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Nitrogen management and fertilizer use efficiency forlowland rice in PakistanMuhammad Sharif Zia a , Muhammad Aslam a b & Maqsood Ahmad Gill a ba Laboratory of Soil Science, Faculty of Agriculture , Kyoto University , Sakyo-ku, Kyoto ,606 , Japanb Land Resources Section, National Agricultural Research Centre , Park Road, Islamabad ,PakistanPublished online: 04 Jan 2012.

To cite this article: Muhammad Sharif Zia , Muhammad Aslam & Maqsood Ahmad Gill (1992) Nitrogen managementand fertilizer use efficiency for lowland rice in Pakistan, Soil Science and Plant Nutrition, 38:2, 323-330, DOI:10.1080/00380768.1992.10416496

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Soil Sci. Plant Nutr,, 38 (2), 323-330, 1992 323

Nitrogen Management and Fertilizer Use Efficiency for Lowland Rice in Pakistan

Muhammad Sharif Zia, Muhammad Aslam*, and Maqsood Ahmad Gill*

Laboratory of Soil Science, Faculty of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606 Japan; and

* Land Resources Section, National Agricultural Research Centre, Park Road, lslamabad, Pakistan

Received July 13, 1990

With a view to develop simpler techniques for improving the efficiency of nitrogen fertilizer use for lowland rice, field studies were conducted in 1986 and 1987. During 1986, dry soil incorporation of urea was compared with puddled soil application of urea and calcium ammonium nitrate (CAN) and deep place- ment of urea super granule (USG). In 1987, the application of urea in puddled soil without standing water (soil saturation) was compared with the application in standing water and deep placement of USG. The results revealed tha t deep placement of USG and dry soil incorporation of urea were comparable in their effect on the increase of the number of productive tillers, straw and paddy yield, and agronomic efficiency. Consequently N utilization and recovery efficiency were higher with these methods of fertilizer application than with the applica- tion of urea and CAN in puddled soil. Application of urea fertilizer under soil saturation conditions and deep placement of USG were found to be comparable in the production of tillers, straw and grain yield and both gave similar agronomic and N recovery efficiencies to the application of urea on the Miranpur soil under standing water conditions.

Key Words: fertilizer use efficiency, lowland rice, method of N application.

Nitrogen is the major element required for rice production, in Pakistan due to the low inherent N fertility of rice soils. Under the soil and climatic conditions of Pakistan, the N fertilizer applied to rice is subjected to numerous reactions, transformations, and N loss mechanisms especially N2 denitrification. The amount of ammonia volatilized increases in alkaline soils. However it is considered that under flooded conditions in Pakistan the losses are higher than the generally reported figures due to poor crop management and the adverse soil and climatic conditions.

In order to decrease the cost of rice production for sustained and enhanced use of fertilizer by farmers, it is essential to enhance the N utilization by the rice crop and thus increase the efficiency of fertilizer use. This has become even more important due to the increase in the price of fertilizers (NFDC 1983).

Generally the losses associated with N2 denitrification and NH3 volatilization have been more pronounced in the surface and standing water application of N fertilizers especially urea (Ventura and Yoshida 1976; Ferrante 1986; De Datta et al. 1987; De Datta

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324 M. SHARIF ZIA, M. ASLAM, and M.A, GILL

and Buresh 1989). With deep placement of urea, the losses due to N2 denitrification and NH3 volatilization can be reduced, which accounts for the superiority of deep placement of USG to prilled urea application (Cao Zhi-hong et al. 1984). Even on acidic soil 3 split application of urea N gave a higher yield than a single basal application for rice (Chamuah 1983). In Pakistan the most common method is to incorporate 1/2 to 2/3 of the nitrogen in puddled soil and to top dress the remaining nitrogen 40-45 d after transplanting (Chaudhry 1986).

Slow release fertilizers especially sulphur coated urea (SCU) and USG are expensive and are not commonly available. Moreover, the deep placement of USG is laborious, time consuming, and costly business. Therefore, it is essential to develop an easily adoptable and more economical fertilizer management technology for improving efficiency of fertilizer use for sustained rice yield. The present investigations were, therefore, carried out to identify a simple, less expensive, and easily adoptable method for enhanced efficiency of fertilizer use to improve rice yield.

MATERIALS AND METHODS

The following experiments were carried out in typical rice growing areas of the country under lowland conditions.

E x p e r i m e n t 1: C o m p a r a t i v e efficiency o f n i t r o g e n sources and t h e i r m e t h o d s of appl ica t ion . In 1986, different N sources viz.: urea and calcium ammonium nitrate (CAN) with NH4:NO3 ratio of 1:1 were examined. Details of treatment are given in Table 1.

Nitrogen sources were supplied either in two split applications in puddled soil or incorporated in dry soil (urea only) and compared for their relative efficiencies with USG deep placement at different rates of application. The study was conducted on a Gujranwala soil series (Udic Haplustalf) with total N, Olsen-P, and available K contents of 0.05%, 6.90 mg kg -~, and 100 mg kg -~ dry soil, respectively. All the other characteristics are listed in Table 3. Fertilizer was applied in deep furrows in the dry soil and the field was planked and irrigated. The field was also planked twice under standing water. The experiment was laid out in a randomized complete block design using three replications. Plot size was 6 • 4 m z. Phosphorus and K were applied to the all plots at the rate of 75 and I00 kg ha -~, respective- ly. Transplanting of IR-6 rice was performed at 2 0 c m • cm spacing. Productive tillers, paddy and straw yield were recorded. Grain and straw samples were analyzed for the total N content to calculate the following N use efficiencies (Mengel and Kirkby 1987).

Agronomic efficiency= grain yieldv--grain yieldc fertilizer N applied '

N u p t a k e v - N uptakec • 100, N recovery efficiency (%)= fertilizer N applied

where subscripts F indicates the fertilized crop and C the unfertilized control. E x p e r i m e n t 2: C o m p a r a t i v e effieiencies of USG and pr i l led u r ea appl ied under

di f fe ren t w a t e r i n g reg imes . This study was carried out on a Miranpur soil series (Usteric Comborthid). The soil consisted of sandy clay loam, was non saline and non sodic with ECe and pH values of 0.05 mS cm -~ and 8.0, respectively. Lime content in the soil was 2.0%. The soil contained 0.8 and 0.06% of organic matter and total N, respectively. Ammp- nium nitrogen content in the soil was 14mg kg-L The soil contained 5.5, 150, and 58 mg kg -1 soil of P (Olsen), K (NH4OAc), and S (NaHCO~), respectively. The study was conduct-

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Nitrogen Management and Fertilizer Use Efficiency

Table 1. Details of treatment.

325

N applied Tr. No. N source (kg ha -~) Method of application

Ta Control 0 Nil T2 PU 46 2/3 incorporation in puddled soil+ 1/3 at PI T3 CAN 46 do T~ PU 46 Whole incorporation in dry soil T 5 USG 46 Deep placement, 4 DAT T8 PU 92 As in T2 T 7 CAN 92 do Ts PU 92 As in T 4

T9 USG 92 As in T5 PU, prilled urea; CAN, calcium ammonium nitrate; USG, urea super granule; PI, panicle initiation; DAT, days after transplanting.

Table 2. Fertilizers used and methods of placement.

Tr. No. N source N applied (kg ha -j) Method of application

T~ Control 0 T2 PU 58 Basal, N application in standing water Ta PU 58 Basal, N application at saturation T4 USG 58 Deep placement at 8 cm soil depth Ts PU 87 Basal, N application in standing water T~ PU 87 Basal, N application at saturation T7 USG 87 Deep placement at 8 cm soil depth Ts PU 145 Basal, N application in standing water T9 PU 145 Basal, N application at saturation T~o USG 145 Deep placement at 8 cm soil depth

PU, prilled urea; USG, urea super granules.

ed in 1987. Fertilizers used and methods o f placement are described in Tab le 2. A randomized complete b lock design was used with three replications. Plot size was 6 •

4 m 2. Rice variety (KS-282) was used. P and K were un i formly applied to all the plots at the rate o f 75 and 100 kg ha -1, respectively. Crop was t ransplanted at 20 cm • 20 cm spacing. At harvest, grain and straw yields were recorded. A g r o n o m i c efficiency defined in experiment 1 was computed. The amount o f ni t rogen recovered in grain and straw was determined after analysis o f the grain and straw samples.

In order to study the effect o f urea-N appl ica t ion in s tanding water and under soil saturat ion condi t ions on the soil pH, a l abora tory experiment was conducted. Three hundred grams of Miranpur soil were put in six beakers. The soil in the three beakers was saturated with distilled water and tho rough ly mixed. In the remaining beakers after satura- t ion with distilled water, 3 cm water was a l lowed to stand on the surface. The beakers were placed in an incubator at 40~ Moisture in the beakers was maintained. After 1 week 200 mg urea-N kg -1 soil was applied in ha l f o f the beakers under saturated condi t ions and in s tanding water in the remaining half. Thereafter a 3 cm layer o f water was main ta ined on the soil surface in all the beakers. F l o o d water pH was moni to red for 1 week.

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326 M. SHARIF ZIA, M. ASLAM, and M.A. GILL

RESULTS AND DISCUSSION

Experiment 1 Physico-chemical characteristics o f the experimental site are given in Tab le 3. In this experiment the various ni trogen sources and methods o f appl icat ion significantly

affected tillering (Fig. 1), straw and grain yield as well as ag ronomic efficiency (Fig. 2). Deep placement o f U SG (T~ and Tg) improved the grain and straw yield and ag ronomic efficiency fol lowed by dry soil incorpora t ion o f urea (T4 and Ts). Statistically, however, there were no significant differences a m o n g these N sources. Dry soil incorpora t ion o f urea resulted in a significant increase in the number o f product ive tillers, straw and paddy yield compared with the incorpora t ion o f C A N (T3 and T~) in pudd led soil. A l though dry soil incorpora- t ion o f urea always resulted in the increase in the number o f product ive tiller, grain and straw yield compared with the incorpora t ion o f urea in pudd led soil, the differences were not statistically significant. The ag ronomic efficiency was the highest with deep placement o f

Table 3. Physico-chemical characteristics of the soil.

Property Unit Gujranwala series Sand % 8.0 Silt % 63.0 Clay % 29.0 Textural class -- Silty clay loam pH -- 7.7 ECe mS cm -1 3.2 Total N % 0.04 NaHCO3-P mg kg -1 7.10 Available K mg kg -~ 105.00

Fig. 1. Effect of nitrogen sources and methods of placement on the increase in the number of productive tillers. T,, control; T2, P.U 46 kg N ha -~ in two split applications in puddled soil; T3, CAN 46 kg N ha -1 as in T2; T~, PU 46 kg N ha -a incorporated in dry soil; Ts, USG 46 kg N ha -1 deeply placed 4 DAT; T6, PU 92 kg N ha -1 as in T2; Tv, CAN 92 kg N ha -1 as in T2; Ts, PU 92 kg N ha -a as in T4; Tg, USG 92 kg N ha -1 as in Ts. PU, prilled urea; CAN, calcium ammonium nitrate; USG, urea super granules.

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Nitrogen Management and Fertilizer Use Efficiency 327

Fig. 2. Effect of nitrogen sources and methods of placement on rice yield and agronomic efficiency, T~, control; T2, PU 46 kg N ha -~ in two split applications in puddled soil; Ta, CAN 46 kg N ha -1 as in T2; T4, PU 46 kg N ha -1 incorporated in dry soil; Ts, USG 46 kg N ha -~ deeply placed 4 DAT; T6, PU 92 kg N ha -~ as in T2; T7 CAN 92 kg N ha -~ as in T2; Ts, PU 92 kg N ha -I as in T4; Tg, USG 92 kg N ha -~ as in Ts. PU, prilled urea; CAN, calcium ammonium nitrate; USG, urea super granules.

Table 4. Nitrogen uptake and recovery in rice as influenced by N sources, rates and method of application.

Treatments Nitrogen uptake (kg ha -1) Nitrogen recovered (%)

Straw Grain Straw+grain Straw Grain Straw+grain

TI 23.63 c 40.75 e 64.38 f 0.0 0.0 0.0 T2 33.16 b 54.00 d 87.16 de 12.02 a 28.80 abc 41.54 b T3 32,44 b 53.33 d 85.77 e 10.47 a 27.33 bc 38.53 bc T4 33.59 b 57.70 bc 91.29 c t3.18 a 36.85 ab 50.66 a Ts 33.14 b 57.41 bc 90.55 cd 11.97 a 36.20 a 48.85 a T5 38.26 a 60.06 b 98.32 b 11.55 a 20.98 cd 32.90 c T~ 36.93 a 55.86 cd 92.78 c 10.10 a 16.42 d 26.89 Ta 37.87 a 66.42 a 104.29 a 11.06 a 27.90 cd 37.99 bc T9 38.52 a 68.33 a 106.85 a 11.18 a 28.77 d 42.18 b

LSD 1.87 3.09 3.74 0.0 7.41 5.83

Values followed by the same letters are not significant at 5% level of significance. TI, control; T2, PU 46 kg 2/3 incorporation in puddled soil+ 1/3 at PI; Ta, CAN 46 kg 2/3 incorporation in puddled soil+ 1/3 at PI; T4, PU 46 kg all incorporated in dry soil; Ts, USG 46 kg deeply placed, 4 DAT; T6, 92 kg PU as in T2; TT, CAN 92 kg as in T2; Ts, PU 92 kg as in T4; T~, USG 92 kg as in Ts.

USG, followed by dry soil incorpora t ion of urea and incorpora t ion of urea and C A N in

puddled soil, in decreasing order. Thus C A N was found to be the poorest source in terms

of agronomic efficiency. The agronomic efficiency decreased with the increase in the fertilizer

dose. Ni t rogen uptake by grain, straw and N recovery efficiencies were s ignif icant ly influ-

enced by the fertilizer treatments (Table 4). Ni t rogen uptake by straw and percentage of

appl ied N recovered in straw were not s ignif icantly affected by the N sources. There were no

significant differences in the ni t rogen uptake by grain and g r a i n + s t r a w between deep

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328 M. SHARIF ZIA, M. ASLAM, and M.A. GILL

placement of USG and dry soil incorporation of urea. At a higher fertilizer level, dry soil incorporation of urea resulted in a greater uptake of N by grain and gra in+st raw than the incorporation of urea in puddled soil, but at a lower level of fertilizer application, the differences were not significant. Incorporation of CAN in puddled soil resulted in the lowest uptake of N by grain and grain+straw. Nitrogen recovery efficiency in s t raw+grain was the highest in the case of deep placement of USG, followed by dry soil incorporation of urea, incorporation of urea and CAN in puddled soil, in decreasing order. Nitrogen recovery efficiency decreased with the increase in the fertilizer rate.

Expe r imen t 2 Deep placement of USG and application of urea either in standing water or under soil

saturation conditions affected the number of productive tillers, yield, N uptake, N recovery, and agronomic efficiency significantly compared with the control (Table 5). Generally the application of fertilizer in standing water resulted in the decrease of the number of tillers at the fertilizer rate of 58 and 145 kg N compared with the deep placement of USG and prilled urea under soil saturation conditions. Straw yield behaved similarly at the lower (58 kg N ha -1) and middle rates (87 kg N ha -1) of application, but the differences at the highest level (145 kg N ha -1) of application between deep placement of USG and the two methods of prilled urea application were not significant. Differences in paddy yield associated with deep placement of USG and the application of prilled urea under saturation conditions at all levels of application were not significant. At higher levels (87 and 145 kg N ha -1) both methods of fertilizer application resulted in a higher yield than the application in standing water. However, the differences among the three methods were not significant at the lowest levels of application (59 kg N ha-l). Differences in N uptake among three methods were only significant at the highest and lowest levels of application. At the middle level of application, although the N uptake was greater in the case of deep placement of USG and application of urea under saturation conditions than the application in standing water, the

Table 5. Productive tillers, yield, N uptake and recovered, and agronomic efficiency as influenced by USG deep placement and application of urea in standing water and at saturation conditions.

Treatments Productive Straw Grain N uptake N uptake N recovered Agronomic

tillers yield yield in straw in grain in grain and efficiency (No.) (kg ha -a) (kg ha -a) (kg ha -a) (kg ha -a) straw (%) (kg paddy kg -~ N)

Ta 10,30 f 3,299 e 3,152 g 15.08 f 31.62 e -- -- T2 12.30 e 4,290 d 4,356 f 20.83 e 46.87 d 36.2 b 20.75 bc T:~ 13.33 de 4,705 c 4,604 ef 23.03 d 47.31 d 40.8 a 25.03 a T~ 14.60 cd 4,690 c 4,035 def 24.08 cd 47.24 d 42,6 a 24.94 a Ts 14.30 cd 5,051 b 4,706 de 23.18 cd 50.57 c 31.1 cd 17.85 c T~ 15.53 bc 5,285 b 4,920 cd 24.97 c 52.25 c 35.1 b 20.32 bc T7 15.80 be 5,329 b 5,090 c 24.56 cd 52.40 c 35,0 b 22.27 ab T8 15.03 c 5,759 a 5,618 b 28.07 b 60.05 b 28,6 d 17.01 c T~ 17.73 a 5,920 a 5,949 a 30.06 a 66.51 a 34.4 bc 19.29 bc Tl0 16.80 ab 6,068 a 5,970 a 30.31 a 66.75 a 34.9 b 19.43 bc

(p<0.01) 1.43 386.4 287.7 1.72 2.59 3.48 3.59 Ta, control; T2, PU 58 kg applied in standing water; T3, PU 58 kg applied under saturation conditions; T4, USG 58 kg deeply placed; Ts, PU 8 kg applied in standing water; T6, PU 87 kg applied under saturation conditions; TT, USG 87 kg deeply placed; Ts, PU 145 kg applied in standing water; Tg, PU 145 kg applied under saturation conditions; Ti0, USG 145 kg N ha -~ deeply placed.

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Nitrogen Management and Fertilizer Use Efficiency 329

differences were not significant. The differences in N uptake by grain associated with fertilizer application in standing water and under saturation conditions were only significant at the highest level of fertilizer application. Uptake was higher with deep placement of USG and application of urea under saturation condit ion than with the application in standing water.

Nitrogen recovery in grain and straw was significantly higher in the case of deep placement of USG and application of prilled urea under saturation conditions than with the application of prilled urea in standing water at all the levels of fertilizer application. The differences between the two former methods of N application were not significant regardless of the fertilizer rates. N recovery decreased significantly as the N rate increased from 58 to 87 kg N ha -1.

Agronomic efficiency at the lower rates was significantly higher in the case of deep placement of USG and the application of urea under saturation conditions than in the case of urea applications in standing water. However, the differences at the highest level of fertilizer application were not significant among these methods. The efficiency also declined with the increase of the fertilizer dose.

The lower efficiency of CAN compared with urea and USG is understandable, because the major part of the nitrate component is denitrified and lost (Reddy and Patrick 1980; Sahrawat I980). Deep placement of N fertilizers in the reduced soil zone has been well documented and it is now well recognized that the N recovery efficiency associated with deep placement is much higher than that with surface application. The superiority of dry soil incorporation of the fertilizer to its incorporat ion in puddled soil lies in the fact that by this technique, fertilizer N is deeply placed in the soil. By deep placement N is likely to be lost by denitrification of N2 and NHa volatilization. This simple technique has been found to be as satisfactory as the deep placement of costly USG (Zia et al. 1987). On the other hand the fertilizer applied in puddled soil is not placed deeply enough and thus N losses due to the large amount of NH3 volatilization and denitrification of N2 may occur in the alkali soil (Fig. 3). However, nitrification-denitrification losses are likely to be greater due to the following factors: dissolution of 02 in flood water, nitrification of NH4+-N to NO3- which finds its way into the reduced soil layer and is lost by denitrification.

These findings revealed that simple techniques of fertilizer application such as the incorporation of urea in dry soil and the application of fertilizer to soil under saturated conditions, are as effective as the use of costly USG. These techniques are very simple, tess

9.0

~ 8 , 5

~.8.o

7,5

~= ~ Saturated soL1

I I Standing wa~er i I I I I l

o I a 2 j 3 /+ 5 6 ?

No. of daya" a f t e r urea-J~ appl icat ion

Fig. 3. Effect of urea-N application in saturated soil and standing water on flood water pH.

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330 M. SHARIF ZIA, M. ASLAM, and M.A. GILL

expensive, and also since no a d d i t i o n a l l a b o r is requi red for the a p p l i c a t i o n they can be

more easi ly adop t ed by the rice growers than the s low release fertil izers. By the a d o p t i o n o f these techniques rice yields can be enhanced and the efficiency of fer t i l izer use can be i m p r o v e d s ignif icant ly,

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Cao Zhi-hong, De Datta, S.K., and Fillery, I.R.P. 1984: Nitrogen 1~ balance and residual effect of urea-N in wetland rice fields as affected by deep placement techniques. Soil Sci. Soc, Am. J., 48, 203-207

Chamuah, G.S. 1988: Effect of timing and method of nitrogen application on dwarf rice grown on inceptisol. J. Indian Soe, Soil Sci., 36, 185-186

Chaudhry, A.M. [986: Agronomy of rice. In Proceedings of the xiith International Forum on Soil Taxonomy and Agro-Technology Transfer, p. 145-152, Soil Survey of Pakistan, Lahore

De Datta, S.K. and Buresh, R.J. 1989: Integrated nitrogen management in irrigated rice. Adv, Soil Sci., 10, 143-169

De Datta, S.K., Obcemea, W.N., Chen, R.Y., Calabio, J.C., and Evangelista, R.C. 1987: Effect of water depth on nitrogen use efficiency and N 15 balance in lowland rice. Agron. J., 79, 210-216

Ferrante, B.D.E., Vander Vorm, P.D.J., and Van Diest, A. 1986: Comparative studies on the usefulness of ammonium sulphate and urea as fertilizers for lowland rice. Fertil, Res., 10, 119-133

Mengel, K. and Kirkby, E.A. 1987: Principles of Plant Nutrition, 4th ed., 337 pp., Int. Potash Inst., Bern, Switzerland

NFDC 1983: Impact of Fertilizer Pricing in Pakistan, Natl. Ferfil. Develop. Cent., Planning and Develop- ment Division Government, Pakistan

Reddy, K.R. and Patrick, W.H. 1980: Losses of applied ammonium ~SN. Urea ~SN and organic ~SN in flooded soil. Soil Sei,, 130, 326-330

Sahrawat, K,L. 1980: Soil and fertilizer nitrogen transformation under alternate flooding and dry moisture regimes. Plant Soil, 55, 223-225

Ventura, W.B. and Yoshida, T. 1976: Ammonia volatilization from a flooded tropical soil. Plant Soil, 46, 521-531

Zia, M.S., Ashraf, M., and Sager, M.A. 1987: Fertilizer efficiency with dry placement, Int, Rice Res. News Lett., 12(1), 31

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