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Karnataka J. Agric. Sci.,25 (1) : (25-29) 2012

Effect of nitrogen, phosphorus and potassium levels on growth and yieldof stevia (Stevia rebaudiana Bertoni.)*

Y. R. ALADAKA TTI, Y. B PALLED, M. B. CHETTI, S. I. HALIKATTI, S. C. ALAGUNDAGI, P. L. PATIL,V. C. PATIL 1 AND A. D. JANAWADE

Department of Agronomy, University of Agricultural Sciences, Dharwad-580005, India1Precision Agriculture Research Chair, King Saud University, Riyadh, Saudi Arabia

Email: yraladakatti@rediffmail.com

(Received: August, 2011 ; Accepted : March, 2012)

Abstract: A field experiment was conducted in medium black, clayey soil under irrigated conditions to assess the response ofstevia to levels of nitrogen, phosphorus and potassium. Five cuttings (crops) were taken in a year. Pooled results indicatedthat significantly higher dry leaf yield was obtained with nitrogen @ 400 kg ha-1 (11.42 t ha-1 ) and it was on par with 300 kgha-1 (10.94 t ha-1 ). Phosphorus @ 200 kg ha-1 recorded significantly highest dry leaf yield (11.14 t ha-1 ) and it was on par with150 kg ha-1 (10.85 t ha-1). Potassium @ 200 kg ha-1 recorded dry leaf yield of 10.78 t ha-1 and it was comparable withpotassium @100 kg ha-1 (10.46 t ha-1 ). The growth parameters viz., plant height, number of branches plant-1 and number ofleaves plant-1 were significantly higher with nitrogen, phosphorus and potassium @ 400 kg ha-1, 200 kg ha-1 and 200 kg ha-1,respectively which were on par with 300 kg ha-1, 150 kg ha-1 and 100 kg ha-1 respectively. In pooled data nitrogen @ 400 kgha-1 (N

2) recorded the highest B:C (3.01) which was on par with nitrogen @ N

2 i.e., 300 kg ha-1 (2.93), but significantly higher

than N1 i.e., 200 kg ha-1 (2.66). Phosphorous P

3 i.e., 200 kg ha-1 resulted in higher B:C (2.96) which was on par with P

2 i.e.,

150 kg ha-1 (2.91). Potassium level influenced the B:C non-significantly. Significantly lowest B:C were recorded withabsolute control in pooled data (2.14). Interactions of N, P and K were non-significant. Nutrient level of 300:150:100 kg ha-1

NPK applied in equal splits to five cuttings (Crops) in year has been considered as an economically optimum level ofnutrients for stevia.

Key words: Nitrogen, Phosphorus, Potassium, Stevia, Uptake

Introduction

Stevia (Stevia rebaudiana Bertoni.) is a herbaceousperennial small bush contaning carbohydrate basedcompounds in its leaves, which are many times sweeter thancane sugar and sugarbeet. Dry leaves are the economic part instevia plant. Stevia leaves have taste 20-30 times sweeter thancane sugar but impotantly without any calories. Hence, steviais a potential natural source of no calorie sweetner, alternativeto the synthetic sweetening agents like saccharine, aspartame,asulfam-K that are available in the market to the diet consciousconsumers and diabetics. Cultivation of stevia crop madesignificant impact in the countries like Japan, China, Korea,Mexico, USA, Thailand, Malaysia, Indonesia, Australia,Canada and Russia (Brandel and Rosa, 1992). Studiesconducted in India so far could suggest only few managementapproaches for improving productivity. Since the productionpotential of stevia in India is 2-3 t ha-1 of dry leaves as against1-2 t ha-1 in China, it has definite advantage over China(Chalapathi et al., 1997 b). Stevia can be cultivated profitablywherever irrigation facilities are available. In India someresearch work was carried out at University of AgriculturalSciences, Bengaluru in Karnataka and at the Institute ofHimalayan Bioresource Technology (IHBT), Palampur,Himachal Pradesh during 1996 and 2003, respectively (Megejiet al., 2005). There is no adequate information on nutrientrequirement for stevia. The present investigation was

undertaken to determine the optimum N, P and K levels forhigher dry leaf yield of stevia.

Material and methods

A field experiment was conducted at Water ManagementResearch Center (WMRC), Belavatagi, (Ta: Navalagund, Dist:Dharwad) under irrigated conditions during 2004-05 to 2005-06.It is located in semi-arid tract of Karnataka at 15o 34' N latitudeand 75o 21' E longitude at an altitude of 578 m above mean sealevel. The soil of the experimental site was medium black, clayeysoil (Vertisols) with a depth of more than 1.5 m having highwater holding capacity (78 %) and low infiltration rate(0.25 cm ha-1) The pH and Ec of the soil was 8.1 and 0.23dSm-1 respectively, with organic carban of 0.64%, available N,P

2O

5 and K

2O were 285 kg ha-1, 26 kg ha-1 and 620 kg ha-1

respectively. The initial composite soil samples from both thesites were collected from 0 to 30 cm soil depth beforecommencement of the experiment. The experiment consistedof 3 levels of nitrogen ( N

1 - 200 kg ha-1, N

2 - 300 kg ha-1,

N3 - 400 kg ha--1), 3 levels of phosphorous ( P

1 - 100 kg ha-1,

P2 - 150 kg ha-1, P

3 - 200 kg ha-1), and 2 levels of potassium

( K1 - 100 kg ha-1, K

2 - 200 kg ha-1). All nutrients in each treatment

were applied in equal splits for five cuttings (Crops) in a yearincluding plant crop. The treatments were laid out in randomizedblock design with factorial concept in three replications andone absolute control with out any nutrients as check. Twomonths old stevia seedlings were planted with a common spacing

* Part of Ph.D. thesis submitted by the first author to the University of Agricultural Sciences, Dharwad-580005, India

26

Karnataka J. Agric. Sci.,25 (1) : 2012

of 30 cm x 30 cm on 24th June, 2004. A common dose of FYM@10 t ha-1 was applied to all treatments before planting. Thenutrients N, P and K were applied in the form of di-ammoniumphosphate (DAP), urea and muriate of potash (MOP),respectively. Entire P and K , fertilizers and 50 per cent Nwere applied a week after transplanting. Remaining 50 percent N was applied in three equal splits at 30, 45 and 60 daysafter transplanting (DAT) for plant crop. But for thesubsequent ratoon crops entire P and K nutrients along with50 per cent N was applied two days after harvest and theremaining 50 per cent N was top dressed in two equal splits at30 and 45 days of harvest of previous crop. This was followedand maintained for each cutting throughout the crop seasonduring both the years. The plots were irrigated at 1.0 IW/CPEratio to a depth of 60 cm in each irrigation. First crop washarvested at 90 days after planting, whereas the succeedingcrops were harvested at a regular interval of 70 days. The plantswere cut uniformly 10 cm above the ground level and the greenbiomass was sun dried for a day, then shade dried for a week.The dried stevia leaves were stripped off from the stem anddried separately under sunlight for a day and stored in cleangunny bags. Totally five cuttings (Crops) per year were takenand the plots were maintained for two years.

Results and discussion

The mean data on plant height, number of branches andleaves plant-1 are presented in Table 1. The pooled data revealedthat the increase in nitrogen levels from 200 kg ha-1 (N

1) to 400

kg ha-1 (N3) increased the plant height, number of branches and

leaves plant-1 progressively. N3

i.e., 400 kg ha-1 recordedsignificantly higher plant height (57.00 cm), maximum numberof branches plant-1 (52.5) and maximum number of leaves plant-1

(847.7) in pooled data, closely followed by N2 i.e., 300 kg ha-1

(54.41 cm, 50.16 and 824.5 respectively). The nitrogen level of200 kg ha-1 (N

1) recorded lower plant height (49.58 cm), less

number of branches plant-1 (43.8), and less number of leavesplant-1 (750.4) at harvest in pooled data. Increase in phosphoruslevels also increased the plant height, number of branches andleaves plant-1 in pooled data, but phosphorus level P

2 (150 kg ha-1)

recorded the plant height, number of branches plant-1, andnumber of leaves plant-1 of 53.72 cm, 49.3 and 817 respectively,which were on par with these parameters recorded with P

3 i.e.,

200 kg ha-1 (56.1 cm, 51.1 and 843.4) in pooled data. Levels ofpotassium did not influence the plant height, number of branchesplant-1, and leaves plant-1 at harvest significantly. However,pooled data revealed that potassium level of K

2 (200 kg ha-1)

recorded the higher plant height (54.3 cm), more number ofbranches and leaves plant-1 ( 49.5 and 816.2 respectively), closely

Table 1. Growth parameters of stevia at harvest as influenced by irrigation schedule and planting geometry

*Treatment Plant height at harvest (cm) Number of branches plant -1 Number of leaves plant -1

2004-05 2005-06 Pooled 2004-05 2005-06 Pooled 2004-05 2005-06 PooledNitrogen levels (N)N

1 (200 kg ha-1) 50.6 48.5 49.6 39.9 47.7 43.8 728.8 772.0 750.4

N2 (300 kg ha-1) 55.2 53.6 54.4 46.5 54.7 50.2 805.0 844.2 824.6

N3 (400 kg ha-1) 57.9 56.0 57.0 48.5 56.5 52.5 825.2 870.1 847.7

S.Em.± 0.91 0.92 0.94 0.53 0.73 0.85 11.95 13.35 12.55C.D. (P=0.05) 2.63 2.65 2.72 1.54 2.12 2.46 34.35 38.37 36.08

Phosphorous levels (P)

P1 (100 kg ha-1) 51.9 50.4 51.20 41.9 50.2 46.1 740.7 783.5 762.1

P2 (150 kg ha-1) 54.8 52.6 53.7 45.2 53.3 49.3 794.7 839.3 817.0

P3 (200 kg ha-1) 57.0 55.1 56.1 47.8 55.3 51.1 823.4 863.4 843.4

S.Em.± 0.91 0.92 0.94 0.53 0.73 0.85 11.95 13.35 12.55C.D. (P=0.05) 2.63 2.65 2.72 1.54 2.12 2.46 34.35 38.37 36.08

Potassium levels (K)

K1 (100 kg ha-1) 53.9 52.1 52.9 44.3 52.3 48.1 776.7 820.9 798.8

K2 (200 kg ha-1) 55.3 53.4 54.3 45.7 53.6 49.5 795.9 836.5 816.2

S.Em.± 0.74 0.61 0.64 0.44 0.60 0.54 9.76 10.90 10.25C.D. (P=0.05) NS NS NS 1.26 NS NS NS NS NSAbsolute control 40.5 36.6 38.6 24.3 21.9 23.1 319.8 307.9 313.8

Control v/s Treatment

S.Em.± 2.26 1.83 1.93 1.28 1.77 1.60 28.62 31.81 29.96C.D. (P=0.05) 6.49 5.25 5.54 3.69 5.10 4.60 82.10 91.22 85.94

All interactions NS NS NS NS NS NS NS NS NS

2004-05 : average of first five cuttings 2005-06 : average of next consecutive five cuttings Pooled : Average of 1 to 10 cuttingsNS: Non significant* N, P and K doses applied for five cuttings (Crops) in equal splits

27

Effect of nitrogen, phosphorus and potassium levels on growth and....

Table 2. Fresh biomass, fresh leaf and dry leaf yield of stevia as influenced by different nutrient levels

*Treatment Fresh biomass yield(t ha-1) Fresh leaf yield (t ha-1) Dry leaf yield (t ha-1)

2004-05 2005-06 Pooled 2004-05 2005-06 Pooled 2004-05 2005-06 Pooled

Nitrogen levels (N)

N1 (200 kg ha-1) 72.59 79.14 75.87 38.29 40.09 39.19 9.24 9.76 9.50

N2 (300 kg ha-1) 84.07 91.61 87.84 43.96 46.86 45.41 10.66 11.22 10.94

N3 (400 kg ha-1) 87.25 96.56 91.90 45.72 49.18 47.45 11.12 11.72 11.42

S.Em.± 1.37 1.09 1.48 0.78 0.83 0.74 0.23 0.18 0.19C.D.(P=0.05) 3.95 3.13 4.28 2.25 2.40 2.14 0.65 0.53 0.53

Phosphorous levels (P)

P1 (100 kg ha-1) 76.47 81.79 79.13 40.18 41.72 40.95 9.68 10.06 9.87

P2 (150 kg ha-1) 82.04 91.17 86.61 43.19 46.67 44.93 10.52 11.18 10.85

P3 (200 kg ha-1) 85.04 94.35 89.87 44.60 47.73 46.17 10.83 11.46 11.14

S.Em± 1.37 1.09 1.48 0.78 0.83 0.74 0.23 0.18 0.19C.D.(P=0.05) 3.95 3.13 4.28 2.25 2.40 2.14 0.65 0.53 0.53

Potassium levels (K)

K1 (100 kg ha-1) 80.22 87.48 83.85 42.08 44.70 43.39 10.19 10.73 10.78

K2 (200 kg ha-1) 82.39 90.73 86.56 43.23 46.05 44.64 10.49 11.07 10.46

S.Em.± 1.12 0.89 2.01 0.63 0.59 0.57 0.19 0.13 0.15C.D.(P=0.05) NS 2.56 NS NS NS NS NS NS NSAbsolute control 36.61 33.48 35.04 17.14 14.86 16.00 4.70 3.76 4.23

Control v/s Treatment

S.Em.± 3.29 2.61 2.76 1.87 1.73 1.67 0.54 0.39 0.44C.D.(P=0.05) 9.45 7.5 7.92 5.37 4.97 4.79 1.55 1.12 1.27

All interactions NS NS NS NS NS NS NS NS NS

2004-05: average of first five cuttings 2005-06: average of next consecutive five cuttings Pooled : Average of 1 to 10 cuttingsNS: Non significant* N, P and K doses applied for five cuttings (Crops) in equal splits

followed by K1 i.e., 100 kg ha-1 (52.9 cm, 48.1 and 798.8 respectively

). Absolute control with out any nutrients recorded significantlylowest plant height (38.6 cm), least number of branches (23.1)and leaves plant-1 (313.8). All the interaction effects between N,P and K had no significant influence on the plant height, numberof branches and leaves plant-1 in pooled data (Table 1). Plantheight at harvest was significantly influenced by higher levelsof nitrogen, phosphorus and potassium which in turn wereresponsible for higher number of branches plant-1 and numberof leaves plant-1 resulting into higher leaf yield. The results arein accordance with the findings of Chalapathi et al. (1999), whoalso reported increased plant height and number of branchesplant-1 with nutrient levels of 40:30:45 kg NPK ha-1 in sandyloam soils at Bangalore. But different potassium levels did notinfluence the total dry leaf yield significantly. These growthparameters might have possibly contributed positively to thehigher leaf yield with higher N, P and K application. Kawatani etal. (1980) at Japan had also reported the increased number ofbranches and leaves plant-1 of stevia with higher nitrogennutrition and also reported positive response to higher levels ofpotassium application. Increased number of leaves plant-1 withincreased levels of N, P and K fertilizers was also reported byBuana and Goenadi (1985) in Brazil.

The cumulative fresh biomass yield, fresh leaf yield anddry leaf yield of stevia recorded during the first year, secondyear and pooled is presented in Table 2. These parameters

were significantly influenced by varied levels of nitrogen andphosphorous but not with potassium levels in pooled data.Highest fresh biomass yield (91.9 t ha-1), fresh leaf yield (47.45 t ha-1)and dry leaf yield (11.42 t ha-1) were posible with nitrogen levelof N

3 i.e., 400 kg ha-1which was on par with N

2 i.e., 300 kg ha-1

and both were superior over N1. Phosphorus level P

3 (200 kg ha-1)

recorded the highest fresh biomass (89.87 t ha-1), fresh leafyield (46.17 t ha-1) and dry leaf yield (11.14 t ha-1) which wereon par with P

2 i.e., 150 kg ha-1 (86.61 t ha-1, 44. 93 t ha-1,

10.85 t ha-1 respectively), but superior to P1. Higher fresh

biomass, fresh leaf yield and dry leaf yield of stevia with higherN, P, and K nutrient levels could be attributed to more numberof branches and leaves plant-1 of stevia due to higher plantheight. Different potassium levels did not influence theseparameters of stevia significantly. Significantly lower freshbiomass (35.04 t ha-1) dry leaf yield of 4.23 t ha-1 was obtainedwith the absolute control as against all other treatments appliedwith nutrients (Table 2), due to the lowest number of branchesand leaves plant-1. Murayama et al. (1980) in Japan alsoexperimentally proved that no manuring resulted in lowestleaf yield of stevia. Increased dry leaf yield was also reportedby Shock (1982a) in Japan with moderate application ofnitrogen, phosphorus and potassium. He also reported lowerdry leaf yield ( 42.39 q ha-1) with absolute control withoutany fertilizer, which was 62 and 63 per cent less as comparedto higher levels of nitrogen and phosphorous. Research

28

conducted at Egypt also showed a significant increase in dryleaf biomass yields of stevia when nitrogen fertilizer wasincreased from 10 to 30 kg N ha-1 wherein the dry leaves yieldincreased by 64 per cent compared to lower dose (Allamet al., 2001). In conformity of these findings growth and yieldof stevia increased significantly with increasing rates of N, Pand K up to 60:30:45 kg ha-1 per crop with the highest dry leafyield which was on par with 40:20:30 kg ha-1 per crop in sandyloam soils at Bangalore (Chalapathi et al., 1999b). Interactioneffects of nutrient levels on dry leaf yield were not significant.

Economics of stevia cultivation as influenced by differentlevels of nutrients is presented in Table 3. In pooled data N

3 i.e.,

400 kg ha-1 recorded a net returns of ` 7,62,615 ha-1 which wason par with N

2 i.e., 300 kg ha-1 (` 7,20,780 ha-1). Higher

phosphorus level P3 i.e., 200 kg ha-1 recorded the highest net

returns (̀ 7,37,880 ha-1) which was on par with P2 i.e., 150 kg

ha-1 (̀ 7,12,680 ha-1). Higher levels of potassium K2 i.e., 200 kg

ha-1 recorded the net returns (` 7,05,905 ha-1) comparable withK

1 i.e., 100 kg ha-1 (` 6,78,015 ha-1) in pooled data. Absolute

control recorded significantly lower net returns of ̀ 2,59,064 ha-1

as compared to rest of the treatments (Table 3). Barathi (2003) atCoimbatore reported a total net profit of about ` 1.8 lakhs acre-1 during first year and ` 4.5 lakhs acre-1 during subsequent years

Table 3. Economics of stevia as influenced by different nutrient levels

*Treatment Gross returns Cost of cultivation Net returns Benefit :Cost(` ha-1) (` ha-1) (` ha-1)

2004-05 2005-06 Pooled 2004-05 2005-06 Pooled 2004-05 2005-06 Pooled 2004-05 2005-06Pooled

Nitrogen levels (N)

N1 (200 kg ha-1) 924000 976000 950000 524826 190652 357739 399600 785370 5924851.76 5.11 2.66

N2 (300 kg ha-1) 1066000 1122000 1094000 540108 206325 373216 526140 915420 7207801.97 5.42 2.93

N3 (400 kg ha-1) 1112000 1172000 1141704 545736 212438 379087 565790 959440 7626152.03 5.51 3.01

S.Em.± 22660 16402 18516 2266 1640 1852 20396 14762 16664 0.03 0.04 0.03C.D.(P=0.05) 65130 47141 53214 6513 4714 5321 58620 42427 47893 0.10 011 0.09

Phosphorous levels (P)

P1 (100 kg ha-1) 968000 1006000 986764 529190 193696 361443 438380 812260 6253201.82 5.18 2.73

P2 (150 kg ha-1) 1052000 1118000 1084998 538681 205951 372316 513300 912060 7126801.95 5.41 2.91

P3 (200 kg ha-1) 1083000 1146000 1114165 542799 209767 376283 539860 935900 7378801.99 5.45 2.96

SEm± 22660 16400 18516 2266 1640 1852 20396 14762 16664 0.03 0.04 0.03C.D.(P=0.05) 65130 47140 53214 6513 4714 5321 58620 42427 47893 0.10 0.11 0.09

Potassium levels (K)

K1 (100 kg ha-1) 1019000 1073000 1046035 535005 201035 368020 484210 871820 6780151.90 5.32 2.84

K2 (200 kg ha-1) 1049000 1107000 1077917 538775 205241 372008 510140 901670 7059051.94 5.37 2.89

S.Em.± 18500 28410 15118 1850 1339 1512 16654 12053 13606 0.03 0.03 0.02C.D.(P=0.05) NS NS NS NS NS NS NS NS NS NS NS NSAbsolute control 470000 376000 423000 472829 114107 293468(-) 2829 261893 259064 0.99 3.29 1.44

Control v/s Treatment

S.Em.± 54100 39202 44095 5410 3920 4410 48690 35282 39686 0.08 0.09 0.07C.D.(P=0.05) 155170 112440 126472 15516 11244 12647 139650 101196 113825 0.23 0.25 0.22

All interactions NS NS NS NS NS NS NS NS NS NS NS NS2004-05: average of first five cuttings 2005-06: average of next consecutive five cuttings

Pooled : Average of 1 to 10 cuttings Seedling cost: ` 3 per seedling Selling price : ` 100/ kg dry stevia leaf NS : Non significant* N, P and K doses applied for five cuttings in equal splits

with a selling rate of ̀ 200 kg-1 dried leaves of stevia. In Canada,it was reported that a leaf yield of 2200 kg ha-1 amounts to thecost of production of $ 8500, with a price of $ 3.85 kg-1 driedleaves (Colombus, 1997). Megeji et al. ( 2005) at Palampur alsoreported a total net returns of ̀ 3.75 lakhs for four years with anaverage annual income of ` 0.93 lakhs ha-1 at a sale price of `100 kg-1 dried leaves, with a benefit cost ratio of 1.89. In pooleddata nitrogen level of 400 kg ha-1 (N

2) recorded the highest B:C

(3.01) which was on par with nitrogen level of N2 i.e., 300 kg ha-1

(2.93), but significantly higher than N1 i.e., 200 kg ha-1 (2.66).

Higher level of phosphorous P3 i.e., 200 kg ha-1 resulted in higher

B:C (2.96) which was on par with P2 i.e., 150 kg ha-1 (2.91).

Potassium level influenced the B:C non-significantly. Significantlylower B:C was recorded with absolute control in pooled data(1.44). However, the interaction effects proved to be non-significant.

Stevia responded significantly up to 300:150:100 kg ha-1 NPKwherein five cuttings were possible in a year. As all interactionsare non significant, based on the main factors effect andeconomics, the combination of N

2P

2K

1 i.e., 300:150:100 kg ha-1

for a total of five crops in a year has been considered as theeconomically optimum level of nutrients for stevia in mediumblack soil under irrigation.

Karnataka J. Agric. Sci.,25 (1) : 2012

29

Effect of nitrogen, phosphorus and potassium levels on growth and....

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