| Published monograph of the Production, Storage, and Exchange (PSE) in a Terraced Environment on the Eastern Andean Escarpment |
Cultivating Diversity: Field Scattering as Agricultural Risk Management in Cuyo Cuyo, Department of Puno, Peru
Footnotes to Chapter 7
1 While this procedure provides accurate estimates of the actual quantities of sheep manure which result from the wanuna, it underestimates nutrients. The penning of sheep in the fields allows the urine they excrete to be captured in addition to dung. Sheep urine contains valuable nutrients. Nitrogen may be excreted, as may sodium, potassium, and chloride. Like other herbivores, sheep excrete most of their phosphorus in the feces (Azavedo and Stout 1974).
2 The principal use of the NPKtot variable will come in the following chapter, where I use it to examine the relation between fertilization and yield. For those purposes, it is necessary to combine the three macronutrients in order to avoid unacceptable levels of multicollinearity in the regression models.
3 The total number of fields in years 2, 3, and 4 of the rotation was 294. Of these, all but 9 (285) were planted in some combination of non-potato tubers, habas, and illaco. A total of 139 of these were fertilized.
