Unconventional feeds for small ruminants in dry areas have a minor effect on manure nitrogen flow in the soil–plant system

Abstract

In dry areas, unconventional feeds are increasingly used for mitigating feed shortages and rangeland degradation. We evaluated how feeding sheep diets containing olive leaves, saltbush leaves and olive cake affects manure quality compared to a barley straw based diet. Soil incubation and plant growth experiments were carried out to measure soil nitrogen (N) mineralization and N uptake by barley plants and to calculate N flow through the feed-animal-soil-plant system. Fresh feces, composts consisting of feces, urine and straw, and ammonium sulfate fertilizer were mixed with soil at rate of 90 mg N kg-1 soil dry matter. Comparisons were made with non-amended soils (control) and soils amended with fresh olive cake applied at 90 and 22.5 mg N kg-1 soil dry matter, respectively. The latter treatment enabled investigation of the effect of passage of olive cake through the digestive tract of sheep on N availability and phenol transformation. Applying fresh olive cake and feces, except the saltbush leaf derived feces, resulted in a net N immobilization. All composts resulted in net N mineralization, although not significantly different from the 0N control soil. Barley growing in soils with amendment that caused N immobilization took up less N than barley growing on the 0N treatment. Reduction in N uptake was most pronounced after amendment with fresh-olive cake. Treatments with net mineralization increased barley N uptake over the 0N treatment with 2-16 % of N applied being taken up. Dietary composition had a minor effect on N fertilizer value of either feces or compost, but feces N alone was not an efficient N source.

RADIX: rhizoslide platform allowing high throughput digital image analysis of root system expansion

“…N content of the shoots was measured with a CN analyser (Flash EA, 1112 series) [42]. As reference plant material Alfalfa was used.…”

“…After drying, shoots were ground using a swing mill (Retsch MM200, Retsch GmbH, Haan, Germany) with a frequency of 25 s −1 for one minute. N content of the shoots was measured with a CN analyser (Flash EA, 1112 series) [ 42 ]. As reference plant material Alfalfa was used.…”

Invited review: Nitrogen in ruminant nutrition: A review of measurement techniques

“…One such example is phenols, especially condensed tannins, which may firmly bind to proteins. Manure from diets rich in such compounds was sometimes Abbeddou et al, 2013), but not always (Tiemann et al, 2009), shown to have a lower plant N fertilizer value, a phenomenon Estermann et al, 2002;Śliwiński et al, 2004;Hindrichsen et al, 2005Hindrichsen et al, , 2006Machmüller et al, 2006;Van Dorland et al, 2007;Klevenhusen et al, 2011 Total gaseous N emissions Model manure storage with mass balance Estermann et al, 2002;Śliwiński et al, 2004;Van Dorland et al, 2007 NH 3…”

“…Comprehensive analyses have to consider total farm system N efficiency. Although urine N is likely best used by the plants, N use efficiency cannot be fully and reliably predicted from this information, because the fertilizer value is a complex matter including C:N ratio, phosphorus content, and anti-nutritional compounds possibly hampering plant growth and thus N utilization (Abbeddou et al, 2013).…”