Nutrient Budget and Economic Assessment of Blended Fertilizer Use in Kenya Tea Industry

Abstract

Kenya’s tea industry depends predominantly on imported compound NPK fertilizers to replenish nutrients removed through plucking. These fertilizers cannot be easily manipulated for specific soils and tea clones. They also frequently become hazardous within tea-growing environments. In this respect, two fertilizer blends containing NPKS 25 : 5 : 5 : 4 + 9Ca + 2.62Mg and NPKS 23 : 5 : 5 : 4 + 10Ca + 3Mg with trace elements have been produced commercially in the country. However, the extent to which the blended fertilizers may contribute to optimal economic gains without degrading the environment has not been determined. This was the knowledge gap that this study seeks to address. The goal of this study was to evaluate the economic efficacy of fertilizer blends with the aim of identifying optimal levels of application which would maximize tea productivity with minimal negative impacts on the environment. The study hypothesized that blended fertilizers maximize productivity of tea clones with minimal environmental damage. The fertilizer blends were evaluated in two study sites, i.e., Timbilil Estate in Kericho and Kagochi farm in Nyeri. The sites were selected purposefully, one in the eastern and the other in the western tea-growing areas. The trial was laid out in randomized complete block design with two fertilizer blends and the standard NPK 26 : 5 : 5 as control. The treatments were applied at four fertilizer rates (0 (control), 75, 150, and 225 kg·N·ha−1·yr−1), replicated thrice. Leaf samples were collected and analyzed for nutrient uptake as well as associated yields and economic trends. The economic optimum nitrogen rate (EONR) was achieved at 75 kg·N·ha−1·yr−1 at Kagochi with all fertilizers, while at Timbilil, EONR was variable, between 75 and 225 kg·N·ha−1·yr−1 with fertilizer types. This study has shown that, based on the economic point of view, Blend “A” was the most efficient and consistent fertilizer in production and economic returns across the two sites.

Nutrient Inputs for Rehabilitation of Non-responsive Soils in the Guinea and Sudan Savannah Agroecological Zones of Ghana: Impact on Grain Yield and Soil Quality

“…The sole application of mineral fertilizers at different rates in both years were highly profitable (average VCR = 11). Findings in this study are consistent with Dicko et al 2017 andSitienei et al (2018) confirming the high profit potential of applying mineral fertilizers on crops. The implication of these results reiterates the integral role of site-specific nutrients application in sustainable crop production, soil fertility management (Angus et al, 2004;Ogundijo et al, 2015), and overall maximizing the net financial returns of farmers.…”

Response of potato to fertilizers applied on different soil types in Kenyan Highlands

“…New Mavuno also contained other nutrients, including K, which is taken up in relatively high amounts by root and tuber crops (Koch et al., 2020; Wortmann et al., 2020). Studies have revealed better crop performance with the application of compound fertilizer (Habte & Ayalew, 2017; Sitienei et al., 2018; van Erp et al., 2014). Apart from the immediate effect on the applied fertilizer, maintenance of soil nutrients is crucial for sustainable production (Koch et al., 2020; Schut & Giller, 2020).…”

“…Site‐specific fertilizer management has been evaluated in recent years through nutrient omission trials to capture the potential presence of limiting nutrients and responses (Kihara et al., 2016; Mugo et al., 2021; Nziguheba et al., 2009). Fertilizer blending is used in Kenya to produce crop‐specific and site‐specific fertilizer (GIZ, 2016; Sitienei et al., 2018), and these fertilizer blends are available in the market. The fertilizers are based on crop nutrient removal as well as the general soil chemical properties of various areas (GIZ, 2016; Kinyua et al., 2013; Mbuthia, 2018; Yara, 2020).…”

“…Site-specific fertilizer management has been evaluated in recent years through nutrient omission trials to capture the potential presence of limiting nutrients and responses (Kihara et al, 2016;Mugo et al, 2021;Nziguheba et al, 2009). Fertilizer blending is used in Kenya to produce crop-specific and site-specific fertilizer (GIZ, 2016;Sitienei et al, 2018), and…”

Impacts of Land Use Types on Shallow Groundwater Quality Sources in Mathira East Sub-County in Kenya

“…Other sources of nutrients were wastes from livestock that grazed around groundwater resources as well as using them as watering points. The unabsorbed nutrients were perhaps leached and percolated with gravity rainwater into the shallow groundwater sources and aquifers (Sitienei et al, 2013(Sitienei et al, , 2018.…”