Todas as características abaixo são da agricultura extensiva, com exceção de: a) Uso de mão-de-obra humana e maior geração de empregos no campo
b) Agricultura familiar, normalmente voltada para a subsistência
c) Uso de maquinários agrícolas tanto no cultivo quanto na colheita
d) Uso de técnicas rudimentares, como as queimadas, para a preparação do solo

This is all you, but i can give you some topics that you could try. if it rained when you want to do something outdoors, it 'limits' that human activity. maybe you want to do an experiment that goes throughout the whole year and you have to have above freezing the entire year. this 'limits' your activity. i thought of those just off of the top of my head. something that gets to me that might be getting to you is you are thinking too hard about what to do. think simply, and if it is too simple, then bump it up just a little bit.