Biochar and Poultry Litter Effects on Maize Growth, Nutrient Uptake and Selected Soil Biological Activities in Different Soil Types

Abstract

South African soils contain lesser percent organic carbon content compared to soils from many parts of the world. The loss in organic carbon content reduces soil fertility and drives an ever increasing demand for the use of soil amendments to enhance soil fertility. The study consiststed of a greenhouse pot experiment and a laboratory incubation experiment. The objective of a greenhouse study was to assess the effects of biochar and poultry litter application on maiize productivity under different soil types. Treatments consisted of different soil types and amendments of biochar and poultry litter. Soils were collected from four sites (Mutshenzheni, Rambuda, Tshiombo Irrigation and Tshiombo Madzivhandila) representing different soil types (Westleigh (We1), Hutton (Hu), Westleigh(We2) and Shortlands (Sd), respectively. Soils were amended with biochar and poultry litter. The amendments consisted of various mix ratios of biochar (BC) with poultry litter (PL) as treatments, which are namely, BC0PL0, BC100PL0, BC75PL25, BC50PL50, BC25PL75, and BC0PL100. Soil amendments were applied at different rates of 0- 5 t ha-1 PL and 0- 40 t ha-1 BC. Treatments were laid out in a completely randomize design (CRD) and replicated three times. Biochar and poultry litter application exerted no significant difference on soil pH of We2, Sd, and Hu soils. However, the effect of biochar and poultry litter application was significant at soil We1. In contrast, application of biochar and poultry litter had no effect on soil total N of soil We1, We2, and Hu and was significant on soil Sd. The results of this study showed that application of biochar and poultry litter treatments had no significant effect on both the maize growth and nutient uptake at early stages ( Week 1 and Week 2). However, the application of biochar and poultry litter treatments had a significant difference ( p ≥ 0.001) on maize growth and nutrient uptake at a later stage ( Week 3 to Week 6). Therefore, there is a potential to ameliorate fertility constraints in agricultural soils using biochar combined with poultry litter. Though biochar possesses some essential elements required for plant growth, sole application reduces its efficiency with its effectiveness confirmed only when applied in combination with organic-based materials such as poultry litter. The laboratory incubation experiment assessed the effects of different biochar rates on soil chemical and bio-quality parameters. Each treatment consisted of a 200 g of soil (We1, Hu, We2 and Sd) homogenously mixed with biochar amendments (0, 10, 20, and 40, t ha-1). The treatments were laid in a completely randomize design (CRD) and replicated three times. Soil sampling was done on day 0, 30, 60, 90, and 120, and samples were analyzed for soil available P and N and bio-quality parameters namely microbial biomass nitrogen, microbial biomass carbon, urease, alkaline and acid phosphatase, β glucosidase, soil organic carbon, and dehydrogenase activity. The results of the study revealed various responses of soil bio-quality parameters and selected soil chemical properties after biochar and poultry litter application. Thus, the effects of biochar rate, incubation days and soil type on soil enzymes and other bio-quality parameters elicited an understanding on microbial activity and soil enzymes mechanism . Therefore, a prolonged study (more than 120 day) is required to evaluate the effects of incubation days, biochar rate and soil type effect on soil nutrients and bio-quality parameters.