Farm efficiency was increased by the use of windmills in the fields to pump water and by allowing villeins their freedom and hiring them as laborers only when needed. Customary service was virtually extinct. A man could earn 5d. for reaping, binding, and shocking into a pile, an acre of wheat. A strong man with a wife to do the binding could do this in a long harvest day. There was enough grain to store so that the population was no longer periodically decimated by famine. The population grew and all arable land in the nation was under the plough. The acre was standardized. Harvests were usually plentiful, with the exception of two periods of famine over the country due to weather conditions. Then the price of wheat went up and drove up the prices of all other goods correspondingly. Although manors needed the ploughmen, the carters and drivers, the herdsmen, and the dairymaid on a full-time basis, other tenants spent increasing time in crafts and became village carpenters, smiths, weavers or millers' assistants. Trade and the towns grew. Smiths used coal in their furnaces. Money rents often replaced service due to a lord, such as fish silver, malt silver, or barley silver. The lord's rights are being limited to the rights declared on the extents [records showing service due from each tenant] and the rolls of the manor. Sometimes land is granted to strangers because none of the kindred of the deceased will take it. Often a manor court limited a fee in land to certain issue instead of being inheritable by all heirs. Surveyors' poles marked boundaries declared by court in boundary disputes. This resulted in survey maps showing villages and cow pastures. The revival of trade and the appearance of a money economy was undermining the long-established relationship between the lord of the manor and his villeins. As a result, money payments were supplementing or replacing payments in service and produce as in Martham, where Thomas Knight held twelve acres in villeinage, paid 16d. for it and 14d. in special aids. "He shall do sixteen working days in August and for every day he shall have one repast - viz. Bread and fish. He shall hoe ten days without the lord's food - price of a day 1/2d. He shall cart to Norwich six cartings or shall give 9d., and he shall have for every carting one leaf and one lagena - or gallon - of ale. Also for ditching 1d. He shall make malt 3 1/2 seams of barley or shall give 6d. Also he shall flail for twelve days or give 12d. He shall plough if he has his own plough, and for every plouging he shall have three loaves and nine herrings ... For carting manure he shall give 2."