黑(hei)(hei)松(song)混(hun)(hun)交(jiao)林(lin)可(ke)以加速林(lin)木生(sheng)長，增加林(lin)木產(chan)量，減少(shao)病蟲害(hai)發生(sheng)，提高(gao)林(lin)分(fen)(fen)穩定性，同時，具有充(chong)分(fen)(fen)利用(yong)地力，培(pei)肥林(lin)地土壤(rang)，改善生(sheng)態環(huan)境的良(liang)好(hao)作用(yong).目 前黑(hei)(hei)松(song)混(hun)(hun)交(jiao)林(lin)對土壤(rang)因(yin)子影響及(ji)其增產(chan)作用(yong)機理研究甚少(shao)，該文(wen)通過對林(lin)地土壤(rang)微(wei)生(sheng)物、土壤(rang)酶及(ji)土壤(rang)養分(fen)(fen)的研究，探討(tao)不同類型混(hun)(hun)交(jiao)林(lin)土壤(rang)生(sheng)化特性及(ji)其與土壤(rang)肥 力的關(guan)系，為營造黑(hei)(hei)松(song)混(hun)(hun)交(jiao)林(lin)提供依據.

　　1材料與方法

　　1.1樣地基本情況

　　山東省龍口市(shi)龍口林場位于北(bei)緯37°40’~ 37°44’，東經120°15’一(yi)120°26’，屬暖(nuan)溫帶(dai)季風(feng)氣候區(qu)，土(tu)壤為濱(bin)海沙土(tu)，肥力較低.設置(zhi)典型(xing)樣地分別為黑松x 刺槐、黑松x麻棟、黑松x紫穗槐等3種(zhong)混交林和黑松純林。

　　1.2土樣的采集和記載

　　在各樣(yang)地(di)中(zhong)，選取一處(chu)做土壤(rang)(rang)剖面觀測記載，然(ran)后(hou)，機械地(di)設置3個樣(yang)點(dian)，采用多(duo)點(dian)混合(he)取樣(yang)法，按0~20 cm, 20 ~40 cm兩層(ceng)分別取混合(he)樣(yang).采集(ji)后(hou)迅速保鮮帶回冷藏供(gong)土壤(rang)(rang)微生物(wu)、土壤(rang)(rang)酶(mei)和土壤(rang)(rang)養分測定用.同時測定土壤(rang)(rang)容重、含(han)水(shui)量等物(wu)理性狀。

　　2結果與分析

　　土壤微生物分析

　 　3種(zhong)類型混(hun)交林(lin)(lin)下(xia)土壤中(zhong)各種(zhong)微(wei)生(sheng)物(wu)數(shu)(shu)(shu)(shu)量(liang)(liang)存在(zai)明(ming)顯差異性，在(zai)總體數(shu)(shu)(shu)(shu)量(liang)(liang)上均以xxx為主，真(zhen)菌(jun)次之，纖維(wei)素分解(jie)菌(jun)較(jiao)(jiao)(jiao)少，且(qie)xxx數(shu)(shu)(shu)(shu)量(liang)(liang)是真(zhen)菌(jun)、放(fang)線(xian)菌(jun)等數(shu)(shu)(shu)(shu)量(liang)(liang)的(de)(de)數(shu)(shu)(shu)(shu)千 倍(bei).xxx、真(zhen)菌(jun)、纖維(wei)素分解(jie)菌(jun)數(shu)(shu)(shu)(shu)量(liang)(liang)以黑松(song)(song)(song)(song)X刺槐(huai)混(hun)交林(lin)(lin)的(de)(de)較(jiao)(jiao)(jiao)多，黑松(song)(song)(song)(song)X麻棟混(hun)交林(lin)(lin)的(de)(de)次之，黑松(song)(song)(song)(song)X紫(zi)穗槐(huai)混(hun)交林(lin)(lin)的(de)(de)較(jiao)(jiao)(jiao)少;放(fang)線(xian)菌(jun)數(shu)(shu)(shu)(shu)量(liang)(liang)以黑松(song)(song)(song)(song)X刺槐(huai)混(hun)交林(lin)(lin)的(de)(de)較(jiao)(jiao)(jiao)多， 黑松(song)(song)(song)(song)X麻棟混(hun)交林(lin)(lin)的(de)(de)次之，黑松(song)(song)(song)(song)X紫(zi)穗混(hun)交林(lin)(lin)的(de)(de)較(jiao)(jiao)(jiao)少;自生(sheng)固氮菌(jun)數(shu)(shu)(shu)(shu)量(liang)(liang)則以黑松(song)(song)(song)(song)X紫(zi)穗槐(huai)的(de)(de)較(jiao)(jiao)(jiao)多，黑松(song)(song)(song)(song)X麻棟的(de)(de)次之，黑松(song)(song)(song)(song)X刺槐(huai)的(de)(de)較(jiao)(jiao)(jiao)少.但各種(zhong)微(wei)生(sheng)物(wu)數(shu)(shu)(shu)(shu)量(liang)(liang)均隨土 層深度增加而(er)顯著(zhu)降(jiang)低.

　　xxx、真菌在土(tu)壤有機物和無機物轉化(hua)過程中(zhong)(zhong)起著(zhu)重(zhong)(zhong)要作(zuo)用.xxx在氨化(hua)過程中(zhong)(zhong)作(zuo)用十分重(zhong)(zhong)要，而真菌則在土(tu)壤碳素(su)和能源循環過程中(zhong)(zhong)起著(zhu)較(jiao)大的(de)作(zuo)用.黑松(song)(song)X刺槐、黑松(song)(song)X麻(ma)棟(dong)、黑松(song)(song)X紫穗槐3種混交(jiao)林(lin)下土(tu)壤xxx、真菌數量均(jun)明顯(xian)高于黑松(song)(song)純林(lin)。

　 　自生固氮(dan)(dan)菌具有(you)固定大氣中(zhong)氮(dan)(dan)氣，豐富(fu)土壤氮(dan)(dan)素的(de)能(neng)(neng)力(li)，其數量的(de)多少也可作為土壤肥力(li)的(de)一個(ge)指標[“].分析表(biao)明(ming)，黑松(song)X刺槐(huai)(huai)、黑松(song)X麻(ma)棟、黑松(song)X紫穗槐(huai)(huai) 3種混交(jiao)林(lin)下土壤自生固氮(dan)(dan)菌數量均(jun)低于(yu)黑松(song)純林(lin)，分別(bie)為純林(lin)的(de)98.0% 43. 7%和(he)51.800.這(zhe)種結果可能(neng)(neng)與(yu)刺槐(huai)(huai)、麻(ma)棟、紫穗槐(huai)(huai)等伴生樹種與(yu)固氮(dan)(dan)菌間存在固氮(dan)(dan)和(he)聯合共生的(de)機制有(you)關，使自生固氮(dan)(dan)菌數量相對減少，其原因(yin)有(you)待(dai)深入研 究.

　　2.2土壤酶活性分析

　　3種(zhong)混交林下(xia)土(tu)壤(rang)酶(mei)活(huo)性存在明顯差異.服(fu)酶(mei)和過氧化(hua)氫(qing)酶(mei)活(huo)性高(gao)低排(pai)列順序(xu)為(wei)黑松(song)(song)X刺槐(huai)黑松(song)(song) X麻棟(dong)(dong)黑松(song)(song)X紫(zi)穗槐(huai)，轉化(hua)酶(mei)活(huo)性高(gao)低排(pai)序(xu)為(wei)黑松(song)(song)X麻棟(dong)(dong)黑松(song)(song)X紫(zi)穗槐(huai)黑松(song)(song)X刺槐(huai)，磷酸(suan)酶(mei)活(huo)性高(gao)低排(pai)序(xu)為(wei)黑松(song)(song)X麻棟(dong)(dong)黑松(song)(song)X刺槐(huai)黑松(song)(song)X紫(zi)穗槐(huai)，但3種(zhong)混交林下(xia)土(tu) 壤(rang)各種(zhong)酶(mei)活(huo)性均(jun)高(gao)于黑松(song)(song)純林.表(biao)明混交林顯著提高(gao)土(tu)壤(rang)酶(mei)的活(huo)性，使(shi)林地土(tu)壤(rang)生化(hua)過程增強(qiang)，有機(ji)物轉化(hua)和循環加快，土(tu)壤(rang)肥力提高(gao)。