N release from livestock waste compost pellets in barley fields

N release patterns from dairy cattle, swine, and poultry waste compost pell ets were studied using the buried glass filter paper method in barley field s. Field experiments with barley were also carried out to study the relatio nship between N release from pellets and N absorption by barley. Results sh owed that about 28, 36, and 44% of N were released from 3 types of compost pellets throughout the growth stages of barley, respectively. However, sinc e more than 60% of N was released before the tillering stage of barley, bar ley absorbed a large amount of N and grew excessively in winter. When poult ry and swine waste compost pellets were incorporated into dairy cattle wast e compost at the N ratio of 1 : 1 or 2 : 1, N release rate from the incorpo rated pellets decreased, but N was still mainly released at early stage aft er application. Compost pellets made of dairy cattle and swine waste compos t at the N ratio of 1 : I led to the highest production of barley in this e xperiment, followed by compost pellets made of dairy cattle and poultry was te compost at the N ratio of 1 : 1 and poultry waste compost pellets. The u se of these three types of pellets resulted in a barely yield higher than t hat obtained with chemical fertilizers at the significant level of 1%. Amou nts of P and K absorbed by barley in the pellet treatments exceeded those i n the chemical fertilizer treatments, suggesting that additional applicatio n of chemical fertilizer containing phosphorus and potassium was not necess ary when animal waste compost was used for barley production as basal ferti lizer. Meanwhile, the balance of nutrients, such as N, P, and K, in the com post pellets should be considered also to achieve comprehensive management of nutrients for crop production.