Bangladesh Agron. J. 2021, 24(1): 71-81 EFFECTS OF IRRIGATION, ORGANIC AND INORGANIC NUTRIENT SOURCES ON THE GROWTH, YIELD AND SOIL FERTILITY STATUS WITH RICE-RICE CROPPING M.A. Khan1, S.A. Shampa1, P.K. Biswas2 and M.B. Hossain3 1Department of Soil Science, 2Department of Agronomy, Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh 3Bangladesh Agricultural Research Council, Farmgate, Dhaka-1207, Bangladesh Corresponding E-mail: makhan_sau@ymail.com (Received: 07 March 2021, Accepted: 26 March 2021) Keywords: Irrigation, fertilizer, manure, rice yield, soil fertility Abstract Continuous cultivation of highly exhaustive cropping sequence in most of the irrigated fertile lands has resulted in the decline of soil physico-chemical condition in general and particularly soil organic matter (SOM) content. The experiment was laid out inasplit- plot design with irrigation (I1: traditional irrigation i.e. continuous flooding, I2: saturated condition, I3: Alternate wetting and drying) in main plots and fertilizers treatments: T0 = Control, T1 =100% (Recommended dose of chemical fertilizer), T2 =50% RDCF + 5 ton cowdung ha- 1, T3=70% RDCF + 3 ton cowdung ha-1, T4 =50% RDCF + 5 ton compost ha-1, T5 =70% RDCF + 3 ton compost ha-1, T6 = 50% RDCF + 3.5 ton poultry manure ha-1, T7 =70% RDCF + 2.1 ton poultry manure ha-1to the sub - plots. The rice yields were not significantly affected by different irrigation but higher grain yields were obtained in continuous flooded irrigation. The treatment T7 gave higher Boro and T. Aman rice yields. The higher Boro rice grain yields were obtained from I1T7 (70% RDCF + 2.1 ton poultry manure ha-1 with continuous flooded irrigation) followed by I3T7 (alternate wetting and drying + 70% RDCF + 2.1 ton poultry manure ha-1). The 100% RDCF was applied to T. Aman rice resulted residual effects of fertilizer and the higher T. Aman rice yields were recorded in I2T2 (saturated condition + 50% RDCF + 3 ton cowdungha-1) followed by I2T3 (saturated condition + 50% RDCF + 3 ton cowdungha-1) treatment combinations due to more residual effects of inorganic plus manure application during Boro rice cropping. The highest organic matter level was found in post-harvest soils where inorganic fertilizer plus cowdung were used and soil pH increased by using poultry manure. The higher levels of available P and K concentrations were observed in the post experiment soils where fertilizer and manure were applied. Introduction Rice-rice is the most important cropping system in Bangladesh. Continuous cultivation of this highly exhaustive cropping sequence in most of the irrigated fertile lands has resulted in the decline of soil physico-chemical condition in general and particularly soil organic matter (SOM) content. Organic matter decomposition, nutrient mineralization, leaching and efficiency of fertilizer and manures in rice field are greatly affected by the soil moisture level. The yield of rice is low in Bangladesh than in the other rice growing countries like South Korea and Japan (FAO, 1999). Organic and chemical fertilizers are applied for higher yield and improvement of soil fertility and physico-chemical properties. More nutrients are leached out from soil when more 72 Khan et al. irrigation water is added during Boro rice growing period. Moisture levels affect the organic matter accumulation and mineralization. Yang et al. (2004) reported that application of chemical fertilizers with farmyard manure or wheat or rice straw in alternate wetting and drying condition increased N, P, & K uptake by rice plants. Organic manure can supply a good amount of plant nutrients thus can contribute to crop yields. The integrated approach by using the organic and inorganic sources of nutrients helps to improve the efficiency of nutrients. Water input can be reduced by reducing ponded water depths to soil saturation or by alternate wetting/drying. Increasing water scarcity necessitates the development of irrigated rice systems that require less water than traditional flooded rice. In irrigated aerobic rice systems, rice grows in non-flooded and saturated irrigation. The present research work was, therefore, undertaken to find out the effect of chemical fertilizers and organic manure on the productivity and fertility and nutrient availability in Boro-T. Aman rice cropping pattern. Materials and Methods Field Characteristics The experiment was conducted in the field of experimental farm at Sher-e-Bangla Agricultural University (SAU), Dhaka during January, 2012 to December, 2014. The area belongs to the Tejgaon soil series of Madhupur Tract (AEZ 28) having 2874N latitude and 9035 E longitude with an elevation of 8.2 meter from sea level. The soil of the experimental field classified as Deep Red Brown Terrace Soils in Bangladesh soil classification system (UNDP and FAO, 1988). The soil is a silt loam with 6.4 pH, 1.12% organic matter (Walkley and Black, 1975), 0.08% total N (Micro Kjeldahl method; Bremner and Mulvaney, 1982), 12.0 μg g-1 available P (0.5M NaHCO3 extractable; Olsen and Sommers, 1982) and 22.5 μg g-1 exchangeable K (1MNH4OAc extractable; Page et al., 1982). Experimental design and treatment The experiment was laid out in a split plot design assigning irrigations to the main plots and fertilizer treatments to the sub-plots with three replications. Three Irrigation treatments (I1= Continuous flooding (3-4 cm water), I2= saturated condition (disappearance of water on the surface) and I3: Alternate wetting and drying) and eight fertilizer treatments T0: Control, T1: 100% Recommended dose of chemical fertilizer (RDCF), T2: 50% RDCF + 5 tha-1 cowdung, T3: 70% RDCF + 3 tha-1 cowdung, T4: 50% RDCF + 5 tha-1compost, T5: 70% RDCF + 3 tha-1 compost, T6: 50% RDCF + 3.5 tha-1 poultry manure, T7: 70% RDCF + 2.1 tha-1 poultry manure were applied in the experiment during Boro rice cultivation. Field Experiment The land was leveled and the experimental plot was partitioned into the unit plots. Treatment wise cowdung, compost, and poultry manures were applied before four days of final land preparation. There were 1.46% N, 0.29% P, 0.74% K in cowdung; 2.2% N, 1.99% P, 0.82% K in poultry manure and 1.49% N, 0.28% P, 1.60% in water hyacinth compost. TSP, MoP, gypsum, zinc sulphate and one third urea were applied during final land preparation. The remaining one third urea was applied at 30 DAT and another one third at 55 DAT. The fertilizer and manures were mixed in the soils of the plots. The first crop boro rice var. BRRI dhan29 was transplanted during first week of January, 2012 and second crop T. Aman rice (var. BRRI dhan32) was transplanted in July 2012. The 35-day old seedlings for Boro rice (dry season rice) and T. Aman (Wet season rice) were transplanted with a spacing of 20 cm × 20 cm. Intercultural operations were done whenever required. Effects of Irrigation and Nutrient Sources on Rice-Rice Cropping Pattern 73 After harvest of Boro rice, T. Aman rice was transplanted and grown in rainfed condition without any manure application in soil but recommended dose (N100P15K45S12Zn2) was applied. Supplemented irrigation was applied as per irrigation treatments during T. Aman growing period. The yield and yield parameters were recorded for each crop. Similarly, third crop Boro rice (2013), fourth crop T. Aman rice (2013) and fifth crop Boro rice (2014) were grown in the same plots with the application of similar fertilizer and irrigation treatments. After harvest of fifth crop, treatment wise post- experimental soils were collected from 0-15cm depth and analyzed for N, P, K, pH and soil organic matter content by using standard methods. Soil analysis: Soil pH was measured by glass electrode pH meter using soil-water ratio 1:2.5 (McLean, 1982). Organic matter content was estimated by wet oxidation method (Walkley and Black, 1975). The total N contents in soil were determined by micro-Kjeldahl method (Bramner and Mulvaney, 1982). The soil P (Olsen and Sommers, 1982) and K (Page et al.,1982) were determined by using spectrophotometer and flame photometer, respectively. Statistical analysis The data obtained for different parameters were statistically analyzed and significance of the difference among the treatment means was estimated by the Duncan’s Multiple Range Test (DMRT) at 5% level of probability. Results and Discussion Effects of irrigation, fertilizer and manure (Boro rice) The number of effective tillers hill-1 was significantly influenced by irrigation in first crop Boro rice and the highest number of effective tillers hill-1 was found in continuous flooded condition (I1) and lowest in I3 (alternate wetting and drying) (Table 1). Higher yields of first and third Boro rice crops were found in continuous flooded condition which was closely similar to other irrigation treatments (Table 1). Table 1. Effects of irrigation on the effective tillers hill-1, grain and straw yield of first (Boro), second (T. Aman) and third (Boro) rice crops Treatments Number of effective tillers hill-1 Straw yield (t ha-1) Grain yield (t ha-1) 1st crop 2nd crop 3rd crop 1st crop 2nd crop 3rd crop 1st crop 2nd crop 3rd crop I1 13.8a 7.15 12.52 7.07 5.98 7.02 7.06 4.37 6.38 I2 11.3b 7.27 12.89 7.08 6.53 6.81 6.94 4.81 6.05 I3 12.6ab 6.94 13.03 6.82 6.52 6.81 6.82 4.58 6.19 I1=Continuous flooded; I2= Saturated condition; I3= Alternate wetting and drying In a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per DMRT Among the different fertilizer treatments, T3 showed maximum number of effective tillers hill-1 (13.9) in first crop Boro rice which was statistically similar to T7 (70% RDCF + 2.1 ton poultry manure ha-1) treatment. In first crop, T7 showed the maximum plant height (89.67 cm) which was statistically similar to all other treatments except T0 (control). In second crop (T. Aman rice), the residual effect of T7 and renewal application of chemical fertilizer showed the highest number (7.6) of effective tillers hill-1. Treatment T4 followed by T3 showed the maximum plant height (124.9 cm) and panicle length (26.06 cm) which was statistically similar to all fertilizer 74 Khan et al. treatments except T0. In the third crop Boro rice, the highest number of effective tillers hill-1 (14.1) was found in T7 treatment and higher plant height, panicle lengths and number of filled grains panicle-1 were found in organic plus inorganic treatments (Table 2). The lowest number of effective tillers hill-1, plant height, and filled grains panicle-1 were observed in T0 treatment. Different fertilizer treatments showed significant variations in respect of grain and straw yields in first, second and third rice crops (Table 3). The highest straw yield of first crop was obtained in T3 treatment which was statistically similar to T4, T5 and T7and the lowest straw yield was obtained in T0 treatment. The highest grain yield (7.47 t ha-1) of first crop was observed in the T7 treatment which was statistically similar with the T1, T3, T4 and T5 and the lowest grain yield (5.02 t ha-1) was observed with T0 treatment. The highest straw yield of second crop (6.78 t ha-1) was obtained in T2 treatment which was statistically similar to all other treatments except T0. The highest grain yield of second crop was observed in the T7 treatment which was statistically similar to all other treatment except T0 (control and the lowest grain yield (3.79 tha-1) was observed with T0 where no fertilizer was applied. The highest straw yield of third crop (7.72 t ha-1) was obtained in T1 (100% RDCF) treatment which was statistically similar to T3, T5. T6 and T7 treatments and the lowest straw yield was obtained in T0treatment. The highest grain yield of third crop was observed in the T1 and T7 treatments and the lowest grain yield (5.02 t ha-1) was observed with T0 where no fertilizer was applied. Table 2. Effects of nutrient sources on the effective tillers, plant height and panicle length of first (Boro), second (T. Aman) and third (Boro) rice crops Treatments Number of effective tillers hill-1 Plant height (cm) Panicle length (cm) 1st crop 2nd crop 3rd crop 1st crop 2nd crop 3rd crop 2nd crop 3rd crop T0 11.8c 6.77 10.53c 77.89b 105.79b 73.02b 23.36b 22.47c T1 13.6ab 7.31 13.87a 89.33a 123.34a 85.57a 24.70ab 25.04ab T2 12.3abc 6.76 11.13bc 85.55a 124.44a 86.46a 26.51a 24.57ab T3 13.9a 7.27 13.22a 87.55a 122.65a 86.57a 26.06a 24.74ab T4 12.8abc 7.36 12.73ab 86.88a 124.99a 84.20a 25.55a 24.75ab T5 11.6c 6.64 13.22a 87.33a 123.36a 84.83a 25.31ab 25.68a T6 12.0bc 7.31 13.73a 86.44a 121.15a 87.55a 25.16ab 24.41b T7 12.4abc 7.56 14.07a 89.67a 124.80a 84.53a 25.24ab 24.84ab In a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per DMRT Table 3. Effects of nutrient sources on the filled grains panicle-1, grain and straw yield of first (Boro), second (T. Aman) and third (Boro) rice crops Treatments Filled grains panicle-1 Straw yield(t ha-1) Grain yield(t ha-1) 1st crop 3rd crop 1st crop 2nd crop 3rd crop 1st crop 2nd crop 3rd crop T0 99.7b 83b 5.63 c 5.201b 4.03c 5.02 c 3.79b 3.47d T1 130.6a 107a 7.01 b 6.71a 7.72a 7.40 a 4.81a 7.01a T2 108.0a 129a 7.01 b 6.78a 6.91b 6.86 b 4.71a 6.40abc T3 122.7a 113a 7.55 a 6.10ab 7.48ab 7.41 a 4.56a 6.91ab T4 123.3a 121a 7.23 ab 6.29ab 6.81b 7.19 ab 4.48a 6.21c T5 122.3a 116a 7.14 ab 6.65a 7.23ab 7.24 ab 4.50a 6.32bc T6 114.2a 129a 7.01 b 6.55a 7.61a 6.95 b 4.85a 6.78abc T7 109.1a 121a 7.36ab 6.48a 7.25ab 7.47 a 4.98a 7.01a In a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per DMRT Effects of Irrigation and Nutrient Sources on Rice-Rice Cropping Pattern 75 Interaction effects of irrigation and fertilizer The highest grain yield of first crop Boro rice (7.93 t ha-1) was recorded with the treatment combination I1T7 which was statistically similar to I1T2, I1T3, I2T5, I2T3, I2T4, I2T5, I3T3 I3T5 and I3T5 treatment combinations and the lowest grain yield (4.48 t ha-1) was found in I3T0 treatment (Table 4). The highest grain yield of second (5.34 t ha-1) and third crops (7.36 t ha-1) were found in I2T7 and I2T7 treatment combinations, respectively. These results indicate that 70% nutrient from inorganic fertilizer and 30% nutrient from poultry manure or cowdung or compost with continuous flooding or saturated condition or alternate wetting drying performed better for increasing the yield of Boro rice and similar results in the second crop T. Aman rice due to the combined application manure and fertilizer. Among the manure poultry manure performed better with different levels irrigation. Table 4. Interaction effect of fertilizer and irrigation on the grain and straw yields of first (Boro rice), second crop (T. Aman rice) and third crop (Boro rice) Treat. Ist Crop 2nd Crop 3rd Crop Grain yield (t ha-1) I1 I2 I3 I1 I2 I3 I1 I2 I3 T0 4.91e 5.66d 4.48e 3.71 3.86 3.81 3.43 3.48 3.51 T1 7.51ab 7.53ab 7.15b 4.96 5.24 4.23 6.86 7.26 7.03 T2 7.32ab 6.37c 6.90bc 4.66 4.89 4.59 6.78 5.82 6.60 T3 7.32ab 7.42ab 7.50ab 4.25 4.46 4.97 7.29 6.69 6.75 T4 7.30ab 7.27ab 7.00bc 4.19 4.46 4.78 6.55 6.40 5.67 T5 7.18b 7.32ab 7.21ab 4.01 4.96 4.52 6.31 6.30 6.35 T6 7.04bc 6.90bc 6.91bc 4.16 5.23 5.15 6.53 6.36 6.23 T7 7.93a 7.08bc 7.40ab 5.04 5.34 4.55 7.31 6.06 7.36 Straw yield (t ha-1) T0 5.57 6.33 4.97 5.00 5.15 5.46 5.57 6.33 4.97 T1 7.37 6.94 6.71 6.75 6.78 6.59 7.37 6.94 6.71 T2 7.23 6.70 7.10 5.56 7.00 7.35 7.23 6.70 7.10 T3 7.32 7.74 7.58 5.78 6.23 6.28 7.32 7.74 7.58 T4 7.27 7.18 7.24 6.01 6.24 6.61 7.27 7.18 7.24 T5 7.08 7.18 7.15 6.23 6.55 7.17 7.08 7.18 7.15 T6 7.04 7.13 6.88 6.19 6.86 6.58 7.04 7.13 6.88 T7 7.65 7.46 6.96 6.32 7.40 6.10 7.65 7.46 6.96 In a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per DMRT The combined effects of different doses of fertilizer and irrigation on the grain and straw yield of rice were not significantly different. The 100% RDCF was applied in all the treatments during T. Aman rice cultivation except control treatment but yields were significantly affected due to the application of different types of fertilizer and manure treatments in the previous Boro rice cultivation. Higher T. Aman rice yields (second crop) were obtained in organic plus inorganic fertilizer treatments with different levels of irrigation due to residual effects of fertilizer and manure which was applied in previous Boro rice cultivation. The highest straw yield (7.74 t ha-1) of third crop was obtained from I2T3 treatment combination. The highest grain yield of third crop (7.36 t ha-1) was recorded with the treatment combination I3T7 which was similar to I1T7 (7.31 t ha-1), I1T3 (7.29 t ha-1) and I2T1 (7.26 t ha-1) 76 Khan et al. treatment combinations. The lowest grain yield (3.43 t ha-1) was found in I1T0 treatment combination. This result indicated that 70% nutrient from inorganic source and 30% nutrient from poultry manure with the application of alternate wetting and drying performed better for increasing the Boro rice yield. Rahman et al. (2019) and Islam et al. (2013) found similar results by using manure and fertilizer in rice with different levels of irrigation. Effects of irrigation, fertilizer and manure on the growth and yield of fourth crop T. Aman rice The results showed that the yield and yield parameters of T. Aman rice were not significantly influenced by irrigation but significantly influenced by residual effects of fertilizer and manure application (Table 5). Among the different fertilizer treatments, T6 showed the highest plant height (123.2 cm). The maximum panicle length (25.26 cm), filled grains panicle-1 (88.1) and 1000 seed weight (21.22 g) were found in the T5, T3 and T7 treatments respectively and the lowest plant height, number of effective tillers hill-1, filled grains panicle-1were observed in T0 treatment. The application of fertilizers plus manure in the previous rice crops had a positive and significant effect on the grain and straw yield of T. Aman rice (Table 5). The highest straw yield (6.26 t ha-1) was obtained due to the residual effect of T5 treatment which was statistically similar to all other treatments except T0. Table 5. Effect of fertilizer and manure on the yield parameters and yield of fourth crop T. Aman rice Treatments Plant height (cm) Panicle length (cm) Number of filled grains panicle-1 1000- grainweight(g) Straw yield (t ha-1) Grain yield (t ha-1) T0 104.9b 21.78c 68.37b 19.56c 4.42b 3.47b T1 118.6a 24.46ab 85.42a 20.78ab 6.03a 4.34a T2 120.7a 24.46ab 87.93a 20.22bc 5.78a 4.48a T3 120.8a 24.77ab 88.09a 20.44abc 6.02a 4.40a T4 119.9a 23.99b 83.69a 21.11ab 5.94a 4.32a T5 118.9a 25.26a 84.71a 21.00ab 6.26a 4.09a T6 123.2a 24.29b 84.77a 20.89ab 5.82a 4.07a T7 119.3a 24.36ab 78.84a 21.22a 5.92a 4.18a In a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per DMRT The highest grain yield (4.48 t ha-1) was observed in the T2 treatment in Boro rice crops which was statistically similar to all other treatment except T0 (control). This result indicates that T. Aman rice yield was increased more due to the residual effects of fertilizer plus manure treatments which were applied during previous Boro rice cropping. The lowest grain yield (3.79 t ha-1) was observed with T0 where no fertilizer was applied. Interaction effects of fertilizer and manure on the grain and straw yield of fourth crop T. Aman rice Plant height, panicle length, number of filled grains panicle-1, 1000 seed weight were not significantly influenced by interaction effect of irrigation and fertilizer. The grain and straw yields were significantly influenced by irrigation and fertilizer treatments. The highest straw yield (7.21 t ha-1) was found in I1T5 treatment combination which was statistically similar to I1T7, I2T1, I2T2, Effects of Irrigation and Nutrient Sources on Rice-Rice Cropping Pattern 77 I2T3 treatment combinations. The highest grain yield of 5.35 t ha-1 was recorded in I2T2 treatment combination which was statistically comparable to I1T5, I1T7, I2T1, I2T3 and I3T4. Table 6. Effect of irrigation and fertilizer and manure on the grain and straw yield of fourth crop (T. Aman rice ) Treat. Grain Yield (t ha-1) Straw yield (t ha-1) I1 I2 I3 I1 I2 I3 T0 3.35h 3.58fgh 3.47gh 4.45fg 4.65efg 4.16g T1 3.96d-h 4.87abc 4.21c-g 5.71b-f 6.65a-d 5.75a-f T2 3.97d-h 5.35a 4.13c-h 5.28c-g 6.88ab 5.20d-g T3 3.80d-h 5.09ab 4.31b-f 5.51b-g 6.70abc 5.84a-f T4 4.37b-f 4.02d-h 4.56a-d 5.61b-g 5.79a-e 6.42a-d T5 4.84abc 3.67e-h 3.77d-h 7.21a 5.90a-e 5.67b-f T6 3.90d-h 3.91d-h 4.42b-e 5.34c-g 6.13a-d 6.00a-e T7 4.56a-d 4.11c-h 3.89d-h 6.72abc 5.63b-f 5.42b-g In a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per DMRT These results indicate that T. Aman rice yield was increased due to the interaction of effects of fertilizer and reduced irrigation treatments where fertilizer, manure were applied combined with reduced level of irrigation during previous Boro rice cropping (Table 6). Individual Effects of Irrigation and Fertilizer on Growth, Yield of fifth crop Boro Rice The number of effective tillers hill-1, plant height, filled grains panicle-1, grain yield were not significantly affected by irrigation but panicle length and straw yields were affected significantly (Table 7). The highest number of effective tillers hill-1 (13.64), were found in continuous flooded condition which was closely similar to (13.58) in alternate wetting and drying irrigation. The highest panicle length (22.29 cm) and straw yield (7.51 t ha-1) were found in I1 and lower and statistically similar panicle length and straw yield were recorded in I2 and I3 treatments. The highest grain yield (7.11 t ha-1) was found in I1treatment which was closely similar to saturated irrigation (6.98 t ha-1) and the lowest (6.87 t ha-1) in I3. Table 7. Effect of irrigation on the growth and yield parameter of fifth crop Boro rice Treatments Number of effective tillershill-1 Plant height (cm) Panicle length (cm) Number of filled grainspanicle-1 Straw yield (t ha-1) Grain yield (t ha-1) I1 13.64 77.40 22.29b 93.48 7.51b 7.11 I2 13.18 76.82 21.62a 98.23 7.22a 6.98 I3 13.58 76.36 21.75a 98.42 7.24a 6.87 I1=Continuous flooded; I2= Saturated condition; I3= Alternate wetting and drying In a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per DMRT 78 Khan et al. The number of effective tillers hill-1, panicle length, filled grains panicle-1, straw and grain yield were significantly affected by application of different fertilizer and manure (Table 8). The highest number of effective tillers hill-1 (14.4) was found in T1 treatment which was statistically similar to all other treatments except T0 (control). The higher plant height, panicle lengths, filled grains panicle-1 were found in organic plus inorganic treatments and lowest values were observed in T0 treatment. The highest panicle length (22.50 cm), filled grains panicle-1 (108.5) were found in T6 where filled grains panicle-1 was statistically similar to T4, T7, T3, T5 and T1 treatments. Table 8. Effects of fertilizer and manure on the yield parameters and yield of fifth crop Boro rice Treatments No. effective tillers hill-1 Plant height (cm) Panicle length (cm) No. of filled grains panicle-1 Straw yield (t ha-1) Grain yield (t ha-1) T0 10.80b 70.91 20.53b 78.3c 5.70.b 5.42e T1 14.36a 78.31 22.30a 94.4abc 7.78a 7.03cd T2 14.09a 78.37 22.28a 90.1bc 7.39a 7.07bcd T3 13.53a 76.13 21.64ab 100.8ab 7.66a 7.37abc T4 13.40a 76.69 21.95a 103.2ab 7.35a 7.19bc T5 14.07a 79.02 22.01a 95.7abc 7.48a 6.74d T6 13.62a 78.21 22.50a 108.5a 7.49a 7.40ab T7 13.87a 77.22 21.87a 102.5ab 7.71a 7.70a In a column figures having similar letter(s) do not differ significantly at 5% level whereas figures with dissimilar letter(s) differ significantly as per DMRT The application of fertilizers and manure had a positive and significant effect on the grain and straw yield of Boro rice (Table 8). The highest straw yield (7.78 t ha-1) was obtained in T1 (RDCF) treatment which was statistically similar to all other treatments except control. The highest grain yield (7.70 t ha-1) was observed in the T7 treatment which was statistically similar to T6 treatments and lowest grain yield (5.02 t ha-1) was observed in T0 treatment. This result indicates that application of 70% nutrient as inorganic fertilizer and 30% nutrient from organic sources increased the yield and yield contributing parameters of Boro rice. Interaction Effects of Irrigation and Fertilizer on the Growth and Yield of fifth crop Boro rice The numbers of effective tillers hill-1, panicle length and straw yield were not significantly influenced by combined effects of irrigation and fertilizer. The maximum plant height (81.60 cm) and filled grains panicle-1 (119.60 cm) were obtained from I1T3 which was closely similar to I1T7, I3T6, I3T7 and lowest was recorded in I1T0 treatment combination (Table 9). The highest grain yield of rice (7.94 t ha-1) was recorded with the treatment combination I1T7 which was statistically similar to I1T3 (7.73 t ha-1), I1T6(7.72 t ha-1), I3T7(7.62 t ha-1), I1T4(7.60 t ha-1) and I3T6(7.55 t ha-1) treatment combinations and the lowest grain yield (5.26 t ha-1) was found in I2T0 treatment combination. The results also indicate that 70% nutrient from inorganic sources plus 30% nutrient from poultry manure or cowdung with continuous flooded (I1) or alternate wetting and drying (I3) condition produced better yield of Boro rice. The best yield performance was obtained from I1T7 treatment combinations followed by I1T3. Lin et al. (2011) reported that reduced irrigation with organic material application increased yield of rice. Effects of Irrigation and Nutrient Sources on Rice-Rice Cropping Pattern 79 Table 9. Interaction effect of fertilizer and irrigation on Plant height, filled grains/panicle and grain yield of fifth crop Boro rice Treat. Plant height (cm) No. of filled grains panicle-1 Grain yield (t ha-1) I1 I2 I3 I1 I2 I3 I1 I2 I3 T0 69.73h 72.43fgh 70.58gh 70.4g 80.8efg 83.8c-g 5.60i 5.26i 5.38i T1 78.78a-d 77.63a-e 78.53a-d 74.3fg 111.4a-d 97.6a-g 6.71gh 7.50a-e 6.87fgh T2 77.60a-e 77.62a-e 79.88abc 82.6d-g 85.1b-g 102.7a-f 7.08c-h 6.99d-h 7.15b-h T3 81.60a 74.20d-h 72.58e-h 119.6a 97.8a-g 85.1b-g 7.73ab 7.16b-g 7.22b-g T4 77.62a-e 77.31a-f 75.16c-g 96.5a-g 112.8abc 100.4a-f 7.60abc 7.40a-f 6.56h T5 79.43abc 81.60a 75.96b-f 86.1b-g 103.8a-f 97.4a-g 5.77i 7.14b-h 7.30b-g T6 75.98b-f 77.87a-d 80.78ab 108.0a-e 103.8a-f 113.7ab 7.72ab 6.93e-h 7.55a-d T7 78.47a-d 75.83b-f 77.36a-f 110.5a-e 90.3a-g 106.6a-e 7.94g 7.53a-d 7.62abc In a column figures having similar letter(s) do not differ significantly whereas figures with dissimilar letter(s) differ significantly as per DMRT Effect of irrigation, fertilizer and manure on the nutrient concentration and chemical properties of post-harvest field soil The application of manure and fertilizer in the Boro seasons influenced the OM content in soil. The lower level of OM matter was found in the post-harvest soils of T0 (control) and T1 (RDCF) treatments. The increasing levels of OM were almost similar in all the treatments where manure plus inorganic fertilizer were used. Similarly, higher levels of available P were found in the T2-T7 treatments where organic plus inorganic fertilizers were used. The highest concentration P was found in the T7 treatment where 70% RDCF + 2.1 ton poultry manure ha-1 used. The level of soil N and K concentrations were increased more where inorganic and organic fertilizers were used. The highest K concentration was found in T5 treatment where 70% inorganic fertilizer and 3 ton ha-1 water hyacinth compost were used. The pH of post-harvest soils increased in T6 and T7 treatments where poultry manure was applied in combination with fertilizer (Table 10). The soil organic matter, pH and nutrient levels were not significantly affected by interaction effects of irrigation and fertilizer treatments. Table 10. Effect of fertilizer and manure on the nutrient concentration and chemical properties of post-experiment soil Treatments Soil pH Soil organic matter (%) Total N (%) Available P (ppm) Available K (ppm) T0 6.6b 1.08c 0.079 11.23d 19.56c T1 6.6b 1.15bc 0.088 13.62c 28.33ab T2 6.6b 1.33a 0.096 15.80abc 29.44ab T3 6.6b 1.32a 0.096 13.82c 27.33b T4 6.6b 1.29a 0.092 14.26bc 30.11ab T5 6.5b 1.33a 0.102 15.21abc 31.94a T6 6.9a 1.31a 0.089 16.50ab 28.44ab T7 6.7ab 1.27ab 0.090 16.59a 29.61ab Conclusion The growth and yield of rice crops were not significantly affected by irrigation but higher yields were obtained in continuous flooded irrigation. The higher Boro rice yields were found from the treatments where 70% nutrient from inorganic fertilizer and 30% nutrients from organic sources 80 Khan et al. were applied. The poultry manure performed better compared to compost and cowdung for increasing the yield of Boro rice. The maxinum grain yield of Boro rice was recorded with the treatment combination I1T7 (continuous flooding +70% RDCF + 2.1 ton poultry manure ha-1) followed by I3T7 (Alternate wetting and drying + 70% RDCF + 2.1 ton poultry manure ha-1) treatment combination. T. Aman rice yields were significantly influenced due to the residual effects of applied fertilizer plus manure treatments during previous Boro cropping. Higher T. Aman rice yields were obtained in I2T7 (saturated condition +70% RDCF + 2.1 ton poultry manure ha-1) or I1T7 (continuous flooded + 70% RDCF + 2.1 ton poultry manure ha-1) treatment combinations. The level of soil organic matter, N, P and K concentrations increased in the treatments where manure plus inorganic fertilizers were used. The application of poultry manure increased the pH of the soil. Acknowledgement The authors gratefully acknowledge the financial support from core research grants of Bangladesh Agricultural Research Council. References Bari, A.S.M.F., M.A. Khan and S. Sultana. 2013. Effect of various inorganic fertilizer and manure applications with different water managements on yield and yield attributes of boro rice. J. Expt. Biosci. 4(2): 1-6. Bremner, J.M. and C.S. Mulvancy. 1982. In: A.L. Page et al. (ed.) Methods of Soil Analysis, Part 2,23 Amer. Soc. Agron. Inc, Madi, Wis. FAO (Food and Agriculture Organization). 1999. Yearbook of Production, FAO Statistics Division. pp.605-607. Islam, M.M.A.F., M.A. Khan and A.S.M.F. Bari. 2013. Effect of fertilizer and manure with different water management on the growth, yield and quality of Boro rice. The Agriculturist 11(2): 44- 51. Ishaque, M., G.M. Panaullah, N. Bhuyian and P.K. Saha. 1998. Integrated nutrient management with inorganic fertilizer and green/organic manures for boro-T. aman rice cropping pattern. In proceedings “National Workshop on Integrated Nutrient Management for Crop Production and Soil Fertility” held on 24-25 March, 1998 at BARI, Gazipur, Bangladesh. pp.111-114. McLean, E.O. 1982. Soil pH and lime requirement. In: Methods of soil analysis, Part 2, Chemical and microbiological properties, A. L. Page,(eds.), Amer. Soc. of Agro. Inc., Madison, WI, USA. pp.199-224. Rahman, M.M., M.A. Khan, A.K. Paul and M.A. Haque.2019. Effect of fertilizer, manure and irrigation on nutrient availability in soil of boro rice field. Euras. J. Soil Sci. 8(4):282-288. Olsen, S.R. and L.E. Sommers. 1982. In: A.L. Page et al. (ed.) Methods of Soil Analysis, Part 2,2 Amer. Soc. of Agron. Inc, Madi, Wis. Page, A.L., R.H. Miller and D.R. Keeney. 1982. Methods of analysis part 2, Chemical and Microbiological Properties, Second Edition American Society of Agronomy, Inc., Soil Sci. Soc. of Amer. Inc. Madison, Wisconsin, USA. pp.403-430. UNDP and FAO. 1988. Land Resources Appraisal of Bangladesh for Agricultural Report No. 2. Agro-Ecological Region of Bangladesh. United Nations Development Program in Food and Agriculture Organization, 212-221. Effects of Irrigation and Nutrient Sources on Rice-Rice Cropping Pattern 81 Walkley, A. and D.R. Black. 1975. An examination of the digestion method for determining soil organic matter and proposed modification of the chronic acid titration method. Soil Sci. 37: 29-38. Xiangin, L., D. Zhu and Xinjunlin. 2011. Effects of water management and organic fertilization with SRI crop practices on hybrid rice performance and rhizosphere dynamics. Paddy Water Environ. 9: 33-39. Xu, M.G., D.C. Li, J.M. Li, D.Z. Qin, Yagikazuyuki and Y. Hosen. 2008. Effects of organic manure application with chemical fertilizers or nutrient absorption and yield of rice in Hunan of Southern China. Agric. Sci. China 7(10): 1245-1252. Yang, C.M., L. Yang, Y. Yang and Z. Ouyang. 2004. Rice root growth and nutrient uptake as influenced by organic manure in continuously and alternately flooded paddy soils. Agric. Water Mng. 70(1): 67-81.