The Role of Soil Organic Matter and Manures in Sustainable Nutrient Cycling - Sustainable Management of Soil Organic Matter - page 274

occur in fertilizer, rainfall or animal feed, either as grasses or as tree fodder.
The most significant loss of N from the household occurs in cereal grains
rather than in leachate, eroded sediment or runoff. The largest flux of N
occurs in the passage of fodder into the animal and so into the manure,
which is returned to the land. Although this particular flux pathway is
relatively conservative of N (apparently little N is lost from or added to this
cycle), the household is not completely self-sustaining with respect to N.
The household N budget depends upon the input of N particularly as
fodder from areas of land external to the household.

Experimental Validation of Two N Fluxes

Fluxes in grain and straw

Two experiments located at ARS-Pakhribas, Dhankuta, Nepal provide
crop yield data and tissue N concentrations. Seven experimental treatments
were applied to a maize-millet rotation on bari land and a rice-wheat
rotation on khet land. The treatments were zero inputs, and inputs of N at
two rates as manure alone, fertilizer alone or manure plus fertilizer (FYM)
in combination. The higher rate of N represented farmer-recommended
practice for a particular crop, while the lower rate was half of the
recommended dose. If these N inputs to bari and khet land are scaled to
represent the area of each land type in an hypothetical household (i.e. 0.66
and 0.33 ha, respectively), then the N input as FYM and fertilizer for each
experimental treatment can be compared with that for the hypothetical
household (see Table 4.7.1). More fertilizer is applied in the experiments

Table 4.7.1. Amounts of N (kg) in fertilizer and manure applied in each of six experimental
treatments (see text for details) to maize-millet and rice-wheat rotations expressed on the basis
of a hypothetical household owning 1 ha divided in a 2 : 1 ratio between bariand khetland.

Maize-millet (bari) Rice-wheat (khet) Total household

Treatment a Fertilizer Manure Fertilizer Manure Fertilizer Manure

HF 60 0 43.3 0 .3 103.3 0 .3

HM 0 60 0 .3 43.3 0 .3 103.3

HFM 30 30 21.7 21.7 51.7 51.7

LF 30 30 21.7 0 .3 51.7 0 .3

LM 0 30 0 .3 21.7 0 .3 51.7

LFM 15 15 10.8 10.8

25.8 25.8

Fig. 4.7.1 26 .3 100 .3

a Treatment symbols: H, high N rate; L, low N rate; F, fertilizer; M, manure.