Abstract:
Objective Based on the differences of the northeast accumulated temperature zones, the effects of subsoiling at different periods on soil physical properties and yield of spring maize were studied.
Method Subsoiling experiments were conducted in the low accumulated temperature zone (Qiqihar), middle accumulated temperature zone (Taonan) and high accumulated temperature zone (Shenyang) in 2014. Three treatments were set up: 30 cm subsoiling in autumn (AS), 30 cm subsoiling in spring (SS) and conventional 15 cm rotary tillage (CT). The soil water content, soil capacity, soil hardness and maize yield were determined at different periods.
Result Subsoiling had positive effects on soil physical properties and yield in different accumulated temperature zones. The overall effect of each treatment on soil moisture enhancement in different accumulated temperature zones was SS > AS > CT. The subsoiling was the most significant in improving soil moisture in the low and high accumulated temperature zones at the spatulation stage (R1), the medium accumulated temperature zone at the 6-leaf stage (V6) and the R1 stage. SS was significantly effective in improving soil bulk density in the low and high accumulated temperature zones. The soil bulk density was 8.23% and 11.12% lower in 10-20 cm and 20-40 cm soil in the low accumulated temperature zone compared with CT (P < 0.05). The soil bulk density in the SS treatment in the high accumulated temperature zone was 7.28%, 5.68% and 2.02% lower than CT at 0-10 cm, 10-20 cm and 20-40 cm soil, respectively. SS improved soil hardness significantly in the low and high accumulated temperature zones. The soil hardness in SS treatment in the low accumulated temperature zone was 32.26%, 27.46% and 33.77% lower than those of CT in 0-10 cm, 10-20 cm and 20-40 cm, respectively. And the soil hardness in SS treatment in the high accumulated temperature zone was 9.50%, 8.63% and 5.29% lower than that of CT (P < 0.05) in 0-10 cm, 10-20 cm and 20-40 cm soil, respectively. Subsoiling had a significant effect on 100-kernel weight, with AS and SS being 2.77% and 5.14%, 8.48% and 8.48% higher in the medium and low accumulated temperature zones compared to CT (P < 0.05), respectively. For yield, The treatments of AS and SS were 8.57% and 11.43%, 15.46% and 12.37% higher in the low and high accumulated temperature zones compared to CT (P < 0.05), respectively.
Conclusion Subsoiling can significantly improve the physical properties of soils in different accumulated temperature zones and increase maize yield. The effects of AS and SS on soil moisture enhancement in different accumulated temperature zones are obvious, and the effects of SS on soil capacity and soil hardness improvement are better than that of AS in general. From the perspective of soil improvement and yield increase, SS is recommended as the best choice for subsoiling in Northeast China.