Various agronomic options on available nutrient status and bulk density of soil under Rajarajan 1000 practice

An Asian Journal of Soil Science Volume 8 Issue 2 December, 2013 Research Article Various agronomic options on available nutrient status and bulk density of soil under Rajarajan 1000 practice MEMBERS OF RESEARCH FORUM : Corresponding author : S. SATHYA, Department of Soil Science and Agricultural Chemistry, Tamil Nadu Agricultural University, COIMBATORE (T.N.) INDIA Email: sathyasivanandham@rediffmail.com Co-authors : G. JAMES PITCHAI AND P. SARAVANA PANDIAN, Department of Soil Science and Agricultural Chemistry, Tamil Nadu Agricultural University, COIMBATORE (T.N.) INDIA K. RAJENDRAN, Department of Agronomy, Tamil Nadu Agricultural University, COIMBATORE (T.N.) INDIA Received : 30.07.2013; Revised : 18.08.2013; Accepted : 01.09.2013 Summary A field experiment was conducted at Agricultural College and Research Institute, Madurai to investigate the effect of Rajarajan 1000 practice with various agronomic options such as nursery technology, age of seedling and weed management practices on availability of nitrogen, phosphorus and potassium (major nutrients) and bulk density at various growth stages of rice var. ADT 36., age of seedling and weed management practices significantly influenced the available major nutrients and bulk density of soil irrespective of growth stage of rice. Vermicompost application to 15 days old seedling along with application of pre emergence herbicide butachlor @ 1.25 kg ha -1 and mechanical weeding twice at 25 and 45 days after transplanting recorded the highest available major nutrients. Available nitrogen and potassium increased from tillering to flowering stage and thereafter decreased at harvest for all the treatments whereas available phosphorus decreased towards the maturity stage of crop growth. Bulk density of soil increased from tillering to harvest stage irrespective of treatments. Among the agronomic options, age of the seedling significantly influenced the bulk density of soil irrespective of growth stage of rice. Nursery management had a remarkable influence on bulk density at flowering and harvest stage whereas weed management practice significantly influenced the bulk density only at harvest stage of rice. Key words :, Age of seedling, practice, Nutrient status, Bulk density How to cite this article : Sathya, S., Pitchai, G. James, Pandian, P. Saravana and Rajendran, K. (2013). Various agronomic options on available nutrient status and bulk density of soil under Rajarajan 1000 practice. Asian J. Soil Sci., 8(2): 235-240. Introduction The major constraints in rice production are lack of integrated management practices involving land, labour, crop, water and inputs, such as seeds, fertilizers, optimum plant population etc. Increasing the rice productivity by the use of appropriate agronomic management practices with proper nutrient management becomes an essential component of rice production technology (Sridevi, 2006). Transplanting is a common practice in rice cultivation. Improper planting technique is one of the important factors limiting rice yield. The traditional rice planting system comprises conventional planting with too much number of seedlings per hill and dumping of nitrogenous fertilizer. Closer spacing is also one of the main constraints in obtaining high yield under conventional planting. Hence, a new method of rice cultivation must be tried aiming at higher crop productivity. Rajarajan 1000 practice is a new approach, now gaining popularity as it is found to increase the productivity and reduce the cost of cultivation. It has its own components viz., transplanting of young seedlings usually 12 to 15 days as single seedling per hill at wider spacing in a square geometry and use of mechanical weeder, need-based fertilizer application and optimum use of water for better growth especially soil aeration (Kumar and Shivay, 2004). In the this method of cultivation marking is done before transplantation to ensure proper spacing. Then laborers preferably women workers transplant one young HIND AGRICULTURAL RESEARCH AND TRAINING INSTITUTE

paddy seedling in each grid of the marking. This method of planting requires careful planting on the grid which is becoming difficult for the workers (Ranagasamy et al., 2008). In order to overcome such difficulties faced by the workers in transplanting the seedling, here transplanting was done by SRI transplanter. With this pre intro, the present investigation was programmed. Resource and Research Methods A field experiment was laid out in the Central Farm of Agricultural College and Research Institute, Madurai. The experimental site is located at the latitude of 9 54 N, longitude of 78 54 E and at an altitude of 147 m above MSL. The experimental soil was sandy clay loam in texture which belongs to Madukkur soil series. Field experiment consisted of 3 factors, of which two were main factor and another one was sub factor. First factor is nursery management (Nt) which included Nt 1 Pot mixture (Red soil : sand : FYM 1:2:1), Nt 2 - Farmyard manure (Soil + FYM 5 : 1), Nt 3 Vermicompost (Soil + vermicompost 5: 1), Second factor is age of seedling (A) which included A 1 15 days old seedling, A 2 19 days old seedling, A 3 22 days old seedling and third factor is weed management (W) which included W 1 hand weeding twice at 25 and 45 days after planting, W 2 mechanical weeding thrice at 10, 25 and 45 days after planting, W 3 mechanical weeding four times at 10,25,35 and 45 days after planting and W 4 pre emergence herbicide (Butachlor @ 1.25 kg ha -1 on third day after transplanting) with mechanical weeding twice at 25 and 45 days after planting. Totally treatment consisted of 36 combinations and replicated thrice in split plot design. Short duration rice variety ADT 36 was grown during Rabi season 2007-2008. Fifteen, nineteen and twenty two days old seedlings were derived from modified dapog mat nursery were used for transplanting. Hand operated mechanical weeder-rotary weeder developed by Department of Agricultural Engineering, Tamil Nadu Agricultural University, Coimbatore was used for weeding practice. Pre emergence herbicide butachlor @ 1.25 kg ha -1 was applied on third day after transplanting. Nitrogen as urea was applied based on Leaf Colour Chart (LCC) schedule. LCC values were recorded as per the standard procedure (IRRI, 1996) at weekly intervals starting from 14 DAT to flowering. Whenever LCC values were found to be below the fixed critical level (4), nitrogen @ 35 kg ha -1 was applied in the form of urea. Thus, on 14, 28 and 42 DAT a total of 105 kg ha -1 of N was applied. Hundred per cent recommended dose of phosphorus @ 38 kg ha -1 was applied basally. The full dose of potassium @ 38 kg ha -1 was applied as muriate of potash in four splits viz., 25% each at active tillering, panicle initiation, booting and flowering stage after the weeding. Zinc sulphate @ 25 kg ha -1 was applied basally before the transplanting of seedlings. Outside the plot area 15 days old seedlings was transplanted manually from modified dapog mat nursery with integrated weed management practices and no nursery management. Soil samples were collected separately in each plot at tillering, flowering and harvest stage of rice, dried in shade and then processed for chemical analysis. Available nitrogen, phosphorus, potassium status and bulk density of soil was analyzed by adopting Alkaline permanganate method (Subbiah and Asija, 1956), colorimetric method (Olsen et al., 1954), neutral normal ammonium acetate method (Stanford and English, 1949) and cylindrical method (Piper, 1966), respectively. The data obtained from the present investigation were subjected to statistical analysis as described by Panse and Sukhatme (1967). Research Findings and Discussion The results obtained from the present investigation as well as relevant discussion have been summarized under following heads : Available nutrients at various growth stages of rice : Nitrogen : Available nitrogen was increased from tillering to flowering and thereafter decreased at harvest (Table 1). This might be due to split application of nitrogen up to flowering, removal of nutrients by crops and other losses by leaching might be responsible for lower concentration at harvest. Under Rajarajan 1000 practice, N application was done based on LCC upto flowering could have increased the supply of N in soil at flowering stage. Rhizosphere region under Rajarajan 1000 practice is in a partially oxidized state wherein nitrogen fixation, ammonification and nitrification are the dominant nitrogen transformation reaction. These transformation reactions would have been highly activated in the rhizosphere and contributed for higher nitrogen concentrations as evident in the rice cultivation strategy. Nitrification would have been favoured by the presence of well root system resulting in more of rhizosphere area, under the use of young seedling (Sudhalakshmi, 2002). Among the nursery technology, the highest value was registered at vermicompost received plot followed by FYM application and pot mixture applied plot. This might be due to higher availability of nitrogen content and lower C: N ratio causing immediate release of N to labile pool than other two sources. Besides, higher clay content of experimental soil naturally had more CEC ultimately would have contributed for more available N. This reason was reported earlier by Misra and Saithantuaanga (2000). The addition of organic sources would have provided compounds as source of N favouring multiplication of microbes and subsequent increase in the N availability. The increase in the available N might be attributed to the immediate release of nutrient elements into soil after the addition of organic sources to the soil. HIND AGRICULTURAL RESEARCH AND TRAINING INSTITUTE 236 Asian J. Soil Sci., (Dec., 2013) 8 (2) :

VARIOUS AGRONOMIC OPTIONS ON AVAILABLE NUTRIENT STATUS & BULK DENSITY OF SOIL UNDER RAJARAJAN 1000 PRACTICE In case of age of seedlings, 15 days old seedling recorded the highest available N and this was followed by 19 and 22 days old seedling. Regarding weed management, the available nitrogen was significantly influenced by the treatment that received pre emergence herbicide viz., butachlor @ 1.25 kg ha -1 with rotary weeding twice at 25 and 45 days after planting. This was superior to rest of other weed management practices. This could be due to weed free environment increased the availability of nutrients in soil. The mechanical weeding by rotary weeder facilitated soil aeration and increased the soil microbial and enzyme activities which resulted in higher availability of nutrients in Table 1 : Available nitrogen (kg ha -1 ) of soil at various stage of rice as influenced by agronomic options Nt 1 - Pot mixture (Red soil: Sand: FYM 1:2:1) 144.03 166.01 126.57 Nt 2 - Farm yard manure (Soil + FYM 5:1) 148.64 170.67 131.30 Nt 3 - Vermicompost (Soil + Vermicompost 5:1) 153.48 177.56 136.67 C.D. (P = 0.05) 2.03 2.80 2.26 A 1-15 days old seedlings 176.64 202.66 160.83 A 2-19 days old seedlings 147.32 169.82 129.74 A 3-22 days old seedlings 122.20 141.75 103.96 C.D. (P = 0.05) 2.09 2.71 2.20 W 1 - Hand weeding twice at 25 & 45 days after planting 139.95 162.41 122.45 W 2 - Mechanical weeding thrice at 10, 25 & 45 days after planting 147.64 170.20 130.31 W 3 - Mechanical weeding four times at 10,25, 35 & 45 days after planting 150.26 172.95 133.07 W 4 - Pre emergence (Butachlor @ 1.25 kg ha -1 )+ mechanical weeding twice at 25 & 45 days after planting 157.02 180.09 140.23 C.D. (P = 0.05) 2.13 2.51 1.92 Interaction Non Significant Non Significant Non Significant Absolute SRI 166.43 198.65 141.21 Table 2 : Available phosphorus (kg ha -1 ) of soil at various stage of rice as influenced by agronomic options Nt 1 - Pot mixture (Red soil: Sand: FYM 1:2:1) 20.87 19.74 17.06 Nt 2 - Farm yard manure Soil + FYM 5:1) 21.83 20.45 18.36 Nt 3 - Vermicompost (Soil + Vermicompost 5:1) 22.63 21.22 18.80 CD (P = 0.05) 0.26 0.24 0.21 A 1-15 days old seedlings 26.68 25.53 22.79 A 2-19 days old seedlings 21.93 20.81 18.50 A 3-22 days old seedlings 16.72 15.07 12.93 CD (P = 0.05) 0.21 0.26 0.19 W 1 - Hand weeding twice at 25 & 45 days after planting 19.91 18.27 16.37 W 2 - Mechanical weeding thrice at 10, 25 & 45 days after planting 21.61 20.51 17.95 W 3 - Mechanical weeding four times at 10,25, 35 & 45 days after planting 22.21 21.35 18.55 W 4 - Pre emergence (Butachlot @ 1.25 kg ha -1 )+ mechanical weeding twice at 25 & 45 days after planting HIND AGRICULTURAL RESEARCH AND TRAINING INSTITUTE 237 Asian J. Soil Sci., (Dec., 2013) 8 (2) : 23.37 21.71 19.42 CD (P = 0.05) 0.35 0.33 0.29 Interaction Non significant Significant Significant Absolute SRI 22.12 20.01 16.54

rhizosphere soil. Creation of weed free situation in rhizosphere region by butachlor application followed by rotary weeding prevents the uptake of nutrients by weeds thereby increased the availability in root zone (Rajendran, 2009). The interaction effect between the treatments was non significant at all the growth stages of rice. Phosphorus : The nursery technology, age of seedlings and weed management practices significantly influenced the available phosphorus status of soil irrespective of growth stages of rice crop. The available phosphorus decreased from tillering to harvest stage which might be due to removal of phosphorus by the crops during the period for its development. The highest available phosphorus in soil of 22.63 kg ha - 1 at tillering, 21.22 kg ha -1 at flowering and 18.80 kg ha -1 at harvest was observed in vermicompost applied plot (Table 2). This might be attributed to increased availability of nutrients in it which released during the course of crop growth. Phosphorus is the element subjected to more of fixation. It gets fixed immediately after the application of phosphatic fertilizers. The release of organic acid by the roots and from decomposition of organic manure would have solubilised and mobilised phosphorus from their sites of fixation. Increased phosphorus concentration in the rhizosphere could be attributed to increased solubilisation of phosphate minerals by rice roots effected by increased phosphatase activity with increased root biomass and due to high population of phosphorus dissolving bacteria. Similar report was reported by Sathya (2010). Available phosphorus was observed to be higher in 15 days old seedlings when compared to 19 and 22 days old seedlings which recorded 26.68 kg ha -1 at tillering, 25.53 kg ha - 1 at flowering and 22.79 kg ha -1 at harvest stage of rice. This might be due to young seedlings required less amount of available nutrients for their establishment which leaves more nutrients in soil whereas elder seedlings taken higher amount of nutrient which leaves lower amount of nutrients in soil. The trend was similar in all stages of crop. Besides presence better root system with 15 days old seedling exploits more of phosphorus from its binding sites. Among the weed management practices, pre emergence herbicide butachlor @ 1.25 kg ha -1 with mechanical weeding twice at 25 and 45 days after planting significantly influenced the available phosphorus in soil at all the growth stages of rice. This was mainly attributed to less population of weeds and consequently resulted in higher availability of phosphorus in soil which ultimately increased the nutrient uptake by the crops. Soil aeration and root pruning as effectd by rotary weeder would have provided conducive environment for P mobilization and for the uptake of the nutrient (Sudhalakshmi et al., 2008). The interaction effect was not significant at tillering but significant at flowering and harvest stage of the crop. Potassium : Available potassium increased from tillering to flowering and thereafter decreased at harvest stage of rice. Split Table 3 : Available potassium (kg ha -1 ) of soil at various stage of rice as influenced by agronomic options Nt 1 - Pot mixture (Red soil: Sand: FYM 1:2:1) 259 284 237 Nt 2 - Farm yard manure (Soil + FYM 5:1) 268 293 246 Nt 3 - Vermicompost (Soil + Vermicompost 5:1) 282 307 260 CD (P = 0.05) 4.01 3.78 2.56 A 1-15 days old seedlings 312 337 290 A 2-19 days old seedlings 268 293 246 A 3-22 days old seedlings 229 254 207 CD (P = 0.05) 3.92 3.69 2.58 W 1 - Hand weeding twice at 25 & 45 days after planting 253 278 231 W 2 - Mechanical weeding thrice at 10, 25 & 45 days after planting 269 294 247 W 3 - Mechanical weeding four times at 10,25, 35 & 45 days after planting 272 297 250 W 4 - Pre emergence (Butachlor @ 1.25 kg ha -1 )+ mechanical weeding twice at 25 & 45 days after planting HIND AGRICULTURAL RESEARCH AND TRAINING INSTITUTE 238 Asian J. Soil Sci., (Dec., 2013) 8 (2) : 284 309 262 CD (P = 0.05) 3.70 3.66 3.54 Interaction Significant Significant Significant Absolute SRI 302 365 283

VARIOUS AGRONOMIC OPTIONS ON AVAILABLE NUTRIENT STATUS & BULK DENSITY OF SOIL UNDER RAJARAJAN 1000 PRACTICE application of K was given up to flowering stage of rice could be the cause for increased availability of potassium in soil upto flowering. In case of nursery technology, vermicompost application recorded more available potassium of 282 kg ha -1 at tillering, 307 kg ha -1 at flowering and 260 kg ha -1 at harvest stage of rice than other treatments (Table 3). The release of organic acids during its decomposition of organic manure and from rice roots which solubilize the K from minerals and made available to crops. The finding was supported by Surya Prabha (2004). Transplanting of young 15 days old seedlings was recorded higher status of available potassium irrespective growth stages of rice when compared to 19 and 22 days old seedlings. Young seedlings required fewer amounts of available nutrients for their growth and, therefore, which leaves more amount of nutrients in soil. Similar trend was not observed while go for transplantation of elder seedlings in all stages of crop. Pre emergence herbicide butachlor @ 1.25 kg ha -1 with mechanical weeding twice at 25 and 45 days after planting significantly influenced the available potassium content at all the growth stages of rice. The highest value of 284 kg ha -1 at tillering, 309 kg ha -1 at flowering and 262 kg ha -1 at harvest stage was noticed in above mentioned treatment. The interaction between factors was significant with each other at all the growth stages of rice. Bulk Density of soil at various growth stages of rice : Bulk density of soil was significantly influenced by various agronomic practices such as nursery technologies, age of seedlings and weed management practices under mechanical transplanting at various growth stages of rice (Table 4). Irrespective of treatments, bulk density of soil was observed higher at harvest stage whereas which found to be lower at tillering stage. Sedimentation of soil particles over a period of time, root degeneration at harvest stage of crop and least or no usage of rotary weeder might be the cause for slight increase in soil bulk density at later stage of crop growth. Regarding treatments effect in the nursery management practices at various growth stages, vermicompost application ((Nt 3 ) significantly influenced the bulk density at flowering and harvest stage whereas the effect was non significant at tillering stage. Bulk density was recorded lower 1.19 Mg m -3 at tillering, 1.31 Mg m -3 at flowering and 1.38 Mg m -3 at harvest stage under vermicompost applied plot whereas higher bulk density of 1.21 Mg m -3 at tillering, 1.36 Mg m -3 at flowering and 1.42 Mg m -3 at harvest stage registered at pot culture applied plot. Organic matter act as a cementing agent between the colloidal particles in soil which had a positive effect on soil structure formation inturn resulted in decreased in bulk density in vermicompost applied soil (Das, 2010). In case of age of seedlings, 15 days old seedlings had a marked influence on bulk density of soil at all the growth stages of rice crop. This was due to increased proliferation of root growth ultimately improved the bulk density and soil structure thereby resulted in lower bulk density of soil. The trend was reverse in 22 days old seedlings transplanted plot. Regarding weed management practices, application of Table 4 : Bulk density (Mg m -3 ) of soil at various stage of rice as influenced by agronomic options Nt 1 - Pot mixture (Red soil: Sand: FYM 1:2:1) 1.21 1.36 1.42 Nt 2 - Farm yard manure (Soil + FYM 5:1) 1.20 1.35 1.40 Nt 3 - Vermicompost (Soil + Vermicompost 5:1) 1.19 1.31 1.38 C.D. (P = 0.05) NS 0.025 0.018 A 1-15 days old seedlings 1.17 1.28 1.32 A 2-19 days old seedlings 1.21 1.35 1.40 A 3-22 days old seedlings 1.23 1.39 1.48 C.D. (P = 0.05) 0.019 0.027 0.016 W 1 - Hand weeding twice at 25 & 45 days after planting 1.22 1.34 1.43 W 2 - Mechanical weeding thrice at 10, 25 & 45 days after planting 1.20 1.35 1.40 W 3 - Mechanical weeding four times at 10,25, 35 & 45 days after planting 1.20 1.34 1.39 W 4 - Pre emergence (Butachlort @ 1.25 kg ha -1 )+ mechanical weeding twice at 25 & 45 days after planting HIND AGRICULTURAL RESEARCH AND TRAINING INSTITUTE 239 Asian J. Soil Sci., (Dec., 2013) 8 (2) : 1.19 1.32 1.38 CD (P = 0.05) Non significant Non significant 0.025 Interaction effect Non significant Non significant Non significant Absolute SRI 1.14 1.25 1.28

pre-emergence herbicide along with mechanical weeding twice at 25 and 45 days after transplanting registered lower bulk density irrespective of growth stages of crop whereas the highest bulk density was noted in the treatment that received hand weeding twice at 25 and 45 days after planting. This might be attributed to mechanical weeding twice with rotary weeder breaks up the soil particles which improves soil aeration status and thus ultimately reduced the bulk density of soil. Interaction of treatment was not significant irrespective of growth stages of rice. Literature Cited Das, D.K. (2010). Organic matter. In: Introductory soil science. pp. 261-283. IRRI (1996). Use of leaf colour chart (LCC) for N management in Rice. Int. Rice Res. Inst., P.O Box. 933, Manila 1099, Philipines. Kumar, D. and Shivay, V.S. (2004). System of rice intensification. Indian Frmng., 54: 18-21. Misra, U.K. and Saithantuaanga, H. (2000). Characterization of acid soils of Mizoram. J. Indian Soc. Soil Sci., 48 : 437-446. 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. Circular No. 939, USDA. Panse, V.G. and Sukhatme, P.V. (1967). Statistical methods for agricultural workers, ICAR, NEW DELHI, (INDIA). Piper, C.S. (1966). Soil and plant analysis. Hans publishers, Mumbai (M.S.) INDIA. Rajendran, K. (2009). Evaluation of crop establishment techniques and weed management practices under System of Rice Intensification (SRI). Ph.D., Thesis, Tamil Nadu Agricultural University, COIMBATORE, T.N. (INDIA) Ranagasamy, K., Ganapathy, S., Surendrakumar, A., John Gunasekar, J. and Sriramajayam, S. (2008). SRI Transplanter. Extended summaries of the third national symposium on system of rice intensification in India policies, institutions and strategies for scaling up mainstreaming SRI as part of achieving food security while reducing water conflicts held during Dec 1-3, 2008 at Tamil Nadu Agricultural University, Coimbatore, India. Sathya, S. (2010). Evaluation of enriched FYM and fly ash on soil fertility and yield of rice under Rajarajan 1000 Practice(SRI) in Periyar Vaigai Command (PVC) area Tamil Nadu. Ph.D. (Ag.) Thesis, Agricultural College and Research Institute, Madurai, T.N. (INDIA). Sridevi, V. (2006). Relative contribution of individual componenets of Rajarajan 1000 Practice(SRI) to the yield of rice crop. M.Sc.(Ag.) Thesis, Pandit Jawaharlal Nehru College of Agriculture and Research Institute, KARAIKAL, PONDICHERRY (INDIA). Stanford, S. and English, L. (1949). Use of flame photometer in rapid soil test K and Ca. Agron. J., 41 : 446-447. Subbiah, B.V. and Asija, G.L. (1956). A rapid procedure for estimation of available nitrogen in soils. Curr. Sci., 25 : 259-267. Sudhalakshmi, C. (2002). Crop management options on nutrient dynamics in rice ecosystem. M. Sc., Thesis, Tamil Nadu Agricultural University, COIMBATORE, T.N. (INDIA). Sudhalakshmi, C., Velu, V. and Thiyagarajan, T.M. (2008). Phosphorus productivity of rice hybrids as influenced by SRI strategy. Extended summaries of the third national symposium on Rajarajan 1000 Practice in India policies, institutions and strategies for scaling up mainstreaming SRI as part of achieving food security while reducing water conflicts held during Dec 1-3, 2008 at Tamil Nadu Agricultural University, COIMBATORE, T.N. (INDIA). Surya Prabha, C. (2004). Studies on nutrient availability, uptake and yield of rice under system of rice intensification. Ph.D., Thesis, Tamil Nadu Agricultural University, COIMBATORE, T.N. (INDIA). 8 th Year of Excellence HIND AGRICULTURAL RESEARCH AND TRAINING INSTITUTE 240 Asian J. Soil Sci., (Dec., 2013) 8 (2) :