Effects of Lime and Nitrogen on Properties of an Acidic Soil and Nutrient Content of Sugarcane under Sugarcane – Soybean Intercropping in Kenya

Abstract

Acidified soils are a constraint to crop production due to imbalance in availability of essential plant nutrients. Liming is known to increase soil pH, however, efficient use is critical to ensure cost effective use. Therefore, determination of efficient lime application method including lime rates and nitrogen rates was the basis of the study. A field study was conducted to investigate whether lime placement methods (LPM), lime rates (LR) and nitrogen rates (NR) for intercropped sugarcane with soybean under acid soils leads to increased soil pH and also soil and sugarcane leaf nutrient status. Split – split plot randomized complete block arrangements was employed. The main plots were; LPM (lime broadcasted [L-BC], lime shallow banded, 0 – 15 cm [L-SB] and lime deep banded, 15 – 30 cm [L-DB]). Sub plots were lime rates (0, 1 and 2 t ha-1) and sub – sub plots were N rates (0, 50 and 100 kg N ha-1). Lime rates significantly affected soil pH for both the 0 – 15 cm and 15 – 30 cm soil depth. Lime rate, 2 t ha-1 led to the highest soil pH. Lime placement methods interaction with LR significantly affected soil pH, N, P, Fe, OC and CEC for 0 – 15 cm depth. This interaction also affected soil pH, N, Mg and OC for 15 – 30 cm depth. LPM alone did not affect soil chemical properties for 0 – 15 cm depth but affected soil pH and N for 15 – 30 cm depth. Some soil chemical properties, specifically, exchangeable calcium (Ca), extractable manganese (Mn), zinc (Zn) and soil OC were affected by the LR but not the LPM. LPM affected sugarcane leaf total K, Ca, Mn and Zn while the LR affected total N and Mg. Lime shallow banded and lime broadcasted led to highest content of these nutrients in sugarcane leaves. Lime rate 2 t ha-1 is recommended for use to ameliorate soil acidity for acidified Cambisols soils of Kibos, Kisumu County, Kenya. Lime broadcasting or lime banding at shallow 0 – 15 cm soil depth should be used as a lime placement method.