Sarah Pettitt said small and medium-sized farmers "running businesses from a mobile phone on their tractor" were the backbone of the industry.
"But they feel their voices are not always heard," she added.
"It's often the small farmers taking all the risks and I feel they need more support. They have a special place in my heart."
Pettitt, a partner in a family farm growing sprouts and purple-spouting broccoli near Boston, Lincolnshire, was vice-chairman for four years and takes over from former chairman Richard Hirst.
She said research and development needed a massive boost, calling for emphasis in the applied arena and the "scientific blue sky" of academic research.
"It's our boys on the ground and they need that support, given the challenges of climate change, loss of chemistry and affordable food. It's in the public interest."
Supply-chain issues and overpowering supermarkets will also be priorities for Pettitt. Relationships had become volatile, fickle and opaque, she said.
"The supply-chain relationship has become very strained and we need to inject transparency and confidence so people understand the risks at each level."
Recent price hikes in supermarkets, blamed on higher input costs, hit a raw nerve, she added: "The price inflation never made it back to the farm gate. That was wrong.
"Many supermarkets are feeling very uneasy. They are not sure whether they have continuity of supply. They know consumers want British. And they know growers are scaling back and a few are (ceasing to grow some crops altogether). That is putting retailers in a very uncomfortable position."
The NFU horticulture board has also appointed a new vice-chairman, Gary Taylor, from Nazeing in Essex. He grows sweet peppers at Valley Grown Salads.