National Agricultural Research Laboratories NARL Kawanda

Kampala, Uganda

National Agricultural Research Laboratories NARL Kawanda

Kampala, Uganda
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Ndungu-Magiroi K.W.,Kenya Agricultural and Livestock Research Organization KALRO Kitale | Kasozi A.,National Agricultural Research Laboratories NARL Kawanda | Kaizzi K.C.,National Agricultural Research Laboratories NARL Kawanda | Mwangi T.,Kenya Agricultural and Livestock Research Organization KALRO Kisii | And 4 more authors.
Nutrient Cycling in Agroecosystems | Year: 2017

Finger millet (Eleusine coracana (L.) Gaertn) is an important food crop of semi-arid to sub-humid Africa where little is known of its response to applied nutrients. Yield responses to nitrogen (N), phosphorus (P) and potassium (K) together with a diagnostic treatment (S, Mg, Zn, B) were determined from field research conducted in western Kenya and eastern and central Uganda. Grain yield was not affected by applied nutrients in some sites in Kenya, likely due to other prevailing stresses. Grain yield increased with N application for all sites and years in Uganda by a mean of 127% from the no N treatment (0 N) yield of 1.00 Mg ha−1. Grain yield increases ranged from 0.76 to 1.40 Mg ha−1 with 30 kg N ha−1 applied, with little added increase with >60 kg N ha−1. The mean economically optimal rate for N in Uganda was 72 and 43 kg N ha−1 with expected net returns to N of 166 and 279 $ ha−1 when the N cost to grain value was 3 and 9 kg kg−1, respectively. Yield was increased with P and K application at two of four production areas of Uganda. Yield was increased by >20% with application of Mg–S–Zn–B in addition to N–P–K for all sites in Uganda with foliar concentrations indicating possible S and B deficiency. There is great profit potential in Uganda, and less for Kenya for N, but not for P and K, application to finger millet. Response to S and B needs further exploration. © 2017 Springer Science+Business Media Dordrecht


Kaizzi K.C.,National Agricultural Research Laboratories NARL Kawanda | Byalebeka J.,National Agricultural Research Laboratories NARL Kawanda | Semalulu O.,National Agricultural Research Laboratories NARL Kawanda | Alou I.,National Agricultural Research Laboratories NARL Kawanda | And 3 more authors.
Agronomy Journal | Year: 2012

Maize (Zea mays L.) is an important smallholder crop in Uganda. Yields are low because of low soil fertility and little fertilizer use. Yield response to nutrient application and economically optimal rates (EOxR, where x = N, P, or K) and N use efficiency (NUE) were evaluated. Twenty-two trials were conducted in four agroecological zones. Yield was consistently increased with N application. Mean maize yield with no N applied (N 0) was 1.79 Mg ha -1 and increased by 120% with N application. Mean EONRs were 45 to 24 kg ha -1 N with fertilizer use cost to grain price ratios (CPs) of 10 to 30. With N applied, the mean increase in yield due to P application was 0.28 Mg ha -1 and mean EOPRs were 9 to 1 kg ha -1 P with CPs of 10 to 50. Yield was not increased with K application. Profitability was greater for N than P application. Mean aboveground biomass N with 0 and 150 kg ha -1 N applied was 46.3 and 94.3 kg ha -1, respectively. Mean N concentration and N harvest index at the EONR were 1.60 and 63.8%, respectively, and higher than for N0. Mean recovery efficiency, partial factor productivity, and agronomic efficiency declined with increasing N rate and were 66%, 86 kg kg -1, and 41 kg kg -1, respectively, at the EONR. Fertilizer N use can be very profitable, with high NUE, for smallholder maize production in Uganda, and the financial capacity of smallholders to use fertilizer will increase with reduced CP.© 2012 by the American Society of Agronomy.


Nansamba A.,National Agricultural Research Laboratories NARL Kawanda | Kaizzi K.C.,National Agricultural Research Laboratories NARL Kawanda | Twaha A.B.,National Agricultural Research Laboratories NARL Kawanda | Ebanyat P.,Makerere University | Wortmann C.S.,University of Nebraska - Lincoln
Agronomy Journal | Year: 2016

Grain sorghum [Sorghum bicolor (L.) Moench] is an important staple crop in Uganda, but its productivity is limited by numerous constraints. Practices including reduced tillage (RT), conventional tillage (CT), sorghum rotation with mucuna (Mucuna pruriens L.) and cowpea (Vigna unguiculata L.), and soil fertility management treatments (SFTs) were evaluated to determine their effects on grain yield over a 7-yr period with two cropping seasons per year at Bulegeni and IkiIki representing high and low potential agroecological zones, respectively. At Bulegeni and IkiIki, respectively, mean grain yield was 13.0 and 8.6% greater with RT compared with CT, 10.9 and 14.4% greater following mucuna compared with cowpea, and 134 and 249% greater with farmyard manure (FYM)+N+P compared with no nutrient applied. At Bulegeni, SFT effects on sorghum yields increased with time. Factor interactions occurred, but grain yield was greatest due mainly to additive effects with a combination of RT, mucuna as the previous crop, and FYM+N+P. The SFTs accounted for >70% of the variation in annual treatment means for grain yield. Trial mean grain and stover yields were less for Years 1 through 4 compared with Years 5 through 7, especially at Bulegeni and with FYM and/ or fertilizer application. Factor interaction effects on some soil chemical properties were inconsistent across locations. Mucuna rather than cowpea as the rotation crop, RT rather than CT with an increasing RT benefit over time, and nutrient application can be used alone or additively to increase sorghum grain yield, but positive factor interactions were inconsistent and accounted for little yield increase. © 2016 by the American Society of Agronomy.


Kaizzi K.C.,National Agricultural Research Laboratories NARL Kawanda | Byalebeka J.,National Agricultural Research Laboratories NARL Kawanda | Semalulu O.,National Agricultural Research Laboratories NARL Kawanda | Alou I.N.,National Agricultural Research Laboratories NARL Kawanda | And 8 more authors.
Field Crops Research | Year: 2012

Smallholder African farmers commonly lack the financial means to purchase enough fertilizer for application at the economical optimal rates (EOR), or the rates for maximization of net returns ha -1, to all of their land. Research was conducted for bean (Phaseolus vulgaris L.), soybean (Glycine max L.) and groundnut (Arachis hypogaea L.) to establish a basis for determining the combinations of crops, nutrients, and application rates to optimize net returns to fertilizer use and the benefit:cost ratio (BC) in Uganda. Yield response to nutrient application, EORs, and equations for estimating BC were determined. Eleven to 17 trials were conducted for each crop. Mean yields were increased by 92%, 111%, and 92% for N applied to bean, and P applied to soybean and groundnut, respectively, at 15kgha -1, with less yield responses for P applied to bean and K applied to soybean and groundnut. Mean yield peaked at 1.81, 1.92, and 1.71Mgha -1 for bean, soybean, and groundnut, respectively. Mean EOR varied with fertilizer cost relative to grain price (CP) and were 27-42kgha -1 N for bean, and 13-29kgha -1 P with higher rates for groundnut compared with bean. The greatest BC was for N applied to bean followed, in decreasing order, by P applied to soybean or groundnut, P applied to bean, and K applied to groundnut or soybean. Consideration of the six sets of crop-nutrient response functions developed enables optimization of smallholder investment in fertilizer by identifying the crop, nutrient, and application rate combinations that maximize net returns on investments in fertilizer use. This approach is applicable for smallholder crop production globally where farmers cannot purchase enough fertilizer to apply at EOR. © 2011 Elsevier B.V.

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