玉米/紫花苜蓿间作对土壤化学性质的影响

Effects of corn/alfalfa intercroppingon soil chemical properties

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。

To understand the effect of corn/alfalfa intercroppingon soil fertility, three planting modes were established in this study, namely corn monolith(row spacing: DY30, DY50 and DY70), alfalfa monolith(row spacing:DZ30) and corn/alfalfaintercropping(JYZ30, JYZ50 and JYZ70),the content of organic matter, total nitrogen, alkali-hydrolyzed nitrogen, total phosphorus, available phosphorus, total potassium and available potassiumin each treatment soil were determined at corn spike period, grout period and wax ripening period of maizeon the basis of the model, and the soil fertility was evaluated by the average membership.The results showed that the contents of soil organic matter, total nitrogen, alkali solution nitrogen, total phosphorus and effective phosphorus decreased at the startand then increased with the increase of row spacing under corn monoculture, and decreased to the lowest at DY50 treatment, each parameter values were 31.98-40.31 g/kg, 1.57-1.77 g/kg, 108.42-143.50 mg/kg, 0.67-0.84 g/kg and 11.09-20.56 mg/kg, respectively. The content oftotal potassium and available potassium increase at the startand then decreased, and reached maximum at DY50 treatment, the contents ranged from 7.93-9.86 g/kg and 85.00-140.33 mg/kg, respectively. Compared with alfalfa monoculture, the nutrient content in the soil showed a decreasing trend under corn/alfalfa intercropping, especially the content of soil effective phosphorus decline was most pronounced, which ranged from 14.50-23.03 mg/kg. Compared with maize monoculture, the content of each index in the soil showed an increasing trendunder corn/alfalfa intercropping. The contents oftotal nitrogen and available potassium in the soil decreased at the start and then increased with the increase of row spacing of maizeunder corn/alfalfa intercropping, and both decreased to the lowest at DY50 treatment, each parameter values ranged from 1.60-1.78 g/kg, 70.00-110.00 mg/kg, respectively. in addition, both maize monoculture and intercropping, the contents of organic matter, total nitrogen, total phosphorus and alkaline hydrolysis nitrogen at grout period were lower than those at corn spike period and wax ripening period. The membership function analysis showed that soil fortility of the single corn was less than the intercropping under the condition of the corresponding row spacing(except that the now spacing of corn was 70 cm).The results indicated that corn/alfalfa intercropping could improve soil fertility.