Irrigation Water/cumulative Pan Evaporation Research Articles

Influence of Irrigation Scheduling on Physiological Growth Parameters and Yield of Wheat under Different Sowing Dates

Sowing time and irrigation play an important role to ensure higher production. Delay in sowing affects the growth and development of crop. Studying the effect of irrigation scheduling and sowing dates can provide a knowledge for improving production in late sowing conditions. A field experiment was conducted during the rabi season of 2020-21 at Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur, Madhya Pradesh to study the influence of irrigation scheduling on physiological growth parameters and yield of wheat under different sowing dates. The experiment comprised of 12 treatment combinations having three sowing dates, 3rd December, 18th December and 2nd January in the main-plot and four Irrigation Water/ Cumulative Pan Evaporation (IW/CPE) based irrigation scheduling, viz. 1.0, 0.9, 0.8 and 0.7 in the sub-plot was analyzed in split-plot design with three replications. The findings of present investigation revealed that the physiological growth parameters and yield were higher in 3rd December sown date. Among the irrigation scheduling, IW/CPE ratio 1.0 recorded significantly higher growth parameters and yield. The results of the present study conclude that adjusting sowing date with irrigation scheduling could assist in enhancing yield.

Influence of Irrigation Scheduling on Weeds among Different Sowing Dates in Wheat under Vertisol

Wheat is an important cereal grain crop and is staple to millions. Weeds are the major constraint that lower the wheat yield. The knowledge of weeds under different sowing dates and Irrigation can assist in controlling weeds. A field experiment was conducted during the rabi season of 2020-21 at Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur, M.P. to study the influence of irrigation scheduling on weeds at different sowing dates in wheat. The experiment was laid out in split-plot design with three replications. The main plot consisted of three sowing dates, i.e., 3rd December, 18th December and 2nd January and four Irrigation Water/Cumulative Pan Evaporation (IW/CPE) based irrigation scheduling, 1.0, 0.9, 0.8 and 0.7 in the sub-plots. The results revealed that lowest weed density and dry weight were observed in 2nd January sown date, as compared to 3rd December and 18th December sown date. Among the irrigation schedules, 0.7 IW/CPE observed lowest weed density and dry weight than 1.0, 0.9, 0.8 IW/CPE ratio. 3rd December sown date exhibited highest grain yield (4637 kg ha-1) and straw yield (6788 kg ha-1) than 18th December and 2nd January sown date. Among the irrigation schedules, 1.0 IW/CPE ratio exhibited maximum grain yield (4510 kg ha-1) than 0.9, 0.8 and 0.7 IW/CPE ratio. The results of the study concludes that sowing dates and irrigation schedules had crucial role for controlling weeds.

Ice nucleation active bacteria and its mitigation on tomato (Solanum lycopersicum)

Microbes play a vital role in ice nucleation, supporting bio-precipitation, and allowing plants to live in low-water environments. A field experiment was conducted during December 2018 with two phyllosphere microorganisms’ spraying viz., Pseudomonas aeruginosa and pink-pigmented facultative methylotrophs (PPFM) and under three moisture regimes (0.6, 0.8, 1.0 IW/CPE (irrigation water/ cumulative pan evaporation) ratio) on tomato (PKM 1) in Tamil Nadu Agricultural University, Coimbatore (Tamil Nadu). A laboratory experiment was conducted to confirm ice nucleation using two phyllosphere microorganisms’ P. aeruginosa and PPFM. The bioprecipitation impacts on tomatoes were assessed using a set of physiological parameters such as photosynthetic rate, average chlorophyll Index and the ice nucleation activity (INA) assessed using tube nucleation test and scanning electron microscope (SEM). The results showed that the mean photosynthetic rate of PPFM sprayed tomato (Solanum lycopersicum) (PKM 1) plants (40.7 μmol CO2/m2/s) at 10 DAS was significantly higher than P. aeruginosa sprayed plant (38.7 μmol CO2/m2/s) under different irrigation regimes. The average chlorophyll Index value of the P. aeruginosa sprayed tomato plants (58.1) was higher than PPFM sprayed plants (56.4). The tube nucleation tests were proved that ice crystallization induced by P. aeruginosa in super-cooled buffer at - 2 to -10°C while PPFM not catalyze the buffer even after 3hours. The scanning electron microscope (SEM) indicated the P. aeruginosa growth at the upper surface of the leaf and PPFM growth more at the lower surface of the leaf compared to without inoculation of microbes on leaves. Overall, the result revealed that P. aeruginosa may assist in ice nucleation activity that will help to make artificial rain in the near future.

Climate nutrient management for various sources and levels of fertilizers on soil nutrients, growth and yield of maize (Zea mays l.) in Madurai district, Tamil Nadu, India

Global climate change is expected to soil processes and properties, which are important for restoring soil fertility and low productivity. The field experiment was conducted at Research Farm, Agricultural College, and Research Institute, Madurai district, Tamil Nadu, during Kharif season 2021 to study of various sources and fertilizers' levels to influence under deficit and excess water conditions on soil fertility, growth, and yield of maize (Zea mays). The study revealed that excess and deficit water condition in moisture regime irrigations at Irrigation water / Cumulative Pan Evaporation (IW/CPE) ratio of 1.0 along with nutrient management practices (N8) 125 % Soil Test Crop Response (STCR) - NPK soil application by 1 % foliar spray of micronutrient mixture. Significantly higher of mean values available nitrogen (225 kg ha-1), available phosphorous (20.81 kg ha-1), available potassium (351 kg ha-1), dry matter production (DMP) (16,404 kg ha-1), plant height (250 cm) and yield (9,030 kg ha-1) and was comparable with IW/CPE ratio of 0.8, 0.6 along with others nutrient management practices at 100 % and 75 % STCR - NPK followed by foliar sprays 2 % NPK (19:19:19) and Pink-pigmented facultative methylotrophs (PPFM) 1 %. Hence, under a normal water availability situation, irrigation at an IW/CPE ratio of 0.8 was good enough to produce a higher yield, while under deficit and excess water conditions IW/CPE ratio of 1.0 along with125 % STCR-NPK by foliar spray of micronutrient mixture of 1 % was suitable for obtaining optimum nutrient management for enhancing soil fertility, growth and yield of maize.

Influence of moisture regimes and nutrient managements on Yield and Quality of Rabi maize (Zea mays L.)

An experiment on rabi maize constituting three moisture regimes viz., Irrigation water / Cumulative Pan Evaporation (IW/CPE) at 0.6 ,0.8 and 1.0 ratio along with ten nutrient management practices viz., application of 100 % RDF only, 125 % STCR-NPK + foliar sprays 2 % NPK (19:19:19)+ 1 % Pink-pigmented facultative methylotrophs (PPFM) + Micronutrient mixture 1 %, 100 % STCR-NPK + foliar sprays 2 % NPK (19:19:19)+ 1 % Pink-pigmented facultative methylotrophs (PPFM) + Micronutrient mixture 1 % and 75 % STCR-NPK + foliar sprays 2 % NPK (19:19:19) + 1 % Pink-pigmented facultative methylotrophs (PPFM) + Micronutrient mixture 1 % was conducted at Research Farm, Agricultural College, and Research Institute, Madurai district, Tamil Nadu during winter seasons of 2020-21 and 2021- 22. The results showed that irrigation scheduled at 1.0 IW/CPE ratio recorded significantly higher grain yield of maize over the scheduling of irrigation at 0.8 with 0.6. Moreover, the application of 100 % STCR-NPK + foliar sprays 1 % Micronutrient mixture was at par with the application of 75 % STCR-NPK + foliar sprays 1 % Micronutrient mixture and both of them recorded significantly higher grain yield than other nutrient management practices. As regards quality parameters viz., chlorophyll content, proline content at roasting or milk stage was numerically higher with scheduling of irrigation at 1.0 IW/CPE ratio but did not reach the level of significance during both the year of the experiment. The quality parameters like chlorophyll content, proline content and yield in maize grain at roasting or milk stage were significantly increased with increasing nutrient management practices. The highest values of chlorophyll content, proline content and yield were recorded with the application of 100 % STCR-NPK + foliar sprays 1 % Micronutrient mixture.

Influence of Irrigation Scheduling with Levels and Times of Nitrogen Application on Root Growth of Aerobic Rice

Aerobic rice is one of the alternative methods for saving water, energy, labour, time and reduced methane gas in rice production ecosystem. The field experimental trial was conducted during summer 2018 at Agricultural College and Research Institute, Madurai. Irrigation scheduling based on different IW/CPE (Irrigation Water/Cumulative Pan Evaporation) ratios and different doses along with various spilt applications of nitrogen were experimented. Results of field experiment indicated that irrigation scheduling at IW/CPE of 0.8 up to panicle initiation stage and thereafter IW/CPE of 1.0 up to dough stage recorded the highest root length of 13.0 cm at active tillering and 18.8 cm at flowering stage. But, irrigating the aerobic rice at IW/CPE of 1.0 up to panicle initiation stage and thereafter IW/CPE of 1.2 up to dough stage recorded the highest root volume (16.9, 27.1 cc·hill-1) and root dry weight (6.1, 12.9 g·hill-1) at active tillering and flowering stage. Application of nitrogen at 150 kg·ha-1 in 5 equal splits at 20, 35, 50, 65 and 80 DAS (Days after sowing) recorded the highest root length of 13.5 cm, root volume of 17.6 cc·hill-1 and root dry weight of 6.4 g·hill-1 at active tillering stage and root length of 19.4 cm, root volume of 27.6 cc·hill-1 and root dry weight of 14.4 g·hill-1 at flowering stage. The interaction effect of irrigation and nitrogen significantly influenced the root growth. Irrigation at IW/CPE of 0.8 up to panicle initiation stage and thereafter IW/CPE of 1.0 up to dough stage along with 150 kg N ha-1 in 5 equal splits at 20, 35, 50, 65 and 80 DAS significantly enhanced the root length (15.7, 23.6 cm) at active tillering and flowering stage. However, irrigation scheduling at IW/CPE of 1.0 up to panicle initiation stage and thereafter IW/CPE of 1.2 up to dough stage along with application of N 150 kg·ha-1 in 5 equal splits at 20, 35, 50, 65 and 80 DAS registered the highest root volume (20.3, 32.8 cc·hill-1) and root dry weight (8.3, 16.4 g·hill-1) at active tillering and flowering stage.

Effect of Varied Irrigation Scheduling with Levels and Times of Nitrogen Application on Yield and Water Use Efficiency of Aerobic Rice

More rice needs to be produced with lesser water to feed the increasing human population. Judicious water management practices and appropriate water saving technologies in rice cultivation are in need in the coming decades. Aerobic rice is one of water saving method of rice cultivation. The field experiment was conducted during Summer season of February 2018 to May 2018 at Tamil Nadu Agricultural University, Agricultural College and Research Institute, Madurai, to find out the effect of irrigation schedules with varied doses and time of nitrogen application on yield of aerobic rice. Irrigation scheduling of IW/CPE (Irrigation Water/Cumulative Pan Evaporation) 1.0 up to panicle initiation stage and thereafter IW/CPE 1.2 up to dough stage recorded higher yield attributes viz., number of panicles hill-1 (9.1), number of filled grains panicle-1 (87.9), test weight (15.3 g), grain yield (4462 kg·ha-1), straw yield (5977 kg·ha-1). However, the highest water use efficiency (6.8 kg·ha-1·mm-1) was recorded in the treatment of IW/CPE 1.0 throughout the crop growth period. Lower yield attributes, yield and water use efficiency were recorded with irrigation scheduling of IW/CPE 0.8 throughout the growth stage. Application of nitrogen at 150 kg·ha-1 in 5 equal splits at 20, 35, 50, 65 and 80 DAS (Days after sowing) recorded higher yield attributes viz., number of panicles hill-1 (9.3), number of filled grains panicle-1 (90.5), test weight (15.4 g), grain yield (4746 kg·ha-1), straw yield (6258 kg·ha-1) and WUE (7.5 kg·ha-1·mm-1). Application of nitrogen 100 kg·ha-1 in 4 equal splits at 20, 40, 60 and 80 DAS recorded lower yield attributes, yield and water use efficiency. The interaction effect between irrigation scheduling and nitrogen management on yield was significant. The combination of IW/CPE 1.0 up to panicle initiation stage and thereafter IW/CPE 1.2 up to dough stage along with application of nitrogen at 150 kg·ha-1 in 5 equal splits at 20, 35, 50, 65 and 80 DAS significantly produced higher number of panicles hill-1 (10.7), grain yield of 5419 kg·ha-1 and straw yield of 6906 kg·ha-1. However, IW/CPE 1.0 throughout the growth period along with application of nitrogen at 150 kg·ha-1 in 5 equal splits at 20, 35, 50, 65 and 80 DAS registered the highest water use efficiency (8.4 kg·ha-1·mm-1) in aerobic rice.

Influence of mulching and irrigation scheduling on productivity and water use of turmeric (Curcuma longa L.) in north-western India

A field experiment was conducted to compute the water use and productivity of turmeric as a function of straw mulching and irrigation scheduling at Punjab Agricultural University, Ludhiana, during 2013 and 2014. The experiment was laid out in split plot design, keeping mulch levels (no mulch and straw mulch 6 t/ha) and irrigation methods (drip and check basin) in main plots and irrigation schedules at 0.6, 0.8, 1.0 and 1.2 irrigation water/cumulative pan evaporation (IW/CPE) in subplots. Turmeric yield was 125.2 % higher with mulching than no mulch with 50 % saving in irrigation water. Drip irrigation resulted in significantly higher turmeric yield and benefit/cost (B/C) than check basin. Irrigation scheduling at 1.2 IW/CPE recorded significantly higher turmeric yield than other schedules. Drip irrigation at 0.8 IW/CPE resulted in statistically at par yield with check basin irrigation at 1.2 IW/CPE, thus saving 40 % irrigation water with significantly higher B/C. However, turmeric yield was at par between drip irrigation at 1.2 and 1.0 IW/CPE schedule, while a significant reduction in yield was recorded in check basin at 1.0 IW/CPE compared to 1.2 IW/CPE. Turmeric should be irrigated with drip at 1.0 and with check basin at 1.2 IW/CPE to realize potential yield.

Economics of Growing Okra under Drip Fertigation

Objective: To study the economic viability of Okra crop grown under different drip fertigation levels and different drip irrigation subsidy percentages. Methods: The field experiment was done at the research farm of department of Soil and Water Engineering, PAU, Ludhiana, India during 2014-15. The Nine drip fertigation treatments consisted of T1 - 60% fertilizer Nitrogen (N) with irrigation applied at 0.60 IW/CPE (irrigation water/cumulative pan evaporation) ratio, T2 - 60% fertilizer (N) with 0.80 IW/CPE ratio, T3 - 60% N with 1.00 IW/CPE ratio, T4 - 80% N with 0.60 IW/CPE ratio, T5 - 80% N with 0.80 IW/CPE ratio, T6 - 80% N with 1.00 IW/CPE ratio, T7 - 100% N with 0.60 IW/CPE ratio, T8 - 100% N with 0.80 IW/CPE ratio and T9 - 100% N with 1.00 IW/CPE ratio. Economical viability of drip fertigation was evaluated by computing Benefit-Cost ratio (B/C ratio) for each of drip fertigation treatment obtained by dividing gross returns by total seasonal cost. Economic analysis was done as per the cost involved in drip irrigation system components and requirement of fertilizer for one hectare area. The seasonal cost of growing okra under drip fertigation was calculated by considering depreciation, life of components, interest, fertilizers, insecticide, labors and cost of cultivation of growing Okra. Findings: In case of no drip irrigation subsidy, 60% drip irrigation subsidy and 75% drip irrigation subsidy, maximum B/C ratio was obtained in T5 treatment (2.25), (2.82) and (3.01) respectively; while minimum B/C ratio was obtained in T1 treatment (1.52), (1.9) and (2.03), respectively. The statistical analysis revealed that combination of fertilizers and irrigation levels had significant effect on B/C ratio of Okra production. Conclusion: It is economically viable to grow okra under drip fertigation with 80% fertilizer (N) along with irrigation applied at 0.80 IW/CPE ratio, only if drip irrigation subsidy provided by the government is higher than 30%.

English

With a view to study the effects of irrigation scheduling on the water use efficiency and physiological response and molecular basis of maize hybrids of different maturity groups, a field experiment was conducted at Water Management Research Center (WMRC), Belvatagi, University of Agricultural Sciences, Dharwad, India during 2010-2011 rabi season in Malaprabha Command Area’. The experiment was laid out in split plot design with three replications. The main plot comprised four irrigation levels (0.4. 0.6, and 0.8 irrigation water/cumulative pan evaporation (IW/CPE) ratio and irrigation at critical growth stages of maize) and subplots were three maize hybrids [PEEHM-5 (extra early), PEHM-2 (early) and 900 M gold (full season)] were tested. The results reveal that significantly higher grain yield (P<0.05) was at 0.8 IW/CPE ratio followed by irrigation at critical growth sages of maize. Among the maize genotypes tested, full season 900 M Gold recorded significantly greater grain yield (84.61 q ha-1) over PEHM-2 (early) and PEEHM-5 (extra-early). The moisture stress due to 0.4 IW/CPE ratio prolonged the days which reached 50% anthesis and 50% silking thus widening the anthesis-silking interval. Significant positive correlations (P<0.05) of maize grain yield with 100 seed weight (r=0.81), cob length (r=0.83), harvest index (r=0.82) and water-use efficiency (WUE; r=0.61) were found. The RWC decreased significantly (P<0.05) from 82.53 to 75.24% with increasing moisture stress on account of variations in the availability of soil moisture in the crop root zone. WUE was significantly low (P<0.05) in 0.8 IW/CPE ratio, despite providing more amount of water which could be attributed to a greater use of water with relatively lesser increase in yield. The present investigation showed that providing four irrigations at critical growth stages of maize hybrids followed by either three or five irrigations seem to have higher WUE. This approach could save water up to 29% with slight reduction of grain yield by 12% over providing full irrigation. Molecular analysis of three hybrids revealed the possibility of introgressing the yield enhancing traits from full season hybrid into early and extra-early hybrids, the latter clustered distinctly with each other. This strategy besides saving water helps tail-end farmers in choosing additional crop for double cropping in the command areas.   Key words: Maize hybrids, IW/CPE ratio, water use efficiency, grain yield.

Productivity and water use efficiency of wheat(Triticum aestivum)under different resource conservation techniques and irrigation regimes

In India wheat is conventionally planted on flat-bed and irrigation is applied by flooding, which results in low water-use efficiency. Efficient use of irrigation water is a major researchable issue in most command areas for improving crop productivity. Resource conservation technologies aimed at improving productivity and water-use efficiency such as raised-bed planting have been found useful in wide row crops like maize, cotton, sunflower, sugarcane, etc. However, such information is not available for a relatively narrow row crop like wheat. A field experiment was conducted during 2002–04 at New Delhi on a sandy loam soil to evaluate the performance of wheat crop under resource conservation techniques (RCTs), viz. furrow-irrigated raised-bed (FIRB), broad-bed and furrow (BBF), raised-bed and sunken-bed (RBSB) and conventional flat-bed (FB) in main plots, and 4 irrigation regimes, viz. irrigation only at crown root initiation (CRI); irrigation at 0.9 and 1.2 IW/CPE (irrigation water/cumulative pan evaporation) ratio and irrigations at six critical physiological growth stages in subplots. Wheat performed equally well under all the RCTs with respect to grain yield. The maximum grain yield was recorded under 1.2 IW/CPE ratio, which was at par with 6 irrigations at critical growth stages, but significantly higher than 0.9 IW/CPE and one irrigation at CRI. Bed planting techniques involving FIRB and BBF recorded significantly lower consumptive use (CU) of water than RBSB and FB. There was saving of 18.2 to 19.5% irrigation water by adopting FIRB compared to FB with flood irrigation. Water-use efficiency under FIRB and BBF was 8.3–22.8 and 4.9–24.8% higher respectively over the FB with flooding.

Sugarcane responses to irrigation and nitrogen in subtropical Iran

Limited information is available on water and nitrogen (N) management of sugarcane (Saccharum officinarum L.) in Khuzestan, southwestern Iran, where this crop is currently and extensively grown under heavy irrigation and N fertilization. Therefore, a field experiment was conducted from September 2000 to March 2002 at the Research Department of Karoon Agro-industry in Khuzestan to determine the effect of four irrigation [irrigation water/cumulative pan evaporation (IW/CPE) ratios of 0.6, 0.8, 1.0, and 1.2)] and four N (0, 86, 172, and 258 kg N ha-1) levels on sugarcane yield and water and N use efficiencies. The experiment was carried out as split-plot arranged in a randomized complete blocks design with four replications. Pan evaporation data was recorded daily using class A open pan. Increased water and N application increased both plant cane crop and sugar yields. The highest sugar yield was obtained under IW/CPE = 1.2 (29 irrigations) and with 172 kg N ha-1 with no significant difference with IW/CPE = 1.0 (25 irrigations) and 86 kg N ha-1, respectively. Higher irrigation and N levels showed a small but not significant reduction in both juice sucrose and purity percentages. Higher N levels significantly increased the N use efficiency (NUE) for cane yield, but NUE for sugar yield was highest at 86 kg N ha-1. Water use efficiency (WUE) increased with higher water application. Thus pan evaporation data and N management can effectively meet both irrigation (IW/CPE = 1.0) and N requirements (86.0 kg ha-1) of sugarcane without any adverse effect on yields and environment and reduces production costs as well.

The effects of different drip irrigation regimes on watermelon [Citrullus lanatus (Thunb.)] yield and yield components under semi-arid climatic conditions

This study was conducted to investigate the effects of drip irrigation on yield and yield components of watermelon [Citrullus lanatus (Thunb.) Crimson Tide F1] under semiarid conditions in the Southeastern Anatolian Project Region, Harran Plain, Şanlıurfa, Turkey, during 2002 and 2003. Using a 4-day irrigation period, 4 different irrigation regimes were applied as ratios of irrigation water/cumulative pan evaporation (IW/CPE): 1.25 (I125), 1.00 (I100), 0.75 (I75), and 0.50 (I50). Seasonal crop evapotranspiration (ETc) rates were 720, 677, 554, and 449 mm in the first year and 677, 617, 519, and 417 mm in the second year for irrigation treatments I125, I100, I75, and I50, respectively. Amounts of irrigation water applied to the 4 respective treatments were 764, 642, 520, and 398 mm in 2002 and 709, 591, 473, and 355 mm in 2003. Maximum yield was obtained from I125, with 84.1 t/ha in 2002 and 88.6 t/ha in 2003. Yield was reduced significantly as the irrigation water was reduced. The values of water use efficiency ranged from 9.6 to 11.7 kg/m3 in 2002 and 10.8 to 13.1 kg/m3 in 2003. The unstressed I125 treatment produced 10.1 kg marketable watermelons/m3 irrigation in 2002, and 11.3 kg/m3 in 2003. By comparison, the least irrigated (I50) treatment produced 12.4 kg/m3 in 2002, and 14.9 kg/m3 in 2003. A yield response factor (ky) value of 1.15 was determined based on averages of 2 years, and watermelon was found to be sensitive to water stress. This result showed that yield loss (1 – Ya/Ym) is more important than evapotranspiration deficit (1 – ETa/ETm). The study demonstrates that 1.25 IW/CPE water applications by a drip system in a 4-day irrigation frequency might be optimal for watermelon grown in semi-arid regions similar to those in which the work was conducted.

Recent Trends in Inter-Relationship of Nutrients with Various Agronomic Practices of Field Crops in India

ABSTRACT The spectacular performance of Indian agriculture witnessed during the second half of the 20th century against the onslaught of rising demographic pressure is a vivid demonstration of the growing effectiveness of our agricultural research and development system. However, the issue of sustainability in agriculture still remains a question. Management of natural resources, especially soil and its fertility status and vegetation following suitable agronomic management practices for sustainable agricultural production, represents a most daunting task and is certainly going to receive much attention in the years to come. Many workers established functional relationships between nutrients and other agronomic factors at different locations in India but systematic compilation of those relationships is a rare effort. The present paper reviews the latest information on inter-relationships between nutrients and other agronomic factors (seed rate, planting density, age of the seedling, planting method, irrigation, weed control, tillage, bacterial inoculation and cultivar etc.) on field crops. Major findings of first and second order interactions are highlighted. None of the second order interaction was found significant; thus only first order interactions were discussed. The interactive effect of nutrients and seed rate varied with soil type. In sandy loam soil when 125 kg seed ha−1 was used, wheat responded up to 60:30:40 kg N, P2O5 and K2O ha−1, whereas in clay loam soil it was up to 80:40:30 kg N, P2O5 and K2O ha−1 with the use of 25 kg higher seed rate. When chickpea was grown with a medium seed rate of 75 kg ha−1 it responded up to 30 kg N and 60 kg P2O5 ha−1 saving 10 kg N and 20 kg P2O5 in comparison to when a higher seed rate of 100 kg was used. Younger seedlings (20–25 days) performed better than old seedlings (35–40 days) in timely sown rice with the recommended dose of N, P2O5 and K2O (120:60:40). However, the adverse effect of late transplanted rice with aged seedling (35 days) on yield was nullified by using higher number of seedling/hill (4–5) and using higher dose of fertilizer (150:75:75 kg N, P2O5 and K2O ha−1). French bean, a negligible nodule-bearing legume responded to higher dose of N (160 kg) even under medium plant density (30 cm × 10 cm) in the tarai belt of North India. In general, interaction between cultivar and nitrogen level was non-significant in cereal but significant in oilseeds. The optimum dose of N for rapeseed cv. TH-68-8 and cv. TCH-2 was calculated to be66.0 kg ha−1, whereas it was 90kg N ha−1 for cv. RH-30. Soil moisture influenced the response of crops to fertilizer and vice-versa. Mustard responded up to 40 kg N ha−1 under residual soil moisture and up to 60 kg N ha−1 under limited irrigation; sunflower up to 120 kg N ha−1 when irrigation was applied at 0.4 irrigation water/cumulative pan evaporation (IW/CPE) ratio. However, at 0.6 IW/CPE ratio the crop responded up to 80 kg N. Significant interaction of nitrogen and weed control on grain yield of wheat was observed. Inter estingly, isoproturon, an urea group herbicide, along with 75 kg N ha−1 gave significantly higher grain yield than with 100 and 125 kg N ha−1 indicating a saving of 25–50 kg fertilizer N. Mustard inoculated with Azotobacter or Azospirillum, and receiving moderate level of fertilizer N (30 kg ha−1) gave similar grain yield to the uninoculated crop receiving higher dose of N (60 kg ha−1).

EFFECT OF IRRIGATION REGIMES, PLANT POPULATION AND PHOSPHORUS LEVELS ON THE YIELD ATTRIBUTES AND YIELD OF SOYBEAN (Glycine max (L.) Merrill)

Field experiments were conducted at Tamil Nadu Agricultural University, Coimbatore, India during the summer (January – April) and kharif (June – September) seasons of 1994 and 1995 in a split plot design. The main plot consisted of three levels of irrigation, with irrigation water/cumulative pan evaporation (IW/CPE) ratios of 0.40, 0.60 and 0.80, and three levels of plant population (0.33, 0.44 and 0.66 million plants ha –1). The subplot treatments consisted of three levels of phosphorus (80, 100 and 120 kg P2O5 ha –1). The results revealed that irrigation at IW/CPE 0.80 with a plant population of 0.66 million plants ha –1 and a P level of 100 kg P2O5 ha –1 is promising in obtaining maximum yield in soybean. Under an irrigation regime of IW/CPE 0.80, the total water consumption varied from 450 to 533 mm, while it varied from 350 to 438 mm at IW/CPE 0.60 and from 250 to 393 mm at IW/CPE 0.40.

Effect of irrigation and manure application on the growth and yield of groundnut

Field experiments were conducted at the Agricultural Research Station, Aliyar Nagar, Tamil Nadu, India during summer 1994 and 1995 on groundnut, adopting a split plot design. Two irrigation regimes based on Irrigation Water/Cumulative Pan Evaporation (IW/CPE) ratios of 0.60 (I1) and 0.75 (I2) were allotted to the main plot. Twelve treatments involving combinations of organic manure with mineral fertilizer were assigned to the subplots. Irrigation scheduled at IW/CPE 0.75 led to higher plant height, number of branches plant –1, dry matter production and leaf area index, resulting in higher yield than IW/CPE 0.60. All the growth attributes and the yield increased in response to a higher level of mineral fertilizer application and organic manure application. The combined application of inorganic and organic manures significantly enhanced the growth attributes and yield of groundnut compared to the sole application of either of them.

Herbage and oil yield of geranium influenced by irrigation, nitrogen and organic mulch grown on alfisol

SummaryTwo field experiments during 1996-98 at Bangalore, India studied the effect of soil moisture regimes (0.3, 0.6 and 0.9 IW:CPE ratios) irrigation water cumulative pan evaporation (IW:CPE) ratios and three levels of nitrogen application (0,100 and 200 kg ha–1). Another experiment investigated three irrigation levels (0.3, 0.6 and 0.9 IW:CPE ratios), two levels of nitrogen application (100 and 200 kg ha–1) and organic mulch (0 and 5 t ha–1) on oil content, herbage, oil yield and quality of geranium grown on alfisols. Soil moisture maintained at 0.6-0.9 IW:CPE ratios significantly increased both the herbage and oil yields of geranium. Application of 200 kg N ha–1 gave maximum herbage and oil yield compared with those obtained from 0 and 100 kg N ha–1. Organic mulch increased the oil yield of geranium. The concentration and quality of essential oil were not influenced either by soil moisture regime, N rates or organic mulch.

Oil and Herb Yields of Java citronella (Cymbopogon winterianusJowitt.) in Relation to Nitrogen and Irrigation Regimes

ABSTRACT Field experiments were designed to study the influence of irrigation at varying soil matric potentials or IW/CPE (Irrigation Water/Cumulative Pan Evaporation) ratios and N applications on the yield and N uptake by Java citronella (Cymbopogon winterianus Jowitt). The results showed that irrigating the crop when soil matric potential reaches -60 kPa or RV/CPE ratio reaches 0.8 resulted in maximum herb and oil yields and N uptake. Citronella responded well to high N applications (400 kg N/ha/year) at -40 kPa soil matric potential.

Performance of Sugarcane (Saccharum officinarum L.) Under Surface Drip, Sub Surface Drip (Biwall) and Furrow Methods of Irrigation

AbstractField experiments were conducted at the Sugarcane Breeding Institute, Coimbatore, India during 1989–93 to study the productivity and water use efficiency of sugarcane under different methods of irrigation. The results showed that there could be a 44 % saving in water with higher water use efficiency in drip irrigation compared to conventional furrow irrigation. Among drip irrigation systems in the plant crop, sub surface drip (Biwall) at 40/140 cm spacing recorded a significantly higher number of millable canes, cane length and single cane weight compared to either conventional furrow irrigation or furrow irrigation based on IW/CPE (Irrigation Water Cumulative Pan Evaporation) ratio. In ratoon crop, Biwall irrigation at 60/120 cm gave significantly higher cane length and single cane weight compared to any other methods of irrigation. However, cane and sugar yields in Biwall irrigations were on par with conventional furrow irrigation but superior to either surface drip or furrow irrigation based in IW/CPE ratio.

STUDIES ON SOIL MOISTURE REG MES DURING CSH-5 HYBRID SEED PRODUCTION SEED GERMINATION, VIGOUR AND STORABILITY

Studies on the influence of soil moisture monitered through IW/CPE (Irrigation Water/Cumulative Pan Evaporation) revealed that germination did not vary due to irri- gation treatments. However, seed quality as estimated through seed weight. protein content. dry weight of seedling, vigour index, germination after soaking in NH.Cl solu- tion and dehydrogenase enzyme activity was maximum in plots receiving irrigation whenever, the ratio reached a value of 0.7.