3. As regards all extensive permanent grassland which is the subject of an agreement—
(1) the farmer shall maintain the land and shall not carry out any mechanical operations except that he may cut or top the grass other than rough grazing from 16th July until 31st August inclusive in any year;
(2) the farmer shall not cut any grass except for hay;
(3) the farmer shall not apply any inorganic fertiliser or slurry;
(4) the farmer shall not apply any farmyard manure on enclosed areas of rough grazing. He shall apply only farmyard manure on other land, shall not exceed existing application rates and in any event shall not exceed 12.5 tonnes per hectare in any three year period. He shall apply farmyard manure only in a single dressing;
(5) the farmer shall not apply lime, slag or any other substance designed to reduce the acidity of the soil;
(6) the farmer shall not erect any permanent or temporary fences without the Minister’s prior written approval.