Deep soil tillage in the coffee planting furrow has long-lasting benefits for improving soil physical quality and enhancing plant vigor in dense soils

Abstract

The deep furrows and additional liming can improve soil quality and reduce drought impact during coffee plant establishment, especially in dense soils. However, the effects of the initial preparer in the medium to long term are scarce. This study aims to assess the five-year impact of different deep tillage strategies and chemical fertility improvement of the planting furrow on soil physical quality and plant growth under Cambisol with coffee cultivation. The experiment was conducted in a Cambisol in Nazareno, Minas Gerais state, Brazil. The experiment followed a randomized complete block design with a split-plot arrangement in space, including three blocks, six soil depths (0–0.05, 0.15–0.20, 0.35–0.40, 0.55–0.60, 0.60–0.70, and 0.75–0.80 m), and five soil preparation methods: SP40, furrower at 0.40 m with conventional fertilization; SP60, rotary hoe at 0.60 m with additional liming (SP60AL); SP80, soil homogenizer at 0.60 m and subsoiler at 0.80 m with additional liming (SP80AL). These soil preparations were compared with a native savannah vegetation area from the Cerrado biome (Natural). Undisturbed samples were collected at different depths five years after the initial soil preparation. In these samples, physical quality indicators were investigated along with the correlation of plant measurements (stem diameter - SD, plant height - PH, and normalized difference vegetation index - NDVI). Analysis of variance and the Scott-Knott and Dunnett tests (p < 0.05) were applied to analyze the data. After five years of soil preparation, improvements up to 0.40 m depth were due to soil homogenization, subsoiling, and liming, reducing bulk density and enhancing water retention. Additional limestone between 0.20 and 0.60 m depth improved SD, PH, and NDVI, mitigating drought. However, initial soil preparation induced compaction at 0.60–0.70 m depth, with subsoiler effects disappearing at 0.80 m. Effective deep tillage improves soil quality but requires careful planning.