Long-Term Effects of Tillage on Physicochemical Properties of Modified Andisol of Northeast Honshu Island

Abstract

Many reports suggest that tillage practices affect crop growth by altering soil properties. However, there is a paucity of information on long-term effects of tillage practices on the properties of modified Andisol in colder region. This study compared the effects of zero tillage (NT_g) with continuous fodder crop, zero tillage (NT_a) with continuous orchard, conventional tillage (CT) with sweet potato and corn (in summer), and wheat, barley, rye and colza (in winter), and puddling (P) with continuous rice on some selected physical and chemical properties of sandy clay pumice Andisol of colder climate. Mean dry bulk density was 0.92 Mg m⁻³ for CT, compared with 1.14 Mg m⁻³ for NT_g, 1.16 Mg m⁻³ for NT_a and 1.21 Mg m⁻³ for P. Total porosity was 63.75% for CT, compared with 55.16% for NT_g, 53.72% for NT_a and 52.24% for P. Highest content of organic matter (OM) was found in NT compared to other practices. On the other hand, soil pH and electrical conductivity (EC) were significantly lower under NT than other practices. The tillage had significant effects on soil hardness at different matric suction. Gaseous phase was greatest in CT soils, compared with NT_a soils, and P soils. Mean solid phase was 44.84%, 45.29%, 47.46% and 36.25%, while liquid phase was 45.50%, 46.06%, 51.21% and 31.65% under NT_g, NT_a, P, and CT, respectively. Conventional tillage held highest moisture at 0 pF. On the other hand, puddled soil showed highest moisture retention capacities between 1.5 and 7.0 pF than zero tillage and conventional tillage. Gravitational water (GW) and gravitational capillary water (GCW) contents was highest while capillary water (CW), shrinkage water (SW) and hygroscopic water (HW) contents were lowest under CT. Gravitational drainage (GD) and non-easily available water (NEAW) were significantly lowest and easily available water (EAW), total available water (TAW) and non-available water (NAW) were significantly highest under puddling condition compared to other tillage systems. Highest content of boron (B) was found in NT compared to other practices. On the other hand, sulfur (S) and manganese (Mn) were significantly lowest under NT than other practices. Tillage practices had no significant effect on zinc (Zn) content. Compared with CT and P, the use of NT may result in soils having different soil physical and chemical properties, because the soil matrix undergoes fewer disturbances with NT.

Acknowledgments