Effects of ditch-buried organic matter and irrigation amount after anthesis on the photosynthetic characteristics and yield of maize.

Management of organic mailer and irrigation after anthesis will increase the capacities of water conservation and supply in maize field, with consequences on photosynthetic performance and yield under water-saving condition. We analyzed the gas exchange parameters and the performance of the photosystem II of ear leaves, and yield of maize cultivars Zhengdan 958, under three modes of ditch-buried organic matter (no straw returned; Mo, wheat straw returned; M,, mixtures of cow manure and wheat straw returned; M₂) before seeding with two irrigation levels after anthesis (normal irrigation; W₁, water-saving irrigation; W₂). The results showed that M₂ treatment significantly increased photosynthetic capacity and dry matter accumulation after anthesis compared with M, treatment. Compared with water-saving irrigation, normal irrigation enhanced the photosynthesis of ear leaves. M₂W₁ treatment significantly increased net photosynthetic rate (P_n), stomatal conductance (g), transpiration rate ( T_t), and performance of photosystem II (σ_po and ω_o) of ear leaves after anthesis, while reduced intervellular CO₂ concentration ( C_i). In addition, M₂W₁ treatment significantly increased light utilization efficiency and maintained higher photosynthetic properties in ear leaves, and significantly increased dry mailer accumulation and grain yield. Water-saving irrigation reduced photosynthetic performance of ear leaves, which declined the yield. But compared M₂ with M₀, water use efficiency, grain growth rate and yield increment under water-saving irrigation were higher than those under normal irrigation. Thus, mixtures of cow manure and wheat straw returned combined with normal irrigation could significantly increase photosynthetic properties of ear leaves and dry mailer accumulation, which were the major reasons for yield enhancement. Importantly, the mixture of cow manure and wheat straw returned combined with water-saving irrigation could decrease the loss of crop yield resulted from lower irrigation. [ABSTRACT FROM AUTHOR]