the parameters used to determine the trophic state of a water body are: total phosphorus (tp),transparency (secchi disk depth) and chlorophyll a. however, these parameters show strong seasonalfluctuations which may hinder the estimation of trophic state. some authors have proposed that sediments be used as an additional tool to evaluate the trophic state of a water body. the aim of this study w...

increasing demand for food production in the recent years has raised the usage of granular fertilizers. consequently, the growing use of fertilizers has reduced the quality and quantity of crop production. in addition pollution problems such as soil and water (surface and subterranean water) contaminations has increased. consistent spreading of fertilizers in the farmlands is of fundamental rul...

abstract- this study aims to model optimal cultivation pattern based on the maximization of importing virtual water and social net income of major crops in marvdasht, iran. for this purpose, a linear programming model was developed considering constraints of virtual water and land limitations followed by other models to include employment restrictions. based on the findings, wheat and tomato we...

abstract in present study, it has been studied to oprimize culture pattern in water consumption reduction and increase in income by use of collected data from kazeroon agriculture organization and forign commercial statistical annals and use of linear planning model due to simplicity and lts application, and to apply in water resources management. the purpose of this study had been to edit one ...

designing and scheduling of drip irrigation systems are often done without enough information about water distribution in the soil. due to tillage operations and crop production practices, agricultural soils can be considered as two layered soils with different bulk densities. the top soil layer has a lighter texture than the sub soil layer. in this research, the development of the wetting fron...

plant cover is one of the most important factors affecting infiltration rate of water into the soil and decreasing runoff. distribution of plants in arid and semi-arid areas is almost patchy and form different patterns. one of the fascinating patterns is ring-shaped growth pattern. ring patterns of varying size are formed by clonally reproducing grasses, sedges and even shrubs growing in resour...