Progressive integrative crop managements increase grain yield, nitrogen use efficiency and irrigation water productivity in rice

It is a major challenge to achieve the goal of increasing grain yield, nitrogen use efficiency (NUE) and irrigation water productivity (IWP) in cereals. This study investigated if progressive integrative crop management technology in rice (Oryza saliva L.) could improve agronomic and physiological performances, and consequently, increase grain yield, NUE and IWP. A japonica rice cultivar and an indica-japonica hybrid rice cultivar were grown in the field, with five crop managements including an unfertilized 0 N treatment (0 N), local farmer's practice (LFP), integrative crop management (ICM) 1-3 ((ICM1, ICM2, and ICM3)). The results showed that, when compared to LFP, the ICM could not only increase grain yield, NUE and IWP, but also improve agronomic and physiological performances. Both ICM1 and ICM2 increased economic benefit. The progressive effect on the yield, NUE, IWP, and agronomic and physiological performance was obvious with the progressive introduction of single cultivation technology. The ICM increased sink size (total number of spikelets), percentage of productive tillers, leaf area index and duration, crop growth rate, non-structural carbohydrate accumulation and remobilization, leaf photosynthetic rate, root dry weight and length, root oxidation activity, root bleeding, and zeatin and zeatin riboside content in roots and leaves. The results suggest that the integrative and optimized crop management could achieve the dual goal of increasing grain yield and resource use efficiency through improving agronomic and physiological performances, especially increases in sink size and shoot and root growth, leading to higher grain yield, NUE, and IWP.