5个热带豆科牧草洗涤纤维的生育期动态及其施肥响应

为了解不同牧草品种在不同肥力条件下洗涤性纤维的生育期动态变化,采用多因素完全随机区组盆栽试验,测定了热研2号柱花草(S1)(Stylosanthes guianensis(Aubl.)Sw.cv.CIAT184)、圆叶决明CPI34721(S2)(Chamaecrista rotundifolia(Pers.)Greene cv.CPI34721)、圆叶决明CPI86134(S3)(C.rotundifolia cv.CPI86134)、圆叶决明ATF3248(S5)(C.rotundifoliacv.ATF3248)、羽叶决明ATF2217(S5)(C.nictitans(L.)Moench cv.ATF2217)在不施肥(F0)、常量施肥(F1)、加倍施肥(F2)情况下,以及生长期内7月25日(C1)、8月29日(C2)、10月8日(C3)、11月14日(C4)分四次进行刈割的牧草洗涤性纤维含量。结果表明:不同牧草品种的洗涤性纤维含量具有较大差异,中性洗涤纤维(NDF)以S4、S1最高(53.4%、52.7%),S5、S3最低(47.9%、46.9%);酸性洗涤纤维(ADF)和酸性洗涤木质素(ADL)均为S5(23.0%、9.1%)极显著地低于其他4个品种(28.0%~29.0%、11.1%~12.3%)(P<0.01)。施肥试验表明,F2极显著地降低了牧草的ADF含量(P<0.01),对NDF、ADL影响不显著。施肥极显著地降低了牧草在C3刈割期的洗涤纤维含量(P<0.01),F1和F2的NDF、ADF、ADL分别比F0下降6.6、5.4,9.7、6.9,2.6、1.6个百分点,且F2的ADF、ADL含量显著低于F1(P<0.05)。刈割试验表明,5个品种的洗涤纤维均随生长时间持续上升,尤其是ADF平均值从C3期的7.9%急剧上升到C4期的24.6%。采用粗饲料相对值(RFV)评价方法表明,S5的平均RFV值最高(143.7),S4、S1最低(118.2、120.9);S5在C3期的RFV值为116,比S4、S1提高16个分值;施肥可以提高RFV值,且与施肥量成正比。该研究结果可为亚热带地区牧草品种选择、最适刈割期和适宜施肥量的确定提供技术借鉴。

Dynamic Variation of the Detergent Fibre of 5 Tropical Leguminous Forages and Their Response to Fertilization during the Growing Period

To understand the dynamic variation of the detergent fibre of tropical leguminous forages and their responses to the fertilization during the growing period,a multifactor random pot-experiment was set up.The five tested tropical leguminous forage species were Stylosanthes guianensis(Aubl.) Sw.cv.CIAT184(S1),Chamaecrista rotundifolia(Pers.) Greene cv.CPI34721(S2),C.rotundifolia cv.CPI86134(S3),C.rotundifolia cv.ATF3248(S4),and C.nictitans(L.) Moench cv.ATF2217(S5),three fertilization levels were no fertilization(F0),ordinary fertilization level(F1;N,P,K were 25,40,50 kg·hm^-2,respectively),and diploid fertilization level(F2;N,P,K were 50,80,100 kg·hm^-2,respectively),and four harvests employed on Jul.25(C1),Aug.29(C2),Oct.8(C3) and Nov.14(C4),respectively.The results show that S4 and S1 had the highest level(53.4% and 52.7%) of NDF(neutral detergent fibre),S5 and S3 the lowest level(47.9% and 46.9%);the difference between the two groups was very significant(P<0.01),but they had no significant differences from S2,respectively.The content of ADF(acid detergent fibre) and ADL(acid detergent lignin) in S5(23.0% and 9.1%) were significantly lower than those of other 4 species(28.0%~29.0% and 11.1%~12.3%)(P<0.01).In comparison with F1 treatment,F2 significantly decreased the ADF content(P<0.01) but less effect on the content of NDF and ADL.Fertilization significantly decreased the content of deterged fiber during the C3 stage(P<0.05);the content of NDF,ADF,and ADL under F1 and F2 treatments decreased by 6.6%,5.4%,9.7%,6.9%,2.6%,1.6% in comparison with F0,respectively;the content of ADF and ADL in F2 were significantly lower than those in F1(P<0.05).The deterged fiber content was increased continuously along with the harvest progress,especially the average ADF values of five forage species were shapely increased from 7.9% in C3 to 24.6% in C4.The average RFV(relative feed value) of S5 was the highest(143.7),and the lowest values were found in S4 and S1(118.2 and 120.9).The RFV values of 5 forage species were positively related to fertilizaiton levels.These results could be useful for variety selection of tropical leguminous forages and making appropriate decisions of harvesting time and fertilization amount.