Leaf area index (LAI) plays an important role in radiation capture, crop growth and yield formation. However, there is limited quantitative data on the influence of poultry manure (PM) and NPK fertilizer rate (NPK) on LAI, as estimated directly. Using a split-plot design with three replications, a field experiment was conducted to determine the effects of three PM rate (0, 2 and 4 t/ha) as main plot and three NPK rate (0:0:0, 60:30:30 and 120:60:60 kg N P2O5 K2O/ha) as sub plot, on LAI and maize grain yield. The maize was planted at a density of 106,666 plants/ha; two rows on a ridge, one plant per stand at 75 × 25 cm. Linear regression was used to establish predictive equations among correlated variables and to describe the degree of associations. The application of PM in maize increased (p < 0.05) number of leaves/plant (NL) at 8 and 10 weeks after sowing maize (WASM). NL, leaf area constant at 6 and 10 WASM, leaf area (LA) and LAI were significantly affected by NPK. LAI correlated positively with NL, LA and grain yield. The coefficient of determination between actual and estimated LA was in the range of 0.85-0.97. The PM × NPK interaction was significant on maize grain yield. The results suggest that small-scale maize farmers faced with challenges in obtaining and transporting large quantities of poultry manure can use 2 t PM/ha with either 60:30:30 kg N P2O5 K2O/ha or 120:60:60 kg N P2O5 K2O/ha to increase grain yield of maize.

The cereal–legume cropping system is a common practice across the tropical world. However, there are limited quantitative data on the effect of cereal–legume intercropping on weed species diversity. A study was conducted in the Guinea savanna zone of Ghana to evaluate the effect of maize–soybean intercropping on yield productivity and weed species control. The treatments used include three maize maturity types (extra‐early: Abontem, early: Sammaz 27 and medium: Obatanpa) intercropped with soybean at three intraspacing (10, 20 and 30 cm), and their sole crop treatments were laid in a randomized complete block design with three replications. Results showed that the land equivalent ratio (LER) for the intercrops was above 1, indicating better intercrop productivity than the sole crops. An average of 40% land was saved for the intercrops compared with the sole crops. Intercropping Sammaz 27 maize with soybean significantly increased LER by 9% compared to the other types. Intercropping maize with soybean significantly reduced weed biomass at 6 and 9 weeks after planting (WAP) and at harvest relative to the sole maize. The weed biomass at 6 and 9 WAP and harvest increased (p < .05) with increasing soybean intraspacing. The grass and broadleaf weed species count at 6 WAP and harvest from the sole crops were significantly higher than that of the intercrops. The results suggest that intercropping early maize maturity type with soybean at 10 cm intraspacing could be used to increase grain yield, LER and control of grass and broadleaf weeds in a maize‐based cropping system in the Guinea savanna zones of West Africa.

Under rain-fed conditions, perfumed rice production in Northern Ghana is associated with high paddy cracking during milling. In this study, 4 perfumed rice varieties, 6 staggered planting times, 6 staggered harvesting cycles, and staggered storage duration from harvest to six months of storage were used in a randomized complete block design to identify the best combination of factors that are associated with low cracking in rice production. The experiment was laid out in a randomized complete block design with three geographically distinct locations serving as replicates. Grain moisture and paddy crackness were determined. The results indicated a mixed factorial interaction for all measured variables. Early planting, early harvesting, and short storage duration reduced paddy cracking compared to late treatments ( P < 0.05 ). For all treatment combinations, milling within two weeks after harvesting was associated with lower cracking as long as the harvesting cycle did not exceed the fourth cycle. After the second month of storage, percentage cracking was high, approaching 90% in most cases.

Peanut forms a major component of the predominantly cereal-based farming systems in Northern Ghana. However, yields are low, prompting the need to evaluate the effects of phosphorus (PR) and rhizobium inoculant (IR) rates on growth, nodulation, and yield of peanut varieties. On-station and on-farm experiments were conducted to determine the interaction effects of three P rates (0, 30, and 60 kg P2O5/ha), three IR rates (0, 3, and 6 g/kg seed), and two peanut varieties [Chinese and Nkatie Savannah Agricultural Research Institute (SARI)] on growth, nodulation, and yield of peanut on Haplic Lixisols of Northern Ghana. Both experiments were conducted using a split-split plot design replicated three times for the on-station experiment and on six farmer's fields (on-farm experiment). In both experiments, combined application of 60 kg P2O5/ha and IR at 6 g/kg seed increased pod number in the Nkatie SARI and Chinese varieties compared to their control counterparts. PR × V interaction influenced growth, effective nodule number, and podding capacity with 60 kg P2O5/ha combined with Nkatie SARI to produce significantly higher values. The interaction of IR × V improved pod number, nodule number, and harvest index, such that inoculant at 6 g/kg seed combined with Nkatie SARI gave the best performance. PR × IR also had a significant interactive influence on peanut grain yield. Higher grain yields were recorded from 60 kg P2O5/ha in combination with 6 g/kg seed of rhizobium inoculant. Therefore, these results suggest that the use of P fertilizer at 60 kg/ha and rhizobium inoculant at 6 g/kg seed increase peanut productivity on Haplic Lixisols in Northern Ghana. However, it was prudent not to suggest any recommendations from the P rates in interaction with IR, since the result between the on-station and on-farm experiments appeared not consistent.