He was speaking to reporters in Bhopal after taking part in Congress' 'Satyagraha' to protest the killing of five farmers in police firing in Mandsaur district.
Small traders would have to file 37 returns in place of the present four, he said.
Meanwhile, Singh has written a letter to the Prime Minister, reminding him of BJP's poll promise on MSP.
"BJP manifesto in 2014 Lok Sabha election had promised that it would ensure that farmers will get MSP equal to one-and-a-half times the cost of farm produce as per the Swaminathan Commission report," the letter said.
However, the NDA government has now told the Supreme Court that it would not be able to pay MSP at this rate, and "should we consider that you are backtracking from your promise," the letter said.
"Farmers could not get adequate price for produce during the Kharif season in 2016 and Rabi season in 2017 due to demonetisation, because more than 85 per cent of traders paid them in cash (which the note-ban made difficult)," it said.
Change in import duty on farm produce also harmed the farmers' interests, it said, adding that in December 2016, the centre reduced the import duty to zero per cent from 10 per cent, and in March 2017 it was again increased to 10 per cent.
"Between December 2016 and March 2017, traders made profit by importing wheat at Rs 1,400-1,450 per quintal while the MSP was Rs 1,650 per quintal. The government can purchase only 30 per cent of total production. The remaining wheat is purchased by the traders, who buy it at lower rate due to abundant availability," he added.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)