Effect of Phosphate rock on growth and yield of wheat under Old Brahmaputra Floodplain soils

Md.Nurul Huda Al Mamun

Abstract

A study was conducted to observe the direct and residual effects of phosphate rock (PR) on the growth and yield of wheat (cv.Kanchan) during rabi season of 2004-2005 under Old Brahmaputra Floodplain soil at Bangladesh Agricultural University Farm, Mymensingh. The experiment was designed with four treatments and laid out in a Randomized Complete Block Design (RCBD) with four replications of each treatment. The treatment combinations were T1:control (0 kg P ha-1),T2 : PR(26 kg P ha-1),T3 :TSP(26 kg P ha-1) and T4: PR(210 kg P ha-1 was applied in previous crop to cover 6 succeeding crops). Dry matter yield at panicle initiation (PI) stage was significantly varied with different treatments. The yield contributing characters such as the effective tillers hill-1, grains panicles-1, varied significantly with P treatments. The highest grain yield (3.10t ha-1) and straw yield (5.54 t ha-1) in control treatment. The yield due to different treatments ranked in the order of T3>T4>T2>T1.The economic analysis demonstrated that the highest net benefit of Tk.24,788 ha-1 was obtained in T3 treatment followed by Tk. 22,964 ha-1 and Tk. 12,292 ha-1 in T4 and T2 treatments, respectively. The highest net benefit was obtained in T3 treatment due to higher grain and straw yields but T4 treatment had shown better performance over T2.

1. Introduction

Wheat (Triticum aestivum L.) is the most important cereal crop and ranks third both in acreage and production of the world (UNDP and FAO,2008).It has been established as the second most important staple food crop after rice in Bangladesh (Razzaque and Hossain,1999).Bangladesh produces 8,44,000 metric tons of wheat per annum from 9,63,300 acres of land (BBS,2008).The cereal crop production like wheat should be increased to meet the demand of the escalating population of Bangladesh, where an individual requires 454 g cereal food (BARI,2004).The Soil and climate of Bangladesh is favorable in winter for wheat production but the average yield of wheat in this country is quite low as compared to that of many wheat growing countries of the world. Improper management of fertilizers is one of the major causes of low production because fertilizer plays an important role in augmenting yield of wheat. Phosphorus is the second key plant nutrient needed in adequate quantity in available source of growth, reproduction, yield and quantity of crop. The phosphorus content of Bangladesh soils is being depleted day by day due to crop removal particularly in intensive culture. So, application of phosphatic fertilizers is recommended for all soils and crops in Bangladesh to obtain better yield (BRAC, 2005).Triple super phosphate (TSP) is the main source of phosphorus, where single super phosphate (SSP) is water soluble and newly introduced phosphetic fertilizer in Bangladesh and its popularity has been increasing day by day. Rock phosphate (PR) is another source of phosphorus. It is the cheapest and economic source of phosphorus (Hoffland, 1991) which is not being used in the crop field due to its insolubility. The direct application of finely ground rock phosphate (PR) may be an attractive alternative to the use of more expensive soluble P-fertilizer for certain crops and soils (Hammond et al., 1986).But in Bangladesh, a little research work has been done in this aspect. Keeping this in this view, the present research has been set up to compare the effect of direct application of PR and TSP on growth and yield of wheat, to study the response of wheat as affected by residual effects of high rate of PR applied in preceding T.aman crop and to compare economic benefits of PR with TSP as the source of P on wheat.

2. Materials and Methods

2.1. Site description

The field experiment was carried out with wheat (cv.Kanchan) grown in sequence after aman rice under some selected treatments. The experiment was set up at Soil Science field Laboratory of Bangladesh Agricultural University, Mymensingh under Old Brahmaputra Floodplain (AEZ 9) agro-ecological region of Bangladesh during the Rabi season of 2004-2005.The farm belongs to the general soil type Non-calcareous Dark Grey Floodplain soil under Sonatal series.

2.2. Treatments and design

The experiment was laid out in a Randomized Complete Block Design (RCBD) with 4 replications. Each block was sub-divided into 4 unit plots. The total number of plots was 16(4X4) and the unit plot size was 8mX5m.The spacing between blocks was 1m and between plots 0.3m.There were four treatments consisting of TSP and two rates of rock phosphate (PR) and a control. The treatment combinations were T1: control (0 kg P ha-1), T2: PR (26 kg P ha-1), T3: TSP (26 kg P ha-1) and T4: PR (210 kg P ha-1 was applied in previous crop to cover 6 succeeding crops).

2.3. Fertilizer application, transplanting and intercultural operations

The experimental field was first opened on 20 days before sowing with the help of power tiller and cross-ploughed 6 times. All kinds of weeds and residues of previous crop were removed from the field. The plant nutrients like Nitrogen, Phosphorus, Potassium, Sulphur and Boron were used in the research field as 100kgN ha-1,26kgP ha-1,33kgK ha-1,20kg S ha-1and 1kg B ha-1 respectably. All fertilizers except N were applied to the soil during final land preparation. Nitrogen as urea was applied in two times; firstly 2/3 of urea was applied during final land preparation. Remaining 1/3 urea was applied as top dressing at the time of 21 days after emergence of seedlings. The seed was shown on November 20, 2004 and seed rate was 120 kg ha-1as recommended by BARI (2004).Line to line distance was 20 cm with continuous distribution of seeds in the lines in each plot. Inter cultural operations such as irrigation, weeding and pest control etc. were done as and when required.

2.4. Harvesting and data collection

At the spike emergence stage and at harvest the plant samples were collected from each plot. Ten hills per plot were collected randomly for the determination of dry matter yield and nutrient analysis. The crop was harvested at full maturity on 14 March, 2005.Sun dried weight of both grain and straw were recorded plot-wise for each treatment.

2.5. Chemical analysis of soil and plant samples

The initial soil sample was collected before land preparation from 0-15 cm and analyzing for both physical and chemical properties in the Laboratory of the Department of Soil Science, Bangladesh Agricultural University, Mymensingh. Particle size analysis of soil was done by Hydrometer method (Gee and Bauder, 1986). Soil pH was measured with the help of glass electrode pH meter using soil water suspension of 1:2:5(Jackson, 1962).Organic carbon in soil was determined by wet oxidation method ( Walkley and Black,1934).Cation exchange capacity (CEC) of soil was determined by sodium saturation method as outlined by Chapman (1965). Total nitrogen of soil was estimated by micro kjeldhal method (Bremner and Mulvaney, 1982).Available soil phosphorus was measured by Olsen method (Olsen and Sommers, 1982).Exchangeable potassium was determined by using flame photometer (Black, 1965) and available sulphur was determined by turbidimetric method. The collected grain and straw samples from each plot were dried in an oven at 650C for 48 hours after which they were ground by a grinding mill. Later the ground samples were sieved through a 20- mesh sieve. The prepared samples were then chemically analyzed for N, P, K and S following diacid digestion procedure (Jones and Case, 1990; Watson and Issac, 1990).The analysis of variance for crop characters and also for the nutrient elements of plant samples were done following the F-test. Mean comparisons of the treatments were made following the Duncan’s Multiple Range Test (DMRT).

3. Results and Discussion:

3.1. Growth of wheat plants at panicle initiation (PI) stage

All the treatments differed significantly in dry matter yield development at PI stage of growth of wheat plant. Maximum dry matter production (2.25t ha-1) was obtained in T3 treatment, which was 48.0% increase over control (Table 1) .The minimum dry matter production (1.52 t ha-1), was observed in control.

3.2. Plant height

Plant height, one of the agronomic characteristics, was found to be statistically insignificant in treatments used in all the experiment. The maximum plant height (105.40 cm) was attained in the treatment T4 and the minimum plant height (102.20 cm) was obtained in T1 treatment (Table 2).

3.3. Effective tillers hill-1

Maximum number of effective tillers (3.26hill-1) was found in T3 treatment (Table 2).TSP treatment showed better result over PR treatment having the same P rate. The minimum number of effective tillers (2.12hill-1) was found in control. Zaman et al.(1997) found increase the effective tillers hill-1 over control due to P application on wheat crop.

3.4. Panicle length

Panicle length was highest in T3 treatment (9.52 cm) (Table 2). TSP treatment showed better result over PR having the same P rate (26 kg P ha-1).The lowest panicle length (7.12cm) was found in T1 treatment. The second highest panicle length was found in T4 (210 kg P ha-1) was applied in previous crop treatment.

3.5. Sterile spikelets spike-1

Maximum numbers of sterile spikelets (5.12) were found in control (T1) treatment, which was statistically similar to PR treatment. However, the percentage of sterile spikelets spike-1 ranged from 5.8 to 19.5 (Table 2). The lowest number of sterile spikelets spike-1 was found in T3.

3.6. Grains spike-1

The highest number of grains spike-1 (35.45) was recorded in T3 (26 kg P ha-1) treatment which was statistically similar to T4 treatment (210 kg P ha-1 was applied in previous crop).However, the percentage of grains spike-1 varied from 80.4 to 94.1 (Table 2).The lowest number of grains spike-1 was obtained in control.

3.7. 1000-grain weight

The weighed of 1000-grain varied from 46.22 to 48.25g.The highest value was found in T3 treatment and the lowest value was observed in T1 treatment. TSP treatment had better effect compared to PR having same rate of P (26 kg P ha-1).However, 1000-grain weight was not significant between the treatments.

3.8. Grain yield

The recoded grain yield due to different treatments of P ranged from 2.05 to 3.10 t ha-1 which differed significantly (Table 3).The maximum grain yield (3.10 t ha-1) increase was obtained by T3 (26 kg P ha-1) treatment, which showed an increase of 51.2% over control. The second highest grain yield increase was obtained in T4 treatment (2.85 t ha-1), which the third highest grain yield was recorded in PR (T2) treatment (2.35 t ha-1). The treatments T2, T3 and T4 were statistically similar. The minimum grain yield was noted in control treatment. Chowdhury and Mian (1978) reported that the grain yield of wheat increased with increasing levels of P from either TSP or PR.

3.9. Straw yield

Straw yield of wheat (cv.Kanchan) was also significantly influenced due to different treatments. The maximum straw yield (5.54 t ha-1) was obtained in T3 treatment, which showed an increase of 89.7% over control. The treatments T3 and T4 were statistically similar. The lowest straw yield was recorded in control. However, TSP treatment showed significant straw yield.

Table 1: Effects of different treatments on dry matter yield at booting stage of wheat at BAU farm, Mymensingh

Treatments	Dry matter yield(t ha-1)	Increase over control(%)
T1 Control (0 kg P ha-1)	1.52d	-
T2 PR (26 kg P ha-1)	1.9c	28.4
T3TSP(26 kg P ha-1)	2.25a	48.0
T4 PR(210 kg P ha-1*)	2.07b	36.4
SE (±)	0.0356	-
CV (%)	3.85	-

*210 kg P ha^-1 was applied in previous crop to cover six succeeding crops.SE (±) = Standard error of means

Figures in a column having common letters do not differ significantly at 5% level of significance by DMRT.

Table 2: Effects of different treatments on yield contributing characters of wheat (cv.Kanchan) at BAU farm,Mymensingh

Treatments	Plant Height (cm)	Effective tiller hill1(No.)	Panicle length(cm)	Sterile spikelets spike-1(No.)	Sterile spikelets spike-1(%)	Grains spike-1(No.)	Grains spike-1(%)	1000-grains weight (g)
T1	102.20	2.12c	7.12c	5.12a	19.5	28.65b	80.4	46.22
T2	103.40	2.63b	8.12c	4.94a	14.5	29.04b	85.4	46.65
T3	105.12	3.26a	9.52a	2.21c	5.8	35.45a	94.1	48.25
T4 *	105.40	2.95ab	9.15ab	3.15b	8.3	34.5a	91.6	46.90
SE (±)	NS	0.0922	0.2801	0.1186	-	1.0158	-	NS
CV(%)	2.21	6.73	6.61	6.15	-	6.37	-	7.1

*210 kg P ha^-1 was applied in previous crop to cover six succeeding crops.SE (±) = Standard error of means

Figures in a column having common letters do not differ significantly at 5% level of significance by DMRT.

Table 3: Effects of different treatments on grain and straw yields of wheat (cv.Kanchan) at BAU farm, Mymensingh.

Treatments	Grain		Straw
	Grain yield t ha-1	Increased over control (%)	Straw yield t ha-1	Increased over control (%)
T1	2.05b	-	2.92c	-
T2	2.35a	14.6	3.62b	23.9
T3	3.10a	51.2	5.54a	89.7
T4 *	2.85a	39.0	5.38a	84.2
SE (±)	0.1667	-	0.1777	-
CV (%)	13.96	-	8.14	-

*210 kg P ha^-1 was applied in previous crop to cover six succeeding crops.SE (±) = Standard error of means

Figures in a column having common letters do not differ significantly at 5% level of significance by DMRT

3.10. Economic analysis

The analysis was done in order to find out the most profitable treatment based on cost- benefit of various treatments. Net benefit was calculated by subtracting the total input cost from the gross field profit. Gross field profit was calculated as the total market value of grain and straw of wheat. The input cost was calculated as the total market value of fertilizer and others material and non- material cost. The data were shown in Table 4.The results of economic analysis of wheat (cv.Kanchan) demonstrated that highest net benefit of Tk. 24,788 ha-1 was obtained in T3 treatment followed by Tk. 22,964 Tk.12, 292 and Tk. 8,504 ha-1 in T4, T2 and control treatments, respectively. The farmers will preferably choose any of these treatments which can give higher net benefit with relatively a lower variable cost.

Table 4. Cost-benefit analysis of wheat (cv.Kanchan) during rabi season 2004-05 at BAU Farm, Mymensingh.

Treatments	Total output (kg ha-1)		Gross field income (Tk ha-1)			Total production cost (Tk ha-1)	Net income(Tk ha-1)	Net benefit due to addition of PR(26 kg P ha-1)over control (Tk ha-1)	Net benefit due to addition of TSP (26 kg P ha-1)over T2 (Tk ha-1)	Net benefit due to addition of PR(210 kg P ha-1)over T3 (Tk ha-1)
	Grain	Straw	Grain	Straw	Total
T1	2050	2920	30750	2920	33670	25166	8504	-	-	-
T2	2350	3620	35250	3620	38870	26578	12292	3788	-	-
T3	3100	5540	46500	5540	52040	27252	24788	-	12496	-
T4 *	2850	5380	42750	5380	48130	25166	22964	-	-	1824

*210 kg P ha^-1 was applied in previous crop to cover six succeeding crops. Production cost other than fertilizer and PR remain same in all treatments. Grain and straw as per current market price

Output cost Input cost

Grain@ Tk.15 kg^-1 a. Material cost b. Non-material cost

Straw@ Tk. 1.00 kg^-1 PR @Tk. 7.00 kg^-1 Labor @ Tk.14560.00 ha^-1

TSP@ Tk.16 Kg^-1 Ploughing @ Tk.1660.00 ha^-1

Urea @ Tk.6.00 Kg^-1

MOP @ TK.16.00 Kg^-1

Gypsum@ Tk. 5.00 Kg^-1

Boric acid @ Tk. 120.00 Kg^-1

Irrigation@ Tk.1800.00 ha^-1

Pesticide @Tk.1400.00 ha^-1

Seed Tk.2100.00 ha^-1

Conclusion: It may be concluded that the use of rock phosphate will entirely be a new source of P fertilizer to be used in the country. TSP had better performance over PR having same rate of P (26 kg P ha1) and (210 kg P ha-1 was applied in previous crop) which was treated as residual effect of PR. Treatment T4 showed comparatively better performance than T2 because of its (PR) low solubility. Although PR bear some toxic substances in soil but its low price and high residual effect of cropping system could be and added factor for easy acceptance of P fertilizer compared to other phosphatic fertilizers. The effect of TSP on growth and yield of wheat was better than the direct application of PR. The residual effects of high rate of PR applied in preceding T.aman crop had shown better performance than the PR which was used in present wheat crop. The highest economic benefit was found in TSP compare to PR.

References

BARC.2005. Fertilizer Recommendation Guide. Soils Pub.43, Bangladesh Agric.Res. Council, Farmgate, Dhaka.

BARI.2004.Hand book on Agro-Technology,3rd Edition, Bangladesh Agricultural Research Institute, Gazipur, Dhaka.

BBS.2008,Monthly Statistical Bulletin Bangladesh (December 2008).Bangladesh Bureau of Statistics, Statistics Division, Ministry of Planning, Government of the People’s Republic of Bangladesh.

Black,C.A 1965.Methods of soil analysis part 1 and 2.Amer.Soc.Agron.Inc.Pub. Madison,Winsconsin,USA.

Bremner,J.M and Mulvaney, C.S.1982.Total Nitrogen, In Methods of Soil Analysis. Miller,R.H. and Xeeny,D.R. 1982.Amer.Soc.Agron.Inc.Madi.Wis.USA.pp.595-622.

Chapman,H.D.1965. Cation Exchange capacity. In Methods of Soil Analysis. C.A. Black Ed.pp. 891-901.Amer.Soc.Agron.,Inc.,Madison,Wisconsin.

Chowdhury,S.U. and Mian,M.H.1978.Effect of superphosphate on the yield of wheat and rice on acid soil of Nagaland and nutrient content of grain. Indian Soc.Soil Sci.32(2):299-302.

FAO and UNDP.2008. Land Respond Appraisal of Bangladesh for Agricultural Development. Report 1 Agro-ecological Regions of Bangladesh. Food and Agricultural Organization and United Nations Development Programme.pp.212-221.

Gee,G.W. and Bauder,J.W.1986. Particle- size Analysis.In Methods of Soil Analysis, Part-1 (2nd edition).A. Klute ed.,pp.383-411. Amer. Soc. Agron., Inc. and Soil Science Soc. Amer.,Inc. Madison, Wisconsin.

Hammond,L.L.; Chien, S.H and Mokwunye, A.U. 1986. Agronomic value of unacidulated and partially acidulated phosphate Rocks Indigenous to the tropics. Adv. Agron. 40:89-140.

Hoffland,E. 1991. Mobilization of rock phosphate by rape (Brassica napus L.). Ph.D. Thesis, Wageningen Agricutural University, Wageningen, The Netherlands, p. 93.

Jackson, M.L. 1962. Soil chemistry analysis. Prentice Hall Inc. Englewood Cliffe,N.J

Jones,Jr.J.B. and Case, V.W. 1990.Sampling,handling and analyzing plant tissue samples. In: Soil testing and plant analysis, 3rd edition, SSSA Book series 3,(ed.) W.S. Westermaan, Soil Science Society of America,Madision,WI,USA,389-427 pp.

Olsen, S.R.; Cole, C.V.; Watanabe,F.S. and Dean, L.A. 1954. Estimation of available phosphorus in soils by extraction with sodium bicarbonate.U.S. Dept. Agric.Cire. p.929.

Razzaque, M.A. and Hossain,A.B.S. 1999.The wheat for development programme Bangladesh. In: Proc. Wheat for non- traditional warm area D.A. Saunders e., UNDP/CYMMYT.

Walkley and Black, C.A. 1934. An examination of Degtjareff method for determining soil organic matter and proposed modification for the chromic acid titration method. Soil Sci.,37:29-38.

Watson,M.E. and Isaac,R.A.1990. Analytical instruments for soil and plant analysis. In: Soil testing and plant analysis, 3rd edition.SSSA Book series 3,(ed.) W.L.Westermaan, Soil Science Society of America,Madision,WI,USA,691-740 pp.

Zaman,S.K.; Razzaque, M.A.; Karim,S.M.R. and Bhuiyan,N.I. 1997. Rice response to phosphorus in wetland soil. Pakistan J.Sci. Indus.Res. 38(11-12): 438-440.