Drip Fertigation Levels Research Articles

Nutrient Uptake and Soil Nutrient Status as Influenced by Drip Fertigation Levels and Schedules in Broccoli

The experiment was carried out to study the effect of fertigation levels and schedules on growth and yield of broccoli (Brassica oleracea var italica) during the rabi season of 2021-22 involving 4 levels of fertilizer (75, 100 and 125 % RDF) along with one control (100 % RDF) through soil application and three fertigation scheduling (S1, S2 and S3) with three replications. The result of study revealed that higher fertigation of broccoli with balanced nutrition; better water and nutrient utilization gave significantly higher plant growth and yield and good quality of broccoli. In general, pooled mean revealed that application of 125 % RDF with fertigation schedule S2 :15 % NPK at transplanting to plant establishment, 1-10 DAT, 50 % NPK at curd initiation stage,11-35 DAT and 35 % NPK at curd development stage, 36-60 DAT recorded maximum NPK uptake in plant (kg/ha) and available NPK in soil (kg/ha).

Sub-surface drip fertigation of nitrogen coupled with crop residue incorporation enhanced the growth and yield of maize in an alluvial soils

A two-year field experiment was conducted at ICAR-Indian Agricultural Research Institute, New Delhi, to standardize the N-fertigation schedule and crop residue management in sub-surface drip fertigated (SSDF) maize [Pusa HQPM 1’ improved: double bio-fortified]. The experiment was laid-out in a split-plot design with 3 replications. There were 8 main-plot treatments comprising different N sub-surface drip fertigation levels (0, 50, 75, 100% RDN) with one conventional cultivation of maize, where RDN (150 kg/ha) was applied as per recommendation. Under sub-surface fertigation of N, each dose of N was divided into 3-and 4-splits, for fertigation. Sub-plot treatments included greengram residue (3 t/ha) and no greengram residue incorporation. P and K (60 kg P2 O5 /ha and 40 kg K2 O/ha respectively) fertilizers were supplied equally in all the plots by SSDF. Results revealed that plant height at various stages statistically varied with levels and splits of SSDF-N and crop residue incorporation. The highest plant height and leaf area were recorded with 100% RDN-4S which remained at par with 100% RDN-3S and 75% RDN-4S. Conventional maize cultivation was inferior to ‘RDN100’ and 75%, however on par with 50% RDN. The nitrogen uptake was found significantly superior in 100 and 75%RDN over conventional and control treatments. Similarly, the grain yield of maize was highest under 100% ‘RDN-4’ &3 S, and 75% RDN-4S, which were at par with one another. Overall, it could be concluded that sub-surface fertigation of N not only improved the growth and yield of maize but also helped in 25–50% saving of valuable fertilizer.

Performance of drip fertigation and foliar nutrition on cotton-black gram sequence in subtropics

Field experiments were conducted over two seasons to study the effect of drip fertigation levels and foliar nutrition on the growth and yield of cotton-black gram cropping sequences. The treatments comprised three levels of fertigation viz., 50, 75, and 100% recommended dose of fertilizers (RDF) and nitrogen, phosphorus, and potassium (NPK), combined with and without two levels of foliar spray, drip irrigation with soil surface application of 100% RDF, and surface irrigation with soil surface application of 100% RDF as a control. Drip-irrigated cotton and black gram registered higher yields during both seasons as compared to the surface methods of irrigation. Application of 100% RDF as drip fertigation combined with a foliar spray of 1% urea phosphate registered the highest seed cotton yield of 3598 kg ha−1 and black gram grain yield of 856 kg ha−1, which was significantly superior over the control. Application of nutrients through drip fertigation improved seed cotton yield by 45.2% and blackgram grain yield by 49.8% compared with conventional surface irrigation with soil application of fertilizers. From the results, it could be concluded that drip fertigation at 100% RDF with foliar spray of 1% urea phosphate can be recommended for higher productivity in the cotton-black gram cropping sequence.

Effects of Water Stress and NPK Levels on Growth and Yield Attributes of Greenhouse-Grown Cucumbers

Judicious use of water and nutrients is a key factor for successful off-season vegetable production in greenhouses. This experiment was conducted under plastic tunnels to evaluate the effect of water stress and NPK levels on the growth and yield attributes of greenhouse-grown cucumbers. Effect of three irrigation levels viz., 100%, 80% and 60% of actual crop evapotranspiration (ETc) and three drip fertigation levels, viz., 100%, 80% and 60% of the recommended dose of NPK (RDF) with control (furrow irrigation with 100% RDF) were studied in a randomized complete block design experiment. The study indicated better plant growth, a greater number of fruits per plant and enhancement in the yield under drip irrigation. Among the various treatments, T5 (W80%ETc.F80% RDF) resulted in the highest mean fresh fruit yield (66.7 ton/ha) while the full irrigation treatments T1 (W100%ETc.F100% RDF) and T2 (W100%ETc.F80%RDF) recorded the lowest mean fresh fruit yield of 12.9 t/ha and 13.9 t/ha, respectively, as against 9.6 t/ha for the control plot. Conversely, the fully stressed T7, T8 and T9 treatments reduced the irrigation requirement by 29%, 26% and 21% but the mean cucumber yield was significantly decreased by 40%, 70% and 59%, respectively. These results suggested that drip irrigation has a great scope for the production of off-season vegetables. A water deficit level of 80% ETc with 80% RDF is the most appropriate treatment and optimal level to obtain better yield, quality and profitability of greenhouse-grown cucumbers under scarce water resources.

Effect of Drip Fertigation Levels on Soil Fertility and Productivity of Cauliflower cv. Pusa Snowball K-1

The field experiment were conducted during 2013-14 and 2014-15 to study the effect of drip fertigation on nutrient availability, plant parameters and yield of cauliflower. The field experiments were laid out in randomized block design with four replications and six fertigation levels (60, 70, 80, 90, 100 and 110 per cent of recommended dose). Recommended doses of N, P and K are 125, 108 and 76kg/ha, respectively for cauliflower in Himachal Pradesh. Fertigation with recommended dose of fertilizer resulted in highest available N (365.3 kg ha-1), P (95.8 kg ha-1) and K (477.8 kg ha-1). Drip fertigation with recommended dose also increased the available Zn, Cu, Fe and Mn content by 8, 29, 21 and 40 per cent, respectively over 60% recommended dose (i.e N- 75, 65 and 46 kg/ha) treatment. The productivity of cauliflower was maximum with the application of 100 percent nutrients through drip irrigation and recorded an increase of 17.9 percent curd yield over 60 percent RD treatment. The study suggests that application of recommended dose of fertilizer through drip irrigation in 10 splits leads to higher and sustainable cauliflower production.

NPK Uptake Studies under Varied Drip Irrigation Regimes and NK Fertigation Levels in Cucumber in Naturally Ventilated Poly House

The present study was conducted in naturally ventilated poly house at Horticulture garden, College of Agriculture, Rajendranagar, Hyderabad, Telangana during rabi 2020- 2021 to standardize the optimum N and K fertigation levels and their effect on growth, yield and uptake of nutrients and to derive the nutrients uptake curves for cucumber under poly house during rabi (yasangi).The experiment was laid out in a split plot design with 12 treatments consist of three irrigation regimes viz.,drip irrigation scheduled at 0.8 Epan (I1), 1.0 Epan (I2) and 1.2 Epan (I3) as main plots and four NK fertigation levels of 75% recommended dose of NK (F1- N112.5 K75), 100% recommended dose of NK (F2- N150 K100), 125% recommended dose of NK (F3- N187.5 K125) and 150% recommended dose of NK (F4- N225 K150) as sub plots and replicated thrice. NPK uptake were significantly higher in irrigation scheduled at 1.2 Epan followed by 1.0 and 0.8 Epan during all stages. Among drip fertigation levels NPK uptake increased with each increment in drip fertigation level from 75% recommended dose of NK to 150% recommended dose of NK at all stages.

Subsurface Drip Fertigation, Irrigation Regimes and Short Duration Pulses on Productivity of Cotton-Maize Cropping Sequence

Fertigation, a latest technology wherein nutrients are applied along with irrigation water. Fertigation opens new possibilities for controlling water and nutrient supplies to crops besides maintaining the desired concentration and distribution of water and nutrients to the soil. Research works on drip fertigation under intercropping situation is very limited. Input information on optimal schedules for micro-irrigation and fertigation to cotton and maize with intercropping of pulses will have to be generated, thus enabling the option of micro irrigation under intercropping situation. The experiment was laid out in split split plot design with three replications. The main plot consists of two irrigation levels viz., 75 and 100 % PE reading, sub plot contains three drip fertigation levels viz., 75, 100 and 125 % and sub sub plot consist intercropping with short duration pulses viz., sole crop of maize/cotton, intercrop with cow pea, blackgram and cluster bean. The result revealed that no significant differences were noticed in number of bolls, boll weight under different irrigation regimes. Among the fertigation level, 125% RDF recorded higher number of bolls plant-1 and boll weight. The cotton equivalent yield of 3860 kg ha-1 with water saving of 24 per cent was accrued under cotton intercropped with blackgram and irrigation regime of 100% PE with application of 125% RDF (150:75:75 kgs NPK/ha) and it was followed by irrigation regime at 75% PE it increased 18.9% cotton yield compared to control (2099 kg ha-1) with water saving of 40.6%. Regarding maize based intercropping system, maize + black gram intercropping with irrigation regime of 100% PE and 100% RDF (250: 75: 75 kg NPK/ha) gave higher maize equivalent yield of 7735 kg/ha. In cotton – maize sequence, intercropping of black gram found to be best suitable system with the irrigation level of 100% PE and 125% RDF (150:75:75 kg NPK/ha) for cotton and 100% RDF (250: 75: 75 kg NPK/ha) for maize is recommended to get higher yield.

Influence of Different Levels of Drip Fertigation and Mulching on Growth, Yield, Water Productivity and Nutrient Uptake of Pigeonpea (Cajanus cajan L.)

Background: Pigeonpea is second most important pulse crop grown after chickpea in India. Pigeonpea is versatile crop can be grown in vast agro climatic condition with low inputs. However, the yield is very low as compared to the potential yield as grown in rainfed condition, the drip fertigation and mulching can increase resource use efficiency. Both these techniques are resource saving and realized maximum yield by reducing the nutrient and water losses as compared to conventional practices. Methods: The experiment was laid out in factorial complete randomized block design and replicated thrice. The experiment consisted of two levels of irrigation (0.50 CPE and 0.75 CPE) as one factor and three fertility levels (100% RDF, 75% RDF and 50% RDF) as second factor and two levels of mulching (without mulching and with plastic mulching 25 micron) as third factor. Result: The results revealed that higher level of irrigation (0.75 CPE) with 100 per cent RDF and with plastic mulching recorded significantly higher growth rate, seed yield and uptake of nutrients by the pigeonpea crop.

Effect of drip-fertigation levels on gobhi sarson (Brassica napus) performance under Punjab conditions

A field experiment was conducted to study the effect of drip irrigation and fertigation levels on performance of gobhi sarson (Brassica napus L.) during rabi 2016-18. The results revealed that application of irrigation through drip at 100% of CPE (I1.0) recorded highest values for growth components, viz. periodic plant height, dry matter accumulation and leaf area index than I0.8 (80% of CPE) and I0.6 (60% of CPE). Maximum seed and oil yield were recorded at I1.0, which was statistically at par with I0.8 but significantly higher than I0.6 and absolute control. Utilization of water-soluble fertilizers through drip at 100% RDF (F1.0) recorded highest growth components along with seed and oil yield than that produced by 80 and 60% RDF (F0.8 and F0.6). Among treatment combinations, drip-fertigation at I1.0 or I0.8 with F1.0 or F0.8 significantly enhanced seed and oil yield of gobhi sarson than absolute control (flood irrigation and manual application of RDF).

Response of Split Application of Nutrients through Fertigation in Pigeonpea

Background: Among the different production factors, irrigation and nutrient management are of immense importance in Pigeon pea cultivation. Drip irrigation can be considered as an efficient irrigation system to maintain optimum moisture content in the root zone. Split application of fertilizers at appropriate stages of crop growth ensure a regular flow of both water and nutrients resulting in increased growth rate and higher yield. Fertigation proposed as a means to increase efficient use of water and fertilizer to increase yield and sustained irrigated agriculture. The current study aims to study the efficacy of split application of N, P and K on growth, water and nutrient use efficiency, productivity and profitability of Pigeon pea.Methods: The field experiment was conducted at Department of Agronomy Farm, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola during three consecutive kharif season of 2016-17, 2017-18 and 2018-19. The experiment was laid out in randomised block design with four replications and eight treatments with an objective to study the efficacy of split application of nutrients on growth, water and nutrient use efficiency, productivity and profitability of Pigeon pea. Result: The results revealed that, all the growth parameters, yield attributes and grain yield of Pigeon pea were substantially enhanced by drip fertigation levels at 125:100:100 per cent recommended NPK than lower fertigation levels (75 and 100%) and over conventional soil application of recommended dose of NPK kg ha-1. Drip fertigation at 125:100:100 per cent recommended dose of NPK ha-1 recorded higher pigeon-pea pooled grain yield of 4053 kg ha-1. The maximum GMR (Rs.226807 ha-1), NMR (Rs.176604 ha-1), B:C ratio (4.52) and highest economic efficiency of Rs.883 day-1 ha-1.

Effect of drip fertigation levels and plant growth regulators on growth and yield of transplanted redgram (Cajanus cajan)

The field trial was conducted during rabi, 2019 at Water Management Research Block, Department of Agronomy, Agricultural College and Research Institute, Madurai to study the influence of drip fertigation levels and growth regulators on growth and yield of transplanted redgram. The experiment was laid out in a randomized block design with ten treatments and replicated thrice. The treatments include two levels of drip fertigation; 100% and 125% RDF (25:50:25 kg NPK/ha) with foliar spraying of 2% DAP, 1% triacontanol, 200 ppm mepiquat chloride and 100 ppm cycocel on 45 and 60 DAP. Among the treatments, drip fertigation of 125% RDF at weekly interval in equal splits from 15 to 90 DAP with foliar spraying of 2% DAP recorded higher plant height (174.9cm) and a number of branches per plant (35.8). It also proved its significance by recording the maximum grain yield (1539 kg/ha) and stalk yield (13,678 kg/ha) which was 37.4% higher than grain yield obtained under drip fertigation of 100% RDF to transplanted red gram.

Physicochemical properties of banana soils as influenced by drip-fertigation system

Field experiments were conducted on banana during 2008-2010 at the Mondouri Research Farm of AICRP on Tropical Fruits, Bidhan Chandra Krishi Viswavidyalaya, West Bengal encompassing Genetic plains of India with three levels of drip irrigation at 50, 60 and 70% of CPE and three levels of drip fertigation at 50, 60 and 80% of recommended NPK fertilizers with one conventional surface irrigation at IW/CPE 1.0laid in an augmented factorial complete block design having three replications to assess the changes of physicochemical properties of soil. The results of the study showed that irrespective of irrigation methods and levels of drip fertigation soil fertilization, the physicochemical parameters of soil such as pH, EC, organic carbon, water holding capacity, permeability, porosity and saturated hydraulic conductivity are consistently increasing with the increase depth of soil profile. However, drip fertigation system is found to be the best option in improving these soil health indices in comparison with the conventional surface irrigation and direct soil fertilization which is likely to increase the fruit yield, water and nutrient productivity of banana crop.

Effect of drip fertigation schedule and different mulches on vegetative growth of gladiolus cv. Psittacinus Hybrid

The field experiment was conducted at Department of Horticulture, Junagadh Agricultural University, Junagadh during the year October 2016 to April 2018. The experiment was laid out in Randomized Block Design with Factorial concept (FRBD) consisting three factors with three replications. The treatment comprised with three levels of drip fertigation viz., water soluble NPK @ 200:200:200 kg/ha (F1), water soluble NPK @ 300:225:225 kg/ha (F2) and water soluble NPK @ 400:250:250 kg/ha (F3); three levels of split application of fertilizer viz. 2 split i.e. 30 and 60 DAP (S1), 3 split i.e. 20, 40 and 60 DAP (S2) and 4 split i.e. 15, 30, 45 and 60 DAP (S3) and three different mulches viz. red mulch (M1), black mulch (M2) and silver mulch (M3). The effects of these treatments were noted on vegetative growth of gladiolus. Significantly maximum sprouting percentage, plant height (at 30, 60 and 90 DAP), number of leaves (at 30, 60 & 90 DAP), number of effective tillers/plant and number of total tillers/plant, while number of non effective tillers/plant was minimum with the application of drip fertigation of NPK @ 200:200:200 kg/ha (F1), 3 split application of fertilizer (S2) and use of red mulch (M1). For interaction effect, the result was found non significant for all parameters except number of effective tillers/plant was recorded in treatment combinations F1S2, S2M1, F1M1 and F1S2M1.

Drip fertigation regimes for winter wheat in the North China Plain

To establish the optimum fertilization rate and propose an appropriate drip fertigation regime for winter wheat in the North China Plain (NCP), a three-year field experiment was conducted to evaluate the effects of drip fertigation levels on soil available nutrients, winter wheat growth, grain yield, partial factor productivity (PFP), and irrigation water use efficiency (IWUE) during 2014-2017. The experiment investigated five fertilization rates: 20%, 45%, 70%, 95%, and 120% of the local recommended fertilizer dose (336 kg/ha N and 169 kg/ha P2O5) for high grain yield. The results showed that with the increase of fertilization rates, the concentrations of the soil available nitrogen (N) and phosphorus (P) in the 0–140 cm layer increased, and especially the N in deep layer (100–140 cm) and the P in surface layer (0–20 cm) increased evidently by 0.64 and 0.06 mg/kg with each unit increased of fertilization rate, respectively. Compared with the initial available nutrient concentrations, the fertilization rate of 45%–70% could basically maintain the balance of soil available N, and the fertilization rate of 70% provided a good balance for soil available P. Different fertilization rates had significant effects on winter wheat plant height (H), maximum leaf area index (LAI), dry matter (DM), grain yield, PFP, and IWUE. With each unit of increase in the fertilization rate, the winter wheat yield increased rapidly by 0.61% in the fertilization rate from 20%–70% and slowly by 0.32% in the fertilization rate from 70%–120%. The PFP decreased according to a power function with the increasing fertilization rate. Compared to the average grain yield and PFP under the local surface irrigation regime, drip fertigation of 70% of the local recommended fertilizer dose resulted in a yield increase of 4.0% and a PFP increase of 48.5%. To achieve a relatively high grain yield, high fertilization use efficiency, and minimize risk of environment pollution, a reduction in the fertilization rate to 70% of the local recommended fertilization dose (235 kg/ha N and 118 kg/ha P2O5) was suggested for winter wheat production under drip fertigation in the NCP.

Effect of Drip Fertigation on Yield, Water Use Efficiency, and Nutrients Availability in Banana in West Bengal, India

ABSTRACTField studies were conducted during 2008–2009 and 2009–2010 at the Gangetic alluvial plains of West Bengal, India, to assess the different levels of drip fertigation at variable evaporation replenishment compared to surface irrigation and conventional soil fertilization on yield, water use efficiency, and nutrients availability in plant and ratoon crop of banana. The experiment was laid in an Augmented Factorial Complete Block Design with three replications having three drip irrigation schedules at 50%, 60%, and 70% of cumulative pan evaporation (CPE) and three drip fertigation schedules at 50%, 60%, and 80% of recommended nitrogen, phosphorus, and potassium (NPK) fertilizers with inclusion of conventional surface irrigation at 100% of IW/CPE. The results showed that fruit yield of plant and ratoon crop increased progressively with increasing levels of irrigation water (up to 60% CPE) and NPK fertigation through the drip system. However, maximum fruit yield and water use efficiency of crops was obtained with drip irrigation at 60% CPE with NPK fertigation at 80% of recommended dose. Drip irrigation, as a whole, registered higher fruit yields and water use efficiency with savings of 38.3–41.5% of water compared to surface irrigation. Availability of N, P, and K in soil at vegetative, shooting, and harvesting stages for plant and ratoon crop consistently increased with increasing rate of irrigation water and NPK fertigation through the drip system. Higher availability of macronutrients in soil was recorded with drip irrigation at 70% CPE with 80% of recommended drip NPK fertigation. Overall drip fertigation system improved the available plant nutrients in the soil as compared with traditional surface irrigation.

Onion seed productivity, nutrient use, and quality response to drip fertigation in semi-arid India

ABSTRACTCrop productivity and nutrient use are mainly water restricted in semi-arid regions. This study was conducted to find out whether the onion seed crop productivity could be elevated through drip fertigation. The effects of irrigation and fertigation levels on yield, yield components, quality, and nutrient use of onion seed crop (Allium cepa L.) were investigated at Mahatma Phule Krishi Vidyapeeth, Rahuri, Maharashtra, western India on a sandy clay loam soil. Irrigation water applied at evapotranspiration (ETc) levels at 80% (I1), 90% (I2), and 100% (I3), whereas drip fertigation levels at 60%, 80%, 100%, and 120% of recommended dose [120:60:60 nitrogen, phosphorus, potassium (NPK) kg/ha] were investigated. Three-year experiment results showed no significant differences in number of seed per umbel, seed yield per umbel per plant, seed and straw yield per hectare from the comparison between 100% ETc and 90% ETc. In fertigation, 120% and 100% levels gave significantly higher values of yield components and seed yield than the 80% and 60% levels. The quality parameters decreased with decrease in ETc, but increased with increase in fertigation levels. Fertilizer-use efficiency (FUE) was highest in 60% fertigation and then declined with the increase in fertigation levels. Irrigation at 100% ETc and fertigation at 120% resulted in higher nutrient use, but the difference with 90% ETc and 100% fertigation was non-significant. The 90% ETc and 100% fertigation dose (120:60:60 NPK kg/ha) appears a useful practice to increase onion seed productivity under the semi-arid climate of western India.

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%.

Drip fertigation effects on yield, nutrient uptake and soil fertility of Bt Cotton in semi arid tropics

Field experiment was conducted for 2 seasons to study the influence of drip fertigation in combination with or without bio fertilizers on yield, plant uptake and soil fertility of Bt cotton. The treatments comprised of four levels of drip fertigation viz., 75, 100, 125 and 150 per cent of recommended dose of fertilizers (RDF, NPK) combined with and without bio fertilizers, drip irrigation with soil surface application of 100 per cent RDF and surface irrigation with soil surface application of 100 per cent RDF as control. Biofertilizers used for fertigation is azophosmet containing Azospirillum, phosphobacterium and pink pigmented facultative methylotroph. Most of the yield attributes viz., number of sympodial branches per plant, number of fruiting points, bolls per plant, plant uptake and available soil N, P and K of Bt cotton were significantly increased by the drip fertigation treatments. Application of 150 per cent RDF as drip fertigation combined with biofertigation of liquid formulation of azophosmet @ 250 ml (10 12 cells ml -1 ) ha -1 registered the highest seed cotton yield of 3395 kg ha -1 and was significantly superior over control. Biofertigation significantly increased seed cotton yield and a progressive increase in seed yield was noticed with increasing levels of NPK fertilizer application. Application of nutrients through drip fertigation improved seed cotton yield by 43.0 per cent compared with conventional surface irrigation with soil surface application of fertilizers. The nutrient uptake pattern and post harvest soil fertility status also followed similar trend and confirmed the significance of drip fertigation with biofertilizers.

Influence of spacing and fertilizer levels on the leaf nutrient contents of Bhendi (Abelmoschus esculentus L. Moench) under drip fertigation system

Field experiments were conducted during 2010 to 2012 to study the effect of spacing and fertilizer levels on the leaf nutrient contents of Bhendi (Abelmoschus esculentus L. Moench) under drip fertigation system at Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore. The treatments consisted two spacings (M1-60 x 45 cm and M2 - 60 x 30 cm) and eight drip fertigation levels. The study revealed that drip fertigation at 125% recommended dose of fertilizers (250:125:125 kg NPK/ha) as water soluble fertilizer combined with Azophosmet (0.5% at750 ml/ha) and humic acid (0.4% at2.5 litre/ha) under wider spacing registered the highest leaf nutrient status like nitrogen (2.31%), phosphorus (0.53%), potassium (1.33%), calcium (0.59%), magnesium (1.46%), zinc (45.55 ppm), manganese (102.81 ppm) and boron content (16.70 ppm), whereas, the leaf copper content (22.31 ppm) was the highest under 100% recommended dose of fertilizers as water soluble fertilizer combination with Azophosmet and humic acid under wider spacing. Key words: Spacing, fertilizer levels, Bhendi, drip fertigation, leaf nutrients.

Root Characters of Maize as Influenced by Drip Fertigation Levels

The efficient use of water by modern irrigation systems is becoming increasingly important in arid and semi-arid regions with limited water resources. Field experiments were conducted during 2008-2010 to study the effect of drip fertigation with water soluble fertilizer on root growth of maize under maize based intercropping system. The experiment was laid out in strip plot design with three replications. The treatment consists of nine fertigation levels in main plots and four inter crops in sub plots. Root spread and root dry mass were increased under drip fertigation practices while rooting depth was more under surface irrigation. Drip fertigation with water soluble fertilizer improved the root system by inducing new secondary roots which are succulent and actively involved in physiological responses. Drip fertigation has pronounced effect on the root architecture especially in the production of highly fibrous root system.