economics of potassium fertiliser application in rice, wheat and

Economics of Potassium FertiliserApplication in Rice, Wheat and Maize

Grown in the Indo-Gangetic PlainsKaushik Majumdar, Anil Kumar, Vishal Shahi and T. Satyanarayana

International Plant Nutrition Institute (IPNI)-South Asia Program, Gurgaon, Haryana, IndiaM. L. Jat and Dalip Kumar

International Maize and Wheat Improvement Centre (CIMMYT), NASC Complex, Pusa, New Delhi, IndiaMirasol Pampolino

International Plant Nutrition Institute (IPNI)-South East Asia Program, Penang, MalaysiaNaveen Gupta

Punjab Agricultural University, Ludhiana, Punjab, IndiaVinay Singh

Dr. B. R. Ambedkar University, Agra, Uttar Pradesh, IndiaB. S. Dwivedi and M. C. Meena

Indian Agricultural Research Institute (IARI), Pusa, New Delhi, IndiaV. K. Singh

Project Directorate for Farming Systems Research, Modipuram, Meerut, IndiaB. R. Kamboj

Cereal Systems Initiative for South Asia (CSISA), IRRI-CIMMYT, Haryana Hub, Karnal, IndiaH. S. Sidhu

Borlaug Institute for South Asia (BISA), CIMMYT, Ladowal, Punjab, Indiaand

Adrian JohnstonInternational Plant Nutrition Institute (IPNI), Saskatoon, Saskatchewan, Canada

Indian J. Fert., Vol. 8 (5), pp.44-53 (10 pages)

Indian Journal of Fertilisers, May 20124 4

Potassium (K) fertiliser cost has increased considerably over the past three years. Thesharp increase in price has raised doubts about the profitability of potassium applicationin cereals where the Minimum Support Prices (MSP) is low. On-farm K response studiesin rice, wheat and maize, spread across the Indo-Gangetic Plains, highlighted that grainyield response to fertiliser K is highly variable and is influenced by soil, crop andmanagement factors. Average yield losses in rice, wheat and maize in farmers’ fields dueto K-omission were 622, 715 and 700 kg/ha, respectively. This suggests that skippingapplication of K in the three cereal crops will cause variable yield and economic loss tothe farmers of the region and will affect overall cereal production in the country. Thereturn on investment of applied potassium in rice, wheat and maize were Rs. 5.5, 4.4 and3.2 respectively per rupee invested on K. Economic assessment based on projected cost ofK fertiliser and projected MSP of the cereals also showed favourable return on investmentfor K fertiliser. Considering the high variability in K response, blanket K recommendationswould most likely lead to economic loss for farmers due to under or over application inmost cases. A site specific potassium management strategy, based on the expected cropresponse to K at a location, would improve yield and profitability of cereal farming.

Indian Journal of Fertilisers, May 2012 4 5

Potassium (K) is one of threeprimary nutrients requiredby crops to complete theirlife cycle and produce food.

It did not receive much attentionin India till the 1980s because of thegeneral belief that Indian soils werewell supplied with K (7). However,the scenario of crop responses to Kin India has been changing withtime. Indeed, there is growingevidence of increasing deficiency ofK as a result of i) sub-optimal or noapplication of K fertilisers and ii)imbalanced use of nitrogen (N) andphosphorus (P). Even under the so-called optimum rates of NPKapplication in long-termexperiments, the K balance undermost of the soils and croppingsystems was negative (9). Suchimbalance in K application,however, has variable impact oncrop production due to the fact thatK-supplying capacities of soilsvary based on mineralogy and Kdynamics of a particular soil type.

Rice, wheat, and maize are themainstays of food security in India,grown in 82 million hectares (mha)of the cultivated land in thecountry and producing over 200million tonnes (mt) of cereal grains(2). These crops are grown ondifferent soil types and agro-ecologies across the country,which reflect the variableproductivity (attainable yield) andsubsequently the variable nutrientrequirement by the crops andnutrient balances in the soils.

Earlier studies (IPNI Unpublisheddata) across regions in Indiarevealed sizable yield response ofcrops to K fertilisation andeconomic returns associated withK application (Figures 1 & 2).Figure 1 shows that yield increasewere more in cash crops (fruits,vegetables, and spices), sugarcane,and potato while three cereal cropshad an average yield improvementof about 900 kg/ha.

The economic return of Kapplication in the above responsescenario, based on minimumsupport prices (MSP) of crops andprevailing unit price of K2O at thetime of conducting theexperiments, indicates thatinvestment of one rupee on Kfertiliser would result in a returnof more than 15 rupees, even forcereals (Figure 2). Site-specificpotassium management studiesconducted in rice- wheat and rice-maize cropping systems in theIndo-Gangetic Plain region (IGP)indicated that response to Kapplication and benefit: cost ratioin cereals could be furtherimproved with cultivation ofmodern high yielding and hybridvarieties (1,11). For other crops, thereturn on K application was muchhigher.

OBJECTIVES

Rice, wheat, and maize utilize the

Figure 1 – Average yield increase (kg/ha) with K fertilisation in different crops across growing environments

Figure 2 – Return on investment (ROI) on potassium# # Cost of potassium= Rs. 7.50/kg K2O

1062717.5

105113955

8209355348

7052

0 2000 4000 6000 8000 10000 12000 14000

RiceWheatMaize

SugarcanePotato

OilseedsPulses

Cash Crops

17 17 16

29

1723

3330

05

10152025303540

Rice Wheat Maize Sugarcane Potato Oilseeds Pulses Cash Crops

majority of fertilisers consumed inIndia. According to estimates (3),these three crops use 53% of N, 46%of P2O5 and 43% of K2O(corresponding to 8.8 mt of N, 3.7mt of P2O5 and 1.5 mt of K2O in 2010-11) of the total nutrients consumedin the country. Considering theimportance of rice, wheat andmaize in the food security scenario,scope of enhancing theirproductivity through judiciousfertiliser use and scarcity ofinformation on yield and economicadvantages of K application inrelation to variable indigenous Ksupplies, we undertook this studyto estimate: (a) response of cerealsto K application in the Indo-Gangetic Plain region, (b) economicreturns on application of K and (c)

profitability of K application withchanging fertiliser price scenario.

MATERIALS AND METHOD

On-farm trials were conductedacross the IGP during 2009-2011 byInternational Plant NutritionInstitute (IPNI) and InternationalMaize and Wheat ImprovementCentre (CIMMYT) under the CerealSystems Initiative for South Asia(CSISA) to capture the nutrientresponse of crops under variablesoil and growing environments.

In all, 45, 141 and 36 on-farm trialson rice, wheat and maize wereconducted in the states of Punjab,Haryana, Uttar Pradesh, Bihar,Jharkhand and West Bengal,

representing irrigated intensiveproduction systems and relativelylarge farm scenario in the WesternIGP to rainfed, low intensityfragmented farming systems ofeastern India (Table 1).

Treatments

Following four treatments wereassessed in the on-farmexperiments:

1) Ample NPK2) Omission of N with full P and K3) Omission of P with full N and K4) Omission of K with full N and P

For rice, application rates of NPKwere 125–175 kg N/ha, 50–80 kgP2O5/ha and 60–90 kg K2O/ha basedon estimated yield target of 5–8 t/ha. For wheat, N application rateswere 150–180 kg/ha for 5–6 t/ha ofyield target, while P and K rateswere fixed at 90 kg P2O5 and 100K2O per hectare. Maize trials wereconcentrated in Bihar and WestBengal and ample NPK rates formaize were 150–180 kg N, 70–115kg P2O5 and 120–160 kg K2O perhectare for yield targets between6–8 t/ha. Nutrients were applied inexcess of actual requirement ofthe crops, following the omissionplot experiment protocol, toensure no limitation of nutrientsexcept the omitted one. Atmaturity grain yields weredetermined from a 10 m2 harvestedarea in each plot; combined afterharvesting from fourpredetermined 2.5 m2 areas withineach plot. After sun-drying forthree days in the field, the totalbiomass (grain + straw) wasthreshed with a plot thresher andgrain yield was weighed, andadjusted to 13% moisture contentfor all the crops.

Yield Response to K andProfitability of K Application

Yield increase due to K fertiliser (Kresponse) and K applicationeconomics were estimated usingthe following equations:

Table 1 – Characteristics of the experimental sites

State Districts Agro- Soil Average Cropping Crops Ecology climatic texture annual system studied Zone precipi- tation (mm)

Punjab Ludhiana, Central Sandy 600- Rice- Rice IrrigatedAmritsar, Plain Zone loam 1020 Wheat, andGurdaspur, to Sub- to silty Cotton- WheatSangrur, Mountain loam WheatFatehgarh UndulatingSahib Zone

Haryana Karnal, North Sandy 400- Rice- Rice IrrigatedKuruka- Western loam 600 Wheat andshetra, Plain zone to clay WheatKaithal, loamAmbala,Yamunanagar

Uttar Agra South Sandy 650 Pearl Wheat IrrigatedPradesh Western loam millet-

Plain Zone Wheat

Bihar Vaishali, North Sandy 1100- Rice- Rice IrrigatedSamastipur, West, loam 1400 Maize andPurnea, North East to silty MaizeKatihar, and South clayBegusarai, Bihar loamPatna and AlluvialJamui Plains

West Uttar Old and Sandy 1300- Rice- Maize IrrigatedBengal Dinajpur New loam 1500 Maize

and Nadia Alluvial to siltyzone clay

loam


1) K response (kg/ha) = Grain yieldin ample NPK plot (kg/ha) – Grainyield in K omission plot (kg/ha).

2) Return on investment (ROI) onK fertiliser = Yield increase due toK fertiliser (kg/ha) MSP of crop (Rs/kg) / Applied K2O (kg/ha) cost of K2O(Rs/kg).

K fertiliser cost has increasedconsiderably over the past threeyears. The sharp increase in pricehas raised doubts about theprofitability of K application inrice, wheat, and maize where theMSPs are low. The omission plotexperiments in the current studyallowed us to estimate the yieldresponse due to K, which isequivalent to the yield loss in Komission plots as compared to theample NPK plot, in each location.We estimated the return oninvestment (ROI) for K (i.e. rupeesper rupee invested on K fertiliser)at four price scenarios of Muriateof Potash (MOP), Rs. 4455 (2009price), Rs. 5055 (2010 price), Rs.11300 (current price) and a furtherhigher price of Rs. 13000/ tonne, atfour different K response levels,200, 500, 1000, and 1500 kg/ha, andat three different K applicationrates (100, 80, and 60 kg/ha). Therange of K response used in thecalculation was taken from thecurrent set of on-farm trials.

In addition, we also used currentand projected prices of K fertiliser

and MSP of rice, wheat and maizeto estimate ROI for the three crops.Calculations were based on thefollowing criteria:

Four price levels of K2O betweenRs. 8.43/kg K2O to Rs. 33.33/kg K2Othat correspond to Muriate ofPotash (MOP) price between Rs.5058 and Rs. 20000/ tonne.

Three K response levelscorresponding to 25th, 50th and 75th

percentile of the actual responsesin each crop. The K response levelswere: 300, 500, and 800 kg/ha forrice; 350, 600, and 1000 kg/ha forwheat; and 500, 700, and 850 kg/hafor maize. Fertiliser K rates assumed to besufficient for the observed Kresponses:

• Rice : K response of 300 kg/hajustifies application of 40 kg K2O kg/ha while K response of 500 and 800kg/ha will require application of 60kg K2O/ha.

• Wheat: calculations are based on40, 60 and 80 kg K2O /ha applicationrates at locations with 350, 600 and1000 kg K response per hectare,respectively.

• Maize: calculations are based onapplication of 60 kg K2O /ha at Kresponse of 500 and 700 kg/ha,while 80 kg K2O /ha was used forlocations with K response of 850kg/ha.

MSP levels of Rs 10 to Rs 15 perkg rice, Rs. 11 to Rs 16 per kg wheat,and Rs 9 to Rs 14 per kg maize.

RESULTS AND DISCUSSION

RiceRice was grown in 41.9 mha inIndia with annual production of95.3 mt of grains in 2010-11. AllIndia average productivity of riceis 2125 kg/ha (2). However, averagerice yield varies widely betweenmajor rice growing states andranges from 4010 kg in Punjab to1120 kg/ha in Orissa (2). Themanagement yield gaps in riceproductivity also varied widelybetween states, for example, 43%in Punjab, 60% in Haryana, 71% inBihar and 69% in Tamil Nadu (3).

On-farm studies across 45locations in the Indo-GangeticPlains revealed that average yieldwith ample application of NPK was4701 kg/ha and yield loss due to noapplication of K was 90–1806 kg/ha with an average yield loss of 622kg/ha across locations (Figure 3).Areas traditionally known as lessresponsive to K application(Punjab and Haryana) showedyield loss of 500-1000 kg/ha in theK omission plot as compared toample NPK plots. Yield loss wasgreater in hybrid rice, which hashigher yield potential than openpollinated high yielding varieties(HYVs) and traditional varieties,and has higher demand for K.

Figure 3 – Rice yield loss in K omission (–K) plots as compared to fully-fertilised (NPK) plots

Indian Journal of Fertilisers, May 2012

270 280

100 120240 220

300230

90

230 200 230

783

522

1,333

278333

778

1,444

500

806 833

611722

528

806

1,806

111

478 433

867

1,356

344

1,244

1,4891,467

456520

660

790680

560

820

630

480

0

500

1000

1500

2000

kg/h

a

Mean: 622 kg/ha

4 7

Economic analysis showed thatROI of K ranged between 0.8–16 Rs/Re (Figure 4), which suggests thatevery rupee invested in fertiliser Kproduced additional rice yieldworth Rs. 0.8 to Rs. 16, with a meanof Rs. 5.5 across the locations(Figure 4). Economic return of < Rs.1 per rupee invested on K wasregistered at three locations only.

Return on investment wascalculated based on minimumsupport price of rice (Rs 10/kg) andcost of potash (Rs. 18.8/kg of K2O).

Results revealed that K applicationis generally less attractive at lowK response levels (yield loss in Komission plots < 200 kg/ha, Table2). However, K application at allthree rates (100, 80 and 60 kg K2O/ha) in rice are profitable, more soat 80 and 60 kg K2O/ha, in areaswhere yield responses in rice dueto K application exceeds 500 kg/ha.

Figure 5 shows that K application,in general, is economicallyprofitable even in areas where Kresponse is < 500 kg/ha. At anapplication rate of 40 kg K2O/ha fora 300 kg/ha response, the ROI at thehighest price of K (Rs. 33.33/kg ofK2O) and the lowest MSP (Rs. 10/kgrice) was 2.3, suggesting profitablereturn on potash application.Obviously the profitabilityincreased as the MSP of the cropwas increased (Figure 5). At highercrop response levels of 500 and 800kg/ha, ROI was 2.5 and 4.0,

Figure 4 – Return on investment on K fertiliser in rice based on actual K rates and current fertiliser costs and MSP

Table 2 – Return of investment (ROI) on K fertiliser in rice at different cropresponse levels cost of MOP and application rates

Yield response to 200 500 1000 1500K (kg/ha) >

Cost of MOP (Rs/ tonne) At 100 kg K2O/ha application rate

4455 2.69 6.73 13.47 20.205055 2.37 5.93 11.87 17.80

11300 1.06 2.65 5.31 7.9613000 0.92 2.31 4.62 6.92

At 80 kg K2O/ha application rate

4455 3.37 8.42 16.84 25.255055 2.97 7.42 14.84 22.26

11300 1.33 3.32 6.64 9.9613000 1.15 2.88 5.77 8.65


4455 4.49 11.22 22.45 33.675055 3.96 9.89 19.78 29.67

11300 1.77 4.42 8.85 13.2713000 1.54 3.85 7.69 11.54

Calculated based on minimum support price of rice (Rs 10/kg of grain)

respectively at the lowest MSP andat an application rate of 60 kg K2O/ha. In the on-farm omission plotexperiments, 60–100 kg K2O/ha wasapplied based on the yield targetsof rice. A yield loss of > 500 kg/ha ofrice due to no application of K wasobserved in more than 50% of

locations. This suggests that in suchlocations, application of K at 40-60kg K2O/ha will provide a good ROIto the farmers and will maintainthe K fertility status of the soil. Itshould be understood that the vastrice growing soils of the Indo-Gangetic Plains have large


>

2.4 2.5

0.9 1.12.1 2.0

2.72.0

0.82.0 1.8 2.0

6.9

4.6

11.8

2.5 3.0

6.9

12.8

4.4

7.1 7.4

5.46.4

4.7

7.1

16.0

1.0

4.2 3.8

7.7

12.0

3.1

11.0

13.213.0

4.04.6

5.97.0

6.05.0

7.3

5.6

4.3

0

5

10

15

20

ROI (

Rs/R

e)

Mean: 5.5 Rs/Re

4 8

variability in K supplying capacityand K management decisions inthis area must be based onexpected K response at a particularlocation. The general perceptionthat Indian soils are rich in K anddo not require K application is nolonger relevant in the intensivecrop production scenario.

Wheat

Wheat was grown on about 29 mhain India with an annualproduction of 87 mt in 2010-11 andaverage yield of 2839 kg/ha (2).Review of current statisticsshowed that there are considerable

management yield gaps betweenthe major wheat growing states inthe country. For example,productivity in Bihar and MadhyaPradesh are about 45% of Punjab,while Uttar Pradesh, with thehighest wheat acreage among thestates (9.7 mha), has a productivityof 2846 kg/ha, about 66% of Punjab.The absolute management yieldgaps in wheat in Punjab, Haryana,Eastern UP and Bihar are 17, 14, 47and 48 %, respectively (3).

On-farm trials (n = 141) across theTrans and Upper Gangetic Plainsshowed that wheat yield withample application of NPK was 5096

kg/ha and the gap between Komission plot yield and full NPKplot yield ranged from 0–2222 kg/ha with a mean of 715 kg/ha (Figure6). The average yield loss of 715 kg/ha translates to economic loss of Rs.8366/ha at the current MSP ofwheat. The majority of theseomission plot trials were set up inPunjab, Haryana and WesternUttar Pradesh that are typicallythought of as areas rich in inherentsoil K and require either no, or lessexternal K application.

ROI of K in the wheat experimentswas 0–13.22 Rs/Rs with a meanreturn of Rs 4.44 per rupee invested

Figure 5 – Return of investment (ROI) of K fertiliser at varying K response levels, cost of K2O and minimumsupport price of rice

Figure 6 – Wheat yield loss in K omission (–K) plots as compared to fully-fertilised (NPK) plots


0

500

1000

1500

2000

2500

kg/h

a

Mean: 715 kg/ha

4 9


(Figure 7) on potassium. The ROIof K was lower than 2.0 only in 24out of the 141 sites studied(17%).

Return on investment wascalculated based on minimumsupport price of wheat (Rs 11.7/kg)and cost of potash (Rs. 18.8/kg ofK2O).

Similar to rice, K application atcurrent K fertiliser price was foundto be uneconomic at locationswhere wheat response to K was <200 kg/ha. However, K applicationwas profitable at current pricelevels at locations where yield lossdue to no application of K is > 500kg/ha (Table 3). Comparativelyhigher MSP of wheat among thethree cereals provides moreopportunity to the farmers interms of K application in theincreasing K price scenario. It isclear that there are two ways ofcoping with increasing fertiliserprice: (1) by improving yield of thecrop by a certain yearly incrementor (2) by increasing the MSP of thecommodity. The first option seemsto be more attractive as severalstudies (6, 8, and 10) have shownthat there are wide gaps betweenfarmers’ plot yield and researchstation yields in the country.Decreasing such yield gap over aperiod of time will increase farmerprofitability and help meet theincreasing food demand. Location

specific nutrient managementstrategies, particularly improved Kmanagement, are expected to playa critical role in bridging such yieldgaps.

Economic calculations based onprojected cost of K and MSPshowed that ROI declined sharplyas the K price increased from Rs.8.43/kg K2O to a projected price ofRs. 33/kg K2O (Figure 8).Nonetheless, Figure 8 suggested

that ROI at the current MSP andthe projected maximum price ofK2O would be 2.9, a return ratio of1:3 even at the low-responselocations. At high-responselocations, K response ~ 1000 kg/ha,the ROI at highest projected Kprice was 4.1 at the current MSPof wheat, making it a profitableoption for the farmers. Kresponse was >1 t/ha in 25% of thelocations in the present study andthose locations would produce ROI

Figure 7 – Return on investment on K fertiliser in wheat based on actual K rates and current fertiliser costs and MSP

Table 3 – Return of investment (ROI) of K fertiliser in wheat at differentcrop response levels, cost of MOP and application rates

Yield responseto K (kg/ha) 200 500 1000 1500 1800

Cost of MOP At 100 kg K2O/ha application rate(Rs/ tonne)4455 3.15 7.88 15.76 23.64 28.365055 2.78 6.94 13.89 20.83 25.0011300 1.24 3.11 6.21 9.32 11.1813000 1.08 2.70 5.40 8.10 9.72

At 80 kg K2O/ha application rate4455 3.94 9.85 19.70 29.55 35.455055 3.47 8.68 17.36 26.04 31.2511300 1.55 3.88 7.77 11.65 13.9813000 1.35 3.38 6.75 10.13 12.15

At 60 kg K2O/ha application rate4455 5.25 13.13 26.26 39.39 47.275055 4.63 11.57 23.15 34.72 41.6611300 2.07 5.18 10.35 15.53 18.6413000 1.80 4.50 9.00 13.50 16.20

Calculated based on minimum support price of wheat (Rs 11.7/kg of grain)

>

>

~

0

2

4

6

8

10

12

14

ROI (

Rs/R

e)

Mean: 4.44 Rs/Re

of 8.0 at the current cost of K andcurrent MSP of wheat.

Maize

Maize is the third major cerealgrown in India. Maize area andproductivity are increasingsteadily over the past years.During 2010-11, 8.55 mha area wasunder maize cultivation in Indiawith an annual production of 21.7mt at an average productivity of2540 kg/ha.

The maize omission plot trialswere conducted in Bihar and WestBengal where maize is coming upas a preferred alternative crop to

both rice and wheat duringmonsoon and winter seasons,respectively. Maize yield reductionin K omission plots, as comparedto ample NPK application, rangedfrom 140–1320 kg/ha and meanyield loss due to no K applicationwas 700 kg/ha (Figure 9). At thecurrent MSP of maize (Rs. 8.80/kggrain), the yield loss in theseexperiments are equivalent toeconomic loss of Rs. 1232 – 11616/ha, with a mean of Rs. 6160/ha.Maize is grown in India in winter,spring, and rainy seasons.Attainable yields of maize differbetween seasons, with highestyields obtained in winter maize.The present data includes both

winter and spring maize. Springmaize average yield in these trialswas 4936 kg/ha whereas that ofwinter maize was 7748 kg/ha.Average yield response to Kapplication in winter maize alonewas nearly 200 kg/ha higher thanthe pooled data of both crops.

Return per rupee invested on K inmaize ranged Rs. 0.65–6.17 and theaverage return across all sites wasRs. 3.27 (Figure 10). Even with thelowest MSP among the threecereals, there were only sixlocations out of 36 locationsreported here that had returnbelow Rs. 2.0 per rupee invested inK fertiliser.

Figure 8 – Return on investment (ROI) of K fertiliser at varying K response levels, cost of K2O and minimumsupport price of wheat

Figure 9 – Maize yield loss in K omission (–K) plots as compared to fully-fertilised (NPK) plots


470

780

340

860

470

820

710

410

630

140

510

270

540

940

590

440

300

700780

570

990 960

1300

1080

810

1320

660600

340

770

650

810

1170

760830 840

0

200

400

600

800

1000

1200

1400

kg/h

a

Mean: 700 kg/ha

5 1

Return on investment wascalculated based on minimumsupport price of maize (Rs 8.80/kg)and price of potash (Rs. 18.8/kg ofK2O).

Table 4 shows that K applicationat existing price is profitable wheremaize yield response to K is morethan 500 kg/ha. The results of theon-farm trials showed that 75% ofthe experimental sites had > 500

kg/ha of K response, and would givereasonably high ROI even atapplication rates of 100 kg K2O/haand fertiliser price of Rs 18.83/kgK2O.

Median response of maize to Kapplication was 700 kg/ha andresponse across sites werecentered around the medianvalue as was evident from the25 th and 75 th percentile of the

response, 500 kg and 850 kg/ha.

Maize MSP is lowest among thethree cereal crops. ROI at thecurrent MSP and cost of K was 4.0,5.6, and 5.1 at 500, 700, and 850 kg/ha K response, respectively. Ourcalculation showed that ROI was2.3, 3.2 and 2.9 for 500, 700 and 850kg/ha K response, respectively atthe current MSP and the highestprojected price of K2O, givingreasonable return to farmers(Figure 11).

CONCLUSION

The on-farm K response studies inrice, wheat and maize, spreadacross the Indo-Gangetic Plains,highlighted that

1) Grain yield response tofertiliser K is highly variable andis influenced by soil, crop andmanagement factors. Thissuggests that skippingapplication of K in the threecereal crops will cause variableyield and economic loss to thefarmers.

2) Average yield losses in rice,wheat and maize in farmers’ fieldsdue to K-omission were 622, 715and 700 kg/ha, respectively. This iscontrary to the general perceptionthat omitting potash for a seasonwill not adversely affect cerealproduction in the country, anddemonstrates clearly the low K

Figure 10 – Return on investment on K fertiliser in maize based on actual K rates and current fertilisercosts and MSP

Table 4 – Return on investment (ROI) on K in maize at different cropresponse levels, cost of MOP and K application rates

Yield response 200 500 1000 1500to K (kg/ha)

Cost of MOP (Rs/ tonne) At 100 kg K2O/ha application rate

4455 2.37 5.93 11.85 17.785055 2.09 5.22 10.45 15.6711300 0.93 2.34 4.67 7.0113000 0.81 2.03 4.06 6.09


4455 2.96 7.41 14.81 22.225055 2.61 6.53 13.06 19.5811300 1.17 2.92 5.84 8.7613000 1.02 2.54 5.08 7.62


4455 3.95 9.88 19.75 29.635055 3.48 8.70 17.41 26.1111300 1.56 3.89 7.79 11.6813000 1.35 3.38 6.77 10.15

Calculations based on minimum support price of maize (Rs 8.80/kg of grain)


>

>

2.2

3.6

1.6

4.0

2.2

3.83.3

1.9

2.9

0.7

2.4

1.3

2.5

4.4

2.8

2.1

1.4

3.33.6

2.7

4.6 4.5

6.1

5.0

3.8

6.2

3.12.8

1.6

3.63.0

3.8

5.5

3.63.9 3.9

0

1

2

3

4

5

6

7

ROI (

Rs/R

e)

Mean: 3.27 Rs/Re

5 2

Figure 11 – Return on investment (ROI) of K fertiliser at varying K response levels, cost of K2O and minimumsupport price of maize

supply levels of most soils inIndia.

3) Generalized K recommen-dations would lead to under orover application in most cases,causing economic losses tofarmers. Strategy for deciding Kapplication rates should, therefore,needs to be based on the expectedcrop response at a location forimproved yield and profitabilityinstead of considering the nativesoil test status for K alone.

The above study showed that abetter understanding of thegrowing environment and cropresponse to potash application incereals are critical for enhancingyield and profitability. However, itmust be understood that potashnutrition, and nutrientmanagement in general, is only apart of the overall cropmanagement strategy. As we lookat economics of fertilisermanagement, it must be kept inmind that water and labourresource costs will also increase,along with increase in fertilisercost, in the near future. Farmerswill need to increase the overallreturn from farming to offset suchincreased costs of production. Thebest way to achieve higher returnwould be to increase productivity

per unit area through overall goodcrop management. Improvedvarieties, better pest management,improved water and nutrient useefficiencies and post-harvesthandling would be critical toachieve such goals. As far asnutrient management is concerned,adhering to the four basicprinciples of applying nutrients atthe right rate, at the right time,using the right source and by theright method would ensure highereconomic return from fertiliser useas well as increased cerealproductivity to meet the foodsecurity goals in the country.

REFERENCES

1. AICRP-CS Annual reports.Project Directorate for FarmingSystems Research, Modipuram,Meerut (2006).

2. Fertiliser Statistics. TheFertiliser Association of India, NewDelhi, India (2010-11).

3. Gupta, Raj; Jat, M. L., Gopal, R.and Kumar, R. In: Souvenir, NationalSymposium on Resource managementapproached towards livelihood security,2-4 Dec, Bengaluru, Karnataka,India, p.1-10 (2010).

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economics of potassium fertiliser application in rice, wheat and

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