玉米/紫花苜蓿间作对土壤化学性质的影响

为了解玉米/紫花苜蓿间作对土壤肥力的影响,试验设置了3种种植模式,分别为玉米单作、紫花苜蓿单作和玉米/紫花苜蓿间作,玉米单作行距分别为30,50,70 cm(DY30、DY50和DY70);紫花苜蓿单作行距为30 cm(DZ30);玉米与紫花苜蓿间作,紫花苜蓿行距为30 cm,玉米行距分别为30,50,70 cm(JYZ30、JYZ50和JYZ70),玉米与紫花苜蓿的行距均为30 cm,分别在玉米抽穗期、灌浆期和蜡熟期测定各处理土壤中有机质、全氮、碱解氮、全磷、有效磷、全钾、速效钾7个化学指标含量,并采用平均隶属函数对土壤肥力进行综合评价。结果表明:玉米单作随着行距的增加,土壤有机质、全氮、碱解氮、全磷及有效磷含量呈先减少后增加趋势,均在DY50处理时降到最低,各指标值分别介于31.98~40.31 g/kg、1.57~1.77 g/kg、108.42~143.50 mg/kg、0.67~0.84 g/kg及11.09~20.56 mg/kg之间;全钾与速效钾大致呈先增加后减少趋势,在DY50处理时含量达到最大,介于7.93~9.86 g/kg与85.00~140.33 mg/kg之间;与紫花苜蓿单作相比,间作土壤中的养分含量大致呈下降趋势,尤其土壤中的有效磷含量下降最为明显,含量介于14.50~23.03 mg/kg之间;与玉米单作相比,间作土壤中各指标含量变化不同,但均呈增加趋势;玉米/紫花苜蓿间作随着玉米行距的增加土壤全氮和速效钾含量呈先减少后增加趋势,均在JYZ50处理时降到最低,各指标值分别介于1.60~1.78 g/kg、70.00~110.00 mg/kg之间;此外,无论玉米单作还是间作,灌浆期土壤中的有机质、全氮、全磷及碱解氮含量大致低于抽穗期和蜡熟期。隶属函数分析表明相应行距的单作玉米土壤肥力小于间作(除玉米行距为70 cm外)。说明玉米与紫花苜蓿间作可提高土壤肥力。

Physiological Response of Paspalum notatum’s Leaf and Root under Persistent Drought Stress

To investigate the correlation and difference between Paspalum notatum’s leaf and root under drought adversity,this study tested the physiological responses of wild Paspalum notatum’s leaf and root under 0(CK),1,3,5,7,14,21,and 28 d drought stress treatment.These physiological responses include osmotic regulating substance,antioxidant enzyme activity,malonaldehyde content,cell membrane permeability,and chlorophyll content.According to the results,the soluble protein content,proline concentration,malonaldehyde content,cell membrane permeability and CAT activity in Paspalum notatum’s leaf and root tended to increase with the prolongation of drought stress;the soluble sugar content and SOD activity first increased and then decreased;POD dropped gradually;the contents of chlorophyll a,b and total chlorophyll first declined,then mounted,and lastly dropped again.During the early stage of drought stress,SOD and CAT acted as the main antioxidant enzymes in Paspalum notatum’s leaf and root.However,with the aggravation of drought stress the predominant antioxidant enzymes became SOD in the root system whereas CAT and POD in the leaf.It implicates drought has a strong influence on root’s CAT and leaf’s SOD and POD.Leaf is the major organ regulating the osmosis and photosynthesis of Paspalum notatum.The findings can provide a useful theoretical basis for improving Paspalum notatum’s drought tolerance.

Effects of Vetiveria zizanioides Planting on Water Quality in Areas Surrounding Coal Gangue Mountain

In order to investigate the correlation between the variations in the environmental water quality indexes and the distance of water bodies from the planting region of vetiver, samples of surface water were gathered from the water bodies surrounding an abandoned coal gangue mountain of Dahead coal mine (Dahe, Liupanshui, Guizhou Province) based on the method of field survey and typical analysis. According to the results, the planting of vetiver could effectively purify the water bodies surrounding the coal gangue mountain. Detailed findings include three aspects:(1) The main pollutants detected in water bodies around the coal gangue mountain were SO4 2-, NO3 -, Fe and Cu, with a concentration of 869.45, 35.16, 26.06, and 40.85 mg/L respectively in wet season and all exceeded the national environmental standards for surface water.(2) The pH values of water bodies 150~200 m away from the vetiver planting region stayed within the limits of national environmental standards for surface water and presented a homogeneous feature, revealing that vetiver has the capacity to adjust the pH of the surrounding water body.(3) The contents of Fe, Mn, Cu, SO4 2-, and NO3 - under all treatments, tended to increase with the increasing distance of water bodies from the vetiver planting region;it means the shorter the distance between the water body and the vetiver planting region is, the higher the adsorption rate and purification effects will be;the optimal concentrations of Fe, Mn, and Cu were 0 mg/L, much lower than the national environmental standards for surface water.