Joyce J. Lelei

The Effect of Organic-Based Nutrient Management Strategies on Soil Nutrient Availability and Maize Performance in Njoro, Kenya

A field experiment based on the concept of organic nutrient management was conducted in Njoro, Kenya, to test the effect of improved legume fallows, crotalaria (CR), lablab (LB), garden pea (GP) and natural fallow (NF, as control) on available soil N and P and maize performance. The experimental design was a split plot fitted to a randomized complete block. The main plots were two cropping systems involving the improved legume fallows and NF preceding sole maize and maize–bean (M/B) intercrop. The sub-plots were two residue management types: residue incorporation and residue removal with farm yard manure (FYM) incorporated instead. Residue incorporation resulted in higher concentrations of N and P in soil than FYM in both cropping systems. Under sole maize, grain yield following LB was significantly higher than after CR, GP and NF. In the M/B intercrop, maize grain yield following LB was significantly higher than after GP and NF, with no significant differences in yields following CR and LB. Maize dry matter (DM) yields followed a similar trend. Overall, maize grain and DM yields were higher in sole maize cropping system than in M/B intercrop but an additional 0.5–0.6 kg ha–1 of bean grain yield was realized in the latter cropping system. The improved fallow legumes enhanced soil productivity, besides the seeds providing ancillary protein in diet locally, with resultant higher yields of the succeeding crop.

Effect of Legume Integration and Phosphorus Use on Maize N and P Concentration and Grain Yield in Kabete - Kenya

Aims: Investigate effect of legume integration and phosphorus application on nitrogen (N) and phosphorous (P) concentration and yield of maize. Place and Duration of Study: The study was carried out in Kabete Field Station of the University of Nairobi during the long (LRS) and short rainy (SRS) seasons of 2012. Methodology: A split plot layout in a randomized complete block design (RCBD), with three replicates was used. The main plots were sole maize, intercropping (chickpea/maize; lupin/maize) and rotation systems (chickpea-maize; lupin-maize) systems. The sub plots were Minjingu rock phosphate (MPR) and triple superphosphate (TSP) fertilizers, applied at 60 kg P ha. Maize P and N concentrations were measured at seedling, mid-flowering and physiological maturity/harvest. Maize grain and dry matter (DM) yield were determined at physiological maturity. Results: During the LRS, significantly (P=0.05) higher maize P concentrations were recorded in Original Research Article Templer et al.; IJPSS, 19(2): 1-9, 2017; Article no.IJPSS.34972 2 chickpea/maize intercrop (C/M) with TSP at seedling; sole maize, chickpea/maize (C/M) and lupin/ maize (L/M) intercrops, with MPR and TSP at mid flowering and L/M intercrop with TSP at harvest. In the SRS at seedling and harvest stages, significantly higher values were recorded in the lupinmaize rotation (L-M) with MPR. At mid flowering, significantly higher P values were observed in L/M with MPR. During the LRS, N concentration in maize was significantly higher in L/M with TSP and L/M with MPR at seedling and mid flowering stages, respectively. At harvest L/M with TSP had significantly higher values. In the SRS, maize N concentration was significantly higher in L-M and chickpea-maize (C-M) rotation with MPR and sole maize with TSP at seedling; and L/M with MPR and TSP, at mid flowering and harvest, respectively. During the LRS, maize grain yields were significantly higher in L/M with TSP and MPR and C/M with MPR. In the SRS, significantly higher maize grain yields were recorded in L/M with TSP and L-M with MPR. DM yields in the LRS were significantly higher in L/M with TSP applied. In the SRS, DM yields were significantly higher in L/M with MPR, C/M with MPR, L-M with MPR and C-M with MPR. Conclusion: The integration of MPR or TSP and legumes increased maize N and P concentration and yields. The use of cost effective MPR in an intercropping system may be preferred by small holder farmers.

Soil Fungal and Bacterial Populations in White Lupin ( Lupinus albus ) - Maize ( Zea mays L) Cropping System Amended With Minjingu Phosphate Rock

Aims: To determine fungal and bacterial populations under white lupin (Lupinus albus ) maize (Zea mays L) cropping system amended with Minjingu Phosphate Rock (MPR). Study Design: A randomized complete block design with four replicates was used. Treatments were; (i) control i.e. fallow (F) – maize (M) rotation with triple super phosphate fertilizer (TSP) applied (M TSP - F), (ii) fallow - maize rotation with MPR applied (M MPR - F), (iii) white lupin (L) – maize rotation with MPR applied (M MPR - L) and (iv) maize/white lupin intercrop with MPR applied (M/L MPR - F). Place and duration of study: The experiment was conducted in Njoro sub-County, Kenya during the long (LRS) and short rain seasons (SRS) of 2010 and 2011.

Influence of Amendments Added to Acid Soils on Biochemical Properties, Nitrogen Uptake and Hybrid Maize Yields in Nakuru County, Kenya

Aim: The current study investigated effect of soil amendments; lime (L), manure (FYM) and minjingu phosphate rock (PR) added to soils on soil microbial biomass carbon and nitrogen (SMB-C and SMB-N), available soil nitrogen (N), crop N uptake and grain yields of two maize hybrids (H513 and H614). Study Design: Two experiments, one for each maize hybrid as test crop, were laid out in a randomized complete block design with a 2 factorial arrangement. The factors each at two levels were L (0 and 3 t ha), PR (0 and 60 kg P ha) and FYM (0 and 5 t ha) giving a total of eight treatments; L, RP, FYM, L+RP, L+FYM, RP+FYM, L+RP+FYM and control (nothing applied). Methods: Soil and plant samples for the determination of SMB-C and SMB-N, available soil N, and crop N uptake were collected at maize seedling, tasseling and physiological Original Research Article Lelei et al.; IJPSS, Article no. IJPSS.2014.004 468 maturity. Place and Duration of the Study: The experiment was conducted in Molo district of Nakuru County, Kenya during the long rain seasons of 2009 and 2010. Results: SMB-C and N levels were higher in 2010 than 2009, with lower levels obtained at maize tasseling for both maize hybrids. Available soil N and crop N uptake were higher at maize seedling and declined towards maturity. Statistically significant (P<.05) increases in SMB-C and SMB-N and available soil N and uptake were obtained with the application of soil amendments over the control. In all treatments, H513 had lower N uptake than H614 at tasseling and maturity stages of maize growth and correspondingly higher available N in soil. Maize yields (t ha) were higher in 2010 than 2009 and in H614 than H513. The H614 yields were significantly higher (P<.05) in L+PR+FYM (3.9) and, L+PR+FYM (4.1) and L+PR (3.9) treatments in 2009 and 2010, respectively. For H513, yields were significantly higher in L+PR+FYM (2.1 and 2.4) and L+PR (1.9 and 2.1) treatments in 2009 and 2010, respectively. Conclusion: The L+PR+FYM treatment is a feasible acid soil amendment for its superiority in the measured soil and crop parameters. The H513 matured faster than H614 and because of this attribute, is a viable option in response to the diminishing rainfall amounts and unpredictable weather patterns experienced in the County.