切根与施肥对姜家甸退化草场羊草产量及土壤肥力的影响

Effects of root cutting and fertilization on Leymus chinensis yield and soil fertility of degraded grassland in Jiangjiadian

为了加快轻度退化刈割草场的恢复,了解切根与施肥对姜家甸退化草场羊草(Leymus chinensis)产量及土壤肥力的影响,试验以姜家甸退化草场为研究对象,采用随机区组设计,以不做任何处理为对照,利用盘齿式草地破土切根机进行切根并配合施肥处理,同时连续观测两年(2014,2015年),分析在切根基础上配合4种施肥梯度,零浓度(不施肥)、低浓度(尿素75 kg/hm,磷酸二胺45 kg/hm^(2))、中浓度(尿素150 kg/hm^(2),磷酸二胺90 kg/hm^(2))、高浓度(尿素225 kg/hm^(2),磷酸二胺135 kg/hm^(2)),对草场羊草株高、密度、盖度、地上及地下生物量、土壤有机质、全氮、铵态氮、硝态氮、全磷、速效磷及草场经济效益的影响。结果表明:处理当年(2014年)和处理次年(2015年)零浓度处理下羊草盖度与对照相比分别提高10.00%和24.17%,羊草密度分别提高23.00%、39.00%,低浓度、中浓度、高浓度处理下,羊草盖度、密度与对照相比均显著升高(P≤0.05)。处理当年羊草地上生物量在中浓度处理时达到最大,为453.6 g/m^(2),显著高于对照(P≤0.05);0~10 cm土壤有机质、全磷、铵态氮含量均在中浓度处理时达到最大,与对照相比分别提高50.82%、25.00%、93.53%。汇总两年草场净产值,中浓度处理时,两年的净产值最大,为2 318.78元/hm^(2)。说明中浓度处理措施为姜家甸轻度退化草地恢复的最佳措施。

In order to speed up the recovery of slightly degraded mowed grassland, to investigate effects of root cutting and fertilization on the yield and soil fertility of Leymus chinensis in the degraded grassland of Jiangjiadian, the degraded grassland in Jiangjiadian was chosen as the research object. In this experiment, a randomized block design was used, the control group was not treated with any treatment, while the experimental group was treated with a disc tooth root cutter and fertilization treatment. The observation lasted for two years(2014,2015 year). The effects of four fertilization gradients set on the basis of root cutting, including zero concentration(no fertilization), low concentration(urea 75 kg/hm^(2), diamine phosphate 45 kg/hm^(2)), medium concentration(urea 150 kg/hm^(2), diamine phosphate 90 kg/hm^(2)), high concentration(urea 225 kg/hm^(2), diamine phosphate 135 kg/hm^(2)), on plant height, density, coverage, aboveground and underground biomass, soil organic matter, total nitrogen, ammonium nitrogen, nitrate nitrogen, total phosphorus, available phosphorus and economic benefits of Leymus chinensis grassland were analyzed. The results showed that compared with the control, the coverage of grassland increased by 10.00% and 24.17% in the first year(2014) and the next year(2015), respectively, and the density of Leymus chinensis increased by 23.00% and 39.00% under zero concentration treatment, respectively. The coverage, density of Leymus chinensis under low, medium and high concentration treatments were significantly higher than those of the control(P≤0.05) in the year of treatment(2014) and the year after treatment(2015). The aboveground biomass of Leymus chinensis reached the maximum(453.6 g/m^(2)) under medium concentration treatment, which was significantly higher than that of the control(P≤0.05). The contents of organic matter, total phosphorus and ammonium nitrogen in 0-10 cm soil reached the maximum under the medium concentration treatment, which increased by 50.82%, 25.00% and 93.53% compared with the control, respectively. The net output value of grassland in two years under medium concentration treatment was 2 318.78 yuan/hm^(2), which reached the maximum. The results indicated that the medium concentration treatment was the best method for the restoration of the slightly degraded grassland in Jiangjiadian.