Effect of Sub-soiling on the Physical Properties of Limestone Red Soil and Maize Growth

PurposeIn order to clarify the suitability and sustainability of sub-soiling cultivation and screen out reasonable tillage method in limestone red soil area of Yunnan Province.

MethodWe carried out a field experiment on maize for three years in this study, and discussed the effects of two tillage methods on soil physical properties and maize growth, including sub-soiling tillage and rotary tillage (CK).

ResultCompared with the rotary tillage, the sub-soiling significantly decreased the soil bulk density (P<0.05) and soil compactness (P<0.05) in plough layer (0-20 cm), the ranges were 7.24% and 12.22%, respectively in 2016, and increased soil total porosity compared with rotary tillage. Sub-soiling improved the water capacity in deep soil layer and contributed to promote the growth and development, and significantly improved the biological yield (P<0.05), increased the economic yield of maize. But the sub-soiling effects increased first and then decreased with the prolongation of tillage years. With the extension of sub-soiling years, the yield increase rate of sub-soiling treatment showed a downward trend, or even decreased. Compared with the rotary tillage treatment in the same year, the sub-soiling treatment economic yield and biological yield respectively increased by 13.73% and 28.21% (2016), 2.32% and 21.38% (2017), decreased by 4.36% and 1.53% in 2018.

ConclusionBased on the above results, sub-soiling has certain suitability in this area. The effect of sub-soiling can last for two years, and is most obvious in the first year. Alternate year sub-soiling is a suitable cultivation measure.