Shirley Tarawali

A few thoughts on potential livestock dimensions of the soil fertility policy debate.  These are not intended to be comprehensive in any way, but to simply raise the issue that in taking an equitable broad based approach to the topic, including consideration of a livestock dimension, whilst in no way a panacea, could be one useful aspect.

Livestock interact with soil in many ways, all of which have the potential to impact soil fertility:

  1. through consumption of material (forage, range, crop residues, in some cases crop grains) that removes these nutrients, vegetation or organic matter from the soil
  2. through the manure and urine that may contribute nutrients, and for the former, organic matter to the soil  – in some instances providing a “redistribution” function for nutrients from rangeland to cropland, or (eg where feed is imported) on a wider scale
  3. through providing soil tillage that affects the soil physical structure and impacts crop (and forage) production
  4. through trampling soil that affects soil structure – such as water holding properties

In much of the developing world, especially for the poorest, inputs to soil fertility from livestock are highly valued.  Many farmers keep livestock for manure even before the milk or meat they may produce.  In the majority of cases however the nutrient inputs from livestock manure are probably only about 10% of those needed to support crop production.  Many studies have shown that combining organic and inorganic inputs gives the best returns on both and helps to maintain soil structure/in a healthy condition.

Policies related to soil fertility directly can be influenced by and have an influence on livestock

  1. policies that make fertilizer easily and cheaply available if promoted in isolation, could mean farmers do not use manure – this would both jeopardize long term soil health (because of a reduction on soil organic matter) and potentially present a problem of manure use/disposal
  2. such policies could also favour the expansion of crop production which may impinge upon livestock grazing and trekking routes leading to conflicts as well as overuse of a restricted land area by livestock

Policies related to livestock production can influence soil fertility

  1. policies that influence the location of intensive livestock production can affect soil fertility.  If policies encourage location of intensive livestock production in localities where crops are produced, along with appropriate manure management guidelines, there can be some win-win opportunities.  If on the other hand, policies favour the separation of livestock production from the land where crops are grown, the soil suffers and the environment suffers
  2. policies that impact livestock movement may impact soil fertility – influencing where livestock deposit manure, or where the soil is adversely affected by over grazing/trampling or vegetation changes because of restricted livestock movement
  3. conversely policies that influence the ability of livestock keepers to be paid for environmental management can positively impact on the soil condition

Policies influencing land use and management impact both livestock and soil fertility

  1. incentives to manage soil in a sustainable way are likely to be higher if there is secure land tenure
  2. pricing of land as an input into livestock and crop production can influence the management of soil
  3. policies influencing the use of conservation agriculture may impact livestock – access to equipment; cover crops (some of which may also be forages); use of crop residues

Shirley Tarawali, Theme Director
International Livestock Research Institute (ILRI)