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Kerala Agricultural University, Thrissur
The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively.
Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively.
On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs.
In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc.
During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU).
Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.
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ThesisItem Open Access Production potential of two fodder grasses under different management practices(Department of Agronomy, College of Agriculture, Vellayani, 1986) Raghavan Pillai, G; KAU; Madhavan Nair, K PThesisItem Open Access Effect of NPK on seed progeny and air layers in cashew ( Anacardium occidentale L. )(Department of agronomy, College of Agriculture Vellayani , Trivandrum, 1985) Harishu Kumar, P; KAU; Sreedharan, CAn experiment was conducted to assess the "Ef f e c t of NPK fertilisers on seed orogeny and air layers in cashew at Cashew Seed Farm, Shanmtigodu under Central Plantation Crops Research Institute , Regional Station, f i t c a l 574 24 3, during 1982-84. fhe treatments consisted of test ing three le v e ls each of d,? and K on seed . rogen/ i.,d ai r layers Ln cashcv/. r ’ne study revc ile 1 t h . t d i f f e r en t grov.'th oar meter 7 i. e . , he L'jl'it, can>py rolLus, surf ice area, le a f area n ; : ; v/erc influenced by increasing le v e ls of I:PR. f ■ r t i I i. s e r s . [' r/ ii chlorophyl l , to I; il v.ug ir , le.it v; .ter f-,■ n* , in-: sp e c i f ic le if w ight v;ere influenced by » b ,n v/11 i I e n i t rci' p n 11 one i n c i i iset i , , ., ii c * * . I', i r 1 y i'ii s r: u I: i- c ’ i I i r r - • * * in f l o w e r i n g , numbt l r, f ft mi. t e, _ .m ,lg ,■ I ; -I -,l puilr-h t'< t-i.l il 'hoots WC IX ; i ? V i . r ‘ I i I -■ 1 nr r r 1.0,1 b y f.f r » i I i d L >n . t’rmt j;un ii r‘ rc rn> r ri o nl; inrl acc' u b i ^ ici-1 c o n t e n t , ] Lc if ion . /c r | , 7 0 1 1 0 ' J W l ! " l p l Mut v Jupic an 1 IglTt wctr drrrc ir.ecl due to d M M, ion w,lH. V ipol ic .Llon ( ivour* rl nut md P i p d i ' - 1 , 4-r d W- i n ( k c - T l u 1 n - Leaf N v;as increased by NPIC. Lear ? was increased by p and K appl icat ion v/hile i t was reduced by N appl icat ion. Leaf K was reduced by H appl icat ion while i t was increased by ? and K appl icat ion. N appl ication resul ted in an Increase in le a f C i, where as P and K reduced i t . M and K reduced le a f Mg while P had no e f f e c t . M increased lui f Zn while P reduced the same. K had no e f f e c t . Cr i t ical levels in Ic if for M and ? are f ixed at 2.09% and 0.14% respectively. hoot CSC was increased by UP.' f e r t i 1 is ition . .1 application reduc’d organic carbon and P ‘./hale- i t i.nere -Scd ^>oil M, h and oH. P appl ication increased o i l d, K and pH. ‘V. ipol icat ion incr*. ia«_ , roi l H, h and oH wher>- as i c r c r\ v c c r: o i l P • rj ind P f spons r, r*. curvul in«. ar while not as i u ■ esnonrs v m Jincir. rhc od.imuni of U and P r , pc-j/trr ,./y ai re no-. c t ivt 1 y . M ixvv.um income W L. 1. ' - * * r t ' l i - r r l In lie 1 IV- r r . rThesisItem Open Access Phosphorus management in a rice based cropping system(Department of Agronomy, College of Agriculture, Vellayani, 1989) Annamma, George; KAU; Sasidhar, V KIn order to standardize an appropriate phosphorus management practice in a rice based cropping system involving rice-rice-cowpea/sesamum, field experiments were carried out in the rice fields of the Instructional Farm, College of Agriculture, Vellayani from June 1984 to September 1986. The experiment was laid out in a randomized block design with three replications. There were eight treatments. The treatments comprised of (1) continuous phosphorus application to all the three crops in the system (2) phosphorus application to the first and second crops of rice (3) phosphorus application to the first crop of rice and third crop of cowpea/sesamum (4) phosphorus application to the first crop of rice only (5) phosphorus application to the second crop of rice and third crop of cowpea/sesamum (6) phosphorus application to the second crop of rice only (7) phosphorus application to the third crop of cowpea/sesamum only (8) control plot with no addition of phosphorus to any of the crops in the system. The salient findings of the experiment are as follows: Phosphorus application had no significant influence on grain and straw yield of first crop of rice. But available nitrogen, available and total phosphorus and available potassium of the soil were increased with phosphorus application. Direct, residual and cumulative effects of phosphorus had no significant influence on grain and straw yield of second crop of rice. Phosphorus uptake could not show any variation due to the different treatments. Available and total phosphorus content of the soil were highest under cumulative phosphorus treatment. All the growth and yield attributes of third crop of cowpea and sesamum were increased by the direct and cumulative effects of phosphorus. Grain yield of cowpea was significantly increased by the direct application of phosphorus. Eventhough not significant the highest sesamum yield was accorded by the direct and cumulative application of phosphorus. Phosphorus uptake in all the growth stages of the crop was highest in direct phosphorus plots. Available and total phosphorus content of the soil was highest in continuous phosphorus applied plots. There was no significant influence on grain and straw yield of first crop of rice after cowpea and sesamum in the direct, residual and cumulative effects of phosphorus. Residual phosphorus was sufficient to maintain the available nitrogen status of the soil. Available phosphorus of the soil was increased by the direct, cumulative and continuous application of phosphorus and total phosphorus by continuous application of phosphorus. Balance sheet of available phosphorus revealed that the soil phosphorus level almost maintained, where phosphorus was applied only to the third crop of cowpea or sesamum. The highest net return and benefit-cost ratio for the rice-rice-cowpea and rice-rice-sesamum system was obtained when phosphorus was applied only to the third crop in the rice fallow and the residual effect being utilized by the succeeding rice crops.ThesisItem 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 NProductivity 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.ThesisItem Open Access Ecophysiology and management of Isachne in rice fields of Onattukara(Department of Agronomy, College of Horticulture, Vellanikkara, 1996) Abraham, Varughese; KAU; Tajuddin, EIsachne 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.ThesisItem Open Access Seed production in stylosanthes gracilis under varying levels of population density, nutrition, moisturiser regimes and cuttings(Department of Agronomy, College of Agriculture, Vellayani, 1989) Balachandran Nair, G K; KAU; Sreedharan, CAn investigation was carried out during the period from July 1980 to March 1982 in the Instructional Farm, College of Agriculture, Vellayani to study the agronomic techniques required for maximum seed production in Brazilian lucerne (Stylosanthes gracilis). The following three separate field experiments were conducted and data collected and analysed. The first experiment entitled ‘influence of cultivars and plant population on seed production’ was laid out as a22 Factorial Experiment in R. B. D and replicated five times with the objective to find out the best cultivar of Stylosanthes gracilis for seed production along with the seed rate. The treatments consisted of combinations of two cultivars of Stylosanthes gracilis viz. Schofield and Cook, and two seed rates viz. 2.5 and 5 kg/ha. The second experiment entitled ‘nutritional requirements of Stylosanthes for seed production’ was laid out as a32 Factorial Experiment in R. B. D and replicated thrice with the treatment combinations of three levels of phosphorus viz.80, 120 and 160 kg P2 O5/ha and three levels of lime viz. no lime, 375 and 750 kg lime/ha. The objective was to assess the phosphorus and lime requirement of the crop for maximum seed yield. The third experiment entitled ‘Effect of moisture regimes and cuttings on seed production’ was conducted as a 32 Factorial Experiment in R.B. D and replicated thrice with treatment combinations of three irrigation schedules (IW/CPE ratios) viz. 0.50, 0.75 and 1.00 and three cutting schedules viz. no cutting, one cutting and two cutting. The objective was to investigate the efficiency of irrigation schedules and cuttings on seed yield. The results from the investigation revealed that the variety cook produced significantly higher seed yield of about 64 kg/ha as against 35 kg/ha obtained from the variety schofield. The seed rate of 5 kg/ha gave the higher seed yield of about 56 kg/ha as against the seed yield of about 43 kg/ha under the seed rate of 2.5 kg/ha. The seed yield attributing characters like setting percentage of seeds and number of seeds per plant were maximum for the variety cook. All the growth characters contributed to about 66 per cent of the variation in seed yield. The highest net return per hectare was obtained when the variety schofield was grown under a seed rate of 2.5 kg/ha. Application of phosphorus at 120 kg and lime at 375 kg per hectare gave maximum seed yield of about 80 kg/ha. It was also found that higher levels of phosphorus like 120 or 160 kg/ha helped to increase the setting percentage of seeds. The biometric characters such as spread of plants, number of branches and LAI were significantly influenced by the application of 120 kg phosphorus and 375 kg lime per hectare. The nutrients uptake was also enhanced by the application of phosphorus and lime at the above levels. The growth characters influenced the seed yield by 53 per cent. The economic optimum doses of phosphorus and lime for maximum seed yield were found to be 149 kg and 593 kg per hectare respectively. The highest gross and net returns were obtained from plots treated with phosphorus and lime at 120 kg and 375 kg per hectare respectively. Irrigating the crop at IW/CPE ratio 1.00 gave the maximum seed yield of 89 kg/ha. When the crop was left without cut it produced the highest seed yield of 92 kg/ha. The maximum setting percentage of seeds and leaf production were observed when the crop was irrigated at ratio 1.00 and without cut. The no cutting treatment gave maximum number of seeds per plant. The biometric charaters like height, spread, number of branches and length of branches were all found maximum in treatments where no cutting was given. Maximum water use efficiency for seed production was recorded by the lowest irrigation ratio of 0.50 and also when the crop was left without cut. About 46 per cent of the variation in seed yield was explained by the growth characters. Maximum net return per hectare was obtained when the crop was irrigated at IW/CPE ratio 1.00 and without cut.ThesisItem Open Access Influence of levels of nitrogen, methods of application and plant population on the performance of the high yielding rice variety sabari(Department of Agronomy, College of Agriculture, Vellayani, 1989) Mohamed Kunju, U; KAU; Sadanandan, NAn investigation was undertaken to study the effect of different levels and methods of nitrogen application and different plant populations on the growth, yield and quality of the rice variety sabari in the southern Region of Kerala. The treatments consisted of four levels of nitrogen (40,80,120 and 160 kg/ha), two methods of application of nitrogen (application of the entire dose through soil and 75 per cent through soild plus 25 per cent through foliage) and three levels of spacing viz.10x10cm (100 hills/m2) 10x15 cm (67 hills /m2) and 10x 20 cm (50 hills m2). The experiment was laid out in split-plot design, replicated thrice and conducted for two years at the Instructional Farm, College of Agriculture, Vellayani. Growth characters like plant height, number of tillers per hill, leaf area index and dry matter production at different stages of growth increased with incremental doses of nitrogen. Closer planting resulted in smaller plants and higher number of tillers per unit area. The leaf area index was high in closer planting. Total dry matter production at harvest was more in 10x15 cm spacing. Foliar application of nitrogen (25 per cent) increased the total dry matter production at harvest. Increasing levels of nitrogen delayed flowering. Number of panicles per unit area, length of panicle, weight of panicle, number of spikelets per unit area filled grains per panicle and number of grains per unit area were increased due to incremental levels of nitrogen. Application of the second top dose of nitrogen through foliage produced more number of panicles. It also increased the weight of panicle, number of filled grains per panicle and number of filled grins per unit area. Test weight of grain was more at higher levels of nitrogen. Foliar application also increased the test weight of grain. Maximum yield of grain was recorded at 120 kg/N/ha which was on par with 160 kg N/ha. The average yields of grain at the 40,80,120 and 160 kg N levels were 3149, 3818, 4106 and 4027 kg/ha respectively. Foliar application of the second top dose of nitrogen was superior to soil application in increasing grain yield. Higher grain yield was obtained at 10x15 cm spacing. Quadratic response curve was found to be a suitable fit for nitrogen dose. The overall economic optimum level of nitrogen was 120 kg/ha. It was low (109 kg/ha) at closer spacing and high (124 kg N/ha) at wider spacing. Straw yield was increased with increasing levels of nitrogen application. Foliar application also increased the straw yield. Foliar application of nitrogen resulted in higher grain straw ratio while higher levels of nitrogen decreased the ratio. Increasing doses and foliar method of nitrogen application increased the nitrogen content of plants at flowering and of straw and grain at harvest. Protein content of grain was high at higher levels of nitrogen. It was also increased due to foliar application. The uptakes of nitrogen, phosphorus and potassium were more at higher levels of nitrogen and foliar application. This was not influenced by different spacings. Increasing levels of nitrogen application resulted in only a marginal increase in the residual available nitrogen status of the soil. Residual available phosphorus and potassium in the soil were not appreciably influenced by any of the treatments. Net income and benefit cost ratio were highest at 120 kg N/ha. Foliar application also increased the net income. Among the different spacings 10x15 cm spacing recorded the maximum net income. A combination of 120 kg N/ha of which 25 per cent applied through foliage at the panicle initiation stage with 10x15 cm spacing was found to be the most ideal for maximum benefit from the rice variety sabari under the agroecological situations of the southern Region of Kerala.ThesisItem Open Access Inter-relationship of applied nutrients on growth, productivity and latex flow characteristics of havea brasiliensis muell. arg.(Department of Agronomy, College of Agriculture, Vellayani, 1993) Punnoose, K I; KAU; Sreedharan, CThree field experiments were conducted in three locations representing the major rubber growing regions in South India to study the response to nutrient applications on growth characters, yield and latex flow characteristics and to study the inter-relationship between soil and plant nutrients on yield. It was also envisaged to assess the relative response in the different locations and to make economic analysis of the benefit of manuring. Three levels of 0, 40 and 80 N ha-1, 0, 30 and 60 kg P2O5 ha-1 and 0, 40 and 80 kg k2O ha-1 and two levels of 0 and 10 kg MgO ha-1 were used. A 33 x 2 partially confounded factorial split plot experiment in randomised block design with two replications was followed. The 80 kg level of N and 30 and 40 kg levels respectively of P and K were optimum for girth increment in all the locations. Application of Mg was also beneficial. For virgin bark thickness the 40, 30 and 40 kg levels of N, P and K respectively were sufficient in all the locations and application of Mg was not beneficial. For bark renewal 80 kg N was optimum at Thodupuzha whereas the 40 kg level was sufficient in the other locations. The 60 kg level of P was useful at Kulasekharam and Thodupuzha while 30 kg was sufficient at Balussery. The 40 kg level of K was optimum in all the locations and application of Mg was not beneficial. The 80 kg level of N gave the maximum weight of leaf litter in all places while for P and K the 30 and 40 kg levels respectively were sufficient. Magnesium was beneficial only at Balussery in one year. The 40, 30 and 40 kg levels respectively of N, P and K gave the highest total volume of latex in all the locations except at Balussery where 80 kg K was superior to 40 kg. Application of Mg was beneficial at Balussery while it had a reducing effect at Kulasekharam and no effect at Thodupuzha. Application of N and K reduced the plugging index and that of P and Mg increased it in all the locations. For dry rubber content, the 80 kg level of N was optimum at Kulasekharam while the 40 kg level was sufficient in the other locations. With regard to P and K the 30 and 40 kg levels respectively were sufficient. Application of Mg was beneficial only at Thodupuzha. In the case of yield of rubber 40 kg N and 30 kg P2O5 were found to be optimum in all locations. The 40 kg level of K2O was sufficient at Kulasekharam and Thodupuzha while the 80 kg gave the highest yield at Balussery. At Thodupuzha and Balussery application of Mg was beneficial while at kulasekharam it reduced the yield. Application of N increased the organic carbon content of soil. The available P, K and Mg contents of soil were increased by the application of the respective nutrients. The N, P, K and Mg contents of leaf and latex were increased by application of the respective nutrients. Application of P as rock phosphorus also increased the available Ca content of soil and Ca contents of leaf and latex. The yield of rubber was positively correlated with girth increment, rate of bark renewal, initial flow rate, total volume and dry rubber content of latex and negatively with plugging index. Yield was also positively correlated with the available N, P, K and Ca contents of soil N, K and Ca contents of leaf and P and K contents of latex and negatively correlated with Mg contents of soil and leaf. The strongest correlations with yield were given by soil N, latex P and K and leaf Ca. Total volume of latex was positively correlated with the available N, P, K and Ca contents of soil, N, K and Ca contents of leaf and P and K contents of latex. The dry rubber content of latex was positively correlated with the available N, P and Ca contents of soil, N, K and Ca contents of leaf and N, P, K and Ca contents of latex. The plugging index was positively correlated with the P and Ca contents and negatively with the N and K contents of soil, leaf and latex. Positive correlations, were obtained between soil and leaf nutrients, soil and latex nutrients and leaf and latex nutrients in the case of N, P, K and Ca. In the case of yield of rubber 40 kg N and 30 kg P were found to be optimum in all the locations. The 40 kg level of K was sufficient at Kulasekharam and Thodupuzha while the 80 kg level gave the highest yield at Balussery. Application of Mg was beneficial at Thodupuzha and Balussery while at Kulasekharam it reduced the yield. An overall evaluation of the economic analysis indicated that 40 kg N, 30 kg P2O5 and 40 kg K2O were the optimum doses in all the three locations. Application of Mg was profitable only at Thodupuzha.ThesisItem Open Access Rice based cropping system analysis in kerala(Department of Agronomy, College of Agriculture, Vellayani, 1993) Chidananda Pillai, M R; KAU; Sreedharan, CWith the objectives of identifying the most economic crop combination for the double crop wet rice fields of Kerala and to assess soil fertility changes due to rice based cropping systems and also to find out the residual effects of the summer crops on the succeeding rice crops an investigation was conducted at the R.A.R.S. Pattambi in a split – split plot design, for a period of two years. The salient findings of the investigation are as follows. In the Cassava-rice-rice system 25 per cent saving was recorded for P and K for maximum grain yield of kharif rice than the recommended doses. A saving of 50 per cent each of P and K was recorded for the maximum straw yield than the recommended doses. In cowpea–rice-rice system for maximum grain yield of kharif rice there was a saving of 25 per cent of P and K than recommended doses. The same trend followed for the maximum yield of strew also. In groundnut –rice-rice system, for maximum grain yield of kharif rice there was a saving of 25 per cent of P and K than recommended doses. For the production of maximum straw yield full dose of recommended nutrients were required. In bhindi– rice-rice system for maximum grain yield of kharif rice there was a saving of 50 per cent of P and K than recommended doses. For the production of maximum straw yield full dose of recommended nutrients were essential. In rice-rice-rice system for maximum grain yield a saving of 25 per cent of P and K was recorded than recommended doses. For the production of maximum straw yield full dose of recommended nutrients were required. In fallow-rice-rice system for maximum grain yield full dose of recommended nutrients were essential, whereas for the production of maximum straw yield a saving of 25 per cent of P and K than the full dose was recorded. In cassava, rice and fallow systems for the manifestation of residual effect to the rabi rice, balanced nutrients at high doses are to be applied to the preceding kharif crop where as in the cowpea, groundnut and bhindi systems, residual effects of nutrients are seen manifested to the rabi rice crop even when the kharif rice crop is applied with medium doses of nutrients. There was a trend of slight decrease in the organic carbon content of the soil under all the cropping systems. The status of available nitrogen and potash after one and two year crop sequences also followed the above trend. Regarding the status of phosphorus in the soil, there was a slight increase after one and two year crop sequences. Cassava system produced maximum yield in terms of energy value followed by groundnut. From the economic point of view bhindi system gave the maximum net return. Maximum dry matter production (biomass production potential) was recorded in the cassava system followed by groundnut system. A vegetable crop like bhindi or a tuber crop like cassava seem to be more profitable than growing rice in summer season in the double crop wet rice fields of Kerala, rice being least economic. Among the cropping systems rice-rice-rice system generates maximum employment opportunities for the farm labourers with maximum job opportunities for women labourers as well.
