Effect Of Irrigation Scheduling Research Articles

Analysis of an irrigation district in northeastern Spain: II. Irrigation evaluation, simulation and scheduling

In the first paper of this series, the Loma de Quinto Irrigation District (LQD) was characterised, and water use was assessed. In this work, the analysis of the LQD is completed with field irrigation evaluations, solid-set sprinkler irrigation simulations and irrigation scheduling for optimal crop yield. The results of the irrigation evaluations indicated that the average Christiansen coefficient of uniformity (CU) for solid-sets, centre-pivots and linear-moves was 68.0, 75.5, and 80.0%, respectively. In solid-sets CU was severely reduced by wind speed. However, in centre-pivots and linear-moves CU was higher in evaluations with wind speeds between 2 and 6 m s −1 than under calm conditions. The evaluation data set was used to validate a ballistic solid-set sprinkler irrigation simulation model. The performance variables used for model validation were CU and the potential application efficiency of the low quarter (PAE lq). Both variables were adequately predicted in the range of the observed values. The model was used to extend the evaluation results to all the solid-set plots in the LQD. CU maps were produced for different wind speeds and operating pressures. These maps can be used to identify plots with low irrigation performance. The effect of irrigation scheduling on crop yield and net benefit was analysed using the CropWat simulation model. Simulations of the 1997 irrigation practices performed on a limited number of plots detected a 12% decrease in crop yield due to deficit irrigation and/or large irrigation intervals. The introduction of an optimal irrigation schedule (avoiding yield reductions) would imply increasing the alfalfa seasonal irrigation depth by 101 mm, and applying light, frequent irrigation events. Due to labour scarcity in the LQD, the implementation of the optimal schedule would require a high degree of irrigation automation, which is currently unavailable. Taking into consideration the value of the additional yield and the costs of the extra irrigation water depth and the automation devices, the resulting net benefit would be 50 ▪ ha −1. The purpose of this analysis of the LQD is to contribute to the diagnostic analysis phase of an incipient Management Improvement Program at the LQD. In order to complete this phase, an interdisciplinary committee will perform a study not just on irrigation but on a wide scope of irrigated agriculture in the LQD.

Effect of irrigation scheduling on potato crop parameters under water stressed conditions

Field experiments were conducted on a local cultivar, Kufri-Jyoti, of potato crop during the four winter seasons of 1995–1996 through 1998–1999. Five irrigation treatments were maintained based on the maximum allowable depletion (MAD) of available soil water (ASW). The treatments were 10% ( T 1), 30% ( T 2), 45% ( T 3), 60% ( T 4) and 75% ( T 5) MAD of ASW during non-critical stages of crop growth. Measurements of fresh tuber yield, dry tuber yield, plant dry matter (including roots but not tubers), total dry matter and leaf area index were made at various stages of crop growth during all four crop experiments. Fresh tuber yield of potato was significantly higher under high frequency than low frequency irrigation. With delayed irrigation, the yield reduced significantly under T 4 and T 5, which resulted in minimum fresh tuber yield and total dry matter yield during all four experiments. With increase in MAD from 45 to 75%, the fresh tuber yield reduced considerably due to reduction in the availability of water. A similar trend was observed for other crop parameters. Crop production functions with respect to crop water use were developed for five measures of plant growth; they were found to be linear. Though the results of the study are applicable for sub-humid sub-tropical climatic conditions with sandy loam soils as that of the study area, the objective methodology developed has universal applicability.

Effect of irrigation scheduling and other agronomic manipulations on yield and water economy in sugarcane

An experiment was conducted during 1988-1989 and 1989-1990 at Main Sugarcane Research Station, Sehore, to evaluate the effect of different irrigation management practices and inigation (IW : CPE) ratio on yield and water economy of sugarcane (Saccharum officinarum L.). Yield, yield attributes and quality of the cane varied significantly. Jnlshokti 20 kg with irrigation in all the rows and full trash mulch with alternate row irrigation proved better than other practices. An IW : CPE ratio of 0.8 was better than that of 0.5. The net realization (Rsha-mrn of water applied) was considerably high under full trash mulch with alternate row irrigation at 0.5 IW : CPE ratio.

Effect of irrigation scheduling and fertigation on nutrient and water-use efficiency in drip-irrigated direct-seeded rice (Oryza sativa)

A field experiment was conducted during the rainy (kharif) seasons of 2016 and 2017 at Gangavathi, Raichur, Karnataka, to study the effect of irrigation scheduling and fertigation on nitrogen and water-use efficiency of drip-ir- rigated direct-seeded rice (Oryza sativa L.) in clay soil. The experiment laid out in split-plot design with 4 irrigation scheduling based on irrigation water : cumulative pan evaporation (IW : CPE) ratios assigned to main plots and 4 drip fertigation levels were allocated in subplots and replicated thrice. Irrigation scheduling at an IW : CPE ratio of 1.50 recorded significantly higher nutrient-use efficiency, viz. nitrogen (35.2 kg/kg), phosphorus (85.4 kg/kg) and potassium (102.5 kg/kg) and but lower water-use efficiency (7.69 kg/ha-mm) and water productivity (0.61 kg/m3). Among the drip fertigation levels, drip fertigation at 75% recommended dose of nitrogen (RDN) recorded higher ni- trogen-use efficiency (41.5 kg/kg). Treatment of 125% RDN resulted in higher phosphorus-use efficiency and po- tassium-use efficiency (84.1 and 101.0%, respectively) and water-use efficiency and water productivity (7.22 kg/ ha-mm and 0.59 kg/m3 respectively).

Effect of irrigation schedule and phosphorus on yield attributes and yield of field pea (Pisum sativum)

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Effect of irrigation scheduling on yield of safflower (Cartlzarnus tinctorius)

Effect of irrigation scheduling on yield of safflower (Cartlzarnus tinctorius)

Effect of irrigation schedule and trash mulch on growth, yield and economics of sugarcane (Saccharum oflcinarum) ratoon

An experiment was conducted during 1998 99 and 1999 2000 at Agricultural Research Station, Rajasthan Agriculture University, Sriganganagar, to study the effect of irrigation schedule and trash mulch on Co 66 17 sugarcane (Saccharum officinarum L.) ratoon. The cane yields of 498.6 and 499.8 qtha recorded, respectively, at IW : CPE of 0.9 (18 irrigations) and 1.2 (23 irrigations) were at par and significantly superior to that of 0.6 ratio and irrigations applied at 21 day interval. Trash mulching at 6 tonnestha resulted in significantly higher cane yield (566.5 qtha) over mulching at 3 tonnestha (493.8 qtha) and no mulch cbntrol (410.8 qtha). Irrigation scheduled at 0.9 1W:CPE along with trash mul ching at 6 tonneslha recorded the highest cane yield (574.0 qtha) as well as 23% saving in irrigation water. The water use efficiency and net return per unit quantity of water applied decreased markedly with an increase of irrigation regime from IW: CPE of 0.6 to 1.2. Benefit :cost ratio, net returns, and water use efficiency increased substantially with trash mulching.

Effect of irrigation schedule on yield, water use and oil content of toria (Brassica napus var napus)

A field experiment was conductcd during 1987--88 1989-90 to on sandy-loam soil at Sriganganagar, to study the effect of irrigation schedule on yield6, water use and oil content of torin (Brmsica napus L. var. napus sensu stricto; syn. 23. conrpestris Hook. f. Tho* vva COM Duthie &Fuller). TOM responded significantly to irrigation levels. Mean maxinium seed yield of 13.5 q h a was recorded under 2 irrigations given at branching and siliquas, development stage-closely followed by that with 2 irrigations at , branching and flowering. Oil yield was significantly higher with 2 irrigations applied at branching and siliqua-development stages. Consumptive use of water and water-use efficiency were 250 nun and 5.39 kgha-mm respectively with 2 irrigations scl~eduled at branching and siliqua-development stages.

Effect of different components of SRI on yield, quality, nutrient accumulation and economics of rice (Oryza sativa) in tarai belt of northern India

A field experiment was conducted on a Typic Hapludoll soil in Indo-gangetic plains of India during the 2008 and 2009 rainy seasons to find out the effect of irrigation schedules and plant spacing on yield, quality, nutrient uptake and economics of two rice ( Oryza sativa L.) varieties under system of rice intensification (SRI) and compare the performance of SRI with conventional transplanting. Treatments under SRI included 12 combinations of 3 irriga- tion schedules, viz. irrigation at 1, 3 and 5 day(s) after disappearance of standing water (DADSW), 2 spacings (20 cm 20 cm, 25 cm 25 cm) and 2 varieties (Pant Dhan 4, Arize 6444), alongwith two control treatments of con- ventional cultivation of each variety. The experiment was set in a RBD with three replications. Irrigation at 1 and 3 DADSW increased uptake of N, P and K in grains, which enhanced grain protein content and milling percentage, and improved grain yield by 8.6 and 5.9% over 5 DADSW (5.82 t/ha), respectively. Net returns and B:C ratio were also better with irrigation at 1 and 3 DADSW. Wider spacing resulted in 4.2% higher yield with better grain quality and 10.8% higher net returns over closer spacing. Yield-wise and profit-wise, both the varieties were suit- able for cultivation under SRI. However, Arize 6444 recorded higher N uptake and protein content. The uptake of P and K was higher in grains of Pant Dhan 4 which showed higher milling percentage. Between two methods, SRI improved N, P and K uptake, milling percentage and protein content. Grain yield was 16.9% higher under SRI compared to conventional method (5.22 t/ha). Due to lower cost of production and higher yields, SRI fetched 56% higher net returns over conventional transplanting.

Effect of irrigation schedules on yield attributes, consumptive use of water, water-use efficciency and moisture-extraction pattern of Frenchbean (Phaseolus vulgaris)

A field experiment was conducted during the winter (rabi) season of 1989-90 and 199G91 to study the effect of 15 irrigation schedules on yield attributes, yield, consumptive use of water, water-u~eeficiency and moisture-extraction pattern of Frenchbean (Phaseolus vulgaris L.). Number of brancheslplant, pods1 plant, grain yieldlplant and seed yieloa were higher with irrigation at irrigatioq water : cumulative pan . evaporation (IW :CPE) ratio of 6 and 2 irrigations at 25 and 100 days after sowing during fust nnd second years respectively. The 1,000-grain weight was higher with 1 &igation at 100 days after sowing. Four irrigations at 25,50,75 and 10Q days after sowing during first year and 2 irrigafl~ns at 25 and 100 days After sowing during second yew produced higher straw yieldha. Consumptiveuse of water and moisture extraction were higher with 3 irrigations at 25, 50 and 45 days and at 25,75 and 100 days after sowi~g during fust year and with 3 irrigation given at 50,75 and 100 days after sowing during second year. Water- use efficiency was higher (74,2 kglha cm) with inigation at 0.6 IW : CPE ratio during first year and 2 jnigations at 25 nnd 100 days after sowing (67.0 kgha-cm) during the.second year.

Effect of irrigation schedule, residue incorporation and nutrient management on system productivity and profitability of soybean (Glycine max)wheat (Triticum aestivum) cropping system in Vertisols of Rajasthan

A 3-year field experiment was carried out at Kota, Rajasthan during 201516 to 201718, to study the effect of irrigation schedule, residue incorporation and nutrient management on system productivity and profitability of soy- bean [Glycine max (L.) Merr.]wheat (Triticum aestivum L.) cropping system in Vertisols of Rajasthan. The treat- ments consisted of 24 combinations of 2 irrigation schedules in soybean, viz. 1 irrigation at flowering stage and 2 irrigations at flowering and other pod-development stages -in main plots; 4 wheat residue-management practices, viz. sowing of soybean after wheat-residue burning, wheat-residue incorporation without irrigation, residue incor- poration with irrigation and application of urea @ 25 kg/ha and residue incorporation with irrigation and application of urea @ 25 kg/ha + cellulolytic microbes @ 2.0 kg/ha in subplots; and 3 nutrient-management practices, viz. 75% recommended dose of fertilizers (RDF), 100% RDF (20 kg N, 40 kg P O , 40 kg K O/ha) and 125% RDF in sub- 2 5 2 subplots. The experiment was laid out in a split split-plot design with 3 replications. Wheat crop was sown every year with the adoption of recommended package of practices. Pooled data of 3 years revealed that 2 irrigations at flowering and other at pod development stages-in soybean crop significantly increased dry-matter production, unit- area efficiency, branches/plant, pods/plant, seeds/pod, seed index, seed and straw yields and net returns of soy- bean, grain yield of wheat, soybean-equivalent yield (SEY), profitability, production- and economic-efficiency of system, available N, P and K status of soil after harvesting of wheat and soybean as compared to 1 irrigation at flowering stage. However, available K status of soil after harvesting of soybean was found non-significant in rela- tion to irrigation. Wheat-residue incorporation with irrigation and application of urea @ 25 kg/ha + cellulolytic mi- crobes @ 2.0 kg/ha resulted in the highest growth and yield attributes, seed and straw yields and net returns of soybean, water-use efficiency (WUE), water productivity (WP), soybean-equivalent yield (4.51 t/ha), system profit- ability ( 96,520/ha), production (12.35 kg/ha/day) and economic (264 /ha/day) efficiency of system, organic car- bon, bulk density of soil after harvesting of soybean and N, P and K status of soil after harvesting of both soybean as well as wheat over wheat-residue burning. Application of 125% RDF resulted in the maximum growth and yield attributes, seed (1.51 t/ha) and straw (2.17 t/ha) yield, net returns ( 25,700), benefit: cost ratio (1.09) of soybean and SEY (4.44 t/ha), system profitability ( 95,740/ha), production (12.15 kg/ha/day) and economic efficiency (262 /ha/day), bulk density (1.42 Mg/m3), N (282, 288 kg/ha) P O (24.6,25.9 kg/ha) and K O (293, 299 kg/ha) of 2 5 2 soil after harvesting of wheat and soybean respectively.

Effect of irrigation schedules on growth and yield of aerobic rice (Oryza sativa) under varied levels of farmyard manure in Cauvery command area

Field experiments were conducted during summer 2005 and 2006 at Mandya, Karnataka to study the effect of irrigation regimes in conjunction with varied levels of farmyard manure (FYM) on growth and yield of aerobic rice ( Or yza sativa L.). The treatments consisted of 4 levels of irrigation based on IW (irrrigation water) CPE (Cumulative Pan Evaporation) ratio (2.5, 2.0, 1.5 and 1.0 with an IW of 5 cm) and three levels of FYM (0, 10 and 20 tonne/ha) was laid out in split plot design with three replications. The results revealed that application of 20 tonne FYM re- corded significantly more number of productive tillers/hill, filled spikelets/panicle and thus more grain yield (6.01 and 6.44 t/ha during 2005 and 2006, respectively). However, no FYM application recorded higher B:C ratio (1.02). Irrigation scheduled at IW/CPE ratio of 2.5 recorded significantly higher yield attributes and grain yield (6.21 and 6.58 tonne/ha during 2005 and 2006, respectively) and same treatment recorded higher B:C ratio. However, irriga- tion scheduled at IW/CPE ratio of 1.0 recorded higher water use efficiency (52.09 kg grain/ha-cm). The N, P and K uptake was higher with application of 20 tonne FYM and with irrigation scheduled at IW/CPE ratio of 2.5.

Effect of irrigation scheduling and organic manures on yield and economics of bread wheat (Triticum aestivum L.)

A field experiment was conducted during the winter (rabi) seasons of 201415 and 201516 at Jobner, Rajasthan to study the effect of irrigation scheduling and organic manures on growth, yield and quality of wheat (Triticum aestivum L.) under loamy sand soil. The treatments consisted of 5 irrigation scheduling, i.e. I , (irrigation 1 at critical stages); I , [0.9 irrigation water: cumulative pan evaporation (IW : CPE ratio); I , 0.6 IW : CPE ratio at veg- 2 3 etative phase + 0.8 IW : CPE ratio at reproductive phase; I , 0.6 IW : CPE ratio at vegetative phase + 1.0 IW : CPE 4 ratio at reproductive phase; and I , 0.8 IW : CPE ratio at vegetative phase + 1.0 IW : CPE ratio at reproductive 5 phase in main plots and 4 organic manures, viz. control (M ), FYM @ 15 t/ha (M ), VC @ 6 t/ha (M ) and FYM @ 0 1 2 7.5 t + VC @ 3 t/ha (M ) in subplots. The experiment was conducted in splitplot design with 4 replications. The 3 pooled results showed that irrigation applied at 0.9 IW : CPE ratio (I ) resulted in the maximum yield (grain, straw, 2 biological and harvest index) and net returns, being superior to I , I and I treatments except treatment I . The 1 4 3 5 treatment I exhibited the maximum value of consumptive use (395 mm). However, the treatment I revealed signifi- 2 5 cantly highest water-use efficiency WUE of 11.34 kg/ha-mm and excelled over rest of the treatments. Application of FYM at 7.5 t/ha + vermicompost at 3 t/ha (M ) resulted in significantly higher yield (grain, straw, biological and 3 harvest index) which was at par with M and superior to rest of the treatments. The highest consumptive use (409 2 mm) by the crop was recorded under the treatment M . Significantly highest WUE was recorded under M (12.40 0 3 kg/ha-mm). The maximum net returns (`55,276) was recorded under the treatment M3 (FYM @ 7.5 t/ha + vermicompost @ 3 t/ha) which remained at par with M but significantly higher to M and M treatment. Thus, 1 0 2 scheduling of irrigation to wheat either at 0.9 IW : CPE throughout the growth or 0.8 IW : CPE at vegetative phase + 1.0 IW : CPE at reproductive phase resulted significantly higher yields (grain, straw, biological and harvest index) and net returns. Irrigating the crop at an IW : CPE of 0.8 at vegetative phase + IW : CPE of 1.0 at reproductive phase was most effective as the above schedule besides producing almost equal yields also curtailed 1 irrigation with highest WUE. Manuring the crop either with 7.5 t FYM + 3 t/ha VC or 6 t/ha VC were the equally effective and net returns.

Effect of irrigation scheduling and organic manures on wheat (Triticum aestivum) yield and soil nutrient status

A field experiment was conducted in a loamy sand during the winter (rabi) seasons of 201415 and 201516 at Jobner, Rajasthan, study to the effect of irrigation scheduling and organic manures on growth, yield and quality of wheat (Triticum aestivum L.). The treatments consisted of 5 irrigation scheduling in main plots and 4 organic manures in subplots were replicated 4 times in a split-plot design. The results showed that irrigation applied at an irrigation water: cumulative pan evaporation (IW: CPE) ratio of 0.9 (I2) resulted in the maximum values of yield (grain and straw) and proved significantly superior to the remaining treatments except treatment I5 (IW: CPE of 0.8). Irrigation at an IW: CPE ratio of 0.9 (I2) exhibited the maximum value of consumptive use (395 mm) and treatment I5 revealed significantly highest water-use efficiency (11.34 kg/ha-mm) over rest of the treatments. The treatment I5 failed to show significant variation in organic carbon, available nitrogen, phosphorus and potassium after harvesting of the crop. An application of FYM at 7.5 t + VC at 3 t/ha (M3) resulted in significantly higher yield (grain and straw) over rest of the treatments but at par with M2 (VC at 6 t/ha). The highest consumptive use (409 mm) by crop was shown by the treatment M0 (Control). The significantly highest WUE was recorded under M3 (12.40 kg/ha-mm). The highest organic carbon (0.149%) was also recorded under this treatment M3. which remained at par with M1 (farmyard manure @15 t/ha) but significantly higher than M0 and M2. The significantly higher available N, P and K contents in soil after harvesting were recorded under the treatment M3, being at par with M2 but superior to rest of the treatments. Thus scheduling of irrigation to wheat either at 0.9 IW: CPE ratio throughout the growth or 0.8 IW: CPE ratio at vegetative phase + 1.0 IW: CPE ratio at reproductive phase resulted in significantly higher yield. Manuring the crop either at 7.5 t FYM + 3 t/ha VC or 6 t/ha VC were the equally effective treatments for available N, P and K status in soil after harvesti

Effect of irrigation scheduling and nutrient management on productivity, profitability and nutrient uptake of wheat (Triticum aestivum) grown under zero-tilled condition in south-eastern Rajasthan

A field experiment was conducted at Agricultural Research Station, Kota, Rajasthan, during the winter (rabi) seasons of 201112, 201213 and 201314, to evaluate effect of irrigation scheduling and nutrient management practices on productivity, profitability and nutrient uptake of wheat [Triticum aestivum (L.) emend. Fiori & Paol.] grown under zero-tillage condition in south eastern Rajasthan. Treatments comparised irrigation schedules in main plots, viz. irrigation water: cumulative pan evaporation (IW: CPE) 0.8 and IW: CPE 1.0, and nutrient-manage- ment practices in sub plots, viz. 100% recommended dose of fertilizers (RDF 120 kg/ha nitrogen, 40 kg/ha P O 2 5 and 30 kg/ha potash), 125% RDF and 150% RDF, were laid out in split-plot design with 4 replication. Irrigation at an IW: CPE of 1.0 significantly increased plant height (85.3 cm), leaf-area index (3.64) and dry-matter accumula- tion (894.2 g/m2) at 90 days after sowing (DAS), effective tillers/m2 (489), ear length (9.27 cm), grains/ear (45.3) and 1,000-seed weight (36.82g), grain yield (4.16 t/ha), straw yield (6.50 t/ha), N (69.6 and 44.0 kg/ha), P (15.7 and 3.52 kg/ha) and K (20.6 and 153.1 kg/ha) uptake by grain and straw, respectively, protein content (10.5%), net returns ( 56,004/ha) and benefit: cost ratio (3.30), production efficiency (28.7 kg/ha/day) and economic effi- ciency ( 386/ha/day) and water-use efficiency (80.1 kg/ha-cm)) than the irrigation at IW:CPE of 0.8. However, maximum harvest index and water productivity were observed with the irrigation at an IW: CPE ratio of 0.8. Among nutrient-management practices, 125% RDF registered significantly higher growth and yield attributes, grain yield (4.04 t/ha), net returns ( 54,058/ha) and all the efficiency indices, N, P and K uptake by grain and straw. How- ever, significant improvement in straw yield was observed up to 150% RDF. Maximum harvest index and benefit: cost ratio were found only with 100% RDF.

Effect of irrigation scheduling and different levels of zinc and boron on yield, economics, water productivity and nutrient uptake in aerobic rice (Oryza sativa)

A field study was conducted during the rainy (kharif) seasons of 2015 and 2016 at Chiplima, Sambalpur, under west central tableland zone of Odisha, to evaluate 6 different micronutrient combinations under 4 different irriga- tion schedules in aerobic rice (Oryza sativa L.). Application of irrigation after 3 rainless days resulted in signifi- cantly highest grain yield (4.05 t/ha) over all other treatments owing to optimum soil moisture and nutrient avail- ability. The highest number of panicle bearing tillers/m2 (375.1), panicle length, filled grains/panicle (108.5) and 1,000-grain weight (26.23 g) attributed to the higher yield under this treatment. It also resulted in the highest net returns ( 30,316/ha), benefit: cost (B:C) ratio of 1.88 and nutrient uptake. Among different levels of micronutrient, an application of recommended dose of fertilizer (RDF, 80-40-40) kg/ha N, P O K O + 5 kg Zn/ha + 0.2% B as 2 5 2 foliar spray (2 sprays) registered significantly highest grain yield of 4.24 t/ha along with higher values of yield at- tributes such as panicle-bearing tillers/m2 (391.1), panicle length (25.52 cm), filled grains/panicle (117.9) and 1,000-grain weight (26.17 g). It also resulted in higher net return ( 30,362/ha), benefit: cost ratio of 1.89 and nutri- ent uptake than all the other treatments. Water use was highest in case of irrigation scheduling after 3 rainless days (91.33 cm) with lowest water productivity (0.43 kg/m3). Out of 6 micronutrient levels, application of RDF (80- 40-40 N, P O and K O Kg/ ha) + 5 kg Zn/ ha + 0.2 % B as foliar spray (2 sprays) resulted in the highest water pro- 2 5 2 ductivity (0.57 kg/m3) owing to higher yield and low water use. However, the interaction effect was statistically non- significant.

Effect of irrigation scheduling and nitrogen application on productivity and profitability of direct seeded rice (Oryza sativa)

A field experiment was conducted during the rainy (kharif), season of 2015, to study the effect of irrigation scheduling and split application of nitrogen on productivity and profitability of direct-seeded rice (DSR) (Oryza sativa L.). The experiment was laid out in split-plot design with 12 treatment combinations including 4 irrigation schedules, viz, 0 kPa; 10 kPa, 20 kPa and 10 kPa during entire stage except 40 kPa at tillering to flowering stages in main plot and 3 N (120 kg/ha) application methods, viz. control (N ), half recommended dose of nitrogen (RDN) 0 as basal + one-fourth RDN at week 2 + one-fourth RDN at week 5, and one-fourth RDN as basal + one-fourth RDN at week 2 + one-fourth RDN at week + one-fourth RDN at week 9 after sowing in subplot were taken with 3 replications. Irrigation scheduling at 0 kPa resulted in the highest yield attributes, grain and straw yields and net returns of DSR, which was remained at par with 10 kPa. Four times split application of N as one-fourth RDN as basal + one-fourth RDN at 2 week + one-fourth RDN at week 5 + one-fourth RDN at week 9 recorded significantly high grain and straw yields and net returns over half RDN as basal + one-fourth RDN at week 2 + one-fourth RDN at week 5 and control. Thus, irrigation threshold of 10 kPa with 4 times split application of RDN can be applied to DSR to get higher yield and net returns.

Effect of irrigation scheduling on performance of summer legumes grown in 'association of sugarcane

A field experiment was conducted during 2001-03 to find out an optimum irrigation schedule for intercrops grown in association with spring sugarcane, on silty clay-loam soil, having 23.4% moisture at field capacity and 8.6% at permanent wilting point (PWP). Daily evapotranspiration (ET) varied from 3.3 to 16.8 mmlday. Mungbean (Phaseolus radiatus L.), urdbean (F! mungo L.) and cowpea [Vigna unguiculata (L.) Walp.] gave highest yield of 4.1, 3.85 qlha and 73.0 qha, respectively with irrigation at, 1W : CPE ratio of 1.2 compared to 3.25, 2.75 and 6.10 qlha with irrigations at flowering and pod-filling stage. All the intercrops reduced cane yield due to decline in number of millable canes and cane weight. Mean reduction in cane yield was 14.2% with cowpea, 11.5% with urdbean and 9.2% with mungbean. Irrigation at 1.2 IW : CPE ratio resulted in highest cane yield of 97.0 tonnesl ha, being respectively 3.7, 8.1 ; : CPE ratio of 1.0, 0.8, and irrigations at critical growth nd 13.3% higher than IW stages. Sugarcane + cowpea g.we highest mean cane-equivalent yield (1 07.0 tonneslha), being 6.8, 10.0, and 8.7% more than sole sugarcane and intercropping with urdbean and mungbean respectively. Sugarcane inter- cropped with cowpea gave highest gross return of R s 101,6501ha followed by sugarcane alone (Rs 951 90) as against Rs 92,435 with sugarcane + urdbean. Respective Benefit : cost ratio was 0.89, 0.90 and 0.73. Irrigation applied at 1.2 IW : CPE ratio gave significantly highest cane-equivalent yield (1 09.5 tonneslha) with benefit : cost ratio of 0.85 as against 92.4 tonneslha and 0.77 with irrigation at critical growth stages of intercrops.

Effect of irrigation scheduling, conjunctive use of water sources and fertilizer levels on yield and water productivity of groundnut (Arachis hypogaea)

A field experiment was conducted for 2 consecutive years 200809 and 200910 at Deras, Mendhasal, Odisha, to study the effect of conjunctive use of water sources and fertilizer levels on yield and water use of winter (rabi) season groundnut (Arachis hypogaea L.). The treatments included 3 levels of conjunctive use of water [C 1 (2 irrigations through canal water only, C 2 irrigations with canal water + 1 irrigation with ground water and C 2 2 3 irrigations with canal and 2 irrigations with ground water)] and 5 fertilizer treatments, [(F , no NPK; F , 100% NPK 0 1 (20, 40 and 40 kg/ha as N, P O and K O), F , sugarcane trash bio-compost (STBC) alone (1 t/ha); F , 75% NPK + 2 5 2 2 3 sugarcane trash bio-compost (0.25 t/ha) and F , 50% NPK+ sugarcane trash bio-compost (0.50 t/ha)]. Pod and 4 haulm yields of groundnut were significantly increased with conjunctive-use of water sources (ground and canal water) compared to canal water irrigation alone. The increase in pod yield was 45.3% and haulm yield 40.3% with conjunctive use of 2 irrigations through canal and 2 irrigations through ground water over 2 irrigations with canal water. This treatment also gave the maximum gross returns ( 47,714/ha), net returns ( 35,166/ha) and benefit: cost ratio (2.80). With application of 75% NPK + STBC (0.25 t/ha) 70.3% and 73.4% increase in pod and haulm yields was observed compared to the control (no fertilizer application). The highest water use (434 mm), water-use efficiency (5.06 kg/ha-mm) and benefit: cost ratio (3.11) were recorded with application of 75% NPK + STBC (0.25 t/ha).

Effect of irrigation and nutrient levels on growth and yield of coriander (Coriandrum sativum)

A field experiment was carried out on sandy loam soil at Morena during winter season of 2006-07 and 2007-08 to study the effect of irrigation schedules and nutrient levels (% recommended NPK fertilization) on growth, yield, quality of coriander (Coriandrum sativum L.). Irrigation at 20, 40 and 60 days after sowing (DAS) maintained higher urnbletslplant, urnbellplant, 1,000-seed weight, production efficiency, nutrient use and N, P, K and S uptake. Maximum seed yield (1.96 tonnelha), biomass production (4.66 tonneslha), net returns (Rs.86,815/ha) and B:C ra- tio (8.1 9) were also recorded under 3 irrigations, which resulted in 38.31 % and 3.93% increase in seed yield over 2 (20 and 40 DAS) and 4 (20, 40, 60 and 80 DAS) irrigation respectively. The application of 100% recommended dose of fertilizer (RDF) (60:17.6:16.6:30 kg N: P: K: Slha) registered significantly higher yield attributes, water use efficiency, production efficiency, N: P: K and S uptake and 20.65% and 12.04% increased in seed yield over 50% and 75% RDF respectively. The: interaction effect of irrigation and fertility levels on seed yield was also found sig- nificant and positive. The maximum yield (2.09 tonnelha) was recorded with the combined application of 3 irriga- tions and 100% RDF followed by three irrigation and 125% RDF (2.02 tonnelha).