The sites for trenching grounds should be carefully selected; light sandy soil unshaded by trees and well open to the south and west will give the best results. They should be well above flood level, at least 5 feet above the highest known flood, situated on the down stream side of the bazaar, connected by good pucca roads with it to allow of quick carriage, as time is the most important factor in the disposal of night-soil, and should not be in the direction of the prevailing winds with the town. A fringe or belt of bamboos between the town and trenching grounds will be found of the greatest use in keeping off flies which might be blown into inhabited neighbourhoods, and which are a most dangerous factor in disseminating disease.

Burdwan Trenching Ground.

At Burdwan in Bengal there is a successful example of what can be done with trenching grounds from a financial point of view. There the night-soil of the Northern Section of the Municipality, where the latrine system is in force, and which has a population of about 23,000, is mainly disposed of in a permanent trenching ground of 18 bighas in area. This is collected from private latrines in covered buckets and deposited in the conservancy carts at the public latrines, whence it is removed to the trenching grounds, where trenchers are told off for each latrine group, who excavate the trenches and are in charge of them; these trenches are 3 feet wide, 1½ feet wide, 12 to 15 feet in length and 1 foot apart. The carts empty the night-soil in from one end until a height of 9 inches of liquid is attained, the excavated earth being then replaced. During the rainy season Indian corn is grown, and in the cold weather cabbage, cauliflower, Bengal pumpkin, and other kitchen vegetables, for which there is a ready sale in the local bazaar.

The trenching ground during the current year 1913–14 has been leased out for Rs. 600.

Cultivation of Jute.

In the damp climate of Bengal jute has been found to grow very luxuriantly on newly-trenched ground and yields an abundant crop; it exhausts the soil so much that after the crop has been cut the field can be re-trenched, an important point when the subsoil water is practically 12 or 18 inches from the surface while the jute is growing. Another advantage in growing jute is that in certain localities there is a difficulty in finding a market for vegetables grown on a trenching ground.

Muzaffarpur Jail.

In Muzaffarpur Jail the trenches were made 1 foot deep, 1 foot wide, and 1 foot apart, and varying in length according to requirements; 3 inches of night-soil are filled in and covered over with the excavated earth; 20 trenches are always kept ready, being excavated the day before. Corn is found to grow luxuriantly after the trench has been filled in for a month, and other kinds of vegetables, excepting potatoes, after two months. Urine and sullage water are buried in different fields and at a considerably greater depth.

Allahabad.

At the Government Farm at Allahabad (United Provinces) the system known as the Allahabad Shallow Trench was in successful operation, and provided for the whole of the cantonment and half the municipal population; there is an unlimited area of land available, the soil being of various kinds, black cotton, sandy loam and stiff clay. The only crops grown are grass and sorghum, and it is found that the manurial value of the night-soil is not exhausted for three or four years. Trenching can, however, be done every third year on the same land without making it “sewage sick;” land which was worth Rs. 2 will, after trenching, fetch about Rs. 10 per bigha for seven or eight years.