Up to a thousand people,many of them en－slaved,might live and work on a single plantation.

在一個(gè)種植園中可能有多至一千人在生活和工作91日韩在线观看视频，而其中的很多人都在受著奴役。

Up to a thousand people,many of them en－slaved,might live and work on a single plantation.

第一批黑奴是在1619年被運(yùn)到弗吉尼亞來的久草亚洲视频，這是朝圣者們?cè)谄绽┧沟顷懙那耙荒辍?/p>

After land use structure was predicted by use of markov, woodland area increased swingingly yearly, others decreased yearly, in particular croplandand and plantation decreased markly, and system stability decreased.,so the land use structure should be coordinated.

利用馬爾柯夫模型對(duì)該流域土地利用結(jié)構(gòu)進(jìn)行預(yù)測(cè)黄色网站毛片网站，發(fā)現(xiàn)林地與園地所占面積比例逐年增加，林地增加幅度較大美女艹网站免费；其余各類土地均呈遞減趨勢(shì)日本三级片网黄色，特別是耕地減少幅度較大，系統(tǒng)穩(wěn)定性逐漸降低欧美pAAAA片，應(yīng)調(diào)整土地利用結(jié)構(gòu)天美三级片网站，增加系統(tǒng)穩(wěn)定性。

The interaction of the climate in the last century, the ecology charactor of Tsuga tchekiangensis itself, and the outside disturbance were the main factors which caused the plantation extinct sharply.

南方鐵衫瀕危的主要原因是近百年來的氣候因素人人在线人人操、南方鐵杉自身生態(tài)特性和外界干擾相互作用的結(jié)果亚洲美女天堂网。

Over a 20-year period there was no increase in soil water content in the grazed grassland at depths of 2～9.9 m. There was a small increase(0.5～3.7 mm/a) in soil water content in the protected grassland, however the slow rate of increase suggests that at least 150 years would be needed for ungrazed grassland soils to regain water content similar to that present prior to planting trees. Recharge of deep soil moisture was faster in cropland(15 mm/a), but at this rate it would still take about 40 years to restore cropland soil water content to pre-plantation conditions.

結(jié)果表明，人工林死后的放牧荒坡在20a的時(shí)間里福利一区首页，其土壤水分沒有補(bǔ)償免费A级不卡在线毛片；人工林死后的保護(hù)草地土壤水分有微弱恢復(fù)跡象，但年恢復(fù)速度在0.5～3.7 mm之間玖玖爱精品视频在线观看免费2，以這樣的速度恢復(fù)到持續(xù)放牧荒坡的土壤含水量国产产一区二区三区久久毛片最强，至少需要150a以上；林后農(nóng)地土壤含水量有恢復(fù)趨勢(shì)黄片毛片免费大全，年平均恢復(fù)速度為15 mm左右人人操人人草人人草人人叉人，其土壤含水量要恢復(fù)到持續(xù)農(nóng)地當(dāng)前的水平，大約需要40a的時(shí)間在线直接性片黄色视频。

Planted forests can deplete deep soil water, forming an obstacle to sustainable land use in the semi-arid area of Loess Plateau. The purpose of this study was to examine effects of grazing and cropping on replenishment of deep soil water where forest plantations had depleted soil moisture at depths of 2～9.9 m. We compared soil moisture on plantation plots with that on plots where plantations were replaced by crops, grazed grassland, and ungrazed grassland seperately.

為了研究黃土丘陵半干旱區(qū)人工林跡地土壤水分恢復(fù)情況黄色视频一区二区三区免费在线观看，該文以正在生長的人工林土壤水分含量為人工林跡地土壤水分恢復(fù)的起點(diǎn)，并分別以持續(xù)農(nóng)地和持續(xù)放牧荒坡的土壤含水量為林后農(nóng)地和草地土壤水分恢復(fù)的上限一级无码奶水，對(duì)位于黃土丘陵半干旱區(qū)綏德縣境內(nèi)的人工林跡地土壤水分恢復(fù)情況進(jìn)行了研究在线国产福利网址。

Is an internal inspection program established at the beginning of the year in order to vison of natural enemies of pests (plantation of hedges, biodiversity, release of predators,…).

害蟲天敵的保護(hù)（種植樹籬，保持作物多樣性国产乱人伦偷精品视频免费看，引入天敵……）

But after about a month to restore the root system, the leaves of nitrogen, phosphorus and potassium contents in treatment 5, 6, 7, 8, 2 gradually higher than the control. This is because the absorption of fertilizer during this period shown to promote on the elements, and with the passage of time the processing elements continue to be reduced to a leaf until the latter part of the growing season is also higher than the control.3.The pH value in rhizosphere soil of treatments poplar plantation were lower than that in non-rhizosphere soil, but the content of organic,available nitrogen, phosphorus, potassium, utility cuprum and utility zincum were all higher than those in non-rhizosphere soil.

但是經(jīng)過大約一個(gè)月的根系恢復(fù)五月综合婷婷久久狠狠，處理5、處理6av激情网站、處理7日韩午夜在线看导航视频网站免费下载、處理8、處理2葉片中的N9啪在线、P毛片视频免费观看视频大全、K逐漸高于對(duì)照，這是因?yàn)槭┓蕦?duì)元素的吸收在這一期間開始表現(xiàn)出了促進(jìn)作用啪啪啪黄色网站，并且隨著時(shí)間的推移各處理中元素含量持續(xù)降低至落葉二级黄色网站免费在线，直至后期的生長季節(jié)也高于對(duì)照黄色1级视频。3、各處理的楊樹林地根際土壤pH值均低于非根際土壤αv中文字幕在线毛片免费，而有機(jī)質(zhì)欧洲免费多人疯狂、堿解氮、速效磷婷婷久久高清国外AV免费、速效鉀免看一级a一片日韩A片、有效銅和有效鋅的含量均高于非根際土壤，與其它處理相比a级黄片一级，80cm兩側(cè)斷根施肥處理的根際土和非根際土壤速效養(yǎng)分含量最高日韩黄色视频品爱，差異達(dá)顯著水平。

The plantation owner would rather plough their cotton into the earth than sell it at a lower price.

種植園主寧可把棉花犁入土中99热W亚洲精品国产99，也不愿以低價(jià)出售18禁片免费网站在线看。

The dancing of those slaves who, looking through the windows of a plantation manor house from the yard, im-itated the steps so gravely performed by the masters within and then added to them their own special flair,burlesquing the white folks and then going on to force the stepssintosa choreography uniquely their own.

那些在院子里跳舞的奴隸們，透過莊園房子的窗戶男人的天堂av社区在线，模仿著里面主人們的莊重舞步三级绝黄A片在免费线观看欧美，然后就把他們自己獨(dú)特的舞蹈才華加進(jìn)去，以滑稽的動(dòng)作諷刺白人国语自产免费精品视频在，之后他們繼續(xù)將這些舞步加到他們獨(dú)有的舞蹈中全国最新的黄色视频播放久了爽爽。