1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Rationalisation of phosphorus and potassium nutrition in cowpea (Vigna unguiculata (L) Walp) in the southern laterites(Department of Agronomy, College of Agriculture, Vellayani xvi,170p., 2023-12-16) Sruthy, H.; Shalini Pillai, P: The study entitled “Rationalisation of phosphorus and potassium nutrition in cowpea (Vigna unguiculata (L.) Walp.) in the Southern Laterites” was undertaken at College of Agriculture, Vellayani, during 2021-2023. The key objectives were to assess the productivity and quality of cowpea in response to varied doses of phosphorus and potassium supplemented with foliar nutrition, and to compute the economics. The field experiment was carried out at the Integrated Farming System Research Station, Karamana, from December 2022 to February 2023. It was laid out in randomised block design with (2 x 3 x 2) + 1 treatments, replicated thrice. The treatments comprised combinations of two levels of P (p1-100 % RDP, p2-50 % RDP), three levels of K (k1 - 100 % RDK, k2 - 150 % RDK, k3 - 200 % RDK) and foliar application at 20 DAS and 40 DAS (f1 - nano DAP @ 0.4%, f2 - PSAP @ 0.4 %), compared against a control (KAU POP). The variety used for the study was PGCP-6 and the fertilizer recommendation followed was 20:30:10 kg NPK ha-1 . All other cultural operations were carried out as per the KAU POP. The treatment, p1 (100 % RDP) resulted in significantly taller plants at 30 DAS, 45 DAS and 60 DAS) with more number of primary branches (45 DAS and 60 DAS), the highest CGR, RGR and NAR at 15-30 DAS, more number of nodules and the highest total dry matter production (DMP). The treatment, p2 (50 % RDP) resulted in the highest CGR and NAR at 30-45 DAS, and RGR at 45-60 DAS. Among the levels of K, 200 per cent RDK (k3) recorded significantly taller plants (45 DAS and 60 DAS) with more number of primary branches (45 DAS), RGR, CGR and NAR (15-30 DAS) and total DMP (4917 kg ha-1 ). Foliar application of nano DAP (0.4 %) at 20 DAS and 40 DAS (f1) resulted in more number of primary branches, LAI and RGR at 60 DAS, and total DMP (4925 kg ha-1 ). Foliar application of PSAP (0.4 %) at 20 DAS and 40 DAS (f2) resulted in more number of nodules per plant, and CGR and NAR at 30-45 DAS. Among the P x K x F interactions, p1k1f1 (100 % RDP + 100 % RDK + nano DAP @ 0.4 %) resulted in higher total DMP, and was on par with p1k3f1. The treatment combination, p2k2f2 resulted in higher NAR and remained comparable with p2k1f1, p1k1f2 and p1k2f2, at 45-60 DAS. The treatment combination, p2k1f1 resulted in significantly higher LAI (2.94) at 60 DAS and CGR at 30- 45 DAS. The treatments were superior to control with respect to growth attributes and total DMP. The treatments, p2, k1 and f2 resulted in the highest number of pods per plant (23.42, 23.17, 22.57), seeds per pod (16.51, 15.81, 15.88), pod yield (1700 kg ha-1 , 1669 kg ha-1 , 1619 kg ha-1 ) and seed yield (1484 kg ha-1 , 1433 kg ha-1 , 1395 kg ha-1 ). However, the highest haulm yields (4451 kg ha-1 , 4235 kg ha-1 ) were observed with 100% RDP (p1) and 200% RDK (k3). Among the interaction effects, p2k1f2 resulted in the highest number of pods per plant (26.17), pod yield (1892 kg ha-1 ) and seed yield (1642 kg ha -1 ) and significantly higher number of seeds per pod (20.17), which was at par with p2k3f2. The treatments were superior to control with respect to yield attributes and yield, except haulm yield. While, p1 (100% RDP) recorded the highest uptake of N and P, and apparent recovery efficiency of P (AREp), the treatments, p2 (50% RDP) and k1 (100% RDK) resulted in the highest partial factor productivity (PFPp), agronomic efficiency (AEp) and physiological efficiency (PEp). While f1 (nano DAP @ 0.4% at 20 DAS and 40 DAS) resulted in the highest N uptake (247.35 kg ha-1 ), f2 (PSAP @ 0.4% at 20 DAS and 40 DAS) resulted in the highest chlorophyll content at 45 DAS (1.92 mg g-1 ) and P uptake (21.55 kg ha-1 ), AEp (24.75 kg kg-1 ) and AREp (53.12 %) of P. Among the P x K x F interactions, p1k3f1 (100 % RDP + 200 % RDK + nano DAP @ 0.4 % at 20 DAS and 40 DAS) resulted in the highest N uptake (265.11 kg ha-1 ) and p1k3f2 resulted in the highest P uptake (28.53 kg ha-1 ). The highest PFPp (98.93 kg kg-1 ) and AEp (44.84 kg kg-1 ) were recorded with p2k1f2. The treatments were superior to control with respect to NPK uptake, PFPp and AEp. The seed quality in terms of zinc content was observed to be superior with 50% RDP (p2) and f1 (nano DAP @ 0.4% at 20 DAS and 40 DAS). The seed crude protein content responded significantly to K and remained comparable among the three levels of K. The treatment, k3 resulted in the highest organic carbon content (1.17 %), available P (65.27 kg ha-1 ) and available K (236.74 kg ha-1 ). The treatment, f2 resulted in the highest soil available P (62.77 kg ha-1 ). Among the P x K x F interactions, the highest net gain in available N (205.10 kg ha-1 ), available P (7.67 kg ha-1 ) and available K (68.24 kg ha-1 ) were observed with the treatment combinations, p2k3f2, p1k3f2 and p1k3f1 respectively. The treatments were superior to control with respect to pH, organic carbon, and available NPK status of the post-harvest soil. Significantly higher net income and benefit cost ratio were recorded with p2 (₹62,879 ha-1 ,1.99), k1 (₹58,307 ha-1 , 1.92), f2 (₹54,256 ha-1 , 1.85) and p2k1f2 (₹76,120 ha-1 , 2.20). Considering the yield, economics and phosphorus use efficiency, application of full dose of N (20 kg ha-1 ) along with 50 per cent recommended dose of P (15 kg ha-1 ) + 100 per cent recommended dose of K (10 kg ha-1 ), supplemented with foliar application of potassium salt of active phosphorus (0.4%) at 20 DAS and 40 DAS (p2k1f2), could be adjudged as the best treatment for higher productivity and profitability of grain cowpea in the Southern Laterites of Kerala (AEU 8)Item Studies on the chemo dynamics of phosphorus in the laterite soils of Kerala and utilization of fixed phosphorus for crop production(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2024-02-05) Kota Adilakshmi; Aparna, BA study entitled “Studies on the chemo dynamics of phosphorus in the laterite soils of Kerala and utilization of fixed phosphorus for crop production” was carried out at the Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, during 2018-2021, with the objectives to characterize in detail the dynamics of inorganic phosphorus and phosphorus fractions in the laterite soils of Kerala, identify the dominant phytoaccumulators of phosphorus, screening of suitable extractants for available P, and evaluate various organic and inorganic solubilizers/mobilizers on the solubility and availability of fixed phosphorus. The study was carried out in four parts. The first part consisted of the collection and characterization of georeferenced soil samples and the identification of dominant phytoaccumulators of phosphorus (P). For that, by following a preliminary survey, a total of 100 georeferenced representative soil samples (0-15 cm depth), 25 from each of the four agro-ecological units (AEUs), viz., southern laterites (AEU 8) of Thiruvananthapuram district, south central laterites (AEU 9) of Kollam district, north central laterites (AEU 10) of Thrissur district, and northern laterites (AEU 11) of Kozhikode district of Kerala were collected for assessing its fertility status. From scrutiny of the data, it was observed that among the four AEUs, AEU 8 reported the highest values for electrical conductivity (EC), organic carbon (OC), available P, sulphur (S), iron (Fe), manganese (Mn), exchangeable hydrogen (H+), anion exchange capacity (AEC), microbial biomass carbon (MBC), microbial biomass phosphorus (MBP), and population of P solubilizers, AEU 9 for available boron (B), exchangeable aluminium (Al3+), hydrogen (H+), acidity, and MB C/P ratio, and AEU 11 for pH, available nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg), zinc (Zn), and copper (Cu). According to the results of frequency distribution, it was observed that, among the four AEUs (8, 9, 10, and 11), sandy clay loam was the prevalent soil textural class. Data on the mean values of pH revealed that the pH ranged between 5.42 and 6.21 among the four AEUs, and the majority of the collected soils were found to be strongly acidic (37%) and moderately acidic (40%) in nature. The EC values of the four AEUs were found to be within the critical limit. The mean values of OC varied from 0.63 From the present study, it can be concluded that the soils of southern laterites (AEU 8) exhibited the highest values for available P. Amaranthus viridis from AEUs 8, 9, and 10, and Synedrella nodiflora from AEU 11, were identified as dominant phytoaccumulators of P. Among the various fractions of P, with respect to the Po fractions such as the labile Po fraction, HCl extractable Po fraction, fulvic acid Po fraction, moderately labile Po fraction, humic acid Po fraction, residual Po fraction, and non-labile Po fraction, the soils collected from AEU 8 showed the highest values compared to other soils. It was also observed that the soils treated with vermicompost @ 15 t ha-1 showed the highest values for all the Po fractions when compared to soils without any manure, including total Po. Similarly, for Pi fractions, the soils collected from AEU 8 treated with vermicompost @ 15 t ha-1 showed the highest values for saloid-Pi, Al-Pi, and Fe-Pi, while the soils collected from AEU 8 without manure showed the highest values for residual/occluded Pi. Furthermore, soils treated with vermicompost @ 15 t ha-1 displayed the highest values for Ca-Pi in AEU 10 and reductant-soluble Pi in AEU 11. Notably, the soils of AEU 8 exhibited the highest capacity for P fixation among all studied soils. From the study, it was also observed that ion exchange resins were found to be the best extractants for available P determination, and biochar was the best amendment for alleviating P fixation, thus augmenting soil fertilityItem Transformation of zinc in soil and zinc nutrition in lowland rice under different levels of Phosphorus(Department of Soil Science and Agricultural Chemistry, College of Agriculture,Vellanikkara, 2021) Najiya Rinthas, K; Moossa, P PPhosphorus and zinc are two important essential elements required by the plants for various metabolic activities, functions and associated with membrane structure. Continuous use of phosphatic fertilisers with less zinc, aggravates zinc shortage also phosphorus applied will be accumulated in the soil leading to formation of zinc phosphate complex that affect zinc translocation to various plant parts. There are contradictions regarding phosphorus zinc interaction that is controlled by native P and Zn status. In this context an investigation entitled “Transformation of zinc in soil and zinc nutrition in lowland rice under different levels of phosphorus” was conducted. Two separate experiments were carried out at Regional Agricultural Research Station, Pattambi. In the first experiment, fractions of Zn under different P levels was studied in Long Term Fertilizer Experiment (LTFE) with six treatments on rice in RBD with four replications. The soil samples were taken after the paddy harvest of kharif 2020 and sequential extraction of Zn (water soluble + extractable, organically bound Zn, amorphous sesquioxide Zn and crystalline sesquioxide Zn) and P (sol-P, Al-P, Fe-P, sesquioxide occluded P and Ca-P) were carried out. In the second experiment phosphorus and zinc interactions was studied using pot culture experiment on rice in factorial CRD with 3 replications. Samples from different locations of Palakkad district having native P <12, 12- 24, >24 kg ha-1 and native Zn <1, 1-3, >3 mg kg-1 were collected. Sixteen treatment combinations were applied with 4 levels of P (0, 25, 50,100 mg kg-1 ) as KH2PO4 and 4 levels of Zn (0, 5, 10, 15 mg kg-1 ) as ZnSO4.7H20 through solution for studying the nutrient uptake and yield. The results of fractionation study showed that continuous use of inorganic fertilisers with organic manures in T5 (100% NPK + FYM) increased various Zn fractions except amorphous sesquioxide Zn fraction which was highest in the control. Even though the increase in P application increased different P fractions significantly higher content was observed in 100% NPK+ FYM and these were proved to be beneficial towards increasing different P fractions. But Ca-P fraction was more in the lime treated plot. Correlation study concluded that most of the phosphorus fractions have negative impact on different zinc fractions. The results of the pot experiment elucidated that P and Zn application increased number of productive tillers and thousand grain weight but higher zinc application decreased plant height. Among different soils, soil type S2 (P > 24 kg ha-1 ) registered higher grain and straw yield, P in grain and straw, total P uptake of paddy, but Zn uptake and Zn in grain and straw were more in soil type S3 (Zn > 3 mg kg-1 ). Combined application of 100 mg kg-1 P and 10 mg kg-1 Zn recorded higher grain (57.27 g pot-1 ) and straw yield (66.82 g pot-1 ). Phosphorus application significantly increased the P content in grain and straw but zinc addition had antagonistic effect on them and treatment combination of P100Zn0 registered higher P content in grain (0.26%) and straw (0.214%). The Zn in grain and straw significantly increased by the application of zinc, but phosphorus was having an adverse effect and treatment combination of P0Zn15 registered higher Zn content in grain (61.28 mg kg-1 ) and straw (44.19 mg kg-1 ). Total P and Zn uptake of paddy increased by the application of both phosphorus and zinc with higher content obtained at P100Zn15 (28.47 mg pot-1 ) and P50Zn10 (0.458 mg pot-1 ) treatment combination. Correlation study concluded that phosphorus and zinc application affected P and Zn uptake in high zinc containing soil (S3) and high P soil (S3), respectively. In future this work can be used to study the changes in various P and Zn fractions under continuous crop removal, various management practices to mobilise fixed P in high phosphorus containing soil and also to study Q/I relationship of both phosphorus and zinc.Item Comparative efficiency of different phosphatic fertilizers in rainfed Nendran Banana(Department of Soil Science and Agricultural Chemistry, College of Agriculture,Vellanikara, 1990) Sheeja, V G; Harikrishnan Nair, KThough phosphorus is one of the key nutrients for plant growth, the consumption rate of phosphatic fertilizers in India is found to be comparatively low. The escalating cost of the imported raw material used for the manufacture of P fertilizers may be one of the possible reasons for the low intake. In this regard, the direct application of cheap native ground rockphosphate as a P source is a fruitful attempt especially in acid soils. The present investigation was conducted to compare the efficiency of different phosphatic fertilizers including rockphosphates in upland soils with ‘Nendran’ variety of banana as the test crop. The present study comprises of two aspects, field experiment and laboratory incubation study. The field experiment was conducted at two locations, viz. at the Instructional Farm attached to College of Agriculture, Vellayani and at Kattakada, in the cultivator’s field. The experiment was laid out in randomised block design with four treatments and five replications. The laboratory study was carried out in the soil, treated with different phosphatic fertilizers after incubation with organic matter under moist conditions to assess the influence of organic matter on the release of P from different P sources. The growth characters of banana plant such as height and girth of pseudostem, number of photosynthetically active leaves, leaf area and period taken for flowering were recorded and analysed upto shooting stages of the crop. The bunch characters like weight of bunch, length of bunch, number of fingers and hands bunch-1, and length and girth of finger were also recorded and analysed. Phosphorus application significantly influenced biometric characters of the crop while the differences between the various P sources were not statistically significant. In most of the growth and yield characters, comparatively higher efficiency was shown by plants treated with superphosphate, eventhough, it was statistically on par with the other sources in both locations. Thus, it indicates the possibility of using cheaper rockphosphates for meeting the phosphorus requirement of banana in upland soils of Kerala, rather than going in for the costly superphosphate. The effect of treatments on the drymatter production was significant at both locations. Phosphorus application significantly increased the P uptake. However the different P sources could not produce significant variation in the uptake of phosphorus in both locations. The phosphorus content in the leaf was found to be maximum from the late vegetative phase to shooting period of the plant growth. With respect to available and total P2o5 content in the soil, the differences between the various sources were not statistically significant though, addition of phosphorus increased the available as well as total P2o5 content of soil significantly over no P treatment. A significant positive correlation existed between the leaf P content and total P uptake. Similarly a significant positive correlation between yield as well as total drymatter content with P uptake was observed. The incubation study revealed that organic matter produced significant effect on the release of phosphorus from different P sources added to the soil under moist conditions. Upto 90 days of incubation, increased availability of phosphorus was recorded in all treatments, and the trend continued till 135 days. A gradual decline in the concentration of available P was noticed thereafter. However, a favourable influence of organic matter on the release of P from different sources has been brought out from this study. When the mean values of available P over all the periods were compared, maximum availability was recorded by soils incubated with organic matter and superphosphate. In general, various sources of P behaved similarly and were on par with respect to the release of phosphorus due to organic matter incubation.Item Spatial arrangement & nutrient management of grain cowpea - Fodder maize intercropping in summer rice fallows(Department of Agronomy, College of Agriculture, Vellayani, 1990) Sunitha, S; Lekha SreekantanAn investigation was carried out during the summer season of 1988-'89 in the Instructional Farm attached to the College of Agriculture, Vellayani to determine the best crop arrangement for a grain cowpea + fodder maize intercropping system in summer rice fallows under different fertility levels. The different crop arrangements tried were pure crop of cowpea at normal row arrangement, pure crop of maize at normal row arrangement, cowpea and maize in alternate rows, paired row of cowpea with one row of maize in between and triple row of cowpea with one row of maize in between. The fertilizer levels tried were 100, 75 and 50 per cent of the recommended doses of nutrients of cowpea, maize and cowpea+ maize, depending on the crop arrangement and the area occupied by each crop. The experiment was laid out in split plot design with four replications. The crop arrangements were allotted to main plots and the fertility levels to the subplots. Plant height of cowpea was maximum in the crop arrangement where cowpea was alternated with one row of maize where as the pure crop of cowpea produced the maximum number of leaves. In the case of maize, plant height and number of leaves were maximum when cowpea and maize were grown in alternate rows. Pure crops of cowpea and maize recorded the highest for their respective LAI values at flowering. Plant height, number of leaves and LAI of both cowpea and maize were affected by different fertility levels. Higher doses of fertilizers were found to be the best. The crop arrangements did not show pronounced variation in the uptake of nutrients by cowpea except potassium. Potassium uptake by cowpea and maize were maximum for their respective sole crops. For maize, nitrogen and phosphorus uptake were maximum when grown in alternate rows with cowpea plants. Full dose of fertilizers recorded the highest uptake values. Number of pods per plant, length of pods, number of seeds per pod, hundred grain weight, pod yield as well as grain yield of cowpea were not affected by different crop arrangements or fertilizer levels. The fodder yield of maize was affected by different crop arrangements and the pure crop of maize was on par with the crop arrangement where cowpea and maize were alternately grown. Hundred per cent recommended dose of fertilizers recorded the highest value for fodder yield of maize. The treatment where cowpea and maize were grown in alternate rows resulted in the greatest protein content of cowpea grains. Seventy five percent dose of fertilizers resulted in the highest crude protein content of maize fodder. The various indices like LER, LEC, IER, net profit, benefit/cost ratio, return per rupee invested on labour and return per cropping day were found to be superior in the crop arrangement where cowpea and maize were grown in alternate rows and at full dose of fertilizers. Hundred per cent and seventy five per cent dose of fertilizers were on par with regard to LER, LEC, IER, net profit and benefit/ cost ratio. From a detailed analysis it is seen that cowpea alternated with one row of fodder maize under 75 per cent of the recommended level of nutrients, is the best in providing higher profit to the farmer.Item Nutritional status of soils in relation to foliar nutrient levels in oil palm(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1988) Solomon Chacko; Abdul HameedAn investigation was taken up in oil palm grown in the plantation of oil palm India Limited at Yeroor (Bharathipuram) of Quilon District, with a view to evaluating the nutritional statusItem Nutritional requirement of pre-release sesamum culture 42-1 in garden land(Department of Agronomy, College of Agriculture, Vellayani, 1987) Raveendran Nair, P; Chandrasekharan, PA 4 raise to 3 fatorial experiment confounding NPK (3 df) totally in replication I and II was conducted under garden land condition at the Instructional Farm, College of Agriculture, Vellayani, during semirabi season 1984, to study the effect of graded doses of nitrogen (10, 30, 50 and 70 kg/ha), phosphorus (5, 15,25 and 35 kg P2O5/ha) and potassium (10, 30,50 and 70 kg K2O/ha) on the growth , yield , quality, content and uptake of mineral nutrients and also to work out the economics of production with the pre-release sesamum culture 42-1 (now released as Soorya or ACV-2). The study revealed that application of nitrogen significantly influenced growth , yield and yield attributing characters. Phosphorus and potassium produced significant influence on number of leaves and leaf area index on 40 and 60 days after sowing. Significant effect of phosphorus was also observed on number of branches, pod-seed ratio, bhusa yield, thousand seed weight and total dry matter production. Applied potassium significantly influenced the yield and yield attributing characters like number of pods , weight of pod per plant, pod seed ratio, seed yield and harvest index.Item Fertility investigations on the soils of South Kerala in relation to their physiographic positions(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1986) Wilfred Godwin, G; Alice AbrahamA study of the soils of South Kerala has been undertaken to investigate the variation in fertility status in relation to their physiographic position. Twelve locations from the districts of Trivandrum and Quilon were selected and from each location soil samples from upper, middle and lower reaches were collected from depths of 0 to 20 cm and 20 to 40 cm. The elevation of the location varied from 20 to 150 meters and the degree of slope from 6 to 27. The lower reaches of all the location were or less level paddy fields. The middle reaches were cultivated to banana, pepper, coconut and tapioca and the upper reaches in addition to the above crop perennials like coconut and rubber.Item Fertilizer management in rice variety cheradi(Department of Agronomy, College of Agriculture, Vellayani, 1986) Vaijayanthi, C P; Ramachandran Nair, VItem Effect of drying and wetting on the physical, Physico-chemical and chemical properties of the submerged soils of Kuttanad(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1988) Raju, P V; Koshy, M MA study was undertaken at the College of Agriculture, Vellayani to know the effect of drying and wetting on the physico-chemical properties of submerged acid sulphate soils of Kuttanad which are known locally as Kerapadom, Kari and Kayal soils. Random soil samples were collected from various parts of Kuttanad and their physico-chemical properties such as pH, conductivity, available NPK status and different forms of iron and aluminium were estimated in moist state itself. Texturally Kuttanad soils were predominantly of clayay nature. Bulk and particle densities were significantly lower in Kari soils due to high organic matter as compared to Karapadom and Kayal soil. The pH values of Kayal soils were significantly higher than that of Kari and Karapadom soils which were extremely acidic. The conductivity of all soil groups were negligible probably due to seasonal effects and also due to the commissioning of Thaneermukkom bund and Thottapally spillway which prevented the ingress of sea water. The availability of major nutrients was fairly high and no significant differences existed between soils. Exchangeable iron and aluminium varied greatly.
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