but changes in the ecological and institutional landscapes in rajasthan marginalized the availability of grazing land which largely affected their pastoral lifestyle and forced them to sell animals and take up lowpaid labour in towns hence their knowledge is irrelevant and thus the changes in their livelihood led to the disappearance of valuable breeds and associated knowledge practical action for example farmers in semiarid parts of south tamil nadu use ploughs made of neem tree timber azadracta indica as one of the integrated methods to control cyperus a notorious weed in cropped fields currently ploughing is carried out using tractors and thus the traditional knowledge of using neem ploughs has become obsolete and its relevance is limited under the changing production practices the cultural value placed on crop diversity and local selection techniques is also declining in many areas and the skills that contributed to evolution of landraces are slowly disappearing as in the case of specific culture in the philippines mentioned earlier changing sociocultural practices make the knowledge irrelevant and reduce sharing and communication at the community level and into the next generation