Albie Speakman suffered fatal injuries following the incident on a farm in Bury yesterday lunchtime.
Greater Manchester CID and colleagues from the Health and Safety Executive are investigating the circumstances behind the tragedy.
Paying tribute to her son, his mum Leah said: “Albie was an incredibly loving, affectionate and caring boy who just wanted everyone to be happy.
"He was so sensitive and wanted everyone to be ok, especially the people that he loved.
“He loved to play – whether it be with his family or friends at nursery – he would always look for little round things wherever he went, stones, polystyrene balls, bouncy balls, beads - I’m not sure why but he just loved anything round, he would just hold onto them.
“His favourite memories are at Cleethorpes beach, with his bucket and spade and his ball."
His mum said Albie's "happiest days were on that beach, we were so free and didn’t have any cares in the world".
She added: "It was just me and Albie and nothing else mattered.
"Whenever I’d ask him what he wanted to do, he’d want to go on holiday to the beach again; that’s how I know he was truly happy there.
“We all love Albie so much more than we can ever put into words – especially his Nan and his ‘Nanny-Nanny’, as he would always call her.
“I will miss absolutely everything about Albie, his voice, his smile, the smell of his skin and the feel of his little hands on my face when he would say ‘I love you mummy girl’.
“I’ll especially miss going on adventures with Albie, anywhere and everywhere we could have fun; nothing will ever fill the whole that he has left in our hearts, we are broken beyond repair.
“I always call him my little sunshine boy because he has brought so much light into my life and he is my little ray of sunshine, and I don’t want his life to end here, I need to carry on living for him and take him with me wherever I go. We still have so many more memories to make, Albie!
“I love him so much and I know he will find his way back to me someday, somehow, because we need each other. Until then I will look for him in everything I do and I will celebrate his life.
“I’m not sure how to carry on this life without you but I will find a way to be strong for you and make you proud.”
Albie Speakman with his mum Leah
PA
Albie Speakman
PA