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ThesisItem Open Access Combined application of granular preparations of pre-emergent herbicides and fertilizers in rice(Department of Agronomy, College of Horticulture, Vellanikkara, 1995) Bindu, N K; KAU; John, P SA field experiment was conducted at the Agricultural Research Station, Mannuthy under the Kerala Agricultural University during the first crop season of 1994 to find out the effect of pre-emergent herbicides and fertilizers in rice. The experiment was laid out in a randomized block design and consisted of fourteen treatments with three replications. Broadleaved weeds and sedges dominated the field. Among broadleaved weeds, Mono choria vaginalis and sphenocleazeylanica were predomint. Shoenoplectus lateriflorus and Cyperus difformis were the prominent sedges present in the field and Echinochloa colonum,saccolepis interrrupta and Isachne miliacea were the important grasses present. Butachlor, anilofos and oxyflourfen under different methods of application reduced the weed Population. Though oxyflourfen recorded high weed control efficiency, it was highly phytotoxic to the rice crop and resulted in poor crop stand. Butachlor and anilofos applied as homemade granular (GP) preparation or as spray alone, or in combination with fertilizer was safe to the crop. The available nutrient in the soil was not affected by the different methods of application of butachlor and anilofos, alone or when combined with fertilizer. Butachlor and anilofos as spray or as GP applied alone, or in combination with fertilizer recorded similar crop growth characteristics, yield and yield attributes. Nutrient up taken by weeds was lower in butachlor and anilofos treatment. Lower weed index values were recorded in butachlor and anilofos treatment. The highest return per rupee was obtained from anilofos treatments. The highest return per rupees was obtained from anilofos treatments. In general, combined application of anilofos or butachlor GP with fertilizer gave efficient control of weed, produced higher grain yields and high return per rupee invested. It also reduced cost, energy and time of weed control operation.ThesisItem Open Access Development of subsurface pad irrigation system for tomato(Department of Agronomy, College of Agriculture, Vellayani, 1995) Abdul Nassar, K; KAU; Jaikumaran, UAn experiment was conducted in the summer rice fallows of the Agricultural Research Station, Mannuthy during 1995 to develop and test subsurface pad irrigation system for tomato and to compare it with surface irrigation. The soil was sandy clay loam, medium in organic carbon and available potassium and high in available phosphorus. The eight treatments comprised of combination of four frequencies of irrigation (IW/CPE ratios of 1.2, 0.9, 0.6 and 0.3) and two irrigation systems (subsurface pad irrigation and surface irrigation). The experiment was laid out in randomized block design with three replications. Poly bags filled with saw dust placed 45 cm beneath the surface at the frequency of one pad for every four plants formed SSPI. Water was supplied to pads by laterals supplying 40 mm of water per irrigation. The study revealed that tomato responded very well to irrigation. Biometric characters like plant height, number of leaves and leaf area index and yield attributing characters like number of flowers, number of fruits and total weight of fruits per plant were favourably influenced by frequent irrigation under both the systems of irrigation. The fruit yield increased with frequency of irrigation and maximum at the IW/CPE ratio of 1.2. The plants irrigated by surface method grew taller, had more leaf area index, produced more number of green leaves, flowers, fruits and total fruit weight per plant compared to the plants irrigated under SSPI system at the irrigation frequencies of IW/CPE ratios 1.2, 0.9, and 0.6. But at the IW/CPE ratio of 0.3, the subsurface irrigated plants performed better than the surface irrigated plants both in terms of growth and yield attributing characters. The crop receiving irrigations through SSPI systems consumed lesser amount of water at all the frequencies of irrigation compared to surface method. This decline at the IW/CPE ratios of 1.2, 0.9, 0.6 and 0.3 were to the tune of 22,30,40 and 18 per cent respectively. The soil moisture extraction from 0-15, 15-30 and 30-60 cm layers in SSPI was 62-70, 24-29 and 6-12 per cent respectively whereas in surface irrigation the respective values were 62-64, 22-23 and 13-15 per cent. The soil moisture redistribution was rapid in the case of surface irrigation whereas it was gradual in the case of SSPI. Moisture content in the case of SSPI was maximum at the radial distance of 15 cm from the pad on either sides whereas in surface irrigation there was no remarkable difference in the moisture content with respect to radial distance from the plant.ThesisItem Open Access Effectiveness and crop seletivity of pre-emergence herbicides under different methods of application in puddled rice(Department of Agronomy, College of Horticulture, Vellanikkara, 1995) Mohan Kumar, P D; KAU; Savithri, K EA field experiment was conducted at the Agricultural Research Station, Mannuthy under the Kerala Agricultural University during the second crop season of 1992-93 to find out the effectiveness and crop selectivity of pre-emergence herbicides under different methods of application in puddled rice. Twelve treatments were com- pared with two controls (hand weeded and unweeded). The experiment was laid out in Randomised Block Design with three replications. Sedges and broadleaved weeds dominated the weed flora. Among the sedges, Schoenoplectus lateriflorus, Cyperus iria, C. difformis and Fimbristylis miliacea were the prominent species, and the broadleaved weeds included Mono- choria vaginalis, Marsilia quadrifoliata, Sphenochlea zeylanica and Nymphaea nouchali. The broad leaved weeds were effectively controlled by pretilachlor + safener, oxyflourfen and pendimethalin, besides butachlor and thiobencarb. All the herbicides except pendimethalin and anilofos gave good control of sedges. Oxyflour- fen spray showed the highest weed control efficiency among the herbicides tested. Sand mixed broadcasting of herbicides was found to be lesser toxic than spray in all the herbicides except pretilachlor + safener, where the safener present protected the crop completely from phytotoxicity. Crop growth characteristics were highly influenced by the herbicide and method of application. Pretilachlor + safener, oxyflourfen and thiobencarb were found superior. Yield attributes were relatively unaffected by the different treatments. Pretilachlor + safener spray recorded the highest yield, among herbicides. Sand mixed broadcasting of all other herbicides produced a slightly higher grain yield compared to spray. Nutrient uptake by crop was directly related to the dry matter accumula- tion. The lowest weed index value was registered by pretilachlor + safener spray. Pretilachlor + safener spray recorded the highest total returns and its sand mixed broadcast realised the highest return per rupee invested on weed control.ThesisItem Open Access Dynamics of the absorption of forms of N by crops plants(Department of Agronomy, College of Horticulture, Vellanikkara, 1995) Retheesh, P K; KAU; Balachandran, P VAn investigation was conducted at the Radiotracer Laboratory, College of Horticulture, Vellanikkara in the year, 1993 which consisted of two parts. In the first part absorption of different forms of nitrogen relative to its concentrations at different growth stages of rice was studied using labelled and non-labelled fertilizers. To know the molecular absorption of urea 14C-labelled urea fertilizer was used and the presence of 14C in the plant was taken as an evidence for the absorption of molecular form of urea. In the case of ammoniacal and nitrate forms of N, 15N-labelled and non-labelled materials were used alternately to find out the preferential absorption. In the second part of the investigation an attempt was made to know the possibility of molecular absorption of urea by a few selected plantation crops. The uptake of N and dry matter production were higher when rice plants were supplied with a combination of ammonium and nitrate in equal proportions. Among the three forms of nitrogen supplied at different combinations, nitrate N recorded the highest uptake when present along with urea N or ammoniacal N or both. Though the presence of urea had a repressing effect on the uptake of nitrate, ammonium enhanced the nitrate uptake. The uptake of nitrate N was more in the presence of ammonium than in its absence. With respect to ammonium uptake it was found that urea and nitrate had more or less similar influence on it. It was seen that rice plants absorbed molecular form of urea even in the presence of other readily available forms of nitrogen. The molecular absorption of urea by rice plants was found to vary from 12-18 percentage of the total N uptake. When urea was supplied along with ammonium and or nitrate the uptake of urea was found reduced. The quantity of urea absorbed by the plantation crops was found negligible and ranged from 0.5-3.3 µg per g of the plant dry weight.ThesisItem Open Access Agronomic evaluation of chemical and bio-agents on phosphorus dynamics in red loam soils of southern Kerala(Department of Agronomy, College of Agriculture, Vellayani, 1995) Viswambharan, K; KAU; Sasidhar, V KThree field experiments were conducted at the Instructional Farm, College of Agriculture, Vellayani during 1992-'93 for two season to study the effect of chemical and bio-agents on phosphorus dynamics in the red loam soils of Southern Kerala. In the experiment No.1 four treatments such as no anions, hydroxide, carbonate and silicate were tested under three levels of phosphorus such as no phosphorus, 50% phosphorus and 100% phosphorus. From the study, it was revealed that carbonates have more desorbing power for phosphorus than the other anions tested. These were reflected in the yield and yield attributes, available phosphorus content of the soil, soil phosphorus fractions, nitrogen and phosphorus uptake of plants. Among the combinations, carbonate anion with 50% phosphorus gave the highest yield. In the experiment No.2, three treatments such as no chelates, EDTA and DTPA were tested with three levels of phosphorus such as no phosphorus, 50 % phosphorus and 100% phosphorus. From the study it has been revealed that EDTA gave better response than other chelates tested. These were reflected in the yield, yield attributes, available phosphorus content of the soil, soil phosphorus fraction, nitrogen and phosphorus uptake of plants. Among the combinations EDTA with 50% phosphorus gave the highest yield. In the experiment No.3, four levels of microbial agents such as no microbes, VAM, PB and VAM + PB were tested with three levels of phosphorus such as no phosphorus. 50% phosphorus and 100% phosphorus. From the study it has been revealed that VAM + PB gave the highest response. This was reflected in the yield attributes, available phosphorus content of the soil, soil phosphorus fractions, nitrogen and phosphorus uptake of plants. Among the combinations VAM+PB with 50% phosphorus gave the highest yield.ThesisItem Open Access Biomass production of green manure crops and mineralization of organic nitrogen in coconut basins(Department of Agronomy, College of Horticulture, Vellanikkara, 1995) Tanie Thomas; KAU; John, P SAn investigation on biomass accumulation of green manure crops and mineralization of organic nitrogen in coconut basins was conducted at the College of Horticulture, Vellanikkara during 1993-94. The experiment was aimed at evaluating the performance of various green manures and cover crops grown in coconut basins based on their biomass accumulation, nutrient accretion and nitrogen dynamics in the soil after incorporation. The mineralization pattern of green manure in red and laterite soils was studied in a laboratory incubation study using 15N labelled green manure. The salient results of the investigation are abstracted below. Crotolaria striata which represented the neglected green manures and pueraria phaseoloides which represented the cover crops produces the maximum dry matter in coconut basins. The popular green manure Crotolaria junecea failed to grew and put forth good biomass accumulation under coconut. The highest N content was found to be with Pueraria. Cassia tora was found to be the richest source of P. The maximum K content was reported in Cassia tora and Sesbania aculeata. Pueraria phaseoloides and Crotolaria striata released the maximum quality of nitrogen to the soil. The ammonium-N accumulation was found to be high in the upper layer of 0 to 15 cm soil when compared to the 0 to 30 cm soil layer. Crotolaria striata and Pueraria released the highest amounts of ammonium-N. In the release of nitrate-N, Pueraria was found to be the most efficient closely followed by Crotolaria striata. In the case of total mineral N (ammonium+nitrate) content the highest quantity was extracted with Crotolaria striata followed by Pueraria. In the incubation experiment to study the pattern of mineralization green manure N, the N release in terms of 15NH4 extracted during different periods of incubation was the highest for Crotolaria striata followed by Sesbania aculeata. The mineralization of green manure 15N took place at a lower rate in laterite soil when compared to red soil.ThesisItem Open Access Evaluation of joint formulation of anilofos and 2,4-dee for the control of weeds in dry -Sown rice(Department of Agronomy, College of Horticulture, Vellanikkara, 1995) Jijimol Kurian, P; KAU; Sreedevi, PAn experiment was conducted at the Agricultural Research Station, Mannuthy during the crop season of 1993 and 1994 to evaluate the joint formulation of anilofos (aniloguard) and 2,4-DEE for the control of weeds in dry-sown rice. The treatments included joint formulation of anilofos and 2,4-DEE (0.3 and 0.45 kg a.i./ha), anilofos (0.3 and 0.45 kg a.i./ha), 2,4 DEE (0.4 and 0.6kg a.i./ha), butachlor (1.25 kg a.i./ha). Unweeded and hand weeded control were included weeded control were included for comparison. The experiment was laid out in split splot desigh, replicated thrice. The main weed species found during the first year were Cynodon dactylon, Digitaris sanguinalis, Eleusine indica, Cyperus rotundus, Cyperus iria, Cleome viscosa and Ageratum conyzoides. In the second year Isachne miliaceae, Saccolepis interrupta, Echinochloa colona, Fimbrystylis miliaceae and Cyperus iria predominated. The population of grasses were reduced by the application of butachlor @ 1.25 kg a.i./ha at 3 DAS and joint formulation of anilofos and 2,4-DEE @ 0.45 kg a.i./ha at 9 DAS. The same treatments were equally effective in loweing the number of sedges and broadleaved weeds. With respect to weed control efficiency hand weeding was superior to the herbicides during the first year. However during the second year joint formulation of anilofos and 2,4-DEE recorded the highest weed control efficiency followed by hand weeding. No severe phytotoxic symptoms and loss were observed consequent to the application of the herbicides. Tank mix application of anilofos and 2,4-DEE recorded the highest number of tillers/m2. Joint formulation of anilofos and 2,4-DEE @ 0.45 kg a.i./ha recorded the highest dry matter production by the crop. Yield attributing characters and yield were higher in plots with joint formulation of anilofos and 2,4-DEE @ 0.45 kg a.i./ha at 9 DAS. The same treatment was more economical over other hericides in terms of total returns and benefit cost ratio.ThesisItem Open Access Yield, quality and vigour of bhindi seed as influenced by number of harvests and nutrient sources(Department of Agronomy, College of Agriculture, Vellayani, 1995) Sheeba Rebecca, Issac; KAU; Pushpakumari, RAn experiment was conducted at the College of Agriculture, Vellayani to study the influence of vegetable harvests and nitrogen sources on the seed yield and quality in hbindi. The treatments consisted of combinations of four different number of vegetable harvests (0, 2, 4, 6) and four sources (12 t FYM + 110:37:74 kg N, P2o5 and K2o ha-1, 12 t FYM + 3.6 t poultry manure, 12 t FYM + 11 t vermicompost and 6 t FYM + 110:37:74 kg N, P2o5 and K2o ha-1. The results revealed that growth characters of bhindi crop were not significantly influenced vegetable harvests except for the height 90 DAS. Frequent picking of green fruits in bhidndi improved the bearing capacity of the plant but the mature fruit yield, seed yield and quality were significantly reduced. Highest seed yield was observed with zero vegetable harvest bur was on par with two vegetable harvests. Among the seed characters, germination percentage, 1000 seed weight, 100 seed volume, seed protein and seed moisture content were not significantly influenced by the vegetable harvests while seedling root and shoot length and vigour index values were better for two vegetable harvest treatments. This treatment apart from a good yield of quality seeds, yielded some vegetable also. The effect of the sources of nitrogen on the germination percentage, seedling root and shoot length and vigour index was not significant while mother crop growth parameters, mature fruit yield and seed yield were significantly high when organic manures were used in conjuction with chemical fertilisers. Farm yard manure at 12 or 6 t coupled with chemical fertilisers gave statistically similar results with regard to the seed yield and quality. Considering the economics, better profits could always be realised when FYM was applied along with chemical fertilisers without any vegetable harvest but, for a satisfactory yield of quality seed and some vegetable, this source should be combined with two vegetable harvests.ThesisItem Open Access Effect of biofertilizers on the growth, yield and nitrogen economy of sesame grown in summer rice fallows(Department of Agronomy, College of Horticulture, Vellanikkara, 1995) Indu, K Paul; KAU; Savithri, K EA field experiment was conducted in the rice fallows of Agricultural Research Station, Mannuthy, during the summer season (January – April) of 1995, to find out the effectiveness of biofertilizers on the growth, yield and N economy of sesame. The experiment was laid out in randomised block design with 1.4 treatments replicated thrice. The treatments included were, the recommended dose of inorganic N,@30 kg/ha alone, inoculation of Azospirillum or Azotobacter along with 50 percent, 25 percent or no inorganic N, either with or without lime and an absolute control. Most of the growth characters, yield attributes and yield were highest in the plots applied with the recommended dose of 30 kg inorganic N/ha alone. The crop nutrient uptake and available soil nutrients were also higher in the above treatment. The better initial physical, chemical and biological conditions of the soil, along with the added inorganic N fertilizer @30 kg/ha might have contributed to a better nutrient supply from the initial growth period itself. Though, both the microbes, Azospirillum and Azotobacter showed almost similar performances regarding various parameters, a slightly better response was shown by Azospirillum in most cases. This might be due to the fact that Azospirillum is a better root colonizer than the freeliving Azotobacter, which led to better nutrient uptake and ultimately yield of the crop, compared to Azotobacter inoculated treatments. Lime application, along with the inoculation of acid tolerant strains of the microbes, had no profound influence on the parameters studied. Thus, the study revealed the necessity of the application of recommended dose of inorganic N fertilizer @30 kg/ha for sesame grown in summer rice fallows. It also showed the lesser possibility of inorganic N substitution with Azospirillum or Azotobacter inoculation in such a situation. Moreover, liming could not bring about any significant influence on the activity of acid tolerant strains of either Azospirillum on Azotobacter.
