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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 S
A 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.
Open Access
Development of subsurface pad irrigation system for tomato
(Department of Agronomy, College of Agriculture, Vellayani, 1995) Abdul Nassar, K; KAU; Jaikumaran, U
An 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.
Open Access
Enhancing the Nitrogen Use Efficiency in Bhindi With Nitrification Inhibitors
(Department of Agronomy, College of Agriculture, Vellayani, 1994) Bindu Kurup, S; KAU; Pushpakumary, R
An experiment was conducted at the Instructional Farm, College of Agriculture, Vellayani inorder to find out the effect of nitrification inhibitors in enhancing the nitrogen use efficiency in bhindi. The treatments consisted of four levels of nitrogen viz., 50 kg ha-1, 100 kg ha-1, 200 kg ha-1 and 300 kg ha-1 and three nitrification inhibitors viz., urea, neem cake and mahua cake. Phosphorus and potassium were applied as per package of practices recommendation. The results revealed that nitrogen levels significantly influenced most of the growth and yield contributing characters, yield of bhindi, uptake of nutrients and available nutrient status of soil. Biometric observations like number of leaves, branches, root spread, DMP, LAI, RGR, NAR and CGR increased with increasing levels of nitrogen and the maximum was produced by the highest levels of nitrogen (300 kg ha-1). F1 produced the maximum height and F2 the longest tap root. Time of 50 per cent flowering and number of flowers per plant was maximum with the highest levels of nitrogen (F4). Whereas other yield contributing characters like number of fruits per plant, percentage of fruit set, length and girth of fruit, fruit yield per plant and total yield of bhindi was maximum with F2 (100 kg N ha-1 ). Quality aspects like crude protein and ascorbic acid content of fruits, uptake of nutrients by plant and fruit as also maximum with the highest levels of nitrogen (F4). However, the height of the first bearing node and chlorophyll content of leaves remain unchanged with increasing levels of nitrogen. The optimum level of nitrogen to get maximum fruit yield and net profit was worked out as 142 kg N ha-1 . Nitrification inhibitors caused significant variation in some of the characters like root spread, LAI RGR, NAR, CGR, number of flowers and fruits per plant, percentage of fruit set, length and girth of fruit, crude protein content and ascorbic acid content of fruit, uptake of nutrients by plant and fruit and available nutrient status of soil. In all these cases neem cake blended urea recorded the highest value followed by mahua cake blended urea. From the economic point of view, the maximum net profit of Rs. 11787.74 was obtained for neem cake blended urea and among nitrogen levels, 100 kg N ha-1 recorded the highest net profit of Rs. 16017.50. Thus neem cake blended urea at 100 kg N ha-1 can be suggested as the best economic dose of nitrogen for getting maximum yield and net profit.
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 E
A 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.
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 V
An 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.
Open Access
Utilization of phosphorus from green manure by rice
(Department of Agronomy, College of Horticulture, Vellanikkara, 1994) Pushpa, Joseph; KAU; Mercy, George
An investigation was undertaken at the College of Horticulture, Vellanikkara, during 1993 – 1994 to study the utilization of phosphorus from green manure by rice. The main objectives of the study were to assess the contribution of phosphorus released from labeled green manure to the phosphorus nutrition of rice and to study the effect of incorporation of green manure on the utilization of applied fertilizer and native soil phosphorus. The effect of incorporated green manure on the dry matter yield of rice was also investigated. The green manure used was Sesbania aculeate. 32p labelled green manure was produced by growing sesbania in sand culture for 50 days. When the plants were 15 days old 32p (carrier free) was applied with water at 30 µCikg-1 sand. The labeled plant material was used for the incubation study and pot culture experiment. The results obtained from the incubation experiment conducted to study the dynamics of P mineralization from green manure revealed that the release pattern of Bray – 1 extractable P was similar both in 0.25 and 0.5 per cent green manure amended soil irrespective of the quantity of green manure added. The available P content of the green manure amended soil was relatively higher at the initial day of incubation, gradually decreased till 25th day and thereafter increased. The contribution of P from green manure and native soil also followed similar trend. As extracts of soil immediately after amending with labeled green manure showed 32p activity, it is possible that Bray – 1 reagent extracted inorganic P from the green manure. The P release from green manure and soil was the least at the 30th day of incubation and then showed an increasing trend for both levels of green manure incorporation. Till 30th day more P was released from 0.5 per cent green manure incorporation, later showed a reverse trend. To study the effect of incorporation of green manure on P utilization by rice, a pot culture experiment was done with 32p labeled green manure and amophos. The results revealed that per cent P derived from fertilizer (% Pdff) increased upto 20 days after transplating and thereafter it decreased, whereas the per cent phosphorus derived from green manure (% Pdfg) was very low during the initial stages, and thereafter it increased considerably. So a combind application of green manure and inorganic P fertilizer will meet the P requirement of the crop throughout the growth period. ‘% Pdfg’ increased with increasing rate of application of green manure. Per cent utilization of P from amophos was high during the initial stages of crop growth, later it decreased while the per cent utilization of P from green manure increased considerably after 20 days of transplanting. The per cent utilization decreased with increasing rate of application of green manure. With regard to crop growth characters, significant increase in plant height and tiller number were observed with the application of 0.25 per cent green manure along with amophos. Among the yield attributing characters, number of spikelets per panicle showed significant increase with the application of 0.25 per cent green manure in combination with amophos. Grain and straw yield were also the highest under the same treatment. Both grain and straw yield were significantly low when green manure alone was applied at the higher rate (0.5 per cent).
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 K
Three 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.
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 S
An 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.
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.

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