The Right To Education In Kenya: A Critical Appraisal Of The Legal And Institutional Framework Dealing With Sexual Violence In Schools
Decline in soil nutrients and organic levels due to continuous cultivation practices combined with erratic rainfall patterns has led to soil fertility decline posing a serious threat to long-term maize (Zea mays L.) production in Nairobi County, Kenya. The current study monitored changes in soil organic carbon, moisture content, nutrient status and maize yield following dolichos (Lablab purpureus (L.) integration and application of fertilizers, as basis for developing sustainable soil fertility management strategies. Field experiments were conducted at the University of Nairobi field station, Kabete Sub-County for two seasons during the mid-March to May 2015 (long rain season; LRS) and October to December 2015/2016 (short rain season; SRS). The experiment layout was a Randomized Complete Block Design with a split-plot arrangement replicated three times. The cropping systems were the main plots; (i) mono-cropping (sole maize) (Zea mays L.), (ii) intercropping (dolichos (Lablab purpureus (L.) /maize) and (iii) rotation (dolichos-maize). The sub-plots were fertilizer types: (i) organic (farmyard manure; FYM), (ii) inorganic (triple superphosphate (TSP) and urea), (iii) integrated fertilizer (FYM +TSP + Urea) and (iv) no fertilizer input (control). Soil moisture, organic Carbon (OC), nitrogen (N), phosphorus (P), and potassium (K) levels were determined at the end of each cropping season. Assessment of ecological sustainability of the technologies being tested was determined by calculating nutrient balances. Soil carbon stocks were also calculated and their changes over a 20-year period projected using Roth-C. Soil carbon (C) inputs were obtained from crop residue and FYM inputs and converted into t C/ha. The C inputs were calculated from grain yield data using a harvest index (HI). The highest levels of soil moisture and organic carbon were respectively observed in maize/dolichos intercrop with application of FYM (31.8% and 2.6%) and FYM + TSP + Urea (30.1% and 2.5%) during the SRS. The same trend was observed in maize/dolichos intercrop with application of FYM and FYM + TSP + Urea in LRS with no significant differences between seasons. Similarly, significantly (P≤0.05) high soil N and P levels were obtained in maize/dolichos intercrop with application of FYM (0.3% and 22.6 ppm; 0.29% and 19.6 ppm) and TSP+FYM+Urea (0.28% and 22.5 ppm; 0.3% and 16.5 ppm) during the LRS and SRS respectively. The soil K levels were significantly (P≤0.05) higher in maize/dolichos intercrop with FYM (1.3 cmol/Kg and 1.8 cmol/Kg) application during the SRS and LRS respectively. Averaged across the two seasons, less negative N balances (kg ha-1yr-1) were obtained in maize/dolichos intercrop with FYM (-9.1) application. Pronounced losses realized in maize/dolichos intercrop with TSP/Urea (-20.1) application. P losses were higher in maize/dolichos with TSP+FYM+Urea (-2.2) and TSP+Urea (-2.4) application. Less negative P balances (kg ha-1yr-1) were obtained in dolichos-maize rotation with the application of FYM (-0.4) and TSP+FYM+Urea (-0.5). Significantly (P<0.5) higher K losses (kg ha-1yr-1) occurred in dolichos/maize intercrop with TSP+Urea (-6.7), dolichos-maize rotation with TSP+Urea (-4.9) and in maize monocrop with TSP+Urea (-4.5) application. Dolichos-maize rotation with FYM application resulted in reduced K losses (-0.2) compared to monocrop with FYM (0.4) and intercrop with FYM (-1.1) application.
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