ABSTRACT

This study investigates the sources of water under four modes, namely, normal fields, Raised Fields, single agriculture in Raised Fields, and agroforest system in Raised Fields, by using a combination of δ¹⁸O, δ²H and δ¹³C and their effects on crop yield and water use efficiency. The results show that the soil electrical conductivity of Raised Fields during summer maize seasons was lower than that during winter wheat seasons, and that in the marginal regions was higher than in the central regions, because of the Water Sources. Under agroforest conditions in Raised Fields, Soil Salinity can be reduced because approximately 10% of the water originates from tree trunks. The biomass yield and intrinsic water use efficiency of winter crops under agroforest was 15.1% and 5.5% higher than that under single agriculture, respectively. Thus, soil salinization can be reduced and productivity can be increased by controlling the Water Sources in ecosystems.

摘要

本研究探讨下四种模式中，水的来源，即，正常的字段，架空字段，在高位字段单农业，并且在凸起的字段农林复合系统，通过使用δ组合¹⁸ O，δ ² H和δ ¹³C及其对作物产量和水分利用效率的影响。结果表明，由于水源的关系，夏季玉米田的耕地土壤电导率低于冬小麦季节，而边缘地区的土壤电导率高于中部地区。在高田的农林条件下，可降低土壤盐分，因为大约10％的水来自树干。农林复合林下冬季作物的生物量产量和内在水分利用效率分别比单一农业下高15.1％和5.5％。因此，通过控制生态系统中的水源，可以减少土壤盐碱化并提高生产力。