Abstract: In dryland agriculture, soil water-holding capacity is closely associated with soil fertility. Exploring soil water dynamics under the conditions of straw-derived organic materials returning can help reveal the dependency between the core of water retention and soil fertility improvement. Based on a long-term maize field experiment with the treatments of control (CK, without straw), carbonated maize straw incorporation (BC), and crushed maize straw direct incorporation (SD), soil moisture was continuously monitored using soil temperature and humidity recorder. The relationship between soil moisture and soil physicochemical factors was explored. The results showed that the average soil moisture increased by 19.8% (P<0.05) and 9.7% during the whole growth period of maize under the BC and SD treatments, respectively. In May when precipitation occurred after the soil had been dry for several days, soil moisture in the BC increased faster than that in the SD. From July to September, soil moisture increased rapidly following heavy precipitations, and then gradually decreased over time after reaching its peak. In this duration, soil moisture displayed a slower rate of decrease under BC compared to SD. Compared to CK, total soil porosity in BC and SD increased by 18.9% and 7.0%, respectively. Soil water-filled pore space increased by 8.2% in BC and 2.5% in SD, compared to CK. Soil water content in BC was significantly correlated with soil available phosphorus and total phosphorus contents (P<0.05), while soil pore structure in SD was closely linked to alkaline hydrolysis nitrogen content (P<0.05). These findings provide a theoretical basis and guidance for using straw as fertilizer resource.

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