precipitation. Results showed that winter wheat grown in this area experienced serious water stress during critical growth stages for the no-irrigation treatment. The amount and timing of irrigation had an important effect on grain yield, but significant differences in yield were not observed between the three-irrigation and the four-irrigation treatments. Grain yield was linearly related (R2=0.66) to SET, but differences in WUE were not significant for any of the treatments. The relationship between WUE and Y was best represented by a second order polynomial (R2=0.65) consisting of a nearly linear portion between 1.5 and 5.0 Mg ha–1. Optimum water management of winter wheat in the Loess Plateau should consist of three 87.5 mm irrigations applied at stem elongation, booting, and anthesis.Communicated by J.E. Ayars 相似文献
7.
Effect of irrigation application depth on cereal production in the semi-arid climate of southern Alberta 总被引：2，自引：0，他引：2
Different water application depths and irrigation intervals were compared for two cereal crops in southern Alberta. Four irrigation treatments and three fertilizer N treatments were applied to soft white wheat in 1987 and 1988 and barley in 1989 and 1990 on a Lethbridge loam. The treatments were light, frequent irrigation for the whole growing season (F), conventional irrigation for the whole growing season (C), light, frequent irrigation until heading, followed by conventional irrigation (FC), and conventional irrigation until heading, followed by light, frequent irrigation (CF). Fertilizer N as ammonium nitrate was broadcast in the spring at 0, 60 and 120 kg N ha-1. Light frequent irrigations for the entire growing season increased wheat straw yield compared to the conventional irrigation treatment (5211kg ha-1 vs 4152 kg ha-1, respectively). Straw yield with F irrigation for part of the growing season was intermediate between the other two irrigation treatments. Irrigation treatment did not affect soft white wheat grain yield. Barley straw yield was not affected by irrigation treatment but barley grain yield was greater for the C irrigation treatment than the F and FC treatments (4924 kg ha-1 vs 4177 kg ha-1, respectively). Lodging was evident in the barley crops, particularly with F irrigation in the first half of the growing season. Grain/straw ratios were greater for the C than the other irrigation treatments. Higher water use in the F than the C treatment in the higher water stress years (1988 and 1989) was balanced with greater vegetative growth. In the lower water stress growing seasons (1987 and 1990), higher water use in the C than the F treatment was attributed to deep percolation. Water use efficiency (WUE) was generally not affected by irrigation treatment except for barley in 1989, when lower WUE values in the F than the C treatment were associated with severe lodging. 相似文献
8.
Summary Cotton was grown under sprinkler irrigation on a silty clay soil at Keiser, Arkansas, for the 1987, 1988 and 1989 growing seasons. Irrigation treatments consisted of maximum soil water deficits (SWD) of 25, 50 and 75 mm and a nonirrigated control. While the irrigated treatments were significantly different from the control for plant height and total seedcotton yield, significant differences among the three irrigated treatments were only observed for plant height. Yields were significantly lower in 1989 than in the other two years of the study, due in part to later planting. The 3-year averages for total seedcotton yield were 3280 and 2870 kg ha–1 for irrigated and nonirrigated, respectively, for an average increase corresponding to irrigation of 416 kg ha–1 or 14.5% of the nonirrigated yield. The maximum increase was observed in 1988 as 602 kg ha–1 or 20.6% of the nonirrigated yield for that year. The 75 mm allowable SWD was the most efficient treatment and resulted in a 3-year average of 3.85 kg ha–1 additional seedcotton (above the nonirrigated) harvested for each 1 mm of irrigation applied. Maintaining the SWD below a 75 mm maximum required an average of four irrigations and 110 mm of irrigation water per year. 相似文献
9.
Evaluation on the irrigation and fertilization management practices under the application of treated sewage water in Beijing, China 总被引：3，自引：0，他引：3
Irrigation and fertilization management practices play important roles in crop production. In this paper, the Root Zone Water Quality Model (RZWQM) was used to evaluate the irrigation and fertilization management practices for a winter wheat–summer corn double cropping system in Beijing, China under the irrigation with treated sewage water (TSW). A carefully designed experiment was carried out at an experimental station in Beijing area from 2001 to 2003 with four irrigation treatments. The hydrologic, nitrogen and crop growth components of RZWQM were calibrated by using the dataset of one treatment. The datasets of other three treatments were used to validate the model performance. Most predicted soil water contents were within ±1 standard deviation (S.D.) of the measured data. The relative errors (RE) of grain yield predictions were within the range of −26.8% to 18.5%, whereas the REs of biomass predictions were between −38% and 14%. The grain nitrogen (N) uptake and biomass N uptake were predicted with the RE values ranging from −13.9% to 14.7%, and from −11.1% to 29.8%, respectively. These results showed that the model was able to simulate the double cropping system variables under different irrigation and fertilization conditions with reasonable accuracy. Application of RZWQM in the growing season of 2001–2002 indicated that the best irrigation management practice was no irrigation for summer corn, three 83 mm irrigations each for pre-sowing, jointing and heading stages of winter wheat, respectively. And the best nitrogen application management practice was 120 kg N ha−1 for summer corn and 110 kg N ha−1 for winter wheat, respectively, under the irrigation with TSW. We also obtained the alternative irrigation management practices for the hydrologic years of 75%, 50% and 25%, respectively, in Beijing area under the conditions of irrigation with TSW and the optimal nitrogen application. 相似文献
10.
Irrigation and tillage effects on root development,water use and yield of wheat on coarse textured soils 总被引：3，自引：0，他引：3
Summary Rapid drying of surface layers of coarse-textured soils early in the growth season increases soil strength and restricts root growth. This constraint on root growth may be countered by deep tillage and/or early irrigation. We investigated tillage and irrigation effects on root growth, water use, dry matter and grain yield of wheat on loamy sand and sandy loam soils for three years. Treatments included all combinations of two tillage systems i) conventional tillage (CT) — stirring the soil to 10 cm depth, ii) deep tillage (DT) — subsoiling with a single-tine chisel down to 35–40 cm, 40 cm apart followed by CT; and four irrigation regimes, i) I0 — no post-seeding irrigation, ii) I1 — 50 mm irrigation 30 days after seeding (DAS), iii) I2 — 50 mm irrigation 30 DAS and subsequent irrigations of 75 mm each when net evaporation from USWB class A open pan (PAN-E) since previous irrigation accumulated to 82 mm, and iv) I3 — same as in I2 but irrigation applied when PAN-E accumulated to 62 mm. The crop of wheat (Triticum aestivum L. HD 2329) was fertilized with 20kg P, 10kg K and 5kg Zn ha–1 at seeding. The rate of nitrogen fertilization was 60 kg ha–1 in the unirrigated and 120 kg ha–1 in the irrigated treatments. Tillage decreased soil strength and so did the early post-seeding irrigation. Both deep tillage and early irrigation shortened the time needed for the root system to reach a specified depth. Subsequent wetting through rain/irrigation reduced the rate of root penetration down the profile and also negated deep tillage effects on rooting depth. However, tillage/irrigation increased root length density in the rooted profile even in a wet year. Better rooting resulted in greater profile water depletion, more favourable plant water status and higher dry matter and grain yields. In a dry year, the wheat in the DT plots used 46 mm more water, remained 3.3 °C cooler at grain-fill and yielded 68% more grain than in CT when unirrigated and grown in the loamy sand. Early irrigation also increased profile water depletion, more so in CT than DT. Averaged over three years, grain yield in DT was 12 and 9% higher than in CT on loamy sand and sandy loam, respectively. Benefits of DT decreased with increase in rainfall and irrigation. Irrigation significantly increased grain yield on both soils, but the response was greatly influenced by soil type, tillage system and year. The study shows that soil related constraints on root growth may be alleviated through deep tillage and/or early irrigation. 相似文献
11.
The effect of irrigation and nitrogen fertilizer on rapeseed (Brassica napus) production in South-Eastern Australia 总被引：1，自引：0，他引：1
Summary A field trial was conducted to determine the response of rapeseed (Brassica napus cv. Marnoo) to two irrigation treatments and six nitrogen fertilizer treatments. Response to nitrogen was greater with than without irrigation. Oil content was increased with irrigation but decreased under increasing nitrogen application, and was inversely related to seed nitrogen concentration. Oil yields averaged 1,168 kg ha–1 under irrigated treatments compared with 835 kg ha–1 under rainfed treatments. Maximum oil yield (approx. 1,557 kg ha–1) was obtained from the irrigated treatment fertilized with 100 kg N ha–1 applied at sowing. 相似文献
12.
The reported study aimed at developing an integrated management strategy for irrigation water and fertilizers in case of wheat crop in a sub-tropical sub-humid region. Field experiments were conducted on wheat crop (cultivar Sonalika) during the years 2002–2003, 2003–2004 and 2004–2005. Each experiment included four fertilizer treatments and three irrigation treatments during the wheat growth period. During the experiment, the irrigation treatments considered were I1 = 10% maximum allowable depletion (MAD) of available soil water (ASW); I2 = 40% MAD of ASW; I3 = 60% MAD of ASW. The fertilizer treatments considered in the experiments were F1 = control treatment with N:P2O5:K2O as 0:0:0 kg ha−1, F2 = fertilizer application of N:P2O5:K2O as 80:40:40 kg ha−1; F3 = fertilizer application of N:P2O5:K2O as 120:60:60 kg ha−1 and F4 = fertilizer application of N:P2O5:K2O as 160:80:80 kg ha−1. In this study CERES-wheat crop growth model of the DSSAT v4.0 was used to simulate the growth, development and yield of wheat crop using soil, daily weather and management inputs, to aid farmers and decision makers in developing strategies for effective management of inputs. The results of the investigation revealed that magnitudes of grain yield, straw yield and maximum LAI of wheat crop were higher in low volume high frequency irrigation (I1) than the high volume low frequency irrigation (I3). The grain yield, straw yield and maximum LAI increased with increase in fertilization rate for the wheat crop. The results also revealed that increase in level of fertilization increased water use efficiency (WUE) considerably. However, WUE of the I2 irrigation schedule was comparatively higher than the I1 and I3 irrigation schedules due to higher grain yield per unit use of water. Therefore, irrigation schedule with 40% maximum allowable depletion of available soil water (I2) could safely be maintained during the non-critical stages to save water without sacrificing the crop yield. Increase in level of fertilization increases the WUE but it will cause environmental problem beyond certain limit. The calibrated CERES-wheat model could predict the grain yield, straw yield and maximum LAI of wheat crop with considerable accuracy and therefore can be recommended for decision-making in similar regions. 相似文献
13.
《Agricultural Water Management》2001,49(3):225-237
In West Asia and North Africa (WANA) including northwest (NW) Iran irrigation is becoming increasingly available and investigation of the effect of limited irrigation (LI) is a research need. Only a few seasons of successful experimentation exist with LI effects. Thus, the objective of this simulation study was to examine potential long-term benefits of limited irrigation in NW Iran in terms of grain yield. To do this, a simple, mechanistic chickpea (Cicer arietinum L.) model and 16 years of weather data of Maragheh (NW Iran) were used. Three LI systems with one, two and three irrigations and each with three plant population densities (25, 38 and 50 plants m−2) were simulated. Results showed chickpea crop experiences terminal drought stress that is started at a time between flowering and beginning seed growth (BSG). This terminal drought stress severely reduces grain yield by 67%, from 2766 kg ha−1 under full-irrigated conditions to 909 kg ha−1 under rainfed conditions. Grain yield was significantly increased with LI compared to rainfed conditions. Grain yields were reached to 60, 75 and 90% of grain yield simulated under full-irrigated (generally requires five irrigations) conditions. In LI with one irrigation its application at BSG, and in LI with two and three irrigations, application of first irrigation at flowering and application of one or two other irrigations when fraction of transpirable soil water dropped to 0.5 in the root zone resulted in higher grain yield. Water use efficiency was, also, increased with LI by 28, 39 and 52% for one, two and three irrigations, respectively. In LI systems with two and three irrigations it was required to a higher plant density (38 or 50 plants m−2) to capture and to use applied water more efficiently. 相似文献
14.
Evaluation of options for increasing yield and water productivity of wheat in Punjab, India using the DSSAT-CSM-CERES-Wheat model 总被引：1，自引：0，他引：1
J. Timsina D. Godwin E. Humphreys Yadvinder-Singh Bijay-Singh S.S. Kukal D. Smith 《Agricultural Water Management》2008,95(9):1099-1110
The DSSAT-CSM-CERES-Wheat V4.0 model was calibrated for yield and irrigation scheduling of wheat with 2004–2005 data and validated with 13 independent data sets from experiments conducted during 2002–2006 at the Punjab Agricultural University (PAU) farm, Ludhiana, and in a farmer's field near PAU at Phillaur, Punjab, India. Subsequently, the validated model was used to estimate long-term mean and variability of potential yield (Yp), drainage, runoff, evapo-transpiration (ET), crop water productivity (CWP), and irrigation water productivity (IWP) of wheat cv. PBW343 using 36 years (1970–1971 to 2005–2006) of historical weather data from Ludhiana. Seven sowing dates in fortnightly intervals, ranging from early October to early January, and three irrigation scheduling methods [soil water deficit (SWD)-based, growth stage-based, and ET-based] were evaluated. For the SWD-based scheduling, irrigation management depth was set to 75 cm with irrigation scheduled when SWD reached 50% to replace 100% of the deficit. For growth stage-based scheduling, irrigation was applied either only once at one of the key growth stages [crown root initiation (CRI), booting, flowering, and grain filling], twice (two stages in various combinations), thrice (three stages in various combinations), or four times (all four stages). For ET-driven irrigation, irrigations were scheduled based on cumulative net ETo (ETo-rain) since the previous irrigation, for a range of net ETo (25, 75, 125, 150, and 175 mm). Five main irrigation schedules (SWD-based, ET-driven with irrigation applied after accumulation of either 75 or 125 mm of ETo, i.e., ET75 or ET125, and growth stage-based with irrigation applied at CRI plus booting, or at CRI plus booting plus flowering stage) were chosen for detailed analysis of yield, water balance, and CWP and IWP. Nitrogen was non-limiting in all the simulations.Mean Yp across 36 years ranged from 5.2 t ha−1 (10 October sowing) to 6.4 t ha−1 (10 November sowing), with yield variations due to seasonal weather greater than variations across sowing dates. Yields under different irrigation scheduling, CWP and IWP were highest for 10 November sowing. Yields and CWP were higher for SWD and ET75-based irrigations on both soils, but IWP was higher for ET75-based irrigation on sandy loam and for ET150-based irrigation on loam. Simulation results suggest that yields, CWP, and IWP of PBW343 would be highest for sowing between late October and mid-November in the Indian Punjab. It is recommended that sowing be done within this planting period and that irrigation be applied based on the atmospheric demand and soil water status and not on the growth stage. Despite the potential limitations recognised with simulation results, we can conclude that DSSAT-CSM-CERES-Wheat V4.0 is a useful decision support system to help farmers to optimally schedule and manage irrigation in wheat grown in coarse-textured soils under declining groundwater table situations of the Indian Punjab. Further, the validated model and the simulation results can also be extrapolated to other areas with similar climatic and soil environments in Asia where crop, soil, weather, and management data are available. 相似文献
15.
《Agricultural Water Management》2006,79(3):312-320
Shrinking water resources in northwest India calls for diversification from a rice–wheat cropping system to low-water-requiring crops and development of water-efficient technologies in Punjab state. Chickpea, because of its lower water demand (evapotranspiration) and irrigation requirement has been identified as a suitable alternate crop to wheat. Simulations, averaged over 18 years, using the CROPMAN model indicated that the yield of chickpea on coarse- to medium-textured soils was higher in a rice–chickpea cropping system compared with maize–chickpea and mung–chickpea systems because of increased availability of water. Yield response of chickpea to irrigation depended upon soil texture, the timings and number of irrigations. The optimum yield (2 t ha−1) on coarse- to medium-textured soils after rice can be obtained with one heavy pre-plant and two post-plant irrigations, i.e., one in mid-February and one in mid-March synchronizing irrigations with flowering and grain development stages. Grain yield with irrigation water followed a quadratic function and linear with evapotranspiration. Water use efficiency and evapotranspiration was curvilinear. Grain yield was significantly sensitive to water stress during the pod setting to grain development period irrespective of soil texture. 相似文献
16.
The growth and nitrogen economy of rice under sprinkler and flood irrigation in South East Australia
E. Humphreys W. A. Muirhead F. M. Melhuish R. J. G. White J. Blackwell 《Irrigation Science》1989,10(3):201-213
Summary Dry-seeded rice (Oryza sativa L., cv. Calrose) was subjected to 4 irrigation treatments — continuous flood (CF) and sprinkler irrigation at frequencies of one (S1 W), two (S2W) and three (S3W) applications per week — commencing 37 d after 50% emergence (DAE). The amount of water applied was calculated to replace water lost by pan evaporation. Urea (120 kg N ha–1) was applied in a 1:1 split 36 and 84 DAE, and there were also unfertilized controls for each irrigation treatment. Amounts of nitrate (NO
3
–
) in the soil were very low throughout the growing season in all treatments, despite regular periods of draining which lasted for up to 7 d in SlW. In all irrigation treatments, the majority of the fertilizer nitrogen (N) was located in the top 20 mm of soil. After each application of fertilizer, levels of mineral N in CF declined rapidly, while levels in S3W and S1W remained high for 1–2 weeks longer. The poor growth of sprinkler-irrigated rice was not due to lower amounts of mineral N in the soil. The greater persistence of fertilizer N in the sprinkler-irrigated treatments was probably due to reduced root activity near the soil surface because of frequent periods of soil drying in between irrigations. Net mineralization of soil N in the unfertilized sprinkler-irrigated treatments was reduced by about half compared with CF.On average, the quantity of water applied (1.2–1.4 × EP) to the sprinkler-irrigated treatments appeared to be sufficient to meet the evapotranspiration demands of the crop, except possibly around flowering time. However, the plants may have suffered from moisture stress in between irrigations. Soil matric potential data at 100 mm suggested little water stress in the sprinkler-irrigated treatments during the vegetative stage, consistent with the similar tiller and panicle densities in all irrigation treatments. However, the crop was stunted and yellow and leaf rolling was observed in the sprinkler-irrigated treatments during this period. Soil matric potential data at 100 mm indicated considerable water stress in S1W beyond the commencement of anthesis, and in S2W during grain filling, consistent with the reduced floret fertility and grain weight in those treatments. 相似文献
17.
Summary Empirical functions to predict the nitrogen uptake, increase in LAI and minimum leaf water potential (LWP) of cotton were incorporated into a water balance model for the Namoi Valley, N.S.W. A function was then developed to describe the lint yield of irrigated cotton as a function of water stress days at 4 stages of development, total nitrogen uptake and days of waterlogging. A water stress day was defined as predicted minimum leaf water potential less than -1.8 MPa up to 90 days after sowing and -2.4 MPa there-after; stress reduced yield by up to 40 kg lint ha–1 d–1 with greatest sensitivity at 81–140 days after sowing and when N uptake was highest. Nitrogen uptake was reduced by 0.98 kg per ha and yield reduced by 33.2 kg lint ha–1 for each day of waterlogging. The model was used to evaluate various irrigation strategies by simulating production of cotton from historical rainfall data. With a water supply from off farm storage, net returns ($ M1–1) were maximized by allocating 7 Ml ha–1 of crop. The optimum practice was not to irrigate until 60 days from sowing and until the deficit in the root zone reached 50%. When the supply of water was less than 7 Ml ha–1 there was no advantage in either delaying the start of irrigation or irrigating at a greater deficit; it was economically more rational to reduce the area shown or, if already sown, to irrigate part with 6 Ml ha–1 and leave the rest as a raingrown crop. Irrigation decisions are compromises between reducing the risk of water stress and increasing the risk of waterlogging. The simulation showed that there is no single set of practices that is always best in every season; in a number of seasons practices other than those which on average are best, give better results. 相似文献
18.
The fate of nitrogen applied to sugarcane by trickle irrigation 总被引：1，自引：0，他引：1
Peter J. Thorburn Ian K. Dart Ian M. Biggs Craig P. Baillie Mike A. Smith Brian A. Keating 《Irrigation Science》2003,22(3-4):201-209
Fertigation can be a more efficient means of applying crop nutrients, particularly nitrogen (N), so that nutrient application rates can be reduced in fertigated crops. However, there is little information on the extent of the possible reduction in N application rate for fertigated sugarcane, one of the major row crops grown under trickle irrigation, nor the fate of N in fertigated sugarcane systems if N application rates are not reduced. An experiment was established to determine the response of cane and sugar production to different N rates (0–240 kg ha–1 year–1) spanning that recommended for conventional irrigation systems (160 kg ha–1 year–1). As well as yield, N removed in the crop and changes in soil mineral N were determined annually for four crops (a plant and three ratoon crops). 15N values were also measured in selected treatments at selected times to assess possible N inputs to the experiment via biological N fixation (BFN). Yields of cane and sugar responded to application of N fertiliser in the three ratoon crops, but they were not significantly increased by applying more than 80 kg ha–1 of N. There were no N responses in the plant crop, as there was >200 kg ha–1 of soil mineral N (SMN) to 2 m depth at the site prior to planting, and much of this SMN was depleted in the treatment receiving no N. There was no evidence of N input from BFN in the experiment. During the 4-year study period, net removal of N from the treatment with no applied N totalled 207 kg ha–1. When 80 or 120 kg ha–1 year–1 of N was applied to ratoon crops, outputs of N from the harvested crop approximately balanced inputs from fertiliser and depletion of SMN during the experiment. Inputs clearly exceeded output at higher N application rates. Assuming that the net removal of N from the treatment with no applied N was the same as the net mineralisation of N from soil organic matter in all treatments in the experiment, 204–639 kg ha–1 of N was unaccounted for in the treatments with applied N over the duration of the experiment. While some of this N (e.g. 45 kg ha–1) may have resulted in small (and undetectable) increases in total soil N, much of it would have been lost to the environment. We suggest that the high soil water contents maintained with daily application of irrigation water through the trickle system promotes mineralisation of soil organic matter and hence losses of N to the environment. Thus, particular care is required to avoid over-application of N in fertigated sugarcane.Communicated by K. Bristow 相似文献
19.
Summary A field trial was conducted to determine the response of rapeseed (Brassica napus cv. Marnoo) to two irrigation treatments and six nitrogen fertilizer treatments. Dry matter accumulation, leaf area development and seed yield were measured. The dry matter and seed yield response to applied nitrogen was greater under irrigated compared to rainfed conditions. Maximum seed yield (approx. 3.8 t ha–1) was obtained from the irrigated treatment receiving 100 kg N ha–1 applied at sowing. This high rate of N application at sowing led to more rapid leaf area development and higher maximum LAI compared to treatments supplied with split application of the same amount of N at sowing and rosette stages. Greater partitioning of dry matter into the leaf component and higher specific leaf areas under the higher N regime were largely responsible for this increase. Higher maximum LAI's were associated with greater numbers of pods per plant, which combined with longer leaf area duration led to higher final seed yields. 相似文献
20.
Ali Osman Demir Abdurrahim Tanju Göksoy Hakan Büyükcangaz Zeki Metin Turan Eyüp Selim Köksal 《Irrigation Science》2006,24(4):279-289
The response of sunflower (Helianthus annuus L.) to 14 irrigation treatments in a sub-humid environment (Bursa, Turkey) was studied in the field for two seasons. A rainfed (non-irrigated) treatment as the control and 13 irrigation treatments with full and 12 different deficit irrigations were applied to the hybrid Sanbro (Novartis Seed Company) planted on clay soil, at three critical development stages: heading (H), flowering (F) and milk ripening (M). The yield increased with irrigation water amount, and the highest seed yield (3.95 t ha−1) and oil yield (1.78 t ha−1) were obtained from the HFM treatment (full irrigation at three stages); 82.9 and 85.4% increases, respectively, compared to the control. Evapotranspiration (ET) increased with increased amounts of irrigation water supplied. The highest seasonal ET (average of 652 mm) was estimated at the HFM treatment. Additionally, yield response factor (k
y) was separately calculated for each, two and total growth stages, and k
y was found to be 0.8382, 0.9159 (the highest value) and 0.7708 (the lowest value) for the total growing season, heading, and flowering-milk ripening combination stages, respectively. It is concluded that HFM irrigation is the best choice for maximum yield under the local conditions, but these irrigation schemes must be re-considered in areas where water resources are more limited. In the case of more restricted irrigation, the limitation of irrigation water at the flowering period should be avoided; as the highest water use efficiency (WUE) (7.80 kg ha−1 mm−1) and irrigation water use efficiency (IWUE) (10.19 kg ha−1 mm−1) were obtained from the F treatment. 相似文献