XI’AN, — For Wei Tian’en, growing watermelons is a white-collar job that needs only a few clicks of the mouse. Most of the day he stays home in north China’s Shaanxi Provinceand tends the crops through software installed in his computer, which allows him to monitor the humidity, temperature and other aspects of the greenhouse. “It makes farming much easier,” said Wei, 41, one of about 100 villagers in the suburbs of the provincial capital Xi’an who have joined the “remote control yo