在盐碱地改良利用过程中，有必要研究土壤酶活性变化，以评价土壤环境质量的改善。龟裂碱土重度盐碱荒地主要分布在我国西北旱区，该土壤碱化度高，结构差，导水率极低。2009年，采用滴头下设置沙穴的方式滴灌种植枸杞，开垦利用该盐碱荒地。2011年枸杞生长季末，在不同种植年限地块土壤剖面上网格状密集取土，进行土壤脲酶、碱性磷酸酶和蔗糖酶活性的测定。结果表明，未种植土壤3种酶活性极低；滴灌种植之后，随着根区土壤水盐特性和养分状况的改善，土壤酶活性显著增加。就整个土壤剖面而言，土壤酶活性自根区向四周逐渐降低，表现出较大的空间变异性。相关性和通径分析结果显示，土壤pH始终是影响该土壤酶活性的主要因子，且在pH7.38~10.00的范围内，3种酶活性随土壤pH的增大呈指数式减小（p < 0.01）。总之，滴灌种植枸杞之后，龟裂碱土重度盐碱荒地土壤生物学性质得到显著改善。
In reclaiming or ameliorating salt-affected soils, it is essential to go in-depth studying soil biological activities so as to evaluate variation of soil environmental quality and sustainability of the amelioration measures. Highly saline-sodic takyric solonetz wastelands are distributed mainly in arid regions in Ningxia Plain, Northwest China. This type of soils is characterized by extremely high content of sodium and high pH, varying in the range of 9~10, and consequent poor soil structure and low saturated hydraulic conductivity (Ks< 0.1 mm d-1). In the 0~40 cm soil layer, the average electrical conductivity of saturated slurry extract (ECe), pH of saturated slurry (pH) and sodium adsorption ratio of saturated slurry extract (SAR) was 10.3 dS m-1, 9.4 and 38.9 (mmol L-1)0.5, respectively. In the past a lot of measures have been tried to reclaim the wastelands, however, most of them failed primarily because of the very low saturated hydraulic conductivity of the soil. In 2009, this type of wastelands was reclaimed by cultivating wolfberry (Lycium barbarum L.) with drip irrigation. Under the drip emitter near the plant, a pit, 0.2 m in diameter and 0.2 m in depth, was prepared and filled with alien sand for planting wolfberry in. The sand-filled pit was to increase the area of contact between soil and water and the area of water infiltration in takyric solonetz under drip irrigation, thus lowering water supply rate down to or approximately to saturated hydraulic conductivity of the native soil. Besides, the sand pit maight also serve as a reservoir to hold surplus water prior to its infiltrating into the soil and extend water infiltration time, thus ensuring water infiltration into the soil and making reclamation of the soil possible. At the end of the wolfberry growing period in 2011 (October 16th, 2011), soil samples were collected intensively from soil profiles, perpendicular to the drip irrigation belt, in fields different in wolfberry cultivation history (1 a, 2 a and 3 a), covering a wide gradient of salinity and alkalinity, for analysis of activities of soil urease, alkaline phosphatase and sucrase, which were the enzymes, respectively, key to N, P and C recycling in soil, and of soil physicochemical properties as well. In order to clarify any potential causal-relationships between soil enzyme activities and physicochemical properties, correlation analysis and path analysis were performed. Results show that all the 3 enzymes were very low in activity in uncultivated soils due to the high saline-alkali stress and low organic matter content. After the soil was reclaimed to cultivate wolfberry with drip irrigation, soil enzyme activities increased gradually with the cultivation going on, displaying high spatial variability within the profile. Enzyme activities were found quite high in the root zone under the drip irrigation belt and declined outwards from root zone. Higher soil enzyme activities in the root zone helped the crop absorb soil nutrients. Both correlation analysis and path analysis show that soil pH is always the dominant factor affecting soil enzyme activities, and activities of all the 3 soil enzymes decreased exponentially with pH in the range from 7.38 to 10.00 (p < 0.01). The exponential relationship between them demonstrates that in soils quite low in pH (< 8.5), any rise in soil pH would induce a sharp drop in soil enzymes activities. In a word, the adoption of such a wolfberry cultivation pattern greatly improves soil biological properties of the highly saline-sodic takyric solonetz wasteland.
张体彬,康跃虎,万书勤,冯 浩.滴灌枸杞对龟裂碱土几种酶活性的改良效应[J].土壤学报,2015,52(6):1392-1400. DOI:10.11766/trxb201410230532 Zhang Tibin, Kang Yaohu, Wan Shuqin, Feng Hao. Ameliorative effect of cropping Lycium barbarum L. with drip irrigation on soil enzymes activities in takyric solonetz[J]. Acta Pedologica Sinica,2015,52(6):1392-1400.复制