亚博app

yiyuebeihongrangqiulingqudeshaoguanshizhenjiangquxinshaozhenmoutaoyuanweiyanjiuduixiang,yangdijunweitaoshu(prunus persica),qidilizuobiaowei113°42'05″e,24°48'38″n,shishaoguanjingneidaibiaoxingguoyuan。turangcaiyangyu2019nian11yue23—24rijinxing,caiyangqijiantianqiqinglang,qiejin2geyuewuyouxiaojiangshui,turanghanshuiliangjidi,geturangcaiyangdiandepingjunhanshuiliangwei5.88%。yangdichaoxiangweidong(81°),haibawei215.1 m,podu17°,nianjiangshuiliang1 601 mm,nianpingjunqiwen22℃。gaiyangdibeicewei9 ashengtaoyuan,yangdinancewei1 ashengtaoyuan。1 ashengtaoyuandibiaoluolu,gaiduyue10%,er9 ashengtaoyuandibiaocunzaishaoshudegouyagen(cynodon dactylon),gaiduyue70%。

zaixuanzejuticaiyangdishi,yangditongyiyuguoshudongnance,julishugan1.1 m,dibiaojunluolu。cedingqiancongkaiwahaodeturangpoumiandebutongcengmianshangyongbengjiequyangqiquyuanzhuangtu,zai1 ashenghe9 ashengdetaoyuandeshangpowei、zhongpoweihexiapoweifenbiequyangsanci,qiquyangshendufenbiewei0—20 cm,20—40 cmhe40—60 cm,zaimeiyicengqu100 gtuyangfangrulvhezhong,daihuishiyanshiyonghongganfacedinggecengturanghanshuiliang; yonghuandaofaqutu,cedinggecengturangrongzhongjikongxidudengturangwulixingzhizhibiao; yonglvhezaigecengquyuanzhuangtu,meicengquyangsanci,cedingturangbengjiexingneng,duimeicengshiyandejieguoqiupingjun。yanjiuyangdideturangphjieyu4.5～5.1,biaocengturangphzhizuidi,suanxingzuiqiang,9 ashengturangphzhijiaogao,1 ashengdejiaodi; turangkeliyishalihefenliweizhu,liangzhebizhongdadao85%yishang。

土壤崩解在实验室内进行测定,利用已知的标记土样,分批进行测定,自制试验装置主要由天平(精确度0.01 g)、崩解玻璃槽、崩解金属网、秒表、金属细线、支架等部分组成(图1)。金属网网孔大小为10 mm×10 mm,崩解金属网为圆形直径10 cm,崩解金属网与天平之间由细线连接,金属网不接触玻璃槽,水位线是指完全淹没土样的水量高度。

tu1 turangbengjiezhuangzhishiyitu

亚博appshiyanqianjiangshengshiliangshuidebengjiebolicaofanghao,xuangua、diaozhenghaobengjiejinshuwangdeweizhi,kongbengjiejinshuwangwanquanjinrushuizhonghoujiangtianpingguiling; shiyanshijiangyichengzhongdetuyangjunyunfangzhiyubengjiejinshuwangshang,xuanguahaobengjiejinshuwanghou,jiangqihuanmanjinrushuizhong,xixianziranbengzhi(bengjiejinshuwangwanquanjinmeiyushuizhong),mei10 sji1citianpingdushu,2 minhoumei30 sjiyici,7 minhoumeifenzhongjiluyici,gongjilu31ci,bengjieshizhangquanbuwei960 s,bengjiehoushuibianhunzhuohoujishihuanshui。shiyanyuanliwei:dangxuanguadekongbengjiejinshuwangwanquanjinmeizaishuizhongshi,yibengjiejinshuwangweishoulifenxiduixiang,xixianxiangshangdelali、bengjiejinshuwangzishendezhongli、bengjiejinshuwangshoudaodefulisanlipingheng,xixiandelalidengyubengjiejinshuwangzishendezhongliyuqisuoshoufulizhicha,erfulizechuandidaobengjiebolicaodedibu。weilegengkeguanfanyingturangbengjiezhuangkuang,caiyongleijiturangbengjiezhishuzhibiaozuoweiturangbengjiexingnengzhibiao,qijisuangongshiwei:

式中:S为崩解时段内的土壤累积崩解指数(%); S₀为崩解开始时的读数(g); S_a为a时间时天平的读数(g); M_b为崩解结束时天平的读数(g)。

turangbengjiesulvbiaoshidanweishijianneidebengjieliang,qijisuangongshiwei:

式中:V为土壤崩解速率(g/min); M₁为第t₁时刻的土壤崩解读数(g); M₂为t₂时刻的土壤崩解读数(g); t₂和t₁为崩解的时间(s)。崩解速率即单位时间内土壤在静水中的崩解量,以土壤崩解率定量表示土壤崩解性能,崩解速率愈低,土壤愈不容易崩解。

采用土壤累积崩解指数与土壤崩解速率代表土壤崩解特征。从图2和图3亚博app可以看出:随着崩解时间增加,土壤累积崩解指数与崩解速率总体呈现先快后慢的趋势,前120 s土壤崩解速率较大,特别是前30 s的崩解速率最大,土壤累积崩解量也迅速增加。在60 s后土壤崩解速率迅速降低,在600 s之后,土壤崩解速率几乎为0,土壤崩解量极小,累积崩解量基本不变。

congleijibengjiezhishulaikan,zaiturangbengjieshiduannei,suoyouyangdianzhongzuidadeturangleijibengjiezhishuwei1 ashengtaoyuanxiapoweibiaoceng(0—20 cm),qileijibengjiezhishuda51.45%; suoyouyangdideturangleijibengjiezhishuzuixiaoweishangpowei20—40 cmshendudeturang,qibengjiezhishuwei18.05%,jinjinweizuidazhide35.08%。congbengjiesulvlaikan,suoyouyangdianbengjiesulvzuidazhiwei1 ashengtaoyuanxiapoweidebiaoceng(0—20 cm),yuzuidaleijibengjiezhishuxiangtong,qibengjiesulvwei14.40 g/min,erzai9 ashengtaoyuanshangpowei0—20 cmshendudeturangzuidabengjiesulvjinwei2.78 g/min,jinjinweiqianzhede19.31%。suoyouyangdiandezuixiaobengjiesulvjunwei0。

亚博apptu2 9nianshengtaoyuanbutongpoweiturangleijibengjielianghebengjiesulvsuishijianbianhuaguocheng

亚博apptu3 1nianshengtaoyuanbutongpoweiturangleijibengjielianghebengjiesulvsuishijianbianhuaguocheng

从图2和图3可以看出:1 a生桃园的累积崩解指数随着土层深度的增加而降低,而9 a生的桃园则呈现不一致的规律:土层深度在0—20 cm的累积崩解指数均在前120 s内为所有土层深度的最低值,在120 s后则在上坡位和下坡位的累积崩解指数居中,中坡位的累积崩解指数最低; 土层深度在20—40 cm的累积崩解指数则随着坡位降低而增加; 土层深度40—60 cm的累积崩解指数在上坡位和中坡位最大,而下坡位则在120 s后土层深度在40—60 cm的崩解指数最低。各土层深度的土壤崩解速率总体表现为随土层深度的增加而降低。

由图2,图3可知,各土层的土壤崩解速率可分为3个阶段:(1)极速崩解期:崩解曲线升高与降低均迅猛。9 a生桃园各土层深度的崩解速率在前60 s达到最大值,1 a生的桃园在前30 s达到最大崩解值,土壤崩解速率在此阶段均达到最大值;(2)缓慢崩解期:曲线缓慢下降,即从60～360 s期间,各土层深度的土壤崩解速率缓慢降低;(3)崩解稳固期:曲线趋近水平,即从360～960 s期间,各土层深度的土壤崩解速率极低,特别是在600 s后基本停止崩解。各土层深度的累积崩解指数变化曲线与崩解速率曲线变化方向相反。土层深度在0—20 cm土壤崩解过程较长,崩解曲线相对平缓,崩解量缓慢增加; 20—40 cm的崩解过程与0—20 cm的规律相似,但土壤崩解速率加快; 40—60 cm的土壤崩解速率相对迅速。

从图2和图3亚博app可以看出:9 a生桃园的上坡和中坡均为下层(40—60 cm)土壤崩解指数较大。上坡表层(0—20 cm)次之,中层(20—40 cm)相对较小。而中坡土壤的崩解指数为下层>中层>表层,下坡为中层>表层>下层。1 a生桃园不同坡位则规律相对一致,上中下三坡位不同土层深度的土壤崩解指数均为表层>中层>下层。对1 a生和9 a生桃园土壤的崩解特性进行比较,当土层深度一定时,不同坡位土壤累积崩解指数与崩解速率均为1 a生桃园土壤大于9 a生桃园土壤。

9ashengtaoyuanturangbengjiesulvzaiqian120 sshangpogecengturangbengjiehenkuai,turangbengjiesulvzai120 shoucaizhujianpinghuan,biaocengturangbengjiesulvkuaiyuzhongcenghexiaceng,dansuizheshijiandetuiyibengjiesulvzhujianxiangjin,960 sshisancengquling。er1 ashengtaoyuanqian60 sdeturangbengjiesulvkuai,zhongcengturangbengjiesulvkuaiyubiaocenghexiaceng,zai480 sshiquling。1 ashengtaoyuanturangdegecengturangbengjiesulvgaoyu9 ashengtaoyuan,qiezai60 shoubengjiesulvquxianzhujianpinghuan。

表1为各个采样点土壤容重与土壤含水量的大小。土壤容重与最大崩解速率线性呈现负相关(p=0,R²=0.599),与最大崩解指数也呈现负相关关系(p=0,R²=0.559); 土壤最大崩解速率与最大崩解指数均随着容重的增加而减少。土壤容重越大,土壤细颗粒间的孔隙占比越小,对进入孔隙水的作用力越小,单位时间内崩解量越小,即崩解速率越小。

土壤含水量与最大崩解速率(p=0.018,R²=0.301)及最大崩解指数(p=0.014,R²=0.321)均呈现线性负相关关系。土壤含水量决定土壤颗粒间胶结的状态,是决定土壤崩解的重要因素之一,土壤含水率越低,土壤崩解速率也随之增强,被破坏现状越显著。

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