An appropriate drip irrigation amount and the straw return method are important ways to save water and achieve efficient maize production in semi-arid areas. A 2-year controlled field plot experiment was performed with two factors: straw return (straw removal, straw mulching) and differing drip irrigation amounts (200, 350, and 500 mm). Changes in growth, development, photosynthesis, yield, the components, and the water-use characteristics of maize under the intercropping conditions of drip irrigation amount and straw return were studied. The results showed that an increase in drip irrigation favored an increase in the net photosynthetic rate (P_n), stomatal conductance (G_s), and intercellular carbon dioxide concentration (C_i) of maize, and promoted an increase in maize plant height and leaf area index, which resulted in the accumulation of more dry matter and increased the maize yield. Compared with straw removal, straw mulching maintained a higher photosynthetic capacity at the later stages of maize growth and development under irrigations of 200 and 350 mm; the average increase in P_n over two years ranged from 4.06 to 19.19%; and good plant growth was maintained, thereby leading to the accumulation of more dry matter, with the average increase over two years ranging from 0.51 to 27.22%. Straw mulching also significantly improved water-use efficiency (WUE) at 350 mm of irrigation, with the average increase in yield over two years ranging from 4.58 to 4.83%. Overall, straw mulching had a positive impact on maize when irrigation was low, and when it was high, straw mulching did not adversely affect maize. Therefore, irrigation combined with straw mulching technology may be used to improve maize yield and WUE in semi-arid areas of Jilin Province.

Optimizing drip irrigation with straw mulch return represents a promising sustainable intensification strategy for revolutionizing regional water management. This 2-year controlled field experiment examined straw incorporation effects (removal and return) and drip irrigation levels (200, 350, 500 mm) on maize carbon-nitrogen metabolism, root bleeding sap characteristics, dry matter accumulation, and yield. Dry matter and yield increased with irrigation amount. Under 200–350 mm irrigation, straw return enhanced root bleeding intensity; elevated nitrogen, phosphorus, potassium, calcium, and magnesium concentrations in bleeding sap; and promoted soluble sugar and hydrolyzed amino acid contents, establishing material foundations for yield formation. Straw mulching increased cytokinin while reducing abscisic acid content, delaying senescence. Leaf activities of nitrate reductase, glutamine synthetase, ribulose-1,5-bisphosphate carboxylase/oxygenase, and phosphoenolpyruvate carboxylase significantly increased under straw return, enhancing photosynthesis and improving 100-grain weight, ear length, ear diameter, and yield while decreasing bald tip length. Low irrigation amplified straw return benefits on maize growth and metabolism, whereas high irrigation negated these effects. Therefore, combining drip irrigation with straw return provides scientific foundations for water resource management in Jilin Province and theoretical bases for sustainable agricultural development in water-limited regions.