Browsing by Author "Harikrishnan Nair, K"

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Assessment of the factors governing response to phosphorus in the rice soils of Kerala
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1986) Harikrishnan Nair, K; Subramonia Aiyer, R
An attempt to asses the various factors and arrive at an integrated picture on response of rice to phosphorus application In rice soils of Kerala has teen made. To reach certain conclutions on some of the possible reasons for response of rice to phosphorus in the acid rice soils of Kerala, the following approaches have been resorted to. Categorising the rice soils with special reference to phosphorus and factors affecting them. Detailed studies on the various phosphorus fractions, both inorganic and organic as well as toe relationships between the p fractions and important soil parameters have been worked out. Elaborate studies have been undertaken on the p fixing capacity of rice soils and the factors governing it. Phosphorus transforation studies, both inorganic p fractions and available f due to waterlogging have also been conducted. Two rice varieties, a medium end a short duration have been tested under pot culture conditions -lO with graded levels of B and finally two p labelled sources of phosphorus, a water soluble monocalcium phosphate and water insoluble tricalcium phosphate have been evaluate in 7 soil types representing the major rice soil types of Kerala
Chemical and physico-chemical characteristics of the red soils of Kerala
(Kerala Agricultural University, 1983) Harikrishnan Nair, K; Koshy, M M
Red soils are acidic with low salt concentration. The low contents of organic matter, major nutrients and their low availability, poor cation exchange ca^a^ity and otherexchange characteristics indicate that these are low fertile soils Since the red soils are with good physical properties, the soil productivity can be substantially increased with ths judxious application of organic manures and chemical fertilizers.
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, K
Though 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.
Development of protocol for quality control of commercial organic manures and their evaluation
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2008) Gowri Priya; Harikrishnan Nair, K
Effect of adding nitrogen in combination with MnO2 on the growth, yield and composition of rice
(Kerala Agricultural University, 1981) Harikrishnan Nair, K; Koshy, M M
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, K
Cassava (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).
Physical properties of the red soils of Kerala
(Kerala Agricultural University, 1982) Harikrishnan Nair, K; Koshy, M M
Substitution of potassium by sodium in banana musa (AAB Group) var nendran
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2000) Lekshmy, R; Harikrishnan Nair, K