The deceased is Shahinur Begum, 35, wife of Rahedul Islam alias Lichu Mia, who is a Bangladeshi expatriate in Saudi Arabia.
Sources said the incident took place in Singhadanga village of Taluknanpur union under the upazila on Friday afternoon.
Sub-inspector (SI) Kalyan Kumar Chakraborti of Gobindaganj police station said Shahinur, also a mother of three, leased out a piece of land to a neighbour named Abdul Karim of late.
On Thursday, Karim prepared seedbed for Boro cultivation on the land, he said, adding, one Anwarul Islam of the same village went to the land to plant Boro paddy on Friday morning.
Hearing the update, Shahinur rushed to the scene and informed Anwarul about the land being leased out and asked him to stop planting the paddy, the SI further added.
The conversation between Shahinur and Anwarul intensified into an altercation. At one stage, Anwarul hit the woman with a spade on the head, leaving her spot dead.
Police, however, detained Anwarul's elder brother Chan Mia and his nephew Laizu Mia over the incident.
The body was later sent to the morgue of Gaibandha Adhunik Sadar Hospital for an autopsy.