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Open Access
Effect of different inputs on productivity and quality relations in njavara (Oryza sativa)
(Department of Agronomy, College of Horticulture, Vellanikkara, 1996) Meera Menon, V; Kau; Potty, N N
Productivity characteristics of Njavara (Oryza sativa), a medicinal rice variety were investigated based on the results of four separate experiments conducted at the Regional Agricultural Research Station, Pilicode, during 1994-96. The experiments were to study (i) growth and development characteristics (ii) crop weather relations (iii) response to nitrogen, phosphorus and potassic fertilizers and (iv) the effect of integrated nutrient management. Two biotypes of Njavara, the black glumed and golden yellow glumed, were tested in the first two experiments. The black glumed biotype alone was studed in the third and fourth experiments. The first experiment, consisting of the two biotypes as treatments, was conducted in wetland, open upland, heavily shaded upland and partially shaded upland, and pooled analyses of the data were conducted. Treatments of the second experiment which studied the effect of date of sowing on productivity of Njavara included 10 dates of sowing at fortnightly intervals starting from the 15th of May. Combinations of three levels of nitrogen, phosphorus and potassium, each at levels of 15, 30 and 45 kg ha-1 along with a standard and absolute control constituted the treatments of Experiment III. The last trial consisted of two treatments, one exclusively with farmyard manure and another with fertilizer alone, both at 30 kg nitrogen equivalent, two treatments with organic and inorganic manure in different ratios and three combinations of Azospirillum with 25, 50 and 75 per cent of the full farmyard manure dose. The second experiment was conducted in open upland and the third and fourth experiment in heavily shaded coconut gardens. Biometric, nutritional and quality criteria estimated through accepted methodology were used for the evaluation of treatments. An abstract of the results obtained has been presented in the following paragraphs. The results showed that three phases could be distinguished in the growth and development of Njavara. They are a primary phase of absorption and accumulation of nutrients, a grand growth phase of rapid accumulation of dry matter and a diversion phase when the seed and quality develop. Continued growth till harvest gave high yield and dry matter decline in the final phase led to superior quality characteristics. Golden yellow glumed biotype exhibited continuous growth and higher yield of grain. Black glumed biotype manifested dry matter decline in the final phase, leading to lower yield of grain and higher free amino acid content in the grain. Profound influence of cropping situation on yield and quality of grain was observed. Lowest yield of 684 kg ha-1 and highest amino acid content of 0.492 mg g-1 were observed in the uplands and highest yield of 2401 kg ha-1 and lowest amino acid content of 0.203 mg g-1 were observed when Njavara was sown in the wetlands. Viewed on the basis of variation in nutrition in the different situations, the results showed that yield limiting influences were not the deficiency of any element but the excess contents of Mg and Mn at maximum tillering and of P, K, S, Zn and Cu at panicle initiation stages in the plant. This appeared to be a highly significant result in the context of stagnant productivity of crops like rice. Content of free amino acids in the grain appeared to be unique characteristic of Njavara rice. Among the amino acids, sulphur containing amino acids, methionine and cysteine were also present. Possibly, these amino acids are related to the medicinal value of Njavara in the treatment of rheumatic complaints, the symptoms of which resemble thiamin deficiency. Inherently high yield potential of Njavara was expressed in the date of sowing trial. Both the biotypes recorded grain yields of 6000 kg ha-1 when sown on most favourable dates. Weather influence contributed to be highest yield through two ways, firstly, by increasing the total dry matter yield and secondly, by improving the grain-straw ratio. The golden yellow glumed biotype produced higher grain yield than the black glumed biotype. Application of N, P and K fertilizers increased the uptake of all the elements studied. Positive interaction of fertilizer elements on content and uptake of elements was also evident. However, application of fertilizers could influence only the straw yield significantly. One possible reason for the absence of significant improvement of grain yield by fertilizer application appeared to be due to the high levels of application. Even 15 kg ha-1 of N, P and K were found to be excess in shaded situations. Results of the integrated nutrient management studies showed that level of application was more important than the source in affecting the ultimate yield. Farmyard manaure application led to a more balanced development of the components of yield whereas fertilizer source improved only the floret number per panicle. Nutritional management at levels below 15 kg ha-1 N equivalent significantly reduced the yield. Azospirillum did not have any effect in increasing the yield of Njavara. The results of the different experiment brought out the role of soil and atmosphere environment as well as the biotype influence on the yield and contributed to the development of the concept of soil-plant-atmospheric continuum on the technical side. On the pracical side they showed that Njavara is an ideal crop for growing in the first crop season in the uplands in North Malabar when no other crop can be grown and that growing in heavily shaded uplands will give high quality grain. Advantageously, the crop will not require intense management.
Open Access
Ecophysiology and management of Isachne in rice fields of Onattukara
(Department of Agronomy, College of Horticulture, Vellanikkara, 1996) Abraham, Varughese; KAU; Tajuddin, E
Isachne miliacea Roth is the most dominant weed in the 28,000 ha of low land rice fields of the coastal sandy Onattukara region, situated in Kollam and Alapuzha districts of Kerala. A serious of investigations were undertaken at Rice Research Station, Kayamkulam, during 1991 to 1994 with the objective to identify the major weeds in the rice ecosystem and to bring out the ecophysiology of 1. Miliacea and to find out a suitable weed management strategy for the rice based cropping system of Onattukara. Isachne miliacea was found to be the dominant weed in rice during Kharif and Rabi seasons. The weed seeds germinate in April – May, attains its peak vegetative growth in July and flowers in October. The seeds mature in November and the plants dry off in January with the onset of summer. The weed is propagated by seeds and stem cuttings. Germination of seeds can be prevented by submerging the seeds in the area in water even to a depth of one centimetre. The forcing of the stem cuttings of 1. Miliacea to a depth of five centimetre below the soil surface or maintaining a submergence for more than five centimetre can effectively check the vegetative multiplication of the weed. Seeds attained physiological maturity in November and remained dormant upto March. Seeds of the season that remain on the surface germinate fully in April – May with the pre – monsoon showers while the buried seeds remain dormant. Burying the seeds to more than five centimetre depth and water stagnation in July to November induced secondary dormancy. Viability of the seeds was lost faster at shallow depth of burial. Crop weed competition studies were conducted in Kharif and Rabi for two years with different densities of 1. Miliacea. Weed competition was severe in dry dibbled Kharif compared to wet transplanted Rabi. Even a small density of five 1. Miliacea plants per square metre produced appreciable biomass and reduced the DMP of rice substantially. Integrated weed management study was conducted in Kharif and Rabi for two years in a split – plot design in three randomised blocks. Kharif season treatments formed the main plots for Rabi trial. In Kharif five pre – emergence herbicides were compared with local practice. Local practice of hoeing on 15 DAS and HW twice on 25 and 40 DAS gave maximum grain yield. Application of oxyfluorfen 0.1 kg ha-1 followed by HW on 30 DAS was on par with local practice and ranked second. The performance of other herbicides anilofos 0.40 kg, butachlor 1.25 kg and thiobencarb 1.25 kg per hectare were also satisfactory when followed by one HW on 30 DAS. Pretilachlor 0.50 kg ha-1 was phytotoxic to rice. The tested herbicides effectively controlled 1. miliacea upto harvest of rice compared to local practice. During Rabi the effect of pre-plant spray of glyphosate and hand weedings were compared. Among the treatments a pre – plant spray of glyphosate after harvest of Kharif controlled 1. miliacea best and gave maximum rice yield in Rabi season. Kharif treatments did not show any significant influence on yield of rice during Rabi. From the study it could be concluded that pre – emergence spray of oxyfluorfen 0.1 kg ha-1 followed by one HW on DAS in Kharif and pre – plant application of glyphosate 0.75 kg ha-1 on residual weeds immediately after the harvest of the Kharif crop gave efficient weed control and economic yield of rice in the rice based cropping system involving rice – rice – fallow of Onattukara region.
Open Access
Nutrient management with biofertilizers in a fodder maize-cowpea intercropping system
(Department of Agronomy, College of Agriculture, Vellayani, 1996) Kavitha, P K; KAU; Raghavan Pillai, K
An experiment was conducted in the Instructional farm attached to the College of Agriculture, Vellayani during the Kharif season in 1994. The object was to study the effect of different bioinoculants {Azospirillum, Rhizobium, Vesicular arbuscular mycorrhiza (VAM) as well as different levels of nutrients ie control, 25, 50, 75 and 100 percent of the recommended dose of fertilizer and their interaction on increasing the forage production of maize - cowpea intercropping system. The height of maize plant, number of leaves, and leaf area index were maximum for the treatment, Azospirilllum - maize + Rhizobium - cowpea but the maximum leaf-stem ratio was observed for Azospirillum- maize + VAM - cowpea. In cowpea, all the growth characters were maximum for the treatment, VAM - maize + Rhizobium-cowpea. It was also seen that fertilizer level above 50 percent didn't produce any significant increase in these characters. In maize, highest root length was observed for Azospirillum - maize + Rhizobium - cowpea treated plants and highest root volume for, Azospirillum - maize + VAM - cowpea treated plants. Maximum nodulation in cowpea was observed for the treatment, VAM -maize +Rhizobium- cowpea and maximum root length for Azospirillum – maize + VAM – cowpea. Mycorrhizal colonization percentage was found to be higher in the roots of inoculated plants for both crops. All these character were found to be maximum under no fertilizer application. . Maximum green matter and drymatter yield of maize occurred for the treatment, Azospirillum – maize + VAM - cowpea and for cowpea, the treatment VAM –maize +Rhizobium – cowpea. It was also noted that 50 percent of the recommended dose of fertilizer was enough for producing maximum yield. The treatment Azospirillum – maize + VAM cowpea produced maximum uptake of nitrogen in maize, phosphorus in cowpea and potassium, calcium and magnesium uptake in both the crops. The treatment VAM –maize + Rhizobium – cowpea produced the maximum uptake of phosphorus in maize and nitrogen in cowpea. The uptake of nutrients do not differ significantly after 50 percent of recommended dose of fertilizer. In maize, crude protein yield and crude fibre yield were maximum for the treatment, Azospirillum – maize + VAM- cowpea under high levels of fertilizer. In cowpea, the treatment VAM – maize + Rhizobium – cowpea at high levels of fertilizer produced maximum value. The available nitrogen, phosphorus, potassium, calcium and magnesium status of the soil varied significantly due to the interaction between biofertilizer and chemical fertilizers. The treatment combination, VAM – maize + Rhizobium – cowpea + 50 percent of the recommended dose registered the highest net profit of Rs.8110.00 and Benefit – cost ratio of 1.502. The treatment combination, VAM- MAIZE + Rhizobium-cowpea + 50 percent of the recommended dose can be given as the final recommendation in fodder maize-cowpea intercropping system.
Open Access
Effect of biofertilizers on N and P economy in palmarosa(cymbopogon martinii)
(Department of Agronomy, College of Horticulture, Vellanikkara, 1996) Regimol, Thomas; KAU; Lalitha Bai, E K
An investigation was undertaken at the College of Horticulture, Kerala Agricultural University, Vellanikkara, during 1994-’95 to study the effect of biofertilizers on N and P economy in palmarosa (Cymbopogon martini stapf. var. motia). The main objective of the study was to assess the possibility of using biofertilizers so as to replace or minimise the expensive synthetic nitrogen fertilizers for palmarosa. The study also aimed to find out the effect of phosphorus solubilising bacteria (Bacillus megatherium var.phosphaticum) in increasing the availability of fixed soil phosphorus, the effect of combination of chemical and biofertilizers on the growth and yield of palmarosa and to work out the N and P economy due to the integration of chemical and biofertilizers. The experiment was carried out using the palmarosa selection ODP-2. The salient findings are abstracted below: The application of chemical fertilizers increased the available N, P and K contents in soil after different harvests, resulted in increased nutrient uptake and thus improved the growth and yield of palmarosa. The oil yield obtained with the application of 20 kg ha -1 each of N and P2O5 was significantly superior to that in the control plot. The different biofertilizer levels were compared with regard to their effect on palmarosa and it was observed that the combined inoculation of Azospirillum and PSB was the best in increasing the available N, P and K contents in soil and the nutrient uptake by the crop. Hence this particular treatment resulted in the highest oil yield which was significantly superior to that in the uninoculated control. The interaction effect of chemical X biofertilizers showed that the oil yield over a period of one year obtained with the application of 20 kg ha-1 each of N and P2O5 was on par with that obtained with the applications of either Azotobacter alone or Azospirillum alone and also the combined inoculation of Azospirillum and PSB. Thus the biofertilizers Azotobacter alone, Azospirillum alone and the combined inoculation of Azospirillum and PSB could substitute chemical fertilizers to the level of 20 kg ha-1 each of N and P2O5. The data again showed that the combined application of chemical and biofertilizers ie, N and P2O5 each at 20 kg ha -1 along with Azospirillum plus PSB resulted in comparable total oil yield, total returns, net returns and benefit-cost ratio as that obtained with the application of N40 P40 along with Azospirillum plus PSB which recorded the highest value.
Open Access
Weed management in cardamom plantations
(Department of Agronomy, College of Horticulture, Vellanikkara, 1996) Sudheesh, M V; KAU; Abraham, C T
A study was conducted during 1995 -96 to develop weed management practices for cardmom at Cardamom Research Station, Pampadumpara under Kerala Agricultural university. A trial was also conducted to evaluate major herbicides in cardamom plantions. Ten major weeds Ageratum conyzoides,Bidens pilosa, Crassocephalam crapioides, synedrella nodiflora, Paspalam conjugatum, Scoporia dulcis, Drymaria cordata, Erigeron Canadensis, Spilanthes calva and Eleusine indica were identified. Survey indicated the dominance of Asteraceae and Gramineae in cardamom tracts of Idukki district. Maximum germination percentage was observed in Bidens pilosa. All the weeds except Bidens pilosa, Scoparia dulcis and Spilanthes calva flowered in May. Rest of the weeds flowered by July and set seeds by the end of September. Maximum seed production and lowest 1000 seed weight was recorded by Scoparia dulcis. Nutrient study revealed the deversion of nutrients to flower heads after flower production. The results of the yield trial to compare efficiency of herbicides revealed the use of paraquat 0.4 kg/ha (bimonthly) or glyphosate 0.8 kg/ha is superior in terms of reducing the weed count, weed dry matter and nutrient removal by weeds from the experimental plots. Except tiller production all the characters, plant height (cm), per cent flowering (%) and yield (Kg/ha) did not differ significantly with treatments. Phytotoxic study revealed paraquat as less toxic than glyphosate. In combination with paraquat, atrazine and diuron residues persisted upto 60 days in the experimental field. More than rupees 6000 can be saved by adopting chemical methods instead of hand weeding.
Open Access
Yield maximisation of direct sown rice under puddled condition
(Department of Agronomy, College of Agriculture, Vellayani, 1996) Sajith Babu, D; KAU; John, P S
An experiment entitled “yield maximisation of direct sown rice under puddled condition” was conducted at Rice Research Station, Moncompu, Kerala Agricultural University, during the additional crop season (Kharif) of 1995 to study the effect of combined use of organic manures and inorganic fertilizers under different plant population for enhancing rice yield in the lowlands of Kuttanad using the variety Pavizham. Factorial combinations of two levels each of organic manure and seed rate and three levels of chemical fertilizers were tried in Randomised Block Design with three replications. Organic manure addition @ 10 t ha -1 was found to have pronounced effect on various growth and yield attributing characters of rice when applied alone and/or in combination with chemical fertilizers at recommended dose of 90: 45: 45 kg NPK ha-1 and at increased seed rate of 133 kg ha -1. At normal seed rate also, organic manuring resulted in higher yields in combination with chemical fertilizers at the higher level of 120: 60: 60 kg NPK ha-1. The available soil N content after harvest was significantly reduced from the content prior to experimentation in all the treatments. The available P status was maintained at the initial level in all the treatments. The efficiency of applied N in terms of grain production/ kg of N applied was greater when organic manures were applied along with inorganic fertilisers. In the absence of organic manure, the apparent recovery of N at normal rates of application was greater than that at higher levels.
Open Access
Agronomic evaluation of biofarming techniques for forage production in coconut gardens
(Department of Agronomy, College of Agriculture, Vellayani, 1996) Sansamma, George; KAU; Raghavan Pillai, G
Two field experiments were conducted at the Instructional Farm, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala State to study the potential of biofarming techniques for forage production in coconut gardens. The study was carried out for a period of two years from September 1993 to August 1995. The influence of the different nutrient management techniques on uptake of nutrients, quality of produce and physico-chemical properties of soil was also investigated. In experiment no.1. the influence of two nitrogen fixing organisms., viz. Azospirillum and Azotobacter and the role of Vesicular Arbuscular Mycorrhiza (VAM) in improving the growth and production of guinea grass and congosignal was studied under inoculation alone and also in combination with chemical fertilizers. The nitrogen fixers were tested under varying levels of fertilizer nitrogen and for VAM the level of phosphorus varied between treatments. The prospects for vermicompost use for guinea grass production was examined under experiment no. 2. It was also envisaged to compare the impact of integrated use of manures and fertilizers with the continuous use of chemical fertilizers alone. Results of experiment no.1 revealed that Azospirillum inoculation alone and in combination with fertilizers had significant positive influence on guinea grass production. Azotobacter inoculation showed only limited effects on growth and yield of the forage grass during the first year but the effect was significant during the second year. The results indicated that 25 per cent of the recommended nitrogen could be saved through the use of either of the biofertilizers. VAM inoculation when combined with full dose of recommended fertilizer nitrogen and potassium, showed significant superiority over the POP treatment at 0, 25 and 50 per cent phosphorus doses while the 75 percent P dose gave comparable yields. The quality parameters of the forage recorded values on par or superior to that of the recommended fertilizer treatment. The use of biofertilizers improved the net income and benefit : cost ratio from guinea grass cultivation. The inoculation treatments were found to have a favourable influence on the physical and chemical properties of the soil. Integrated use of the nitrogen fixing organisms with chemical fertilizers was found effective for Congosignal cultivation. Pooled analysis studies indicated that when inoculated with either Azospirillum or Azotobacter, 50 per cent of the recommended fertilizer nitrogen was adequate for yields. VAM inoculation alone elicited significant yield increase over the absolute control. Combind doses of VAM with chemical fertilizers at all levels of applied phosphorus responded more or less similar to the recommended fertilizer treatment. This indicated the possibility of completely substituting the need for fertilizer phosphorus in VAM inoculated congosignal. The VAM effect in promoting growth and yield of the forage was found to decline in the presence of applied phosphorus. The data on economics also favoured the use of biofertilizers. Experiment no. 2 revealed that guinea grass responded well to integrated use of manures and fertilizers. As per pooled analysis vermicompost @ 5 t ha-1 or Farm yard manure @ 10 t ha-1 when combind with 75 per cent of the recommended NPK were comparable with the 100 per cent NPK treatment. Application of the organic manures improved the quality of the produce. The physic-chemical properties of the soil was also favourably influenced by the integrated use of manures and fertilizers. The economic analysis of the data emphasised the need for reducing the reliance on purchased inputs. Coconut yield was found favourably influenced by intercropping of the fodder grasses.
Open Access
Response of piper longum in coconut gardens to differential spacing and manurial regimes
(Department of Agronomy, College of Horticulture, Vellenikkara, 1996) Sheela, N; KAU; Mercy George
An experiment was conducted during 1994-95 in the KADP farm of the College of Horticulture, Vellanikkara, to evaluate the response of piper longum as an intercrop in coconut gardens to differential spacing and manorial regimes. The experiment was laid out in randomised block design with three replications. The study revealed that plant height, number of branches, number of leaves and total dry matter increased with higher dose of organic manure and 30:30:60 NPK kg ha-1. The optimum spacing was found to be 50 x 50 cm. the above treatment recorded the maximum number of spikes and total dry spike yield (449 kg ha-1). The NPK content of spikes was more than vegetative parts. The nitrogen content decreased as the crop grew but phosphorus content increased and potassium content remained more or less same. The uptake of N,P and K was highest in fertilizer applied plots. The total alkaloid yield was highest in the treatment receiving 50 x50 cm spacing, 20 t ha-1 organic manure and 30:30:60 NPK kg ha-1. The organic and inorganic fertilizers and their combinations did not have any significant effect on the chemical properties of soil. However the plots receiving inorganic fertilizers alone showed a reducing trend in available N, P and K. Thippali cultivation involves high investment for planting material and maintenance and harvesting are also labour intensive. The labour cost in Kerala is very high. It is a crop which requires a periodical harvesting (maximum yield in July –August and October – November months) and care should be taken to harvest only the mature spikes. Thippali being a perennial crop, no net return could be obtained in the first year of planting. The yield level indicated that it should be a profitable crop from the second year of planting.
Open Access
Improving fertiliser use efficiency in sesamum in Onattukara tract
(Department of Agronomy, College of Agriculture, Vellayani, 1996) Regy, V J; KAU; Chandrasekharan, P
An experiment was conducted in the summer rice fallows of the Rice Research station, Kayamkulam during 1995 to study the effect of two levels of nitrogen (22.5, and 30 kg N ha-1) three levels of potassium (0, 22.5 and 30 Kg K2O ha-1) and two methods of application (75 per cent) each of nitrogen and potassium as basal and 25 per cent each of nitrogen and potassium as foliar spray at branching (m1), 50 per cent each of nitrogen and potassium as basal and 50 per cent each of nitrogen and potassium as foliar spray as to equal splits at branching and just before flowering (m2) on the growth, yield, oil and protein content, chemical composition of oil cake, nutrient status of soil after the experiment and economics. The study revealed that nitrogen affected LAI, LAD and NAR, but failed to have any influence on height of the plants, number of branches plant-1, height at which first bearing node formed, RGR, CGR, yield attributing characters, yield and oil content. Test weight, net return, benefit cost ratio, protein content, uptake of nitrogen, phosphorus and potassium at harvest were significantly affected by the applied levels of nitrogen. Nitrogen and phosphorus status of soil after the experiment decreased with higher levels of nitrogen. Higher level of nitrogen resu1 ted in higher nitrogen and phosphorus status of oil cake than lower level of nitrogen. Applied potassium affected most of the growth characters, protein content, oil content, nutrient uptake by the plant at harvest, nutrient status of soil after the experiment, nitrogen and phosphorus content of oil cake, but not the potassium content of oil cake. Oil content increased with increasing levels of potassium from 0 to 30 kg K2O ha-1, but protein content increased only upto 22.5 kg K2O ha-1. Further increase to 30 kg K2O ha-1 decreased the protein content. Methods of application failed to influence most of the growth characters except LAI, LAD,NAR, RGR and CGR. Yield attributes, yield, and quality attributes also had not influence by different methods of application, while nutrient uptake by the plants at harvest, total nitrogen and available potassium status of the soil after the experiment and phosphorous content of oil cake were affected significantly by different methods of application. Interaction between nitrogen and potassium significantly influenced height at first bearing node formed, LAI, LAD, NAR, RGR, CGR, grain yield, net return, benefit cost ratio, oil content, protein content, nutrient uptake by the plants and available potassium status of soil after the experiment, Interaction between nitrogen and methods of application had significantly influenced growth characters, uptake of nutrients and nutrient status of soil after the experiment, Phosphorus content of oil cake was only influenced by different combined application of nitrogen and methods of application.

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