EFFECT OF PHOSPHORUS APPLICATION ON WHEAT AND RICE YIELD UNDER WHEAT- RICE SYSTEM

Sarhad J. Agric. Vol. 23, No. 4, 2007 851 EFFECT OF PHOSPHORUS APPLICATION ON WHEAT AND RICE YIELD UNDER WHEAT- RICE SYSTEM Rahmatullah Khan *, Ali Raza Gurmani **, Akber Hussain Gurmani *, and M.Sharif Zia *** ABSTRACT A field experiment was conducted to study the response of wheat and rice to phosphorus during 20004-05 at D.I.Khan. The basal dose of N at 120 kg and K 2 O at 60 kg ha -1 was applied with P levels (0, 45 and 90 kg P 2 O 5 ha -1 ) to both wheat and rice crops. Wheat variety Naseer 2000 and rice variety IRRI-6 were used in the study. The experiment was carried out in RCB design with three replications. Phosphorus application significantly increased the grain yield of wheat from 2920 kg ha -1 in control to 3560 kg ha -1 in the treatments receiving P at 90 kg P 2 O 5 ha -1 giving an increase of 22 % over control. The number of tillers, spikes, spike length and plant height of wheat were also significantly increased by P application. The rice also showed positively response to P application and hence both yield and yield parameters were significantly greater in the P than in the check treatment. Paddy yield was increased significantly by P application up to 75% over control. Plant height and 1000 grain weight were also significantly increased with P application over control. The application of P significantly increase number of spike plant -1 and spike length over control, however no statistical difference was recorded among the treatment. The cumulative application of 90 kg P 2 O 5 ha -1 gave the highest increase of 75% while direct application of the same level gave an increase of 54% however 47% increase over control was recorded by the residual application of 90 kg P 2 O 5 ha -1. The highest VCR of 3.7:1 was achieved with the cumulative application of 45 kg P 2 O 5 ha -1. Keywords: Phosphorus, Rice, Wheat INTRODUCTION The average yield of wheat in Punjab, Sindh and NWFP is 2.50, 1.70 and 1.38 t ha -1, respectively while for rice it is 2.47, 2.50 and 2.12 t ha -1 in respective provinces. However, the national average yield of wheat and rice has been reported as 2.37 t ha - 1 and 1.97 t ha -1, respectively (MINFAL, 2004). Phosphorus is the second major plant nutrient. It plays a vital role in several physiological processes viz photosynthesis, respiration, energy storage and cell division/ enlargement. It is also an important structural component of many biochemicals viz nucleic acid (DNA and RNA enzymes and coenzymes) and also stimulates root growth and associated with early maturity of crops. It offers increased disease resistance to plants. It prevents from lodging by providing strength to straw. The wheat-rice system brings repeated transactions from aerobic to anaerobic soil conditions that result in unique changes in the physical, chemical, biological and nutritive properties of soil. The wheat-rice rotation in one of the world s largest agricultural production system and occupies about 14 million hectares of cultivated land in India, Pakistan, Bangladesh and Nepal (Zia et al., 2000). Wheat-rice rotation is very common in northern and some parts of the central Punjab. Nitrogen and phosphorus are applied to both the crops. Since the utilization of phosphate fertilizer is very low (10-30 %) and its availability increases under submerged conditions Nadeem and Ibrahim (2002). Rehman et al. (1991) revealed that on the average 68 % of D.I.Khan soils were deficient, 29 % medium and 3 % adequate in P. Zia (1990) found that most of the soil in wheat-rice area are low to medium in available P. Wheat being a winter crop responds more to P application. The high temperature and submerged under flooded rice helps to improve the availability of native P. Thus the recommended rate of P applied to wheat can meet P requirement of the submerged rice crop. Singh et al. (2000) worked on optimal P rates for wheat-rice cropping system during 1997. They used P levels (P 0-0, P 0-26, P 13-13, P 26-0, P 26-13, P 39-0 and P 26-26 kg ha -1 (P applied to wheat followed by P applied to rice both in kg ha -1 ). Grain yield and P accumulation by wheat were highest for higher P rates. Phosphorus application to rice increased P accumulation but did not consistently increase rice yields because flooding decreased soil P sorption and increased P diffusion resulting in higher P supply to rice relative to wheat. Applying only 26 kg P ha -1 to wheat and no P to rice was not economical and led to negative P balance and decline in soil P. Applying 32 kg P ha -1 to wheat and 15 kg P ha -1 to rice was optimal for economical production. Its production provides grains for more than one billion people or about 20 percent of the world s population (Singh et al., 2002). Phosphorus is an * ** *** Arid Zone Research Institute, Dera Ismail Khan - Pakistan National Agricultural Research Centre, Islamabad - Pakistan Pakistan Agricultural Research Council, Islamabad - Pakistan

Rahmatullah Khan et al. Effect of Phosphorus Application on Wheat 852 expensive nutrient as compared to nitrogen. It is therefore very important to manage properly for achieving of maximum benefit especially under submerged condition where its availability increases Terman et al. (1970), Ahmed and Ghafoor (1984), Saggar et al. (1985) and Bhatti and Khattak (1985). Zia et al. (2000) concluded during his study that wheat grain yield increased with increasing level of P over control. The maximum increase in wheat grain yield over control was recorded with 36 mg kg -1 soil. They further added that significant residual effect of P in rice-wheat system was observed. Residual effect of 50 % acidulated rock phosphate resulted in significantly greater yield of wheat than the residual effect of SSP and DAP. A similar study was also conducted by Hussain and Yasin (2004) and concluded that paddy yield was increased from 2 to 21 % by the residual application of P over control. The direct application of P increased the yield by 11.4 to 35 % while cumulative application of P increased the yield by 18 to 39 % over control. The P level used were 0, 15, 30 and 45 kg ha -1. Khattak and Bhatti (1986) conducted research work on the residual effect of phosphorus and potassium on the yield of maize and wheat. They found that P applied to the first crop was sufficient for the subsequent second and third crop. Potassium applied to the first crop may be sufficient up to fourth or even fifth crop. Keeping in view of the above facts this study was planned to study the residual/ cumulative and direct application of P on paddy yield in wheat-rice system. MATERIALS AND METHODS A field experiment was conducted during 2004-05 to study the effect of applied phosphorus on wheat and its residual/cumulative effect on subsequent rice crop. The experiment was laid out at Arid Zone Research Farm D.I.Khan in Randomized Complete Block Design with five treatments replicated three times. The treatments comprised of check (T1), 90 kg P 2 O 5 ha -1 to wheat and nil to rice (T2), nil to wheat and 90 kg P 2 O 5 ha -1 to rice (T3), 90 kg P 2 O 5 ha -1 each to wheat and rice (T4), 45 kg P 2 O 5 ha -1 each to wheat and rice (T5). The basal dose of N and K 2 O of 120-60 kg ha -1 along with P levels were applied in the form of urea, SOP and TSP respectively. All P, K and half N was applied at sowing while the remaining half N in wheat was applied at 2 nd irrigation while in rice at panicle initiation. The wheat Naseer 2000 and IRRI-6 rice varieties were used. The wheat was sown during second week of November 2004 and rice was planted during first week of June 2005. The treatment plot size of 2.40 m x 6 m was kept. All the other cultural practices were followed uniformly throughout the growing season. A composite soil sample was taken before sowing of wheat crop for physico-chemical analysis (Table. I). Electrical conductivity and ph of the soil were determined in 1:2 soil water suspension methods according to Black (1965). Soil texture was determined by the hydrometer method Moodie et al. (1954) whereas lime was estimated by acid neutralization method Richards (1954). Organic matter was determined by the modified method of Walkley and Black (Nelson and Sommers, 1982). Olsen P and NH 4 OAC extractable K were determined according to (Black, 1965). The post harvest data i.e. number of tillers, spike m -2, spike length, spike per plant and plant height in wheat and rice were recorded at proper time. The net plot of 0.60 m x 5.00 m was harvested manually for 1000 grain weight and grain yield of both wheat and rice. All the relevant data was statistically analyzed using MSTATC computer program. RESULTS AND DICUSSION The result revealed that grain yield of wheat was significantly increased by P fertilization compared with control treatment (Table. II). The highest grain yield of 3560 kg ha -1 was obtained from 90 kg P 2 O 5 ha -1 giving an increase of 21.9 %. The P at 45 kg P 2 O 5 ha -1 produced significantly lower grain yield of 3367 kg ha -1 which was statistically at par with 90 kg P 2 O 5 ha -1. The application of P also affected the yield parameters significantly over control. The highest number of tillers m -2 (558) and spike m -2 (388), spike length (11.2 cm) and plant height (106.6 cm) were achieved with application of phosphorus at 90 kg P 2 O 5 ha -1. The lowest number of tillers m -2 (419), spike m -2 (352), spike length (10.2 cm) and plant height (101.3 cm) were obtained from check. Thousand grain weight was also increased significantly over check. The highest weight (33.84 g) was obtained from 90 kg P 2 O 5 ha -1 but there was no significant difference within the P levels. These results are supported by Alam et al. (2003). The data obtained on rice crop after wheat revealed that grain yield of paddy was significantly increased by P application (Table. III). The maximum paddy yield 6319 kg ha -1 was obtained from treatment receiving 90 kg P 2 O 5 ha -1 during both wheat and rice crops. The treatment increased the yield by 75 % over control. A significant response was also noticed in plant height and 1000 grain weight due to P application. The maximum plant height of 113 cm and 1000 grain weight of 23.18 g were achieved with application of 90 kg P 2 O 5 ha -1 during both the crops wheat and rice. The application of P at any level had

Sarhad J. Agric. Vol. 23, No. 4, 2007 853 no significant effect on number of tillers m -2. The number of spike m -2 and spike length were also affected significantly over check but there was no difference within P levels. The maximum number of spike m -2 (23) and spike length (25.33 cm) were recorded with cumulative application of P at 90 kg P 2 O 5 ha -1. The lowest number of spike m -2 (16.13) and spike length (21.0 cm) were obtained from check. The cumulative application of 90 kg P 2 O 5 ha -1 gave the highest increase of 75% while direct application of the same level gave an increase of 54 % however 47 % increase over control was recorded by the residual application of 90 kg P 2 O 5 ha -1. The highest VCR of (3.7:1) was achieved by the cumulative application of 45 kg P 2 O 5 ha -1 while lowest VCR (2.4:1) was obtained from cumulative application of 90 kg P 2 O 5 ha -1. These results are supported by Zia et al. (2000), Hussain and Yasin (2004), Singh et al. (2000) and Singh et al. (2002). CONCLUSION Phosphorus application significantly increased the grain yield of wheat and rice. The highest yield advantage of 22% in wheat grain over check was recorded from 90 kg P 2 O 5 ha -1 while the cumulative application of same level enhanced paddy yield up to 75%. With direct application of 90 kg P 2 O 5 ha -1 the increased in paddy yield was 54% where 47% increased occurred due to residual effect. The cumulative application of 45 kg P 2 O 5 ha -1 proved more economical. Table-I: Physico-Chemical characteristics of Soil Soil properties Unit Value ph (1:2) - 8.00 E.C (1:2) DSm -1 0.46 CaCo 3 equivalent % 10.5 Organic matter % 0.79 Nitrogen % 0.039 NaHCO 3 Olsen P (mg kg -1 ) 04 NH 4 OAC Extractable K (mg kg -1 ) 80 Sand % 21.0 Silt % 45.0 Clay % 34.0 Textural class Silty Clay Table-II : Wheat response to P application under wheat-rice system Treatments P 2 O 5 kg ha -1 to crop Wheat Rice Number of tillers m -2 Number of spike m -2 Spike length Plant height 1000 grain weight (g) Grain yield (kg ha -1 ) T1 0 0 419 b 352 b 10.2 c 101.3 c 32.05 c 2920 b - T2 90 0 558 a 388 a 11.0 a 106.6 a 32.93 ab 3560 a 21.9 T3 0 90 434 b 353 b 10.3 bc 101.5 c 33.34 a 3040 b - T4 90 90 509 ab 385 a 11.2 a 105.0 a 33.84 a 3468 a 18.7 T5 45 45 504 ab 358 b 10.6 b 103.5 b 33.26 a 3367 a 15.3 LSD 0.05 96.41 14.36 0.3812 1.727 1.010 249.2 Means followed by same letter(s) within the columns do not differ significantly at P< 0.05 Percent increase over control %

Rahmatullah Khan et al. Effect of Phosphorus Application on Wheat 854 Table-III: Rice response to P application under wheat-rice system P 2 O 5 kg ha -1 to crop Wheat Rice No. of spike m -2 No. of spike/ plant Spike length Plant height 1000 grain weight (g) Grain yield (kg ha -1 ) T1 0 0 302 16.13 b 21.00 b 106.7 c 21.25 d 3606.33 e - T2 90 0 303 22.20 a 24.60 a 110.7 b 22.82 b 5328.00 d 47.7 T3 0 90 304 22.60 a 24.93 a 111.3 ab 22.57 b 5569.66 c 54.4 T4 90 90 308 23.0 a 25.33 a 113.0 a 23.18 a 6319.66 a 75.0 T5 45 45 307 22.80 a 24.73 a 111.3 ab 21.88 c 5696.33 b 58.0 LSD 0.05 N.S 1.159 1.158 2.254 0.34 103.7 Means followed by same letter(s) within the columns do not differ significantly at P< 0.05 Table-IV: Economic analysis of P use in rice under wheat-rice system Percent increase over control Treatments Treatments P 2 O 5 kg ha -1 to crop Paddy yield kg ha -1 Increase over control Value of yield increase Cost of fertilizer Rs. ha -1 Value cost ratio Net Return Rs. ha -1 Wheat Rice kg ha -1 Rs. ha -1 T1 0 0 3606 - - - - - T2 90 0 5328 1722 10228 3325 3.1:1 6903 T3 0 90 5569 1963 11660 3325 3.5:1 8335 T4 90 90 6320 2714 16121 6650 2.4:1 9471 T5 45 45 5696 2090 12414 3325 3.7:1 9089 Value of paddy rice = Rs.5.94 kg -1 Cost of TSP = Rs.36.95 kg -1 P 2 O 5 REFERENCES Ahmed, N.M. Idrees and A. Ghafoor. 1984. Effect of flooding, organic matter and sources of P on rice yield and P uptake. J. Agric. Res. 22: 37-44. Alam S.M., S.A. Shah, S. Ali and M. M. Iqbal. 2003. Wheat yield and P fertilizer efficiency as influenced by rate and integrated use of chemical and organic fertilizer 22(2): 72-76. Bhatti, A.U. and J.K. Khattak. 1985. Yield response of rice to phosphorus. Int l. Rice Res. Newsl. 10: 21. Black, C.A. 1965. Methods of soil analysis. Part II. Amer. Soc. Agron., Madison, Wisconsin, U.S.A. Hussain, F. 2004. Soil fertility monitoring and management in wheat rice system. Annual Report LRRI, NARC, Islamabad. Khattak, J.K. and A.U. Bhatti, 1986. Coop. Res. Prog, National Out Reach Research Project, Soil. Fertility and Fertilizer use in Pakistan. Deptt of Soil Sci. N.W.F.P. Agric. Univ. Pesh. 60-69 pp. MINFAL. 2004. Agric. Statistic of Pakistan. Ministry of Food. Agric and Livestock. Govt of Pakistan. Islamabad. 4-14 pp. Moodie, D., H.W. Smith and R. A. McCreary. 1954. Laboratory Manual for Soil Fertility. Washington State College, Monograph. 31-39 pp. Nadeem, M.Younus and M. Ibrahim 2002. Phosphorus management in wheat and rice cropping system. Pak. J. Soil Sci. 21 (4): 21-23. Nelson, D.W. and L.E. Sommer. 1982. Total carbon, organic carbon and organic matter. p.539-577. In. A.L. Page, M. H. Miller and D.R. Keeny, (eds) Methods of Soil Analysis, Part-2. 2 nd Ed. Am. Soc. Agron. Madison. WI. Nisar, A. 1996. Annual Fertilizer Review. NDFC Public. Islamabad. 11/96: 31. Rehman. N., M. Ibrar, H. Rehman and A. H. Gurmani. 1991. On farm soil test values of Agriculture soils of D.I.Khan District. Directorate Soil and Plant Nut, Tarnab Peshawar.

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