苏丹草—黑麦草轮作中不同施肥措施对饲草产量及土壤性质的影响

在盆栽试验条件下研究了苏丹草—黑麦草轮作中不同施肥措施对饲草产量、养分吸收及土壤性质的影响。结果表明:各施肥处理均可显著提高饲草产量，整个轮作期，单施化肥（NPK）、石灰和化肥配施（NPK+Lime）、有机肥和化肥配施（NPK+OM）处理的鲜草产量分别比不施肥处理（CK）增加6.1倍、6.8倍和7.3倍；在化肥基础上配合施用石灰和有机肥，鲜草分别增产9.5%和17.2%。养分吸收结果显示，不同施肥处理明显提高饲草N、P、K含量并促进饲草对养分的吸收。土壤养分分析结果表明，与CK及NPK处理相比，增施石灰和有机肥提高酸性土壤pH值，促使其向中性靠近；在NPK基础上配合施用石灰，轮作结束时土壤有效钙含量比NPK处理提高了20.7%，有效铁和有效锰含量降低了26.5%和41.2%；在NPK基础上增施有机肥，能显著提高了土壤中的氮、磷、钾养分含量。

Effects of different fertilization treatments on forage yield and soil properties in sudangrass-ryegrass rotation

Sudangrass and ryegrass rotation was adopted and developed as a new cultivation technique in many pisciculture regions in south China. Because cultivated soil had low pH, poor soil fertility and extensive cultivation with poor soil management, forage yield was insufficient and hindered the development of the productive forces in forage-fish system. A pot experiment was carried out in Hubei Province, central area of China and the objective was to determine the effects of soil amendments including fertilizers (NPK), lime and organic matter (OM) application on forage yield and soil properties in sudangrass-ryegrass rotation. The results showed that the application of soil amendments increased forage yield significantly. In the whole rotation, forage yield in NPK, NPK+Lime, and NPK+OM were 6.1, 6.8 and 7.3 times higher than that in the control (CK), respectively. Based on NPK treatment, the application of lime and OM increased yield by 9.5% and 17.2%. Nutrients uptake results demonstrated that different fertilization treatments significantly increased N, P, K content of forages and promoted nutrient uptakes. N, P and K uptake amounts of sudangrass and ryegrass in NPK treatment increased by 6.3 times, 7.7 times and 7.0 times, respectively, when compared with that in CK, and NPK+Lime treatment increased by 6.5 times, 8.6 times and 7.4 times, and NPK+OM treatment increased by 6.2 times, 9.2 times and 7.4 times, respectively. The soil analysis results showed that the application of lime and OM increased pH value in the acidic soil compared with that of CK and NPK treatments after the experiment. Based on NPK treatment, lime application increased soil available Ca by 20.7%, and decreased soil available Fe and Mn by 26.5% and 41.2%, respectively. Based on NPK treatment, OM application improved soil available N, P and K content significantly.