不同杂交苏丹草对比试验

通过对7个杂交苏丹草品种的比较试验,表明不同品种间的种籽千粒重、生长速度、鲜草产量和营养成分等存在较大差异。根据鲜草产量和质量,生产中以选择美国Supper(A)、PacesettewPlus(B)、Lush(D)、丹麦SweetNHoney(C)、澳大利亚Jumbo(E)5个品种较好。从不同家畜饲用牧草特点考虑,建议牛、羊用以种植产量高、青贮性能好的A、B、C、D品种为好,兔用宜选择再生能力强、草质优嫩、种籽小、用种量低、适口性好的E品种。

7个杂交苏丹草品种的特性分析

通过对7个杂交苏丹草品种的比较试验,表明不同品种间的种籽千粒重、生长速度、鲜草产量、营养成份等存在较大差异。根据鲜草产量和质量,生产中以选择美国Supper(A)、Pacesettew Plus(B)、Lush(D)、丹麦Sweet N Honey(C)、澳大利亚Jumbo(E)、阿根廷Don Verdeo(F)和国产(G)5个品种较好。从不同家畜饲用牧草特点考虑,建议牛、羊用以种植产量高、青贮性能好的A、B、C、D品种为好,兔用还可选择再生能力强、草质优嫩、种籽小、用种量低、适口性好的E品种。

Inclusion Levels of Fermented Apple Bagasse on in Vitro Rumen Fermentation of Alfalfa Hay

The aim of this study was to assess the effect of inclusion of fermented apple bagasse （FAB） obtained through solid state fermentation on pH, ammonia nitrogen （N-NH3）, volatile fatty acids （VFA） content, in vitro dry matter digestibility （IVDMD）, lactic acid and microbial counting of alfalfa hay under in vitro rumen environment; four levels of FAB were evaluated （0, 0.25, 0.50 and 0. 75 g/dry matter of FAB） replacing 1.5 g dry matter （DM） of alfalfa hay and incubated at different fermentation times （0, 4, 8, 12 and 24 h） using a complete random design with repeated measures on time. Counts of live yeast colonies （6.08, 6.33, 6.24 and 6.51 CFU/mL expressed as log 10） was higher when FAB was included in the different levels up to the 12 h of fermentation （P 〈 0.0001）; lactic acid content also increased as FAB was included in the different levels （10.61, 13.86, 16.84 and 14.57μg/mL） up to the 12 h of incubation （P 〈 0.001）. Nevertheless, the other variables measured as pH, N-NH3, VFA, IVDMD, total bacteria and fungi counts, were not affected by the treatments. It is concluded that substitution of FAB by alfalfa hay in an in vitro rumen ecosystem positively modified live yeast colonies and lactic acid concentration, without effect on the other fermentative and microbial parameters of the in vitro rumen environment, but considering mixes of FAB and alfalfa hay as a quality ingredient for the feeding of ruminants.

Effects of nitrogen addition and mowing on nitrogen-and water-use efficiency oi Artemisia frigida in a grassland restored from an abandoned cropland

Aims Competition among plants in a community usually depends on their nitrogen(N)-use efficiency(NUE)and water-use efficiency(WUE)in arid and semi-arid regions.Artemisia frigida is an indicator species in heavily degraded grassland,however,how its NUE and WUE respond to N addition in different successional stages is still unclear,especially with mowing,a common management practice in semi-arid grasslands.Methods Based on a long-term controlled experiment with N addition and mowing in an abandoned cropland from 2006 to 2013,we investigated the NUE and WUE oi A.frigida in two patches(i.e.grass and herb patches)in 2013 which represented two potential successional stages from herb to grass communities.The coverage of A.frigida was higher(about 50%)in the herb patch than in the grass patch(about 10%).Stable isotopic C(δ^(13)C)and N(δ^(15)N)as well as C and N pools were measured in plants and soils.NUE was calculated as leaf C/N,and leafδ^(13)C values were used as a proxy for WUE.Important Findings N addition did not affect WUE of A.frigida,but significantly decreased NUE by 42.9%and 26.6%in grass and herb patches,respectively.The response of NUE to N addition was related to altering utilization of different N sources(NH_(4)^(+)vs.NO_(3)^(-))by A.frigida according to the changed relationship between leafδ^(15)N/soil 615N and NUE.Mowing had no effect on NUE regardless of N addition,but significantly increased WUE by 2.3%for A.frigida without N addition in the grass patch.The addition of N reduced the positive effect of mowing on its WUE in grass patch.Our results suggested that decreased NUE and/or WUE of A.frigida under mowing and N addition could reduce its competition,and further accelerate restoration succession from the abandoned cropland to natural grassland in the semi-arid region.