An agroclimatic assessment of the crop growth potential of south india

Usually, under rainfed conditions the growing period exists in the humid months. Hence, for agricultural planning knowledge about the variabilities of the duration of the humid seasons are very much needed. The crucial problem affecting agriculture is the persistency in receiving a specific amount of rainfall during a short period. Agricultural operations and decision making are highly dependent on the probability of receiving given amounts of rainfall; such periods should match the water requirements of different phenological phases of the crops. While prolonged dry periods during sensitive phases are detrimental to their growth and lower the yields, excess of rainfall causes soil erosion and loss of soil nutrients. These factors point to the importance of evaluation of wet and dry spells. In this study the weekly rainfall data have been analysed to estimate the probability of wet and dry periods at all selected stations of each agroclimatic zone and the crop growth potentials of the growing seasons have been analysed. The thesis consists of six Chapters.

Nutritional studies in juvenile penaeus indicus with fererence to protein and vitamin requirements

Man in his quest to explore food has turned towards the oceans and during the last five decades there has been phenomenal increase in the exploitation of the marine fisheries resources. The present study is carried out to determine the requirement of protein and water-soluble vitamins in the diet of juveniles of the Indian white prawn p.indicus using purified diets and to evaluate the nutritive value of a few plant and animal protein sources for the same species. A total of ten statistically designed experiments are conducted in the laboratory undermost identical conditions and following similar methodologies. The study also tries to suggest the essential and optimal requirements for protein as well as water-soluble vitamins in the diet of juvenile p.indicus

Water relations, growth and gas exchange in Acacia auriculiformis under experimental and natural conditions

Investigations on the water relations and gas exchange of/tcacia aun'culiji_2rmis were carried out in natural and controlled environments. The experiments were performed in both seedlings and five year old trees. Different sets of experiments were conducted in Acacia plantations, at Kothachira, Palakkad District and in .seedlings, at KFRI campus nursery mainly during the summer months. Investigations were also extended to seedlings of A.mangium, Aaulacocarpa and /Lholocericea, which are also phyllodinous species with the intention of comparing their physiology with Acacia auriculifomus. Potted seedlings of four species of Acacia viz., A. auriculi/E)/7r:i.r, /I. aulacocarpa, A. holocericea and A. mangium were used for the study. Measurements of relative water content (RWC), water potential, photosynthetic rate, transpiration, stomatal conductance, water use efficiency etc. of phyllodes were measured diumally in plants subjected to three stress conditions namely, drought, salinity and flooding

Activated packed bed bioreactor for rapid nitrification in brackish water hatchery systems

A packed bed bioreactor (PBBR) was developed for rapid establishment of nitrification in brackish water hatchery systems in the tropics. The reactors were activated by immobilizing ammonia-oxidizing (AMONPCU- 1) and nitrite-oxidizing (NIONPCU-1) bacterial consortia on polystyrene and low-density polyethylene beads, respectively. Fluorescence in situ hybridization demonstrated the presence of autotrophic nitrifiers belong to Nitrosococcus mobilis, lineage of b ammonia oxidizers and nitrite oxidizer Nitrobacter sp. in the consortia. The activated reactors upon integration to the hatchery system resulted in significant ammonia removal (P\0.01) culminating to its undetectable levels. Consequently, a significantly higher percent survival of larvae was observed in the larval production systems. With spent water the reactors could establish nitrification with high percentage removal of ammonia (78%), nitrite (79%) and BOD (56%) within 7 days of initiation of the process. PBBR is configured in such a way to minimize the energy requirements for continuous operation by limiting the energy inputs to a single stage pumping of water and aeration to the aeration cells. The PBBR shall enable hatchery systems to operate under closed recirculating mode and pave the way for better water management in the aquaculture industry.