ABSTRACT
Using stable isotopes to study water uptake characteristics of summer corn under different fertilizer treatments

Lihua Lü1, Jiahong Hu2, Mengjing Zheng1, Yukun Hu2*, and Jingting Zhang1*
 
Water and fertilizer are the major limiting factors in crop production. At present, the utilization of chemical fertilizers is not reasonable, and excessive use of chemical fertilizers makes a serious threat to the environment, while organic fertilizer is a green and sustainable fertilization method for crops. The objective of this study was to determine the water uptake characteristics of corn (Zea mays L.) after applying chemical and organic fertilizers, using dual stable isotopes (delta Oxygen-18 [δ18O] and delta deuterium [δD]) to study the main water uptake soil layers and the contributions of soil water at different depths to corn. A field experiment was carried out using a randomized block design in Gaocheng, China. For T1, chemical fertilizers were applied in both wheat (Triticum aestivum L.) and corn seasons. For T2, chemical and organic fertilizers were applied during the wheat season, and chemical fertilizers were applied during the corn season. Results showed that water uptake mainly came from the 0-0.2 m depth at the milk growth stage (81%), 0-0.4 m depth at the 6th leaf growth stage (85%), and 0-0.7 m depth at the 9th leaf growth stage (86%), 13th leaf growth stage (91%), tassel growth stage (89%), silking growth stage (87%), blister growth stage (95%), and dough growth stage (94%). Fertilization led to clear differences in the proportional contribution of soil water from 0-0.2 m (average 35% and 44% for chemical and organic fertilizer, respectively), 0.2-0.4 m (25% and 21%), and 0.7-1.2 m (10% and 5%). The manure fertilizer reduced soil bulk density, and increased soil stable aggregates, saturated water content, soil porosity, and water retention capacity of shallow soil. Our results provide a theoretical basis for developing a reasonable fertilization plan combining inorganic and organic fertilizers in arid areas.
Keywords: Corn, fertilization mode, hydrogen and oxygen stable isotopes, water uptake.
1Hebei Academy of Agricultural and Forestry Sciences, Institute of Cereal and Oil Crops/Key Laboratory of Crop Cultivation Physiology and Green Production of Hebei Province, Shijiazhuang, China.
2Chinese Academy of Sciences, Institute of Genetics and Development Biology, Center for Agricultural Resources Research, Shijiazhuang, China.
*Corresponding author (huyk@sjziam.ac.cn, jingting58@126.com)