農(nóng)業(yè)凍土冰含量測(cè)量方法試驗(yàn)研究

摘" 要：農(nóng)業(yè)凍土中的冰含量作為凍土凍融過(guò)程的關(guān)鍵變量之一，影響著土壤水分動(dòng)態(tài)變化、土壤養(yǎng)分流失和農(nóng)田生態(tài)環(huán)境維穩(wěn)等。根據(jù)質(zhì)量守恒原理和體積變換關(guān)系，自制一種農(nóng)業(yè)凍土冰含量測(cè)量的試驗(yàn)裝置，進(jìn)行-20、-25、-30 ℃和土壤含水率為15.7%、23.5%、31.4%的冰含量測(cè)量試驗(yàn)。結(jié)果表明，農(nóng)業(yè)凍土樣品中冰含量隨凍結(jié)溫度降低冰質(zhì)量含量增加。凍結(jié)溫度達(dá)到-30 ℃時(shí)，冰質(zhì)量含量達(dá)到一個(gè)恒定的峰值。相同凍結(jié)溫度不同含水率狀態(tài)下，冰質(zhì)量含量百分比趨于一個(gè)平均值，且最大值和最小值之差約為2%。

關(guān)鍵詞：農(nóng)業(yè)；凍土；冰含量；測(cè)量；凍結(jié)溫度

中圖分類號(hào)：S271" " " 文獻(xiàn)標(biāo)志碼：A" " " " " 文章編號(hào)：2095-2945（2024）25-0080-04

Abstract： As one of the key variables in the freezing and thawing process of agricultural permafrost， the ice content in agricultural permafrost affects the dynamic change of soil moisture， the loss of soil nutrients and the stability of farmland ecological environment. According to the principle of mass conservation and volume transformation， a self-made experimental device for measuring ice content in agricultural frozen soil was made， and ice content measurements were carried out at-20，-25， and -30 ℃ and soil moisture content of 15.7%， 23.5% and 31.4%. The results show that the ice content in agricultural frozen soil samples increases with the decrease of freezing temperature. When the freezing temperature reaches -30 ℃， the mass content of ice reaches a constant peak. At the same freezing temperature and with different moisture content， the percentage of ice mass content tends to be an average， and the difference between the maximum value and the minimum value is about 2%.

Keywords： agriculture; frozen soil; ice content; measurement; freezing temperature

凍土是指具有負(fù)溫且含冰的各類土，由土壤顆粒、冰、液相水和氣體組成[1]。按凍結(jié)保持的時(shí)間分為短時(shí)凍土、季節(jié)性凍土和多年凍土。其中季節(jié)性凍土面積占全國(guó)總面積的53.5%[2]。季節(jié)性凍土凍融過(guò)程中，土壤的物理特性會(huì)發(fā)生改變，如土壤顆粒的重新排列、土壤結(jié)構(gòu)的改變等，影響了土壤肥力和通透性，不利于農(nóng)作物生長(zhǎng)。解凍過(guò)程中下層土壤解凍速度比上層土壤解凍速度遲緩，中間形成不透水層，土壤水分滲透性下降，導(dǎo)致耕作層土壤過(guò)濕，地溫較低，推遲了農(nóng)作物播種時(shí)間。土壤水分運(yùn)移和根系生長(zhǎng)速度減緩，導(dǎo)致土壤墑情不佳，限制農(nóng)作物吸收養(yǎng)分和水分的能力，抑制土壤微生物繁衍及代謝活動(dòng)，導(dǎo)致農(nóng)作物正常生長(zhǎng)緩慢，產(chǎn)量和品質(zhì)下降。此外，農(nóng)業(yè)生產(chǎn)中的灌溉定額、旱澇、地下補(bǔ)水和農(nóng)田水利設(shè)施等均受到一定的影響[3-8]?！?br>