Objectives Tillage affects the development of maize root system and the utilization of plant nutrients. We compared the root development and morphology of maize under different tillage practices in the rain-fed areas of northeastern China, in order to provide technical support for the establishment of reasonable tillage modes.
Methods A field experiment was conducted for two years (2011–2012) in Jilin Province. Four sets of tillage were set up, including seeding following light stubble (T1), deep loosening and compaction in seedling belts (T2), deep loosening between rows and compaction in seedling belts (T3), deep loosening in both intra- and inter-seedling rows (T4). At the 6-leaf stage, silking stage and maturity stage, both plant and root samples in 0–60 cm soil layer were collected for the analysis of yield, nutrient uptake and root system indexes.
Results Tillage modes had significant effects on maize yield. The average grain yields in two years were in order of T3 > T2 > T1 > T4. Compared with T1 treatment, the grain yields in T2 and T3 treatments were increased by 8.1% and 10.2%, respectively. The accumulation of N, P and K and their contribution to grain were all increased significantly at the post-silking and maturity stage (P < 0.05), and which were increased by 0.4%–3.6%, 16.9%–33.8%, 70.5%–82.1% significantly in T2 and T3 treatments at the post-silking stage (P < 0.05), and all above increment in T3 treatment were higher than those in T2 treatment. Compared with T1 treatment, the total root weight, total root length, and total root surface area in T2 and T3 treatments were increased by 9.8%–22.8%, 16.1%–33.1% and 19.9%–38.2% from 6 leaf stage to maturity stage, respectively. The root morphology in T2 and T3 treatments were better than those in seeding following light stubble treatment (T1), especially in 20–40 cm soil layers (P < 0.05). Compared with T1 treatment, the root dry weight, root length, root surface area and root diameter in the 20–40 cm soil of T3 treatment were increased by 34.1%, 48.3%, 47.8% and 22.1%, respectively.
Conclusions Deep loosening in both intra- and inter-seedling rows without compacting is adverse to the root growth. Deep loosening between rows and compaction in seedling belts treatment could promote the deep development and longitudinal extension of roots, especially in the 20–40 cm soil layer, which is beneficial to absorb the soil nutrients, and thus increase the nutrient accumulation after silking and the allocation to the grains, and achieve higher grain yield.
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