Evaluation of residual effect of the residual recycled paper pulp on growth and yield of intercropped corn and soybean in two different soil and climatic conditions using precision agriculture methodologies

Abstract

Paper and pulp mill industries produce large quantities of waste in liquid and solid form, which comprise significant disposal problems. Traditionally, paper and pulp sludge has been disposed of mainly by being burned or thrown into a landfill, but considering its high organic matter content it appears realistic that it could be used as an organic amendment in agricultural soils. This field study involves two objectives. The primary objective is to investigate the residual or remaining effects of recycled residual paper pulp (powder RRPP) applied in a pulverized form on soils and crops that was integrated two years before on two diverse soil types (clay loam and sandy loam) at the rates of 0%, 1%, 2%, and 4% v/v on the 0.15 m soil surface. The secondary objective of the study is to investigate primary effects of raw form of RRPP applied this year, on soil properties, yield and other agronomic characteristics of corn (Zea mays L var. Sakata) and soybean (Glycine max L. var. Hutchinson) in companion study, conducted next to the previous study in both soil-climate locations. To achieve the set objectives various soil and crop agronomic properties were measured, namely soil organic carbon (SOC), bulk density (BD), soil pH, soil electrical conductivity (EC), soil volumetric water content, crop yield and relative leaf chlorophyll content. Generally, the residual as well as the primary effects of paper sludge significantly increased the crop yield and the relative leaf chlorophyll content for both crops on both locations. In addition, increases were observed for SOC and the material decreased BD and did not affect pH and EC. Due to encouraging results, the study will be continued for years to come and include other plant species and properties of crops and soils in the investigation. It is concluded that RRPP could be effectively used as a soil improving material with lasting positive effects, both if pulverized and in raw form.