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2020 - 20212
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Subject: Soil and Water Conservation × Author: KAU × Start date: 2015 × Type: Thesis × Thesis Type: M.Tech. ×
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    ThesisItemOpen Access
    Assessment of greenhouse cultivation problems in Kerala
    (Department of Soil and Water Conservation Engineering, KCAET, Tavanur, 2021) Deepthi S, Nair; KAU; Jinu, A
    Greenhouses are framed or inflated structure covered with transparent or translucent material large enough to grow crops under partial or fully controlled environmental conditions to get optimum growth and productivity. Greenhouse have many advantages and some limitations also. Due to this farmer are abandoning this cultivation method citing crop failures after the initial phase. Thus, a survey was conducted to explore the reasons of failures of greenhouse farmers in Kerala covering all fourteen districts. Major problem faced by farmers was crop failure due to ageing of cladding material. So that fungal growth and dust deposit over the cladding material reduce the light transmission to the greenhouse which affect its microclimate and growth and yield parameters. To prove this, a field experiment was conducted during the period from April to June 2021 in the instructional farm of KCAET, Tavanur, Kerala. CO-1(Amaranthus green variety) was planted inside both cleaned greenhouse and uncleaned greenhouse (greenhouse without cleaned cladding material) and compared the microclimate and performance of Amaranthus in both conditions. Mean monthly values of light intensity and temperature were higher inside the cleaned greenhouse than the uncleaned one while relative humidity was higher inside the old greenhouse. Thus, crop growth parameters like plant height, number of leaves, number of branches and average yield per plant were higher inside the cleaned greenhouse than the old one whereas the inter nodal length of the plant was higher inside the old greenhouse. From this experiment, it was clear that the aging of cladding material has much influence on crop performance under the greenhouse. Other major problems faced by farmers were a decrease in soil fertility, Fungal/Insect attack inside the greenhouse, high maintenance cost 101 and structural problems of greenhouse, no demand and marketing facility of greenhouse products, etc. From the statistical analysis of survey details, it was clear that farmers are not satisfied with the greenhouse.
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    ThesisItemOpen Access
    Determination of subsurface stormflow using tracer method
    (Department of soil and water conservation engineering, Kelappaji college of Agricultural engineering and technology, Tavanur, 2020) Adarsh, S S; KAU; Sathian, K K
    The state of Kerala in India is a typical example of a region facing droughts of varying degrees despite receiving high annual rainfall. This is because a lion share of the precipitation received is going out as runoff without recharging the groundwater. The subsurface stormflow is considered as the fast moving component of subsurface runoff on which very little information is available due to its complex mechanism of movement through subsurface. Hence, this study has been taken up for gathering more knowledge on the phenomenon of subsurface stormflow with the help of monitoring of soil moisture movement and tracer method. For data collection, three experimental setups in two experimental plots have been setup in KCAET campus, Kerala, India. It is a lateritic terrain having sandy loam type of soil and a general slope. Through-flow trenches were constructed for all the three setups and studied the soil moisture variation on the trench face at three depths (0-40 cm, 40-80 cm and 80-120 cm) in order to study the subsurface stormflow through different depths. For the experimental setup 1, simulation of rainfall was done using a butterfly sprinkler as the input. Line application of water was done for the experimental setup 2. Natural rain was taken as the input for the experimental setup 3. The subsurface stormflow through the soil matrix is also studied by the salt tracer experiment for obtaining its velocities. From the study it was found that the subsurface stormflow discharge is greatly affected by the soil dry density and soil suction. The subsurface stormflow discharge was found to have negative correlations with both soil suction and soil dry density. The subsurface stormflow velocities through 0-40 cm, 40-80 cm and 80-120 cm depths obtained from the soil moisture variation studies were 23.74 cm day-1, 36.23 cm day-1 and 17.41 cm day -1 respectively and the same obtained through the tracer studies were 27.27 cm day-1, 30 cm day-1 and 26.67 cm day-1 respectively. It was also concluded that the prevailing subsurface stormflow in the experimental sites is due to matrix flow rather than the preferential flow. The results gave the conclusion that high value of rainfall along with low values of soil dry density and soil suction can induce the subsurface stormflow even in the area having gentle slope (<10 %).