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ThesisItem Open Access Investigation on allelopathic influence and control of purple nuts edge(Department of Agronomy, College of Agriculture, Vellayani, 1999) Ameena, M; KAU; Sansamma, GeorgeLab and field experiments were conducted at the Instructional farm, College of Agriculture, Vellayani to study the allelopathic influence of Purple nutsedge (Cyperus rotund us L) on important field crops; to investigate the effectiveness of systemic herbicides for control of nutsedge and also to assess the effect of chemical weed control on growth and yield of subsequent field crops. In Ex. no. I, allelopathic influence of purple nutsedge on important field crops like rice, ragi, cowpea, green gram, bitter gourd and bhindi were studied. The treatments comprised of aqueous extracts and blended extracts of fresh and dry plant parts of nutsedge. The results revealed that aqueous extracts of nutsedge inhibited germination of rice, ragi, bitter gourd and bhindi while it had some stimulatory effect on germination of cowpea and green gram. The early growth characters of the field crops were found suppressed by the aqueous extract treatment while the blended extract showed no effect. In general, the dry plant parts showed greater effect than the fresh material. Under Ex.no.Il, field studies were made to investigate the effectiveness of systemic herbicides viz. Glyphosate and 2,4-D for control of nutsedge. The treatments included different doses of the herbicides with and without adjuvants and Glyphosate combined with sublethal dose of 2,4-D. The results revealed that lowest dose of the herbicides were sufficient for complete kill of the purple nutsedge plants in the experimental area and there was no regrowth upto 6 weeks. There was significant reduction in viability of tubers collected one month after herbicide application, but the tubers tested 45 days after spraying showed an increase in germinability over the record on 30th day. Tubers from treatments involving Glyphosate with sublethal dose of 2,4-D recorded the lowest sprouting percentage indicating the possibility for weed control for a longer period. In Ex. no. In, the persistence of the herbicides in soil were monitored and it was observed that early growth of cucumber sown on the same day of herbicide application was affected while that sown on soils collected 10 days after spraying recorded growth characters comparable to that of control. From Ex.no.IV, it could be inferred that chemical weed control did not show any deleterious effect on growth and yield characteristics of ragi and cucumber sown 15 days after the treatments. Application of 2,4-D for nutsedge control was found superior to other treatments in terms of net income and B:C ratio and the lower unit cost of the chemical was precisely the reason for its superiority.ThesisItem Open Access Response of cucumber (Cucumis melo L.) to drip irrigation under varying levels of nitrogen and potash(Department of Agronomy, College of Agriculture, Vellayani, 1997) Lakshmi, S; KAU; Sasidhar, V KTwo field experiments and one observational trial were conducted in the Instructional Farm, College of Agriculture, Vellayani during 1992 and 1993 to study the effect of drip irrigation and application of N and K fertilizers on the growth and yield of cucumber. In the preliminary observation trial (Experiment I a) three levels of drip irrigation, (2, 3 and 4 I plant-1 day-1) four timings of irrigation (1, 2, 3 and 4 hours) and two number of drippers per plant (1 and 2 dripper plant-1) were evaluated and based on the results of this experiment, the number of drippers per plant and duration of drip irrigation was standardised. Experiment 1 b was conducted to standardise the method of application of fertilizers in Experiment 2 and 3 for which cucumber plants raised under different levels of drip irrigation (2, 3 and 4 I plant-1 day-1). This was conducted during April 1992. The results of these experiments indicated the duration for drip irrigation as 3 hours per day and one number of dripper per plant to be the best. The spread and depth of root system of cucumber plants raised under drip irrigation pointed out that the fertilizers as a ring around the base of the plant at a distance of 20 cm will be within the root zone of the plant. The experiments 2 and 3 were laid out in the field with three levels of drip irrigation (2, 3, and 4 I plant-1 day-1), three levels of nitrogen (35, 70 and 105 kg ha-1) with three levels of potassium (25, 50 and 75 kg ha-1) with three drip irrigation controls (2, 3 and 4 I plant-1 day-1) and farmer's practice. The yield of cucumber was highest at the drip irrigation level of 31 planr-1 day-1. Irrigation at this level favourably influenced the vegetative characters, yield attributes and yield. But root dry matter was not influenced by the different drip irrigation level while the root spread and root depth were highest at the drip irrigation level of 41 plant-1 day-1. When different levels of nitrogen applied were observed, the vegetative characters yield attributes and yield were found to be favourably influenced at 70 kg N ha-1. The root spread of cucumber was highest at the highest level of N applied (l05 kg ha-1). Potassium at 50 kg ha-1 produced the highest yield due to its favourable influence on the vegetative and yield characters. There was no influence of potassium on my of the root characters studied. The soil moisture status was highest up to 30 cm depth in all drip irrigated treatments while in pot watered plots, the soil moisture was higher in the lower layers below 30 cm. The field water use efficiency was highest at the drip irrigation level of 3 I plant-1 day-1, 70 kg nitrogen ha-1 and 50 kg potassium ha-1. The nitrogen, phosphorus and potassium uptake by the plants and fruits were highest at the drip irrigation level of 31 plant day I, 70 kg N ha-I and 50 kg K ha-I. The physical optium levels of drip irrigation was 31 plant -1 day -1, 93 kg N ha-1 and 65 kg K ha-1 in the first season. When another crop is repeatedly grown in the same field, the Nand K levels can be reduced to 75 kg ha-1 and 60. kg ha-1 but drip irrigation is required at the rate of 31 plant-1 day-1. This resulted in higher benefit cost ratio of 2.83 and internal rate of returns of 23%. The payback period of this project worked out to 1.13 years.ThesisItem Open Access Soil test crop response studies in cassava in laterite soils of Kerala(Department of Agronomy, College of Agriculture, Vellayani, 1997) Kumari Swadija, O; KAU; Sreedharan, CAn investigation was undertaken at the College of Agriculture, Vellayani to establish soil test crop response correlation for soil test based balanced fertilizer prescription for cassava var. M-4 in laterite soils of Kerala. The field investigation consisted of fertility gradient experiment, STCR experiment and technology verification trial. The fertility gradient experiment was conducted during April- May 1994 in the Instructional farm, Vellayani. The desired gradient in soil fertility was created in one and the same field by applying graded doses of N, P and K fertilizers and raising fodder maize var. African Tall. The STCR experiment was conducted in the same field during June '94-March '95 using the test crop, cassava var. M-4. The treatments consisted of factorial combinations of four levels of N (0, 50, 100 and 150 kg ha-1), three levels of P (0, 50 and 100 kg P2O5 ha-1) and five levels of K (0, 50, 100, 150 and 200 kg K20 ha-1) along with three levels of farmyard manure (0, 6.25 and 12.50 t ha-1) fitted in a response surface design. Using multiple regression model, the fertilizer adjustment equation for N at varying soil test values for available N for maximum tuber yield (t ha-1) of cassava in laterite soil was derived as FN = 136.6 - 0.2 SN where FN is fertilizer N (kg ha-1) and SN is soil available N (kg ha-1). The equation becomes FN = 136.6 - 0.2 SN - R for economic tuber production where R is the ratio of cost of one kg of fertilizer N to price of one kg of tuber. At varying soil test values for organic carbon% (OC) the above equations become FN = 226.13 - 378.13 OC for maximum tuber yield and FN = 226.13 - 378.13 OC - 1.25 R for economic tuber yield. The behaviour of fertilizer P and K was found to produce responses other than 'normal' and hence optimisation could not be done for fertilizer P and K for maximum and economic tuber yield at varying soil test values. The nutrient requirements of cassava var. M-4 were estimated to be 6.58, 2.37 and 6.28 kg N, P2O5 and K2O respectively to produce one ton of tuber. In the laterite soil, the efficiencies of contribution of nutrients from the soil for cassava were calculated as 40.17, 41. 3 3 and 48.60% N, P2O5 and K2O respectively. The fertilizer efficiencies were worked out as 54.38, 47 and 52.650% N, P2O5 and K2O respectively. The efficiencies of contribution of nutrients from farmyard manure were calculated as 78.24, 57.33 and 69.66%) N, P2O5 and K2O respectively. From the above basic data, fertilizer prescription equations for specific yield targets of cassava var. M-4 in the laterite soil were derived as given below. Without FYM FN = 12.10 T - 0.74 SN FP2O5 - 5.04 T - 2.02 SP FK2O = 11.93 T - 1.10 SK With FYM FN = 12.10 T - 0.74 SN - 1.44 ON F P2O5 - 5.04 T - 2.02 SP - 2.79 OP FK2O = 11.93 T - 1.10 SK - 1.58 OK where FN, F P2O5 and FK2O are fertilizer N, P2O5 and K2O respectively in kg ha-1, T is the target of tuber yield in t ha-1, SN, SP and SK are soil available N, P and K in kg ha-1 respectively and ON, OP and OK are quantities of N, P and K supplied through organic manure in kg ha-1 The technology verification trial was undertaken during June '96-March. '97 in the laterite soil in three farmers' fields in Thiruvananthapuram district and also in the Instructional Farm, Vellayani. The treatments consisted of Package of Practices recommendation for fertilizer, fertilizer recommendation by the Soil Testing Laboratory and fertilizer doses for the yield targets of 15, 20 and 25 t ha-1 along with a uniform dose of 6.25 t ha-1 of farmyard manure for all treatments. The fertilizer doses based on targeted yield equations recorded higher tuber yield and net income, benefit cost ratio and net returns per rupee invested over the fertilizer recommendation by the Soil Testing Laboratory and Package of Practices recommendation emphasising the need for site specific recommendation based on soil tests. The yield targets of 15 and 20 t ha-1 recorded more than cent per cent achievement and the yield target of 25 t ha-1 recorded about 90% achievement. Higher tuber yield, benefit cost ratio and net returns per rupee invested could be achieved for the yield target of 20 t ha-1. The fertilizer dose for the yield target of 15 t ha-1 recorded the highest returns per rupee invested on fertilizers. The study has revealed the superiority of fertilizer application based on targeted yield approach over the semi-quantitative approach employed in the soil testing laboratories and generalised state level Package of Practices recommendation for the crop. In this approach, the fertilizer dose can be adjusted in accordance with the specific objective and available resources of the farmer.ThesisItem Open Access Bio farming in vegetables : effect of bio fertilizers in amaranth(Department of Agronomy, College of Agriculture, Vellayani, 1998) Niranjana, N S; KAU; Meerabai, MAn experiment was conducted at the Instruction farm attached to the College of Agriculture, Vellayani, during April - Sept 1996 with objectives of finding out the impact of biofertilizers Arospirillum , AMF and dual inoculation under varying and varied levels of fertilizer on amaranthus. Study also aimed to note the economics of the integrated approach and to identify the best economic combinations which improve yield and quality of amaranth varieties Arun and Kannara local. The study had three controls and two number of replications. The results of the study revealed that yield attributing characters like no: of harvests, yield harvest", marketable yield and dry weight were highest in plots applied with dual inoculation of Azospirillum and AMF with 75 per cent dose of p.op. Azospirillum with 50 per cent POP also gave good results. Both these treatments were on par and was better than our state recommendation. Growth characters viz: Seedling growth rate, plant height, number of leaves per plant, number of branches per plant, LAI were highest. for Azospirillum inoculation at early stages. While AMF inoculation gave notable results at later stages. Physiological parameters namely Biomass, NAR, Root dry weight were significantly improved with dual inoculation and higher dose of chemical fertilizer. Leaf dry weight, RGR and CGR responded most to inoculation with Azospirillum at early stages, while at later stage AMF performed well. Kannara local was superior to 148 Arun at early stages. But Arun performed superior to Kannara local with the progress of time. Stem dry weight was significantly influenced by application of AMF. Vermicompost gave high biomass till 45 DAT. Quality of amaranth improved when biofertilizer was given with higher dose of chemical fertilizer in almost all parameters discussed. Dual inoculation with 75 per cent POP gave maximum content of total mineral and moisture. Ascorbic acid content was highest for the treatment dual inoculation with 25 per cent POP. AMF with 75 per cent POP recorded high protein content, the same bioagent with 50 per cent POP gave lowest content of oxalates. Less fiber flush of amaranth w.as got from plots given Azospirillum + 75 per cent POP. Uptake of major nutrients namely Nand P was influenced by inoculation of Azospirillum along with higher dose of chemical and AMF with lower inorganics respectively. Major nutrient status in the soil after the experiment was more in case N,P,K for dual inoculation, Arospirillum and AMF respectively. Irrespective of biofertilizer higher dose of inorganic gave greater residual amount of nutrients. Dual inoculation with 75 per cent dose and Azospirillum along with 50 per cent dose gave maximum l?:C ratio and net returns. Vermicompost recorded minimum disease score. Lower levels of chemical fertilizers recorded less infection.ThesisItem Open Access Nutrient Status of the soil and plant as influenced by spacing and continued manuring in Coconut(Department of Agronomy, College of Agriculture, Vellayani, 1998) Pratheep, M S; KAU; Purushothaman Nair, NA study was conducted during 1995-96 at Coconut Research Station, Balaramapuram of Kerala Agricultural University to asses the nutrient status of . the soil and plant in West Coast Tall coconuts planted at three different spacings and manured with three levels of macro nutrients. The treatments were three spacings (5 m x 5 m, 7.5 m x 7.5 m and 10 m x 10 m) and three fertilizer levels (control i.e., zero NPK, the lower level i.e., 340 g N + 225 g P205 + 450 g K20 per palm per year and the higher level i.e., 680 g N + 450 g P205 + 900 g K20 per palm per year). The basic experiment was started in 1964 and being continued. The data collected during the study (1995-96) was statistically analysed and the results are presented here under. Closer spacing increased height of palms. The spacings of7.5 m x 7.5 m was statistically superior since it gave the highest nut yield per palm per year. Manuring increased height of palms, girth and leaf production. At the highest level of NPK closer spacing of 5 m x 5 m could give the highest yield per unit area. Female flower production was higher under 7.5 m x 7.5 m spacing. Fertilizer application also increased flower production. Fruit setting was not influenced by palm density and fertilizer application significantly increased fruit setting. Number of nuts per bunch was higher at the spacing of 7.5 m x 7.5 m and progressively increased with manuring. The weight and volume of unhusked nut was the lowest at the closest spacing and in unfertilized palms. There was increase in weight of husk with increase in spacing. Similarly there was an increase in the ratio of weight of husk to unhusked nut with increasing spacing. Maximum thickness and weight of kernal was recorded at the spacing of 7.5 m x 7.5 m. Copra out turn was more at the spacing of 7.5 m x 7.5 m. In manured palms there was a higher copra out turn per hectare contributed by the higher yield. The oil content of copra was negatively correlated with per palm yield. Available NPK of soil decrease with wider spacing. The soil nutrient status increased with application of macronutrients and the accumulation of fertilizer was more in the upper layer of 0 to 25 cm. There was decline in NPK status with increase in depth. The Ca and Mg content of soil decreased with increase in spacing up to 7.5 m x 7.5 m. Both Ca and Mg content of soil decreased with increase in macro nutrient application. Ca content of soil decreased with increase in depth. However, the decrease of Mg content was seen only up to 50 cm depth. Available micro nutrients (Fe, Cu, Mn and Zn) decreased with increase in spacing and application of fertilizers. Available Fe, Cu and Mn content of soil decreased with increase in depth. Nand P content of leaf of coconut increased with wider spacing. However K content decreased with spacing. All the three macro nutrients increased with increase in fertilizer application. Ca and Mg content of leaf also increased with increase in spacing and fertilizer application. By fertilizer application Fe, Mn and Cu content of leaf increased whereas Zn and Na decreased.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 Yield maximisation of banana through organic and inorganic manuring(Department of Agronomy, College of Agriculture, Vellayani, 1998) Baiju, B R; KAU; Shahul Hameed, S M. An experiment was conducted at the Instructional farm attached to College of Agriculture, Vellayani during January 1995 to November 1995 with the objective of finding out the different sources of organic and inorganic nutrients for increasing the productivity of Nendran banana, the effect of post shooting application of urea and growth regulators on the bunch weight and to work out the benefit cost ratio by the integrated use of organic and inorganic fertilizers. Four levels of manures and three levels of post shooting treatments were tried in RBD with 3 replications. The results of the study revealed that application of poultry manure at the rate of five kg plant-1 increased total crop duration. Farm yard manure at the rate of 10 kg plant-1 and 2,4-D 10 ppm spray recorded maximum height at all stages. Bunch yield was maximum of (11.39 kg) with poultry manure at 5 kg plant-1, Highest bunch weight was recorded by 2,4-D 10 ppm spray and total number of fingers with urea 1 per cent spray. Among the ripe fruit characters, highest pulp / peel ratio was with poultry manure at the rate of five kg plant-1 even though higher finger weight, pulp weight and lower peel weight were recorded with poultry manure at the rate of five kg plant-1. Application of urea one per cent spray increased weight of finger. Among the quality attributes, higher values for TSS were noticed with level M1. Lowest value for acidity was observed for five kg poultry manure and tying urea 15 g. Total sugar was high with 10 kg farm yard manure and 2,4-D 10 ppm spray and non reducing sugar was high with level farm yard manure at 10 kg plant-1. Sugar-acid ratio was low for vermicompost at the rate of five kg plant-1. Sensory evaluation revealed that all treatments produced fruits with similar taste, flavour and colour. N content of index leaf showed significant variation at harvest with maximum value recorded with neem cake at the rate of five kg plant-1. P content of leaf was maximum with level neem cake five kg plant-1 and minimum with level farm yard manure 10 kg plant-1. The K content of leaf was maximum with neem cake level five kg plant-1 among manurial treatment. When the economics of production was worked out, it was observed that a combination of farm yard manure at 10 kg plant-1 and 2,4-D 10 ppm spray (M1P1) recorded the highest benefit cost ratio. The highest net profit of Rs. 1,49,045 was realised per hectare in farm yard manure at 10 kg plant-1 and 2,4-D 10 ppm spray. The present study revealed that application of poultry manure at five kg plant-1 and 2,4-D 10 ppm spray was beneficial for better growth, yield and quality of fruit in 'Nendran' banana.ThesisItem Open Access Standradisation of organic and inorganic fertiliser comnbinations for maximising productivity in bitter gourd (Momordica Charantia L.)(Department of Agronomy, College of Agriculture, Vellayani, 1999) Rajasree, G; KAU; Raghavan Pillai, GAn investigation was carried out during 1995-96 and 1996-97 at the Instructional Farm attached to College of Agriculture, Vellayani to study the efficacy of different levels of N applications (200, 250 and 300 kg N ha") in different ratios of organic - chemical N substitutions (l : 1, 1:2 or 2: 1) at different frequencies (F I - full quantity of organic source as basal, F2 - organic source at basal and at 40th and 70th DAS, F3 - organic source as basal + fortnightly equal splits and chemical N source as basal + fortnightly intervals in equal splits in all the frequencies) of application. Two different organic sources ie. farm yard manure and poultry manure were used in two simultaneous experiments viz. Experiment I and 11. The experiments were separately and simultaneously laid out as confounded 33 design in 9 plot blocks with 2 replications, confounding LR2F in RI and LRF2 in R 11. Higher levels ofN nutrition was found to reduce days taken to flower in farm yard manure applied trial while sex ratio was narrowed at 90 DAS in poultry manure applied experiment. Higher jassid population was noticed at 60 DAS when higher levels ofN was supplied predominantly through organic source as farm yard manure. Fungal leaf spot infestation was higher with the application of200 kg N at 90 DAS and was also more with split applications of both farm yard manure and chemical N source at early stages of growth. Full basal application of poultry manure was found to promote the per hectare yield of fruits, fruit yield planr I and number of fruits planr I compared to its split applications. When highest level ofN (300 kg) was supplied through 2: 1 ratio of organic - chemical N substitution using poultry manure as organic source, it effectively increased the fruit yield and number of fruits plant". 2 Shelf life of fruits at room temperature was more when nutrient N was supplied through 2: 1 ratio of organic - chemical N substitution using farm yard manure or poultry manure as an organic source. When N level was increased beyond 200 kg, shelf life of fruits at room temperature slightly decreased even when it was predominantly supplied through organic source of farm yard manure or poultry manure. Similar trend was noticed at refiigeratory condition too. Nitrogen nutrition showed depressing effect on ascorbic acid or vitamin-C content of fruits in Experiment I. Iron content in fruits was more with the application of 200 or 300 kg N level in Experiment ll. When 300 kg N was applied through a major source of poultry manure (2: 1 ratio) it produced higher iron content in fruits. Higher nitrogen levels or nitrogen nutrition through 2: 1 ratio of substitution promoted the soil bacterial population in both Experiment I and II. Full basal application of farm yard manure or poultry manure favourably influenced the soil bacterial population. Nitrogen nutrition showed depressing effect on fungal population of soil in Experiment I while it stimulated the fungal growth in Experiment 11. Soil actinomycetes population was higher with 2: 1 substitution ratio using farm yard manure as organic source ofN. When farm yard manure or poultry manure as organic source was used in equal or higher proportion with chemical N source, it showed moderating effect on the soil acidity. Full basal application of farm yard manure also enhanced the soil pH from the acidic range and the organic carbon content. Application of higher levels ofN increased the net loss ofN, P and K of soil in both the Experiment I and H. Net loss ofN was higher with 1:2 ratio ofN substitution or few or more split applications of organic source (farm yard manure) in Experiment 1. Net loss of nutrients was moderated during the second year of field experimentation. Nitrogen 3 nutrition in 1:2 ratio of substitution enhanced the net loss ofN in Experiment H. Nitrogen nutrition through 2: 1 ratio ofN substitution or basal + 2 split doses of farm yard manure increased the net loss of P in soil. The net loss of K in soil was more when farm yard manure and chemical N sources were applied in 2: 1 or 1: 1 ratio of substitution. Net gain of K was observed in Experiment H, when chemical N source was substituted in higher proportion compared to poultry manure or when full dose of poultry manure was applied as basal dressing. Higher levels ofN application have resulted in negative net energy returns or energy loss in both the experiments. The 1: 1 or 1 :2 ratio ofN substitution caused higher net energy losses in Experiment I while split applications of poultry manure resulted in more energy loss in Experiment H. Total energy output was higher with full basal application of poultry manure in Experiment I. Energy ratios registered a negative value and was higher with low level ofN application in Experiment I and II. Higher gross returns were obtained when full quantity of poultry manure was applied as basal dose in Experiment 11. Application of300 kg N through 2: 1 ratio of organic- chemical N substitution registered higher gross returns in Experiment II. Net returns was higher when 200 kg N ha! was applied. Increasing N level beyond 200 kg was not economic in Experiment I using farm yard manure as organic source. When full quantity of poultry manure was applied completely as basal dose, higher net returns was obtained in Experiment H. Benefit-cost ratio decreased when N level was enhanced beyond 200 kg ha' in Experiment I. Higher benefit - cost ratio was recorded when poultry manure was applied in full dose as basal dressing. Study revealed the favourable influence of organic sources; farm yard manure and poultry manure on fruit quality, shelf life and soil properties. The suitability of poultry manure as organic source for vegetable cultivation was also established by this study.ThesisItem Open Access Nutrient management for yield improvement of transplanted rice in the southern region of Kerala(Department of Agronomy, College of Agriculture, Vellayani, 1999) Sudha, B; KAU; Chandini SAn experiment entitled "Nutrient management for yield improvement of transplanted rice (Oryza sativa L.) in the southern region of Kerala" was conducted at Cropping Systems Research Centre (CSRC) Karamana, during the kharif season of 1998 to study the efficacy of organic manures in conjunction with varying levels of NPK nutrients and sulphur in enhancing rice yield using the variety Kanchana. The experiment was laid out in 33 partially confounded factorial RBD with two replications. Combinations of three levels each of organic manures (M), inorganic NPK fertilizers (F) and sulphur (S) constituted the treatments. FYM @ 5 and lOt ha-l as well as vermicompost @ 5 t ha-l included the different manure levels. The normal NPK rates of 70 : 35 : 35 kg ha-l and enhanced rates of 87.5 : 43.75 : 43.75 and 105 : 52.5 : 52.5 kg ha-l were the three fertilizer levels. The different S levels were no sulphur, S @ 12.5 and 25 kg ha-1 Higher order interactions of MFS and M2FS were confounded in Rep I and Rep 11 respectively. Results of the field experiment revealed that the main effects of organic manures, chemical fertilizers and sulphur as well as their combinations exerted significant positive influence on most of the growth and yield attributing characters of rice. The higher NPK levels upto 105 : 52.5 : 52.5 kg ha-l and S levels of 25 kg ha-l were found significantly superior to lower levels. Organic manuring with FYM @ 10 t ha-1 and vermicompost @ 5 t ha-1 were found to be equally good in influencing growth and yield of rice. The available NPK status of soil after the experiment was maintained well above the initial status. The available sulphur status of soil was found to be considerably reduced in treatments which didn't receive sulphur addition. FYM levels recorded better benefit : cost ratio over verrnicompost addition. Increase in NPK levels upto 105 : 52.5 52.5 kg ha-l and sulphur addition @ 12.5 kg ha-l was found profitable. The combination of 5 t ha-l FYM along with the highest NPK level of 105 : 52.5 : 52.5 kg ha-I and S @ 25 kg ha-I recorded the highest B : C ratio, but this was comparable to that obtained with the combined effect of 5 t ha-l FYM, NPK @ 87.5 : 43.75 : 43.75 and S @ 12.5 kg ha-I.
