Evaluating groundnut (Arachis hypogaea L.) performance due to genotype and phosphorus source on p-poor alfisols in two Nigerian agro-ecologies

Legumes require substantial quantities of phosphorus (P) for effective growth and yield. Under deficient conditions, P fertilisation will improve these. Field experiments were conducted in 2016 cropping season, at two Nigerian agro-ecologies, to evaluate effects of genotype and P source on yield of groundnuts grown on P-poor soils. The experiments were conducted at two experimental sites of the Institute for Agricultural Research, Ahmadu Bello University, Zaria (Minjibir and Samaru). The treatments consisted of 16 groundnut genotypes and three P sources. The P source was laid out in main- and genotype in sub-plot of a split plot design with four replicates. Data on pods, haulms and chlorophyll content (CC) were observed. There was no significant (P>0.05) difference between the genotypes in terms of pod yield, although higher pod yield was recorded at Samaru than Minjibir. SAMNUT 22 recorded the highest haulm yield (27.85 g plant-1) among all the genotypes, while SAMNUT 21 (18.57 g plant-1) and SAMNUT 24 (18.18 g plant-1), which were statistically similar, recorded the least haulm yield. Highest CC was recorded in SAMNUT 23 (40.39 mg plant-1), which was at par with ICGV-IS 07083 (39.06 mg plant-1) while Kwankwaso had the lowest (34.18 mg plant-1) CC. Higher CC and haulm yield were recorded at Minjibir than at Samaru. The P source significantly contributed to dry haulm (P<0.05) and pod (P<0.01) yields, but not in terms of CC (P>0.05).Keywords: Alfisols, genotype, haulm yield, Nigerian agro-ecologies, pod yield, P poo

Morpho-phenological variation in Lablab purpureus

The morphological and phenological variations in 46 accessions of Lablab purpureus were evaluated in 2000 and 2001 in Samaru, Zaria in the moist savanna zone of Nigeria. Accessions were classified into various groups according to plant structure, flowering time and pod and seed characters. Based on flowering time, 6 maturity groups were identified: very early ( 40-50 days after planting) (7 accessions), early (51-60 days (20), intermediate (61-80 days (4), late (91-110 days) (6), very late (111-130 days) (8) and extremely late (131-150 days) (1). In 140 days, nitrogen production increased from 15 kg/ha for the very early-flowering accessions and then decreased to 135 kg/ha for the extremely late-flowering accession with a mean nitrogen yield of 64.1 kg/ha. Fifteen accessions were identified as having potential for fresh pod production and 11 accessions for grain with a smaller number suitable for both grain and fodder productio

Does crop-livestock integration lead to improved crop production in the savanna of West Africa?

Integrated crop-livestock farming in the Guinea savanna of West Africa is often assumed to lead to synergies between crop and livestock production, thereby improving the overall productivity and resilience of agricultural production. Whether these synergies actually occur remains poorly studied. On-farm trials were conducted in northern Nigeria over a period of four years to assess the agronomic and economic performance of maize-legume systems with and without the integration of livestock (goats). Groundnut-maize rotations with livestock achieved the highest carry-over of nutrients as manure from one season to the next, covering approximately one-third of the expected N, P and K uptake by maize and reducing the demand for synthetic fertilizers. However, the advantage of lower fertilizer costs in rotations with livestock was offset by higher labour costs for manure application and slightly lower values of maize grain. Overall, no clear agronomic or economic benefits for crop production were observed from the combined application of manure and synthetic fertilizer over the application of synthetic fertilizer only, probably because the amounts of manure applied were relatively small. Legume-maize rotations achieved higher cereal yields, a better response to labour and fertilizer inputs, and a higher profitability than maize-based systems with no or only a small legume component, irrespective of the presence of livestock. Livestock at or near the farm could nevertheless make legume cultivation economically more attractive by increasing the value of legume haulms. The results suggested that factors other than crop benefits, e.g. livestock providing tangible and non-tangible benefits and opportunities for animal traction, could be important drivers for the ongoing integration of crop and livestock production in the savann

Potential contribution of Lablab residues to maize production in moist savanna of West Africa

Soils of the moist savanna of West Africa are poor in nitrogen; the natural fallow regeneration time has shortened; fertilizer costs and scarcity makes nitrogen (N) fertilizer input inadequate; and crop yields are low. In the region, lablab (Lablab purpureus L., sweet also known as Dolichos lablab L.) has the potential to improve soil quality, provide food, and supply feed simultaneously. In this context, response of maize to N following natural fallow or lablab fallow was investigated in the northern Guinea savanna of Nigeria. Lablab plots were maintained for 2 years—first planted in 2000 and replanted in 2001. In 2001, at the beginning of the growing season and before planting, lablab residues on the plots from 2000 planting were incorporated. In 2002, prior to maize planting, lablab residues on the plots from 2001 planting were also incorporated. Similarly, vegetation on the fallow plots was incorporated. The natural fallow and six lablab accessions of different maturity group formed the main plots with 0 and 60 kg/ha N as subplots in a split plot design with three replicates. Maize (Oba Super 1) in lablab plots grew taller and produced more stover and grain yields than natural fallow. With 0 kg/ha N, maize grain yield from lablab plots was 6.0 t/ha, 57% higher than from natural fallow. Where 60 kg/ha N was applied, maize mean grain yield from lablab plots was 6.6 t/ha, 31% more than from natural fallow plot. Thus, adding N fertilizer to plots formerly grown to lablab enhanced the productivity of subsequent maize. The study showed that late maturing lablab would contribute more to maize production than early maturing lablab when lablab residues are incorporated; without N fertilizer input it would be possible to obtain up to the potential yield of maize with incorporated lablab residues

Potential of Lablab purpureus accessions for crop-livestock production in the West African savanna

The introduction and use of herbaceous legumes may contribute to agricultural intensification, especially in the context of sustainable crop and livestock production systems. In the context of evaluating different legume species for these systems in moist savanna zone of West Africa, the present study involved the evaluation of 46 accessions of Lablab purpureus (L.) Sweet between 2000 and 2002 at Samaru, Zaria in the northern Guinea savanna of Nigeria to identify accessions with the potential to contribute to grain or forage production and those with the potential for multiple use. Grain yields (0.6-2.4 t/ha) with a mean seed crude protein and phosphorus content of 25.3 and 0.46 g/kg, respectively, were obtained. Dry matter yields (leaf : 0.3-3.1, stem: 0.2-4.6, root: 0.03-0.3 t/ha) were produced between 40 and 140 days after planting. Within this same period up to 1152 kg shoot crude protein/ha, equivalent to 184 kg N/ha, were recorded for accessions. Ten accessions that may contribute to grain production, eight accessions that may contribute to forage production and six accessions with drought tolerance were identified. Some white-seeded accessions (Grif 1246, ILRI 4612 and PI 183451) with good grain and forage yield and high-protein content have the potential to provide more and higher quality food for people and feed for livestock. The observed potential to contribute to grain production for protein-rich food, feed for livestock and green manure for soil N improvement suggests lablab may be an acceptable legume option for use in cereal-legume livestock systems in the moist savanna zone of West Africa

Effect of crop rotation and nitrogen fertilization on yield and nitrogen efficiency in maize in the northern Guinea savanna of Nigeria

Two crop rotation cycles were evaluated to determine the effect of cropping systems and N fertilization on the yield and efficiency of N in maize. Maize was grown on plots which had previously supported monocrops of two genotypes each of soybean (TGx 1448-2E and SAMSOY-2) and cowpea (IT 96D-724 and SAMPEA-7), natural fallow and maize. In a split-plot experimental design, three N fertilizer rates (30, 60 and 90 kg ha-1) and an unfertilized control were compared. On average, maize following legumes had higher grain yield of 1.2 and 1.3-fold compared with maize after fallow or maize after maize respectively. Similarly, legume rotation resulted in significant increase in total N uptake compared to continuous maize. In both years, N agronomic efficiency (AEN) and N fertilizer recovery efficiency (REN) of maize following grain legumes were on average 14 and 34% greater than of maize following maize and 12 and 20% greater than of maize following fallow respectively. On the other hand, all N efficiency indices except N physiological efficiency significantly decreased with increasing N levels. These indicate greater N use efficiency for the legume-rotation and poor efficiency for maize monoculture as well as the inefficiency of the current method of N fertilizer application