Abstract
This study aims to investigate the responses of carbon assimilation, grain yield, leaf stay-green rate, nitrogen uptake and distribution to soil compaction in the hard plow pan caused by repeated use of tractor-driven cultivator in Northeast China. The typical hybrid maize variety “Zhengdan 958” was exposed to two treatments of simulated plow pan (SP) and simulated subsoiling (SS, control) in pot experiments from 2012 to 2014. Compared with SS, SP significantly reduced net photosynthetic rate (Pn) during growth stage, leading to a decrease in dry matter accumulation (DMA) and grain yield (GY) in three consecutive experimental years. Leaf stay-green degrees (LSD), which showed a fast descending trend from 20 days after silking (DAS), significantly decreased in the later filling stage under SP treatment. The translocation efficiency of the stored N (TEN) in stalk and leaf to the grain during pre-silking was enhanced, whereas leaf and grain N concentration (LNC/GNC), together with N accumulation amounts at maturity were significantly reduced under SP treatment. Also, plough pan reduced the N distribution to the organs of stalk, leaf and grain. In conclusion, subsoiling is a possible way to delay leaf senescence and achieve higher DMA and GY, and increased grain N in the corn belt of Northeast China.
Highlights
Maize (Zea mays L.) is one of the world’s three major cereals crops, which is considered as a major source of staple food
The grain protein concentration is closely related to the nitrogen (N) content (Li et al, 2016), and dry mass in maize grains is an important nutrition factor, which is associated with human health and animal feeding (Masclaux et al, 2008)
Compared with SS plants, photosynthetic rate (Pn) was significantly reduced by 13.66%, 13.02% and 25.51% in in V12, VT and R3 stage in 2012 (Fig. 1a); whereas, it was reduced by 5.48%, 12.13% and 17.98% in 2013 (Fig. 1b), respectively
Summary
Maize (Zea mays L.) is one of the world’s three major cereals crops, which is considered as a major source of staple food. The genetic gain in total grain yield can be attributed predominantly to the increased dry matter accumulation (Tollenaar, 1989). It has been well-known that maize grain accumulation could be explained by post-silking dry matter accumulation and/or remobilization of dry matter stored in the stem and leaf during vegetative growth (Ning et al, 2013). Enhancement of post-silking dry matter accumulation and remobilization of dry matter stored in the early growth stage is important approachs to increase maize grain yield in modern agricultural manage practice. Many precious researches have demonstrated that leaf stay-green ability has a significant positive correlation with maize grain yield (Martin et al, 2005). The increment in ear fertility and grain-filling rate, and delayed leaf senescence with unchanged net photosynthetic rate are the significant characteristics for a modern breeding maize hybrids (Chen et al, 2013)
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