James Mills has spent a lot of time thinking about chicken muck lately.

After the 51³Ô¹ÏÍø disrupted supplies of conventional nitrogen fertilizers, the English farmer began scouring the Yorkshire countryside for substitutes to keep his crops growing. That led Mills to the poultry shed of a relative¡¯s friend, whose chicken manure is suddenly so sought after that he now has a long list of buyers.

¡°Everyone is doing the same, looking for alternatives,¡± said Mills, who harvests wheat, barley and oats on a farm dotted with sheep.