Theses

Browse

Search Results

Now showing 1 - 9 of 31

Open Access
Concurrent growing of green manure crops in dry and wet seeded rice
(Department of Agronomy, College of Horticulture, Vellanikkara, 2008) Anitha, S; KAU; Jose, Mathew
An investigation entitled ‘Concurrent growing of green manure crops in dry and wet seeded rice’ was conducted at Agricultural Research Station, Mannuthy to develop a comprehensive technology package for the system of concurrent growing of green manure crops in direct seeded rice. The investigation consisted of four experiments viz., Experiment Ia - Concurrent growing of green manure crops in dry seeded rice, Experiment Ib - Residual effect of concurrent growing of green manure crops in dry seeded rice, Experiment IIa - Concurrent growing of daincha in wet seeded rice and Experiment IIb - Residual effect of concurrent growing of daincha in wet seeded rice. The experiment on concurrent growing of green manure crops in dry seeded rice consisted of two green manure crops (horse gram and cowpea), three methods of incorporation (Incorporation by cono weeder, desiccation by 2,4 - D spray @1.0 kg ha-1 and allowing for self decomposition) and two levels of nitrogen (100 and 75% of recommended N) and a control without green manure crops . Among the two green manure crops, cowpea was the best in supplying the required quantity of green matter with 25 per cent savings of N fertilizer and a substantial reduction in weed incidence. All the three methods of incorporation were found to be equally effective. Hence in places where there is a difficulty in self decomposition, cowpea can be effectively incorporated by conoweeder or by spraying 2, 4-D. The cowpea variety used in this study was a short duration bush type variety facilitating additional pod yield from cowpea before it was incorporated. Concurrent growing of cowpea along with dry seeded rice is a viable system as it resulted in increased productivity, profitability and sustainability dry seeded rice. In the experiment to study the residual effect of concurrent growing of green manure crops in dry seeded rice, the main plots of dry seeded rice crop during the 1st crop season were divided into two sub plots and applied 100 and 75 per cent N to the subplots. The results revealed that concurrent growing of green manure crops were effective in increasing the yield and sustaining soil fertility status compared to pure crop of rice receiving 5 t ha-1 of FYM and 100 per cent of the recommended nitrogen. But there was no savings of N fertilizer to the succeeding transplanted rice crop as the highest yield of succeeding rice was achieved only when it received 100 per cent of the recommended N. The profitability of the rice- rice cropping system was the highest with concurrent growing of cowpea in dry seeded rice. The experiment on concurrent growing of daincha in wet seeded rice consisted of two stages of incorporation of daincha (20 DAS and 30DAS), three methods of incorporation (Incorporation by cono weeder, desiccation by 2, 4 - D spray @1.0kg ha-1 and Desiccation by Chlorimuron ethyl+ met sulfuron methyl spray @ 4.0 g ha-1 met sulfuron methyl spray @ 5 g ha-1) and two levels of nitrogen (100 and 75% of recommended N) and a control without daincha. Results indicated that concurrent growing of daincha can be successfully practiced in wet seeded rice with improved productivity. Incorporation of 30 days old daincha employing any of the three methods of incorporation was equally effective in increasing the productivity and profitability of wet seeded rice. Incorporation of daincha at 30 DAS could add about 14 t ha-1 of green matter with minimum investment and resulted in 70 per cent weed suppression. Concurrent growing of daincha receiving both 100 and 75 per cent of recommended N produced significantly higher yield than pure crop of rice receiving 5 t ha-1 of FYM and 100 per cent of the recommended nitrogen. Hence there was a saving of 25 per cent N without affecting the yield. The highest yield was obtained when 100 per cent of recommended N was applied to the system. The treatments for the experiment to study the residual effect of concurrent growing of daincha in wet seeded rice were similar to that of dry seeded rice. The results showed that concurrent growing of daincha and its incorporation at 30 DAS was effective in increasing the yield of succeeding rice and sustaining soil fertility status compared to pure crop of rice receiving 5 t ha-1 of FYM and 100 per cent of the recommended nitrogen. The highest yield of succeeding rice was achieved only when it received 100 per cent of the recommended N hence there was no savings of N fertilizer to the succeeding transplanted rice crop. Concurrent growing of daincha in wet seeded rice increased the profitability of the rice- rice cropping system. Concurrent growing of green manure crops in dry and wet seeded rice is a management alternative to reduce the production cost and to increase the yield of rice and is a practical model for sustainable rice production.
Open Access
Integrated weed management under system of rice intensification (SRI)
(Department of Agronomy, College of Horticulture, Vellanikkara, 2011) Musthafa, Kunnathadi; KAU; Abraham, C T
An experiment was conducted to assess the performance of system of rice intensification (SRI) vis-à-vis conventional system with special emphasis on weed problems under SRI and to develop an economic weed management strategy. Aiming at reducing drudgery while using manual cono weeder, it was also envisaged to develop the prototype of a self propelled cono weeder. The field studies laid out in randomized block design with 16 treatments in three replications were conducted at RARS, Pattambi in Palakkad district and in farmers’ fields at Alappad Kole in Thrissur district, during the Mundakan seasons of 2007 and 2008. The soil at Pattambi was lateritic sandy clay loam with pH 4.96 and medium fertility, and that at Alappad Kole was clayey in texture with pH 5.0 and of high fertility. At both locations, the density and dry weight of weeds at 45 and 60 days after transplanting (DAT) were higher in all the SRI treatments especially when weed control was done through repeated cono weeding. At Pattambi, weed density and weed dry weight were the lowest in conventional system with post emergence herbicides, which recorded lower nutrient removal by the weeds and the lowest weed index and also higher gross return, net return and B:C ratio. The weed density and dry weight in the SRI fields were the lowest with pre emergence herbicide followed by hand weeding at 30 DAT, but the use of post emergence herbicides showed higher B:C ratio. At Alappad Kole, the weed density and dry weight, both at 45 and 60 DAT, were the lowest in conventional system with cono weeding at 10 DAT followed by post emergence herbicides. Cono weeding followed by hand weeding, pre emergence herbicides followed by hand weeding as well as the use of post emergence herbicides were also equally effective in controlling the weeds 233 in the conventional system, and were on par in the B:C ratios. In the SRI plots cono weeding at 10 DAT followed by post emergence herbicides recorded the lowest weed density and dry weight, however, use of post emergence herbicides recorded the highest net return and B:C ratio among the SRI treatments. Thus, considering the acute shortage and high wages for the labourers in Kerala, weed management through post emergence herbicides will be the preferable option for the farmers in both conventional and SRI systems of rice cultivation. Comparison between the two systems of rice cultivation at two different rice growing ecosystems showed that SRI improved the performance of individual hills through higher number of tillers hill-1, root length and root dry weight hill-1. On the other hand, the tiller number, dry matter production, root dry weight and productive tillers per unit area were higher in the conventional treatments. Owing to higher number of productive tillers per unit area the grain yield of conventional treatments was significantly higher than that of the typical SRI. At Pattambi, conventional system with post emergence herbicides recorded higher number of productive tillers m-2, panicle length, number of filled grains panicle-1, 1000 grain weight and grain yield (2877 kg ha-1), which was 33 per cent higher than the grain yield in the typical SRI. This treatment also recorded significantly higher B:C ratio (1.27) compared to that (0.91) of the typical SRI. However, the highest straw yield (2510 kg ha-1) at Pattambi was observed in ‘SRI with cono weeding at 10 DAT followed by post emergence herbicides’, which was on par with the typical SRI treatment. At Alappad Kole, higher number of productive tillers m-2, more filled grain percentage, highest 1000 grain weight, highest grain yield (6073 kg ha-1) and highest straw yield (5109 kg ha-1) were recorded by conventional system with cono weeding followed by hand weeding, which showed an increase of 93 per 234 cent in grain yield, with an additional yield of 2934 kg ha-1, and 109 per cent in straw yield over the typical SRI and recorded the highest gross return, net return and B:C ratio (2.46). Thus, the study showed the superiority of conventional system of rice cultivation at a spacing of 20 cm x 10 cm over the SRI system at a spacing of 30 cm x 30 cm at both the two different rice growing ecosystems studied viz., the sandy loam soils at Pattambi and the clayey soils at Alappad Kole. Prototype of the self propelled cono weeder was developed and field tested. It works satisfactorily in a single forward pass, and covers an area of 0.1 ha h-1. The field study showed that the self propelled cono weeder is effective for inter row weeding in rice, however, further refinement is needed to improve its weeding efficiency.
Open Access
Input optimization for medicinal rice (Oryza sativa L.) cv. Njavara.
(Department of Agronomy, College of Agriculture, Vellayani, 2011) Sriramkumar, N; KAU; Geethakumari, V L
The investigation entitled “Input optimization for medicinal rice (Oryza sativa L.) cv. Njavara” was conducted at Instructional Farm, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala, during the summer seasons of 2007 and 2008 (January to April) to standardize an ideal nutrient schedule under two moisture regimes for sustaining Njavara production in lowlands, to investigate the soil physical, chemical and biological properties as influenced by regimes and sources of nutrients and to work out the economics of Njavara cultivation. Both the experiments (submerged and saturated situations) were laid out in randomised block design with ten treatments each and three replications. The treatments comprised four nutrient regimes viz., N1 - 30:15:15, N2 - 30:30:30, N3 - 40:20:20 and N4 - 40:40:40 kg NPK ha-1, two nutrient sources viz., organic nutrient source (S1) and integrated nutrient source (S2) and two controls viz., absolute control (no nutrient was applied) (C1) and POP for local rice variety (C2). Growth components like plant height, leaf number plant-1, leaf area index (LAI), number of tillers m-2, culm strength and flag leaf area, yield and yield attributes like number of productive tillers m-2, panicle length, number of grains panicle-1, number of filled grains panicle-1, 1000 grain weight, harvest index, sterility percentage, dry matter partitioning, paddy grain ratio and grain husk ratio were recorded. Leaf chlorophyll content was also estimated. Uptake of nutrients (N, P, K, S, Fe, Mn and Zn) and economics of cultivation were computed. Biochemical components of grains such as total, free and sulphur containing amino acids, phenols, starch, amylose, amylopectin and protein content were estimated. Data on weed biomass, weed flora and crop duration were also recorded. Soil enzymes (urease, phosphatase and dehydrogenase), soil microbial population (bacteria, fungi and actinomycetes population) and soil fertility status (available nitrogen, phosphorus, potassium, sulphur, iron, zinc and manganese) were assessed before and after the crop. Effect of nutrient regimes Effect of nutrient regimes on all growth parameters was significant. Growth parameters like plant height, leaf number plant-1, leaf area index (LAI), number of tillers m-2, culm strength and flag leaf area were significantly higher in N2. N2 recorded leaf chlorophyll content which was significantly higher than N3 and N1 and was on par with N4. All yield attributes except 1000 grain weight were significantly influenced by nutrient regimes resulting in significant variation in the crop yield (grain and straw). Maximum grain yield was recorded in N2 (30:30:30 kg NPK ha-1) (2.78 and 2.66 t ha-1) which was on par with N4 (40:40:40 kg NPK ha-1) (2.67 and 2.58 t ha-1) and was significantly superior to N1 and N3 under submerged and saturated situations respectively. Duration of the crop did not show significant variation due to nutrient regimes. Total amino acid and protein content of grain were significantly influenced by nutrient regimes and were maximum in N2. Nutrient regimes significantly influenced N, P and K uptake. Uptake of N, P and K in N2 was significantly higher than that in the other three nutrient regimes. Nutrient regimes did not significantly influence uptake of S, Fe, Mn and Zn. Results of the study also revealed that Echinochloa colona (L.) Link, Isachne miliacea Roth ex Roem. et Schult; Cyperus iria L., Cyperus difformis L. Fimbristylis miliacea (L.) Vahl.; Marsilea quadrifoliata Linn., Monochoria vaginalis (Burm. f.) Presl. ex Kunth and Ludwigia perennis L were the most predominant weed species in the experimental field under both situations. Weed biomass at 20 and 40 DAS were not significantly influenced by nutrient regimes during both the years of experimentation. Nutrient regimes showed significant influence on available nitrogen, phosphorus and potassium status of the soil after the investigation. Available sulphur, iron, zinc and manganese status of the soil after the experiment revealed non-significant effect of nutrient regimes in both the years of study. Among the soil enzymes, urease activity was influenced significantly by the nutrient regimes and it was in the order N4 > N3 > N2 > N1. Bacterial population was influenced significantly by the nutrient regimes and it was in the order N4 > N3 > N2 > N1. Effect of nutrient sources Nutrient sources had significant influence on all the growth characters, yield attributing characters like number of grains panicle-1, number of filled grains panicle-1, harvest index as well as crop yield (grain and straw). Highest number of grains panicle-1, filled grains panicle-1 and crop yield (grain and straw) were realized in integrated nutrient source and they were significantly higher than that realized from organic source. Duration of crop did not differ significantly between the nutrient sources. Integrated nutrient source registered significantly higher nitrate reductase activity and root weight compared to organic source. Biochemical components such as total, free and sulphur containing amino acids, phenols, starch, amylose, amylopectin and protein content of grain did not differ significantly between nutrient sources. Highest uptake of N, P and K was in integrated nutrient source. Sources of nutrients did not influence uptake of S, Fe, Mn and Zn during both the years of experimentation. Weed biomass under different nutrient sources at both 20 DAS and 40 DAS differed significantly from one another. Weed biomass during both stages and both the years of experimentation was more in organic source compared to integrated nutrient source. Highest weed biomass was recorded in absolute control at both stages during both the years. Available nitrogen, available phosphorus and available potassium status of the soil after the experiment in the plots receiving integrated nutrient source and organic nutrient source differed significantly from each other. Available N, P and K status of the soil were higher in integrated nutrient source. Organic carbon, available sulphur, iron, zinc and manganese status of the soil after the experiment were not significantly influenced by nutrient sources. Urease activity and bacterial population in the soil were influenced significantly by nutrient sources. Highest activity of urease and bacterial population in the soil were recorded in organic source compared to integrated nutrient source. Phosphatase and dehydrogenase activity as well as fungal and actinomycetes population in the soil were not influenced by nutrient sources. Economics of crop production Gross income, net income and BCR were highest in N2S2. Application of FYM @ 5 t ha-1 along with 30:30:30 kg NPK ha-1 (50 % N as organic + 50 % N as chemical fertilizer) (N2S2) recorded a net profit of Rs 57,586 ha-1 and Rs 53,546 ha-1 under submerged and saturated situations respectively. The lowest gross income, net income and BCR were recorded in N1S1 (FYM @ 5 t ha-1 along with 30:15:15 kg NPK ha-1 as organic source). The ideal nutrient schedule for sustaining Njavara production in lowlands under both submerged and saturated situations is N2S2 - FYM @ 5 t ha-1 + 30:30:30 kg NPK ha-1 (50 % N as organic + 50 % N as chemical fertilizer). This nutrient system realised highest grain yield, straw yield and net income.
Open Access
Floristic diversity, autecology and competitive behaviour of weed flora in wetland rice ecosystem
(Department of Agronomy, College of Agriculture, Vellayani, 2010) Sajith Babu, D; KAU; Sansamma George
Floristic diversity, autecology and competitive behaviour of weed flora in the wetland rice ecosystem were studied by conducting a field survey and two field experiments. The field survey was conducted during the first and second crop seasons of 2003 in the rice fields of 30 panchayaths in Thiruvananthapuram district having more than 50 hectares of net sown area, covering all the four thaluks of the district. Weed flora was surveyed from both cultivated and fallow fields. The design adopted for conducting the floristic survey was Stratified Multistage Random Sampling and the methodology was Census Quadrate Method. The field experiments were conducted during the first crop seasons of 2003 and 2004 at College of Agriculture, Vellayani. The design adopted was Strip plot. The treatments included four levels of nutrient management and three levels of crop spacing and the number of replications was five. Part III of the investigation was an autecological study wherein the growth and development pattern of two of the major weed flora observed in the experimental area was studied by keeping an area of 1.2 X 4.2 m2 on the same side of all the plots in Part II. Perusal of the results of the field survey indicated that substantial diversity of weed flora existed in the wetland rice ecosystem in Thiruvananthapuram district of Kerala. In the cultivated rice fields, there were 46 weed specii during the first crop season and 49 species during the second crop season. In the rice fallows during the first crop season there were 43 specii while during the second crop season there were 54 specii. In the cultivated fields during both seasons, the most prominent species among the different classes of weeds (grasses, sedges and broad leaved weeds) were Isachne miliacea Roth ex Roem et Schult, Cyperus iria L. and Monochoria vaginalis (Burm.f.) Presl. Ex Kunth respectively. Isachne miliacea Roth ex Roem et Schult was the dominant grass weed in the fallows as well. However the dominant sedge weed in the fallows was Cyperus distans L.f. during the first crop season while it was Fimbristylis miliacea. during the second crop season. Monochoria vaginalis (Burm.f.) Presl. Ex Kunth and Ludwigia perennis topped the list of broad leaved weeds in the rice fallows during first and second crop seasons respectively. Results of the field experiment showed that weed growth in the rice field was influenced significantly by the sources and levels of nutrients as well as by crop spacing. During both the years at 20 and 40 DAT the weed density and dry weight were the lowest when the rice crop was treated with NPK @ 90:45:45 kg ha-1 applied with 25 per cent N as organic (N2) while at 60 DAT enhanced nutrient level (NPK @ 112.5:56:25:56.25 kg ha-1) applied with 25 per cent N as organic (N4) recorded the lowest value. During both the years, at all growth stages the weed density and dry weight were the lowest under the closer spacing of 15 X 15 cm (P1) The grain and straw yield were maximum under NPK @ 112.5:56:25:56.25 kg ha-1 applied with 25 per cent N as organic in combination with widest spacing (n4p3). Dead heart occurrence was minimum under the widest crop spacing The net income and Benefit : Cost ratio were the highest when rice crop was treated with 125 per cent of the recommended NPK with 25 per cent organic substitution in combination with widest spacing (n4p3) Autecological studies showed that the growth and development of Isachne miliacea Roth ex Roem et Schult. was significantly influenced by the management practices for the associated rice crop. The higher dose of NPK applied as chemical fertilizers only (N3) along with widest spacing (P3) stimulated all the vegetative parameters (shoot / root length and plant spread) of the weed. During both the years plants growing in rice fields treated with recommended dose of NPK with 25 per cent organic substitution (N2) and rice crop planted at wider spacing (P3) recorded delayed flowering but produced more seeds per panicle The root and shoot length of Cyperus iria L growing in rice fields treated with 100 per cent recommended NPK as chemical fertilizers (N1) with minimum spacing (P1) recorded the maximum value during the both years. Delayed flowering of the sedge was noticed under N2. The number of seeds produced per plant was significantly high under N4 and P3. The general trend was that addition of organic manures in rice delayed flowering but increased seed production in the associated sedge weed From the studies it may be concluded that by altering nutrient management and adjusting the plant population, the competitive ability and productivity of rice crop can be improved substantially. Though, closer spacing of 15 X 15 cm significantly reduced the density and dry weight of weeds, the wider spacing of 20 X 20 cm in conjunction with enhanced fertilizer dose of 112.5:56:25:56.25 kg NPK ha-1 applied with 25 per cent N as organic manures significantly enhanced the rice grain and straw yield. The treatment also resulted in significant enhancement in net income and B:C ratio in medium duration variety Aiswarya in first crop season.
Open Access
Productivity of rice in laterite soil in relation to nitrogen-sulphur interaction
(Department of Agronomy, College of Horticulture, Vellanikkara, 2010) Rathish, S T; KAU; John, P S
The research programme entitled “Productivity of rice in laterite soil in relation to nitrogen - sulphur interaction” was conducted mainly to study the nitrogen and sulphur availability and their interaction as influenced by organic manure sources, particularly straw incorporation in rice cultivation. The “Mineralization pattern of nitrogen and sulphur” was studied in pot culture experiment at College of Horticulture, Vellanikkara during the rabi season (Mundakan) Sep 2007 – Feb 08. “Response of rice to nitrogen and sulphur mineralization from organic matter with varying C:N ratios” was studied in farmers field, Pudhunagaram, Palakkad during the rabi seasons (Mundakan) Sep 2006 – Feb 07 and Sep 2007 – Feb 08. The mineralization of nitrogen and sulphur from the organic materials was influenced by time after application. The straw incorporated treatment released noticeably lower amount of nitrogen and sulphur in the initial stages than no manure application. The early growth characters of rice such as plant height, tiller production and dry matter production were significantly lower in straw incorporated treatments. Straw incorporation followed by application of nitrogen and sulphur or both, did not make any significant change in growth pattern probably due to inadequacy or improper timing. Increasing levels of nitrogen and sulphur positively influenced the vegetative growth and yield. The interactive effects of manures × N/S were significant for several characters. Beneficial effects of higher nitrogen and sulphur with straw incorporation were less evident in the early stages and was pronounced in the later stages. Nitrogen application with cow dung showed better performance during vegetative stage, but declined towards harvest. The tiller decline was lower in the straw incorporated treatments than either cow dung applied or unmanured treatments. Yield attributing characters were significantly influenced by incorporation of straw and cow dung along with nitrogen and sulphur. Grain yield increased from 3432 kg ha-1 in the absolute control to 7085 kg in the straw + N90 + S30 treatment in first year and from 3657 kg to 7116 kg in the cow dung + N90 + S30 treatment in second year. The interaction effects of manures × N/S were more pronounced than N × S. Combined application of organic manures and nitrogen noticeably increased protein nitrogen and protein sulphur content. Most of the plant nutrients were positively correlated with each other and positively correlated with grain yield. N × Fe and S × Fe have showed significant negative correlation. Agronomic efficiency of nitrogen or sulphur (kg grain/kg nutrient applied) was not influenced by organic manure application. Apparent recovery of nitrogen as well as physiological efficiency of nitrogen was the highest in combination of organic manures with 45 kg nitrogen and 30 kg sulphur. The utilization or physiological efficiency was also highest (kg grain/kg nutrient taken up) for the above combination. Straw incorporation resulted in long term maintenance of soil fertility as evidenced by higher mineral nitrogen and sulphur in soil upto a period of 110 days. In sulphur deficient soil, sulphur fertilizers could increase the rice yield and the use efficiency of nitrogen. The finding of the study points to beneficial effects of rice straw left in the field after harvesting using combine harvesters. However 37 to 52 kg ha-1 less mineral N was observed in the straw incorporated soil during the 30 days after incorporation and 20 days after rice planting compared to cow dung, both incorporated at 10 t ha-1. If this deficit could be compensated by N added at appropriate time, the straw will be a better and cheaper source of organic matter than cow dung.
Open Access
Response of medicinal rice (Oryza Sativa L.) cv njavara to SRI and other management systems
(College of Agriculture, Vellayani, 2010) Rani, S; KAU; Sukumari, P
Field experiments were conducted at Cropping Systems Research Center, Karamana, Thiruvananthapuram, Kerala, during the summer seasons of 2007 and 2008 (January to April) to study the response of medicinal rice (Oryza sativa L.) cv Njavara to nutrient sources under different management systems like SRI, ICM, PoP of KAU and Farmers’ practice. The experiment was laid out in split plot design with four replications. The treatments consisted of four management systems viz., SRI (M1), ICM (M2), PoP (M3) of KAU and Farmers’ practice (M4) in main plots. Nutrient sources viz., organic sources (S1), integrated sources (S2) and inorganic sources (S3) were the sub plot treatments. Growth components viz., plant height, number of leaves hill-1, leaf area index (LAI), leaf area duration (LAD), culm strength, number of tillers m-2, root dry matter production hill-1 and flag leaf area were recorded. The data on yield attributes like number of productive tillers m-2, panicle length, number of grains panicle-1, number of filled grains panicle-1, 1000 grain weight, harvest index, sterility percentage, dry matter partitioning, paddy grain ratio, grain husk ratio were also worked out. Yield and uptake of nutrients (N, P, K,S Fe, Mn and Zn by grain, straw and crop (grain + straw) were also recorded. Biochemical components such as total free amino acids, phenols, starch, amylose, amylopectin and crude protein content of grain were estimated. Data on weed dry matter production and weed flora and crop duration in the treatments were also recorded. Soil enzymes (urease, phosphatase and dehydrogenase) and soil fertility status were assessed after the harvest of the crop. D. Effect of management systems Growth parameters like height of plants, number of leaves hill-1, leaf area index (LAI), culm strength, root biomass and number of tillers m-2 were significantly influenced by management systems. Leaf area duration and flag leaf area showed significant variation only in 2008. Plant height and leaf area index (at physiological maturity) were in the order Farmer’s practice > PoP > SRI > ICM and they differed significantly from one another. Number of leaves hill-1, leaf area index at panicle initiation, flag leaf area and number of tillers m-2 (from 4 WAS/WAT till physiological maturity) were in the order Farmer’s practice > PoP > ICM >SRI . Number of tillers m-2 in the four management systems differed significantly from one another. Culm strength (physiological maturity) and root biomass production all the management systems differed significantly from one another. Culm strength and root biomass production (7 WAS/WAT to physiological maturity) were in the order SRI > ICM > PoP > Farmer’s practice. All the yield attributes except 1000 grain weight were significantly influenced by management systems resulting in significant variation in the crop yield (grain and straw). Number of productive tillers m-2, sterility percentage and dry matter accumulation in panicle were in the order Farmer’s practice > PoP > ICM > SRI and they all differed significantly from one another. Grain and straw yield in the management systems differed significantly from one another and their order was Farmer’s practice > PoP > SRI > ICM. Number of grains panicle-1, number of filled grains panicle-1 and dry matter partitioning in root and straw were in the order SRI > ICM > PoP > Farmer’s practice. All the characters except dry matter partitioning in straw differed significantly from one another. Among the biochemical properties of grain total free amino acid content and amylopectin content (2007) were significantly influenced by management systems. Free amino acid content of grain was in the order SRI > ICM > PoP > Farmer’s practice. Amylopectin (2007) was in the order ICM > Farmer’s practice > PoP > SRI . Weed biomass at 15 and 35 DAS/DAT in the management systems differed significantly from one another. Weed biomass recorded at 15 DAS/DAT were in the order Farmer’s practice > PoP > SRI > ICM and that at 35 DAS/DAT Farmer’s practice > ICM > PoP > SRI. Management systems showed significant influence on nutrient uptake by grain (N, P, K, Fe and Mn), by straw (N, K, Fe, Mn and Zn) and total uptake by the crop (N, P, K, Fe, Mn and Zn). Uptake of all the nutrients in Farmer’s practice was significantly higher than that in the other three management systems. Management systems did not show significant influence on the available nutrient status of soil after the experiments. Among the soil enzymes phosphatase activity was influenced significantly by the management systems and it was in the order SRI > ICM > PoP > Farmer’s practice. Crop raised under PoP had the longest duration (108 days) followed by ICM with 98 days, SRI with 94/95 days (2007/2008) and Farmer’s practice with 87 days. Farmer’s practice which realized highest crop yield was significantly higher than PoP, SRI and ICM with respect to many growth characters (plant height, number of leaves hill-1, leaf area index, leaf area duration, flag leaf area and tiller production) and yield characters (number of productive tillers, percentage of dry matter accumulation in panicle). Duration of the crop was lowest in Farmer’s practice and it was significantly lower than that in all other management systems. Effect of nutrient sources Sources of nutrients did not influence growth characters in Njavara. Yield attributing characters like number of grains panicle-1, number of filled grains panicle-1 and harvest index as well as crop yield (grain and straw) were significantly influenced by nutrient sources. Highest number of grains panicle-1, filled grains panicle-1 and crop yield (grain and straw) were realized in integrated nutrient source and they were significantly higher than organic and inorganic sources. Effect of nutrient sources on yield attributing parameters and crop yield (individual years and pooled analysis) were in the order integrated nutrient source > organic source > inorganic source and the order was just the reverse with respect to harvest index (inorganic source > organic source > integrated nutrient source). Duration of the crop also showed significant variation due to variation in sources of nutrients and it was in the order inorganic source (98 days) > integrated nutrient source (97 days) > organic source (95 days). Among the biochemical properties starch (2008), crude protein and amylopectin were significantly influenced by nutrient sources whereas total free amino acids, phenols and amylose content of grain remained unaffected. Starch and amylopectin content of grain were in the order organic nutrient source > integrated nutrient source > inorganic nutrient source. Crude protein content of grain was in the order organic nutrient source > inorganic nutrient source > integrated nutrient source. Available N status and organic content of soil were in the order organic sources > integrated sources > inorganic sources. Available N status of soil supplied with different nutrient sources differed significantly from one another. Organic carbon content in soils receiving organic and integrated nutrient sources were on par and significantly higher than that in soil receiving only inorganic source of nutrients. Soil enzyme activity (urease, phosphatase and dehydrogenase) was influenced significantly by nutrient sources and it differed significantly from one another. Effect of nutrient sources on urease activity was in the order organic source > inorganic source > integrated source and on phosphatase and dehydrogenase activity were in the order organic source > integrated source > inorganic source. Highest total nutrient (P, K, Fe and Zn) uptake by crop (grain + straw) occurred in integrated nutrient source. Crop uptake of K and Zn in integrated source was significantly higher than that in other nutrient sources and organic and inorganic sources were on par. Interaction effect Effect of interactions did not influence growth characters in Njavara. Yield attributing characters like number of grains panicle-1, number of filled grains panicle-1, crop yield (grain + straw) and harvest index were significantly influenced by interaction effect. SRI with organic source and Farmer’s practice with inorganic source recorded highest and lowest value of number of grains panicle-1 and number of filled grains panicle-1. Farmer’s practice with integrated nutrient source recorded highest (1198.00/2251.57 kg ha-1 grain/straw yield) and ICM with inorganic source recorded lowest grain and straw yields (788.08/1167.52 kg ha-1 grain/straw yield). Interaction effect showed significant influence on nutrient uptake by grain (N and Mn), straw (K and Zn) and total uptake by the crop (K and Zn). Nutrient uptake by crop (K and Zn) was highest in Farmer’s practice with integrated nutrient source. Phenological study The developmental phenology of Njavara rice under different management systems was studied. Panicle initiation occurred at 32 DAS in Farmers’ practice, 40 DAT in PoP, 42 DAT in ICM and 45 DAT in SRI. Maximum tillering stage occurred at 36 DAS in Farmers’ practice, 45 DAT in PoP, 46 DAT in ICM and 49 DAT in SRI. Booting stage occurred at 46 DAS in Farmers’ practice, 51 DAT in PoP, 53 DAT in ICM and 57 DAT in SRI. Flowering stage occurred at 53 DAS in Farmers’ practice, 59 DAT in PoP, 60 DAT in ICM and 64 DAT in SRI. Maturity stage occurred at 86 DAS in Farmers’ practice, 88 DAT in PoP, 86 DAT in ICM and 88 DAT in SRI. Economics of crop production Cost of cultivation, gross income, net income and BCR among the management systems, nutrient sources and interactions differed significantly. Cost of cultivation was highest in SRI, organic nutrient source and SRI with organic nutrient source. Gross income, net income and BCR were highest in Farmer’s practice, integrated nutrient source and Farmer’s practice with integrated nutrient source. Farmer’s management practices coupled with integrated nutrient source can be considered as the ideal crop production package for Njavara rice in lowlands. This production package realised the highest crop yield (grain and straw), gross income ha-1(Rs 52,423), net income ha-1 (Rs 28,027) and BCR (2.15).
Open Access
Integrated weed management for rice based cropping system of Onattukara tract
(Kerala Agricultural University;Thiruvananthapuram, 2000) Rajan, S.; KAU; Nair, V. Muraleedharan
Open Access
Yield and quality of betelvine (Piper betel L.) as influenced by planting material and integrated nutrient management
(Kerala Agricultural University;Thiruvananthapuram, 2004) Thomas, Usha C.; KAU; Chandini, S.
Open Access
Crop intensification and resource management in banana based cropping system
(Kerala Agricultural University;Thiruvananthapuram, 2004) Venugopal, Vandana; KAU; Sheela, K.R.

Theses

Browse

Thesis Type

Type

Author

Date

Subject

Search Results