Residual Effects of Applied Phosphorus Fertilizer on Maize Grain Yield and Phosphorus Recovery from a Long-Term Trial in Western Kenya
- 565 Downloads
Phosphorus (P) application is essential for crop production in the weathered, P-fixing soils of Western Kenya. It is hypothesized that a single large application of phosphorus fertilizer can shift soil-available P levels above a critical threshold, while further seasonal applications are requisite for sustaining yields. A field study was conducted in Siaya district to evaluate maize yield, P uptake, soil P balance and economic returns from P applied at different initial P rates and further seasonal P additions. In the first season, triple superphosphate (TSP) was added at rates of 0, 15, 30, 50, 100, 150 and 250 kg P ha–1, and maize yield and P uptake were assessed during 10 consecutive seasons. Additional treatments were included where an initial application of 100 kg P ha–1 was supplemented with seasonal additions of 7 kg P ha–1, supplied as TSP, manure or Tithonia diversifolia. Residual benefits of maize in terms of increased grain yields were high with cumulative yields ranging from 17.4 to 54.8 t ha–1 when P was applied at rates above 100 kg P ha–1. Resin-extractable P increased significantly with initial P addition but decreased rapidly with time, particularly for treatments with one-time high dose of P application. Economic evaluation of these technologies revealed that application of initial P as 100 kg P ha–1 with seasonal additions of 7 kg P ha–1 as TSP would give the best marginal returns to investment.
KeywordsMaize yield P uptake P recovery P balance
We gratefully acknowledge the BMZ-ISFM through TSBF-CIAT for providing financial support for this study. The assistance of John Mukalama and Wilson Ngului in field data collection and laboratory analysis is highly acknowledged.
- Anderson JM, Ingram JSI (1993) Tropical soil biology and fertility. A hard book on methods. CAB International, Wallingford, UK, 221ppGoogle Scholar
- Buresh RJ, Smithson PC, Hellums DT (1997) Building soil phosphorus capital in Africa. In: Buresh RJ, Sanchez PA, Calhoun F (eds) Replenishing Soil Fertility in Africa. Soil Sci. Soc. Am. J. Special Publication 51, 193–217. SSSA, Madison, WI, pp 111–149Google Scholar
- Chang SC (1975) Utilization and maintenance of the natural fertility of paddy soils. Experimental Research Bulletin No. 61. ASPAC. Food and Fertilizer Technology Center, Taipei, TaiwanGoogle Scholar
- CIMMYT (1998) From agronomic data to farmer recommendations: an economics training manual. CIMMYT_Mexico, D.F., MexicoGoogle Scholar
- Nelson DW, Sommers LE (1975) A rapid and accurate method for estimating organic carbon in soil. Proc Indiana Acad Sci 84:456–462Google Scholar
- Okalebo JR, Gathua KW, Woomer PL (2002) Laboratory methods of soil and plant analysis: a working manual, 2nd edn. TSBF-CIAT and Sacred Africa, Nairobi, KenyaGoogle Scholar
- SAS Institute (1995) SAS users guide, 6th edn. SAS Institute, Cary, NCGoogle Scholar
- Shepherd KD, Olson E, Okalebo JR, Ndufa JK, David S (1993) A statistic model of nutrient flow in mixed farms in the highlands of western Kenya to explore the possible impact of improved management. Paper submitted at the international conference on livestock and sustainable nutrient cycling in mixed farming systems of Sub-Saharan Africa, Addis Ababa, Ethiopia, 22–26 Nov 1993Google Scholar
- WRB (1998) World reference base for soil resources. World soil resources report 84. FAO ISRIC ISSS, Rome, ItalyGoogle Scholar