Water and Nitrogen balance studies of Rice crop grown under drainage lysimeters

Transcription

1 International Conference on Emerging technologies in Agricultural Engineering, IIT Kharagpur Water and Nitrogen balance studies of Rice crop grown under drainage lysimeters Ashish Patil 1, K. N. Tiwari Agricultural and Food Engineering Department, IIT, Kharagpur West Bengal, India 1 MS Scholar 2 Professor 1 - patilashish@agfe.iitkgp.ernet.in 1 Abstract- Drainage Lysimeter experiments were conducted on rice crop during monsoon season (July to October 2014) to assess the effect of different levels of Nitrogen fertilizer on movement & balance of water, Nitrogen fertilizer in the root zone, yield response, Water Use- efficiency (WUE) and Nitrogen Use- efficiency (NUE) for better management of fertilizers for rice crop with a constant ponding depth of 3 cm water in all lysimeters. The experiment included four levels of Nitrogen fertilizer applications. N Fertilizer treatments were: N: P 2 O 5 : K 2 O as 80:50:60 kg ha -1 (T-1), N: P 2 O 5 : K 2 O as 100:50:60 kg ha -1 (T-2), N: P 2 O 5 : K 2 O as 120:50:60 kg ha -1 (T-3) and N: P 2 O 5 : K 2 O as 0:0:0 kg ha -1 (T-4). The required quantity of chemical fertilizers were met through application of Urea (46% N), SSP (16% P 2 O 5 ) and Muriate of potash (60% K 2 O). The experimental results indicated that increase in rice yield due to increase in N application rate. Different levels of N fertilization had a considerable effect on water loss via deep percolation, water use by the crop, Nitrogen leaching loss and N uptake. The analysis of results also show that with increase in N fertilizer applications cause considerable increase in Water Use Efficiency whereas considerable reduction in Nitrogen Use Efficiency. The treatment T-2 (100:50:60 kg ha -1 ) was found to be most effective fertilizer treatment among all the treatments. Keywords Rice, Drainage Lysimeters, Deep Percolation, Nitrogen Dynamics, Grain Yield 1. INTRODUCTION Importance of Rice crop in the world is immense. 50% of the world s population depends on Rice crop. Worldwide annual production of milled Rice is around 480 million metric tons. World s major rice growing countries are India (42.7 M ha) and China (31.3 M ha). Both countries can alone grow and consume 50% of the rice worldwide. For enhancing agricultural production, peoples adopting higher amount of fertilizers without considering the cost of production and adverse effect on the water and soil quality. Water and chemical fertilizers are very important for the rice cultivation system. Dry matter production and biometric response of a rice crop is depends upon Nitrogen (N) fertilizer use (Behera et al. 2009). One of the major crop nutrient and groundwater contamination source is Nitrogen (N) in the form of NO 3 -N which is highly susceptible for leaching. In order to maximizing water and N use efficiencies and minimizing water and Nitrogen loss, it is needed to assess the impact of varying amounts of N fertilizers on water movement & water balance and N fertilizer in the root zone profile. With this goal, Lysimeteric investigations were carried out for different levels of N fertilizer with constant ponding depth of 3 cm. of water in all lysimeters. The objectives of the study were: (1) observing the impact of different amounts of N fertilizer on crop yield, water use efficiency (WUE) and nitrogen use efficiency (NUE); (2) examine the impact of different amounts of N fertilizer on distribution of soil water and N fertilizer, for better management of crop.

2 International Conference on Emerging technologies in Agricultural Engineering 2 2.MATERIALS AND METHODS The experiments were performed in drainage type lysimeters at the Experimental Research farm of Agricultural and Food Engineering Department, Indian Institute of Technology Kharagpur, India during the Kharif monsoon season (July to October 2014). Experimental site is located at an altitude of 48 m above mean sea level with latitude of N and longitude of E. with sub-humid climatic condition. Average annual rainfall of Kharagpur is 1200 mm. During July 2014 to October 2014, the maximum temperature ranged from C to 38 0 C and the minimum temperature ranged from C to C. Total mm rainfall received during July to October 2014 with the highest rainfall of 48.5 mm observed on 20 th September, The lateritic sandy loam type soil was used in the lysimeter, which is taxonomically grouped under the order Alfisol (Oxyaquic haplustalf) and it was collected from the experimental research farm and placed inside the lysimeters one year before the transplanting of the rice crop. The soil properties of the lysimeters are given in Table 1. Table1 Lysimeter Soil properties. Soil depth Particle size distribution (%) Bulk density Saturated hydraulic conductivity (cm) Clay Silt Sand (g cm -3 ) (cmd -1 ) 0-20 cm cm cm cm Lysimeters- The dimensions of the lysimeters are given in figure 1. It consisted of four lysimeters and a leachate collection chamber. Four lysimeters were placed on four opposite sides of the central leachate collection chamber. An underground concrete leachate chamber of dimensions 1.5 m 1.5 m 1.5 m was constructed for leachate collection, from all the four lysimeters. Each lysimeter was made of a rectangular mild steel metal sheet of dimensions 85 cm 85 cm 100 cm rested within an outside tank of dimensions 87 cm 87 cm 100 cm. Both the tanks rested on a concrete platform of about 15 cm thickness. The upper level of both the tanks was 15 cm above the ground surface, so as to avoid water circulation inside to outside the lysimeter or vice versa. Each lysimeter had a corrugated perforated PVC strainer placed at their bottom, followed by a 5 cm layer of gravel and sand, for free drainage mm diameter pipe was attached at the bottom of the inner tank to collect the drainage water in the leachate chamber. The lysimeters were installed by digging four pits, slightly larger than their size. While digging the pits, the soil from each depth was carefully removed in 20 cm layers and stored in a safe place for repacking inside the lysimeter. The soil was repacked according to the natural sequence of soil horizon, in 20 cm layers up to the 90 cm depth. Each soil layer was compacted to its dry bulk density using wooden hammers. Lysimeters were then subjected to wetting and drying cycles to promote settling of soil particles. The soil profile in each lysimeter was uniformly set with no signs of swelling and settling. 2.2 Crop and Fertilizer IR -36 variety of Rice crop was transplanted in all lysimeters at row to row spacing of 20 cm. 21 days old seedlings were transplanted in and around the lysimeters. The crop was harvested in the month of October. Fertilizer was applied to soil in two splits, one at the time of transplanting (Basal dose) and other 30 days after transplanting (Active tillering dose). Fertilizer treatments consist of varying amount of N fertilizer with constant amount of P 2 O 5 and K 2 O fertilizers in all the treatments. Application of fertilizer ranged between no N fertilizers to almost 1.2 times higher the recommended dose of N fertilizers. The treatments of consist of: Treatment N: P 2 O 5 : K 2 O (kg ha -1 ) T1 80:50:60 T2 100:50:60 T3 120:50:60 T4 00:00:00

3 International Conference on Advances in Engineering Science and Management, Agra, 08 th November, Fig. 1 Layout of drainage lysimeter The Required amount of Chemical Fertilizers s through Urea (46% N), Single super phosphate (16% P 2 O 5 ), Muriate of potash (60% K 2 O). Rice crop in and around the lysimeters was grown under continuous submergence. A Constant Ponding depth of 3 cm in rice field (lysimeters) maintained for obtaining higher yield, maximum grain weight and for reducing N leaching losses. 2.3 Water balance studies Soil water movement- To evaluate the soil water movement, the soil water pressures were measured at 20, 40, and 75 cm soil depths by using piezometers in all the lysimeters. Water level indicator was used to measure pressure head in the piezometers. Maximum root zone depth of the rice crop was considered as 75 cm Deep percolation- During the crop growing period, the deep percolated water was collected in leachate collection chamber through the leachate collection pipe which was at the bottom of the inner tank and it was collected weekly after transplanting Water use efficiency (WUE) It was estimated as, kg ha -1 cm -1 (1) Y grain yield in kg ha -1 WU water used by the crop in cm Crop evapotranspiration by water balance- Amount of water used by the rice crop evaluated by using the measured amount of water drained from the lysimeter, total input water in the form of irrigation & precipitation, evapotranspiration loss and soil moisture retained in the soil profile. S = (I+P) - (ET+DP) (2) I irrigation (mm) P precipitation (mm) ET evapotranspiration (mm) DP deep percolation loss of water (mm) S soil moisture storage (mm) ISBN: T R Publication

4 International Conference on Emerging technologies in Agricultural Engineering Weather data- Data was collected from the weather station which was located near the lysimeters area. The weather station consist of humidity sensors, anemometers, one net radiometer, a tipping bucket rain gauge, a wind direction sensor and the soil heat flux plates. The sensors were operated by lead acid battery (12 V supply) connected with the solar panel. The weather sensors were attached to the datalogger. Weather station was automatic type and it was recorded hourly and 24 hours values of weather data in the datalogger. The average minimum and maximum temperatures and rainfall during the cropping seasons are given in Figure Crop evapotranspiration by reference evapotranspiration- Reference ET 0 estimated by using the daily weather data (FAO Penman-Monteith method) ET 0 = (3) The crop evapotranspiration ETc for the rice was calculated by multiplying the crop coefficient (Kc) with the daily reference evapotranspiration (ET 0 ) as ETc = Kc ET 0. (4) The Kc values are for the initial, intermediate and mature stages of rice crop are 1.05, 1.2 and 0.75 respectively. 2.4 Nitrogen balance studies Nitrogen movement in soil layers- Distribution of different N ions such as NH 4 -N and NO 3 -N ions in different soil layers, their ionic concentration with respect to time and leaching loss of nitrogen, assess the N movement in soil. For monitoring chemical composition of soil water, samplers were installed at 20, 40 and 75 cm soil depths in each lysimeter. An extracted sample from the sampler transfer to the laboratory for further analysis. For 90 cm depth, collected leachates from leachate collection chamber were used for laboratory analysis. Soil water sampling was done immediately after fertilizer application as well as before the fertilizer application. The collected soil samples were analyzed by using Ion Chromatography system Nitrogen Leaching loss - It was considered as the downward entry of N below the depth of 75 cm in the soil. N leaching was assessed by the amount of percolated water below the root zone of the crop with the concentrations of NH 4 -N and NO 3 -N ions. LLN = DP X C (5) Where C is the average concentration of the NO 3 -N and NH 4 -N ions water below the root zone of the crop (mg l -1 ). DP is the volume of percolated water (l) Nitrogen uptake N uptake was measured once at the maturity stage (end of crop growing season). Concentration of N in grain and straw yield was considered for calculating N uptake. N uptake (kg ha -1 ) = (N concentrations (%) yield (Grain and straw in kg ha -1 ))/ 100 (6) Nitrogen use efficiency (NUE) - (7)

5 International Conference on Advances in Engineering Science and Management, Agra, 08 th November, Fig. 2 Daily max., min. & average air temperatures and rainfall during crop growing season 3. RESULTS AND DISCUSSION 3.1 Yield responses (Grain yield and Straw yield)- Statistical parameters by one sample T- test, measured grain yield and straw yield, for different amount of N fertilizers obtained during crop growing season are presented in Table 2. Maximum grain yield and straw yield was obtained in the treatment T3, i.e kg ha -1 and 4400 kg ha -1 followed by the treatment T2, T1 and T4 due to higher dose of N fertilizers. Different amount of N fertilizer had a greater impact on grain yield and straw yield during all the crop experiments. Maximum yield was found in treatment T3 and T2 than T1 and T4. This was due to fewer uptakes of nutrient by treatment T1 & T4. Statistically there was significant difference in grain yield and straw yield at both 5% and 1% level of significance. Table 2 Effect of fertilizer application rate on grain yield, straw yield Treatments Grain yield (kg ha -1 ) Straw yield (kg ha -1 ) T T T T Average SD LSD (P=0.05) LSD (P=0.01) Soil Water Dynamics- A constant 3 cm ponding depth was maintained during crop growing season. Soil water pressure head measurement was done using the water level indicator at 20, 40, and 75 cm soil depths in all treatments on daily basis. Soil water pressure changes with respect to time under different amount of N fertilization during crop growing season are presented in figure 3. The maximum deviation in the soil water pressure was observed at 20 cm piezometer depth as compared to others, this may be due to contribution of rainfall and irrigation. There was no definite trend was observed at different crop growth stages. In between treatments, very less difference were observed in the soil water pressures. ISBN: T R Publication

6 International Conference on Emerging technologies in Agricultural Engineering 6 T1 T2 T3 T4 Fig. 3 Soil water pressure at different soil layers of rice crop under T1, T2, T3 and T4 fertilizer treatments 3.3 Evapotranspiration and deep percolation- The data of deep percolation, crop evapotranspiration from lysimeter and crop evapotranspiration from meteorological parameters [ETc = ET0 Kc] are given in table 3. Table 3 Water balance analysis of rice crop Treatment Irrigation +Precipitation (mm) Deep percolation (mm) Soil Moisture Storage (mm) Crop evapotranspiration by water balance analysis ET cw (mm) Crop evapotranspiration by FAO- PM, ET c (mm) T T T T Maximum deep percolation was observed in treatment T4 (340 mm) followed by the treatment T1, T2 and T3. Maximum ETc was found in treatment T3 followed by the treatment T2, T1 and T4 during the crop experiment. This may be due to differential growth of plant and root system under different treatments. Crop evapotranspiration by water balance analysis ETcw is found higher than Crop evapotranspiration by FAO- PM, ETc in all treatments. 3.4 Dynamics of NH 4 -N (Ammoniacal Nitrogen) concentration under different treatments- The outcomes of the NH 4 -N ionic concentration at different depth and at different times are presented in Figure 4. Application of basal dose of urea causes sharp increase in concentration of NH 4 -N at 20 cm soil depth and attained peak at 8 days after transplanting. Same trend was observed at 40 and 75 cm soil depth with low concentration at 8 DAT. Thereafter concentration of NH 4 -N deceases gradually at all depths upto 33 DAT (upto application of remaining 50% N

7 International Conference on Advances in Engineering Science and Management, Agra, 08 th November, (Urea)). After application of remaining 50% N (Urea) in active tillering stage NH 4 -N concentration in 20 cm soil depth increased steeply and attained peak concentration at 42 DAT. At 40 cm soil depth and 75 cm peak concentration increased gradually and attained peak concentration 42 DAT. T1 T2 T3 Fig. 4 Depth and time changes of NH4-N concentration (mg l-1) under T1, T2 and T3 treatment 3.5 Dynamics of NO 3 -N (Nitrate Nitrogen) concentration under different treatments- - The outcomes of the NO 3 -N ionic concentration at different depth and at different times are presented in Figure 5. Application of basal dose of urea influenced increase in concentration of NO 3 -N gradually at all depths (20 cm, 40 cm and 75 cm). Peak concentration attained at 14 DAT in 20 cm soil depth; 28 DAT in 40 cm soil depth; 14 DAT in 75 cm soil depth in all treatments. Thereafter concentration of NO 3 -N decreases upto 24 DAT in 20 cm soil depth and 33 DAT in 40 cm and 75 cm soil depth. After application of remaining 50% N (Urea) in active tillering stage the peak concentration attained at 42 DAT and then decreases gradually in all depths. T1 T2 ISBN: T R Publication

8 International Conference on Emerging technologies in Agricultural Engineering 8 T3 Fig. 5 Depth and time changes of NO 3 -N concentration (mg l -1 ) under T1, T2 and T3 treatment 3.6 N uptake and leaching loss- The leaching loss of N assessed from the quantity of leachable nitrogen in the solution of soil and volume of drainage water. N uptake by the rice crop was estimated from plant sample analysis after harvesting of the same. The effect of different amount of N fertilizers on N leaching and N uptake are presented in Table 4. Values in Table 4, shows that increase in amount of nitrogen fertilizer application caused increase in leaching loss and also increase in nitrogen uptake by the rice crop. Table 4 Impact of different amount of N fertilizer on leaching and uptake of nitrogen during rice growing season Treatment Nitrogen leaching loss (kg ha -1 ) Nitrogen uptake by plants (kg ha -1 ) T T T T Water Use- efficiency of Rice crop- It was calculated from the grain yield per unit amount of water used. The data of WUE under different amount of N fertilizers are shown in Table 5. The WUE was found to be minimum in T4 treatment (7.11 kg ha -1 mm -1 ) whereas WUE was found to be maximum in T3 treatment (8.3 kg ha -1 mm -1 ). Increase in doses of N fertilizer, shows that WUE improved considerably due to increase in water use and grain yield. Table 5 Impact of different amount of N fertilizer on WUE of rice crop Treatments Water use (mm) Grain yield (kg ha -1 ) Water Use- efficiency (kg ha -1 mm -1 ) T T T T Nitrogen Use- efficiency of Rice crop- Nitrogen Use and NUE under different amount of N fertilizers are shown in Table 6. NUE was found to be highest i.e. 87% in treatment T1 followed by T2 and T3 treatments due to greater leaching loss from the higher doses of N treatments. Nitrogen use increased with increase in amount of N fertilizers

9 International Conference on Advances in Engineering Science and Management, Agra, 08 th November, whereas NUE decreased with increase in amount of N fertilizers. It indicates that, T2 treatment is the most suitable fertilizer treatment from environmental aspect, grain yield and nitrogen use. Table 6 Effect of different levels of N- fertilizer on NUE of rice crop Treatments Nitrogen applied (kg ha -1 ) Nitrogen uptake by plants (kg ha -1 ) Nitrogen use efficiency (%) T T T T CONCLUSIONS 4.1 The response of rice crop in terms of grain yield and straw yield is influenced by the levels of N-fertilizers. 4.2 The increase in level of N fertilization has a little impact on deep percolation losses and water use by the rice crop. 4.3 Nitrogen leaching loss and uptake of nitrogen were considerably affected due to Levels of N fertilization. 4.4 With respect to crop yield, nitrogen use and environmental pollution the fertilization rate of N: P 2 O 5 : K 2 O as 100:50:60 (T2) is the most appropriate fertilizer treatment for this region. ACKNOWLEDGEMENT The authors are thankful to ITRA, (Ministry of Communications and Information Technology (MCIT), Government of India, for providing funds for this research. REFERENCES [1] Behera S.K., Panda R.K., 2009a, Integrated management of irrigation water and fertilizers for wheat crop using field experiments and simulation modeling. Agricultural Water Management 96, [2] Behera S.K., Panda R.K., 2009b, Effect of fertilization and irrigation schedule on water and fertilizer solute transport for wheat crop in lateritic soil. Agricultural Ecosystem Environment 130, 3 4, [3] Behera S.K., Panda R.K., 2013, Effect of fertilization on crop responses and solute transport for rice crop in a sub-humid and sub-tropical region. Paddy Water Environ 11, [4] Allen R.G., Pereira L.S., Raes D., Smith M., 1998, Crop evapotranspiration. Guidelines for computing crop water requirements. FAO, Irrigation and Drainage Paper, 56. FAO, Rome, p 300. [5] Panda S.C., Rath B.S., Tripathy R.K., Dash B., 1997, Effect of water management practices on yield and nutrient uptake in the dry season rice. Oryza. 34, [6] Anbumozhi V., Yamaji E., Yabuchi T., 1998, Rice crop growth and yield as influenced by changes in ponding water depth, water regime and fertigation level, Agricultural Water Management, 37, [7] Talpur M. A., Changying Ji, Junejo S.A., Tagar A. A., Ram B. K., 2013, Effect of different water depths on growth and yield of rice crop. African Journal of Agricultural Research. Vol. 8(37), [8] Singh Y. V., Singh K. K., Sharma S. K., 2013, Influence of Crop Nutrition on Grain Yield, Seed Quality and Water Productivity under Two Rice Cultivation Systems. Rice Science, 20(2), ISBN: T R Publication

10 International Conference on Emerging technologies in Agricultural Engineering 10 [9] Jha R. K., 2014, Simulation of Soil Water and Solute Transport Dynamics under Rice Land Use Condition using HYDRUS- 1D Model., M.Tech. Thesis, IIT Kharagpur. [10] Tyagi N.K., Sharma D.K., Luthra S.K., 1999, Determination of evapotranspiration and crop coefficients of rice and sunflower with lysimeter, Agricultural Water Management 45 (2000),