Loading...
Theses
Browse
3 results
Search Results
ThesisItem Open Access Fertiliser scheduling for the short duration cassava variety vellayani hraswa(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2004) Sekar, J; Harikrishnan Nair, KCassava (Manihot esculenta Crantz), popularly known as tapioca, is one of the world’s most important staple food crops. It ranks sixth among the major contributors of food in the world. It has been a major contributor of food, nutrition and income especially for the poor. Its biological efficiency and multi use characteristics warrant for crop management strategies to exploit its production potential to the maximum. Due to the high cost of labour and lack of timely availability of labour, the farmers show interest to introduce cassava as a substitute for rice in his crop cafeteria. “Vellayani Hraswa” is a short duration variety of cassava released by the Kerala Agricultural University recently. Branching habit and short duration nature coupled with greater production potential make this variety physiologically unique and outstanding compared to other cassava varieties ever released. These characters warrant for separate package in nutrient management. Keeping these views in mind, an experiment entitled “Fertilizer scheduling for short duration cassava variety “Vellayani Hraswa” was conducted with the objective of studying the influence of NPK fertilizers on the performance of short duration cassava variety “Vellayani Hraswa” and to arrive at a fertilizer recommendation for the same. The experiment was laid out at the Instructional Farm, College of Agriculture, Vellayani during the period from 25th June to 25th December 2003 in a 33 Factorial Randomized Block Design (FRBD) with two replications and three factors (NPK) each with three levels (50,75 and 100 kg ha-1). The crop was raised adopting the agronomic practices for cassava outlined in the Package of Practices Recommendation: Crops of Kerala Agricultural University KAU (2002). The results of the experiment are summarized as follows. There was no significant difference on the plant height at all the growth stages of the plant due to the treatments. However, there was an increasing trend on the height of the plant as the dose of nitrogen increased. Higher dose of nitrogen increased the number of leaves produced in cassava at all the growth stages. At harvest stage, the plants retained maximum number of leaves for all the treatments which indicates that the leaf fall is minimum, a peculiar characteristic of the variety. Tuber production was influenced significantly by all the treatments. Application of 100 kg K ha-1 resulted maximum tuber yield. NPK @ 50: 50: 100 kg ha-1 produced maximum tuber yield (47.09 t ha-1). This variety favours a 1:1:3 NPK ratio for higher tuber production. Length of tubers was not influenced by different levels of N, P and K. However, NPK @ 75:50:75 kg ha-1 produced tubers with maximum length in cassava. Girth of tubers was significantly increased due to the application of nitrogen alone @ 100 kg ha-1 in cassava. Application of NPK @ 75:100:100 kg ha-1 produced the highest quantity of dry matter. No significant influence on LAI due to the application of N, P and K fertilizers was observed. Stomatal conductance in cassava leaves was maximum due the application of P and K @ 75 kg ha-1 (p2k2) with significant effect. Chlorophyll content of cassava leaves was not influenced significantly due to different levels of N, P, K application. The highest dose of NPK (n3p3k3) recorded highest chlorophyll content. Phosphorus has influenced significantly on tuber starch content. An increasing trend due to incremental doses of K up to 100 kg ha-1 was also observed. Treatment n3p3k3 (100:100:100 kg ha-1) recorded the highest starch content in tubers. Crude protein content was significantly influenced by the nutrients NPK. Application of N @ 100 kg ha-1 registered the highest protein content. NPK @ 100:100:75 kg ha-1 produced tubers with maximum protein content. Hydrocyanic acid content was mainly affected by higher doses of nitrogen. Nitrogen alone @ 100 kg ha-1 produced maximum HCN content in the tuber. But there was significant decline in HCN content as the dose of K increased. When the treatment n3p3k1 (100:100:50 kg ha-1) produced tubers with the highest HCN content, the treatment n1p2k3 produced tubers with lowest HCN content. Cooking quality of tubers was significantly influenced by potash. Maximum cooking quality could be obtained when K was increased to 75 kg ha-1. In general, the uptake of N, P and K by plants was maximum for the highest doses of N, P, K. A fertilizer dose of N, P, K @ 50:50:100 kg ha-1 produced maximum tuber yield (47.09 t ha-1) with moderate cooking quality of tubers. The moderate fertilizer cost resulted high BC ratio of 3.32 for the treatment n1p1k3, the best dose arrived at and to be recommended for the short duration cassava variety “Vellayani Hraswa”. It has to be concluded that the cassava variety “Vellayani Hraswa” is most economical due to its short duration (about 6 months), high yield (45-50 t ha-1) good cooking quality (1.5) and moderate fertilizer requirement (50:50:100 NPK ha-1).ThesisItem Open Access Assessment of selective retention sites of cadmium and lead in tomato (Lycopersicon esculentun Mill)(Department of Soil Science Agricultural Chemistry,College of Horticulture,Vellanikkara, 2004) Vanisri, K; KAU; Sam Kurumthottical, TThe bio-availability of the toxic heavy metals like cadmium and lead together with its selective retention sites in tomato (Lycopersicon esculentum Mill.) was one of the major concerns in the crop. For this, pro-calculated quantities of cadmium and lead were applied to the soil mainly as water-soluble sources (cadmium chloride and lead nitrate respectively) to assess the finite objectives envisaged in the study. In order to meet the objectives, a pot culture experiment was conducted in the Vegetable Research Farm attached to the Department of Olericulture, College of Horticulture, Vellanikkara during the rabi season of 2003 with five treatments and four replications. Pre-treatment analyses of all basic inputs and soil were carried out to quantify the possible inclusion of heavy metals from them. After providing pre-calculated quantities of metals in pots, 42 day old and uniformly grown tomato plants of variety Sakthi were transplanted to pots. The plants were allowed to establish till majority of the plants (50 per cent) were at the turning stage. Biometric observations on the plants due to the impact of the metals were recorded. Fruits as and when they turned ripe were harvested with proper acknowledgment to their identity in treatments for yield and its subsequent dry weight. At harvest, the plants were carefully uprooted, cleaned properly and separated into root and shoot portions. After recording the weight of each portions, these parts were taken for analysis. Post-harvest soil samples were also collected and analysed to see the extent of availability of major nutrients and heavy metals, particularly cadmium and lead. All the inputs including soil maintained variable amounts of cadmium and lead, with maximum metal load contributed from phosphatic sources. It is seen that growth of tomato plants in pots, particularly under the influence of different levels of cadmium and lead, manifested differential growth and development. Internally also, the plants exhibited differential metal load and retention patterns apart from recording variation in the uptake of major nutrients. A brief resume of the major influence of different levels of cadmium and lead in soil and on the tomato plants is presented hereunder. Variation in cadmium levels in soil could influence significant variations In the available nutrient status in post-harvest soil samples. Accordingly, an increase in metal load permitted enhanced potassium availability in soil while the same status had an opposite effect particularly with respect to the available phosphorus and nitrogen. The nitrogen content of root and shoot of tomato plants was seen to be positively influenced with higher levels of cadmium application. However, a reverse trend in nitrogen content was observed with lower levels of application except for the shoot portions observed from Treatment 4. Among the various plant parts analysed, the fruits maintained the maximum nitrogen content and this content was roughly observed to be twice as that of its content in roots. Enhancement in cadmium level in soil resulted in a corresponding increase in the phosphorus content of roots, shoot and fruits. As observed for nitrogen, fruit portion maintained the maximum phosphorus content. A very similar trend was noted for the potassium content in tomato, consequent to the application of different levels of cadmium. Much before an apparent growth or' yield reduction was noted in tomato with cadmium application, the tomato plants readily exhibited certain characteristic symptoms, which could be associated with the metal toxicity on that plant. Preliminary indications appeared on leaves with such leaves picking up yellowing and inter-veinal chlorosis depending upon the metal load. At high concentrations of the metal, invariable splitting up of the stem at the collar region leading to complete death of such plants has been noted. As concentration of the cadmium load increased beyond 1.5 mg kg" soil, the tomato plants failed to fruit and at the highest concentration of the metal envisaged in the study (2.0 mg Cd kg" soil), the very establishment of the transplanted tomato crop was questioned. However, the successful survival and fruiting of the transplanted tomato plants was noted only at lower levels of cadmium addition (0.5 and 1.0 mg Cd kg" soil). Lower doses of addition of cadmium had exhibited negative influence on growth and development in tomato with the manifestation of significant reduction in number of branches, leaf length, leaf number, plant height, the production of trusses and subsequent reduction in yield. Reduction in growth and yield of tomato plants from different levels of application of cadmium, necessarily brought significant reduction in dry matter yield, whose influence is clearly reflected in the roots, shoot and fruits portions underlining a negative influence of cadmium on the dry matter production. At all levels of cadmium application, there was sufficient retention of the metal in plant whether it is root, shoot or fruits Roots of tomato are seen to preferentially harbour more of cadmium than its other plant parts particularly at higher levels of addition. However, at lower levels of addition, shoots preferred to maintain more cadmium than its root portions. Increasing levels of lead invariably decreased the root nitrogen content . significantly while shoots content of nitrogen increased generally with lower doses of metal addition. Variation in, lead levels permitted a significant increase in the phosphorus content in roots, shoot and fruits. No specific trend was noted in the retention of potassium by roots while shoot portions indicated significant influence of the same by offering differential content of potassium in them. Among all the plant parts, fruits maintained the maximum nitrogen, phosphorus and potassium content. Higher doses of lead rendered some fruits, if not all with certain malformations. This together with the total absence of any phyto-toxicity testifies that the tomato plants are able to tolerate high concentrations of lead inside them. Quite contrary to the expectations, an unusual increase in dry matter production was observed from lead treated tomato plants. Lead application in soil, irrespective of its levels, permitted maximum accumulation of the metal in fruits followed by shoots and roots. All accumulations noted in the plant were observed to be significant, projecting serious concern for the silent inclusion of lead in the economically important part of the plant. Variable amounts of cadmium and lead have been detected in the post-harvest soils indicating that the entire quantity of the applied cadmium and lead could not be completely absorbed by the plant.ThesisItem Open Access Vermicompost Enriched with Organic Additives for Sustainable Soil Health(Department of Soil Science and Agricultural Chemistry College of Agriculture, Vellayani, 2004) Sheeba, P S; KAU; Ushakumari, KAn investigation was carried out at the Instructional Farm, attached to the College of Agriculture, Vellayani to evaluate the effect of vermicompost enriched with organic additives viz., neem cake and bone meal on physico-chemical and biological properties of soil, to evaluate its impact on crop performance and the feasibility of substituting farmyard manure and inorganic fertilizer using amaranthus as test crop. The study consist of three parts 1) Preparation and analysis of vermicompost and enriched vermicompost 2) laboratory incubation experiment 3) Field experiment. On enriching biowastes with neem cake and bone meal, improved the manurial value of vermicompost produced using earthworm species Eudrillus eugeniae. C/N ratio was reduced by enrichment. Microbial population also increased considerably by enriching vermicompost with organic additives. Second part of our investigation was an incubation study and it was conducted to evaluate relative efficiency of enriched vermicompost to release nutrients from soil and its influence on physico-chemical and biological properties of soil. The results revealed that available nitrogen, phosphorus and potassium content of the soil increased upto 45 days of incubation then the availability slowly declined. Organic carbon, pH and EC increased whereas bulk density reduced due to the effects of various organic sources. Application of organic matter had a positive effect on microbial count also. Third part of the study was field experiment, and it was laid out in RBD with 10 treatments and three replications. The biometric observations viz., plant height, number of leaves, number of branches, stem girth, leaf stem ratio all were significantly influenced by different treatments. Significant differences were observed among yield attributing characters like yield per cutting (t ha-1), total yield per plant (g plant-1), total marketable yield (t ha-1), and total dry matter production (t ha-1). Highest yield per cutting was recorded by the treatments T0 (FYM + full NPK), T4 (EVC – NC two per cent + full NPK) and T8 (EVC – NC 1 per cent + BM 1 per cent + full NPK]. With respect to plant contents of nutrients, for nitrogen, highest value was recorded by the treatment T4 (EVC – NC two per cent + full NPK), for P, highest value was recorded by T6 (EVC – BM two per cent + full NPK) and for K, highest value was recorded by the treatment T8 (EVC – NC 1 per cent + BM 1 per cent + full NPK). For plant uptake highest values were registered by the treatments T4, T6 and T8 for N, P and K respectively. With respect to quality characters, treatments with organic sources of plant nutrients viz., T8 [EVC- NC 1 per cent + BM 1 per cent + full NPK) recorded highest value for -carotene content in all the three cuttings, for moisture content T3 (VC+1/2NPK) recorded the highest value in all cuttings, for protein T4 (EVC – NC two per cent + full NPK) recorded the highest value in all cuttings. For fibre content treatment T1(Full NPK as mineral fertilizer) recorded the highest value and T2 (VC + full NPK) recorded the lowest value. Oxalate content is also influenced by different treatments. Vermicompost enriched with bone meal and treatment received NPK alone recorded highest oxalate content. Post harvest analysis of the soil indicated that organic carbon, available phosphorus, pH, EC and microbial count were increased by applying enriched vermicompost. But available nitrogen and available potassium were slightly decreased. Bulk density was found to be influenced favourably. From the investigation it was proved that enriched vermicompost established its superiority over other organic sources and POP recommendation with respect to soil health and quality of amaranthus. Study also revealed the feasibility of substituting FYM and inorganic fertilizer with enriched vermicompost.