Intercropping oil palm with food crops in Ghana: 1. Effect on nutrient dynamics, soil moisture retention and light interception

Nutrient dynamics, soil moisture retention, and light interception by oil palm in different cropping systems were examined in an oil palm-food crop intercropping trial at the Oil Palm Research Institute, Kusi, in Ghana between 1999 and 2002. There were four treatments consisting of a sole oil palm with pueraria cover crop, and three oil palm-food intercrops: oil palm + maize + cassava; oil palm + maize + plantain; and oil palm + maize + maize. The treatments were arranged in a randomised complete block design with four replicates. Generally, oil palm + maize + maize and oil palm with pueraria cover crop seemed to have favoured higher soil moisture retention, nutrient uptake and accumulation, and light interception by the oil palm than what pertained with oil palm + maize + cassava and oil palm + maize + plantain treatments. Oil palm with maize planted in the major and minor seasons seems to be a better intercropping option to be recommended to farmers because the food crop does not affect the growth of the oil palm during the establishment phase, and could also provide revenue to defray part of the substantial capital outlay required for establishing oil palm plantati

Crop-livestock interaction effect on soil quality and maize yield in northern Ghana

Open Access ArticleKeeping livestock overnight on fallow arable lands (Corralling) is a traditional method of soil fertility amendment in West Africa. However, there is limited quantitative data on the interaction effects of stocking density of sheep and goats corralling (SDSG), maize plant density (MPD) and nitrogen fertilizer rate (NFR) on soil quality and yield of maize. A 2-yr study was conducted to determine the interaction effects of three SDSG (0, 70, and 140 head ha–1), three MPD (66,667, 100,000, and 133,333 plants ha–1) and three NFR (0, 60, and 90 kg ha–1 N) on soil quality index (SQI) and maize yield in northern Ghana. The study was conducted using a split-split plot experiment replicated on eight farms. An adult sheep or goat was corralled in an area of 4 m2 and 1 m2 for the 70 and 140 head ha–1 SDSG respectively for five nights during the dry seasons of 2014 and 2015 cropping seasons. Principal component and correlation matrix analysis were used to select minimum data set for SQI. The SQI for sheep and goats corralling increased by 51% compared with the control. The SDSG×MPD, SDSG×NFR and MPD×NFR interactions were significant on maize grain and biomass yields. The results suggest that, small-scale maize-livestock farmers could use either SDSG of 70 head ha–1 with 90 kg ha–1 NFR or SDSG of 140 head ha–1 with 60 kg ha–1 NFR and MPD at 133,333 plants ha–1 to increase grain yield on Ferric lixisols in northern Ghana and similar ecologies in West Africa

Does nitrogen matter for legumes? Starter nitrogen effects on biological and economic benefits of cowpea (Vigna unguiculata L.) in Guinea and Sudan Savanna of west Africa

Open Access JournalThe hypothesis that application of starter nitrogen (N) fertilizer to cowpea may increase grain and fodder yields and profitability was tested in the Guinea and Sudan savanna zones of northern Ghana. Two cowpea varieties (Apagbaala: grain-type and Padi-Tuya: dual purpose) and three N fertilizer rates (0-30-30, 15-30-30 and 30-30-30 N-P2O5-K2O kg/ha) were evaluated using a 2 × 3 factorial treatments arrangement in a randomized complete block design with three replicates. Grain and fodder yields, 100 seed weight (SW) and net return of Padi-Tuya increased significantly compared with Apagbaala in both zones. Application of starter N fertilizer increased grain yield, fodder yield, N use efficiency (NUE) and net return by more than 30% compared with the control in both zones. Padi-Tuya cowpea with 15 kg/ha N fertilizer was risk efficient at all risk aversion levels when only grain was considered, but Padi-Tuya with 30 kg/ha N fertilizer becomes the most risk efficient option when the value of fodder was included. The results suggest that small-scale farmers could apply starter N fertilizer at either 15 kg/ha N for grain only or 30 kg/ha N for both grain and fodder yields improvement of cowpea in West Africa and similar ecologies

Fertiliser requirements for balanced nutrition of cassava across eight locations in West Africa

Insufficient and unbalanced fertiliser use widens cassava yield gaps. We assessed the spatial variability of optimal fertiliser requirements of cassava for enhanced nutrient use efficiency and increased yield using the balanced nutrition approach of the QUEFTS model. Two datasets comprised of five fertiliser experiments conducted at eight locations across Southern Togo, Southern Ghana and Northern Ghana from 2007 to 2012 were used. The ratio of storage roots dry matter yield over the sum of available N, P and K expressed in crop nutrient equivalent from the soil and nutrient inputs was used as a proxy to estimate nutrient use efficiency. Nutrient use efficiencies of 20.5 and 31.7kg storage roots dry matter per kilo crop nutrient equivalent were achieved at balanced nutrition at harvest index (HI) values of 0.50 and 0.65, respectively. N, P and K supplies of 16.2, 2.7 and 11.5kg at an HI of 0.50, and 10.5, 1.9 and 8.4kg at an HI of 0.65 were required to produce 1000kg of storage roots dry matter. The corresponding optimal NPK supply ratios are 6.0-1.0-4.2 and 5.3-1.0-4.2. Nutrient use efficiencies decreased above yields of 77-93% of the maximum. Evaluation of the performance of blanket fertiliser rates recommended by national research services for cassava production resulted in average benefit:cost ratios of 2.4±0.9, which will be unattractive to many farmers compared to 3.8±1.1 for the balanced fertiliser rates. The indigenous soil supply of nutrients revealed that, at balanced nutrition, K was the most limiting nutrient to achieve storage roots yields up to 8Mg dry matter ha-1 at most sites, whereas N and P were needed at greater yields. Dry weight of storage roots measured on the control plots in our researcher managed experiment ranged from 5.6 to 12.2Mgha-1, and were larger than the average weight in farmers' fields in West Africa of 4Mgha-1. Substantial yield increase could be attained in the region with improved crop management and fertiliser requirements formulation on the basis of balanced nutrition.</p

Corralling, planting density, and N fertilizer rate effect on soil properties, weed diversity, and maize yield

The interaction effect of stocking density of sheep and goat corralling (SDSG), maize planting density (MPD), and N fertilizer rate (NFR) on soil properties, weed diversity, and maize yield were evaluated on-farm in a smallholder maize-livestock farming system of Northern Ghana during the 2014 and 2015 cropping seasons. A split-split plot design replicated on eight farms was used to study the effect of three SDSG (0, 70, and 140 head ha−1), three MPD (66 667, 100 000, and 133 333 plants ha−1), and three NFR (0–40-40, 60–40-40, and 90–40-40 NPK kg ha−1). The SDSG at 70 and 140 head ha−1 increased (P < 0.01) soil chemical and biological properties and weed diversity compared with the control in both cropping seasons. Maize growth, yield and yield components, and weed biomass were affected (P < 0.05) by the SDSG, MPD, and NFR interactions. Maize-livestock farmers with smaller flock size could use SDSG at 70 head ha−1 with NFR at 90 kg ha−1, whilst those with large flock size could stock at 140 head ha−1 with NFR at 60 kg ha−1 and MPD at 133 333 plants ha−1 for increased maize yield and weed management

Nutrient release patterns of compost and its implication on crop yield under Sahelian conditions of Niger

Published online: 16 April 2016In Niger, farmers rely largely on organic resources such as manure and compost to address soil fertility problems and improve crop production. Ironically, they do not improve the fertilizer value of these organic resources or take into account their decomposition and nutrient release patterns before the application. This study aimed to assess the decomposition and nutrient release patterns of composted manure under field conditions and its implication on millet and cowpea grain yield. Litterbags arranged in randomized complete block design (RCBD) with three replications were used to assess decomposition and nutrient release of the compost. For the effect of composted manure and mineral fertilizer on millet and cowpea grain yield, two types of soil amendments were used; three levels of compost and four levels of mineral fertilizer. A 3 × 4 factorial experiment arranged in RCBD with three replications was used. After 84 days of decomposition, 40.3 and 56.5 % of compost mass losses were recorded respectively in 2013 and 2014. In 2013, 31, 74 and 97 % of N, P and K, respectively were released at 63 days of decomposition. Furthermore, in 2014, N, P and K release values of 58, 60 and 99 % were obtained at 84 days of decomposition. Combined application of 2500 kg ha−1 compost + 175/100 kg ha−1 NPK significantly (P < 0.001) recorded the highest millet yields of 1762 and 866 kg ha−1 while the highest cowpea yields of 360.5 and 389 kg ha−1 resulted from the application of 2500/5000 kg ha−1 compost + 75 kg ha−1 DAP. These findings suggest that, compost resulting from cattle manure plus cowpea haulm can be used by smallholder farmers to address soil fertility decline, improve nutrient availability and raise pearl millet and cowpea grain yield under strip cropping system

Understanding cassava yield response to soil and fertilizer nutrient supply in West Africa

Background and aims: Enhanced understanding of plant and nutrient interactions is key to improving yields. We adapted the model for QUantitative Evaluation of the Fertility of Tropical Soils (QUEFTS) to assess cassava yield response to soil and fertilizer nutrients in West Africa. Methods: Data from on-station and farmer’s field experiments across Togo and Ghana were used. Results: Soil nutrient supply ranged from 86 to 177, 18–24 and 70–104 kg ha−1 of N, P and K, respectively, and induced variable cassava responses to fertilizer application. Considering harvest (HI) in deriving the physiological nutrient use efficiencies for maximum dilution (PhEmax) and for maximum accumulation (PhEmin), which are key QUEFTS parameters, improved model predictions with reduction in normalized root mean square error from 32 to 13% at Davié (Southern Togo) and from 18 to 13% at Kumasi (Southern Ghana). Model overestimated yields in Nyankpala (Northern Ghana) where drought stress reduced yields. Estimated PhEmin and PhEmax at HI of 0.50 were 41 and 96 kg kg−1 N, 232 and 589 kg kg−1 P, and 34 and 160 kg kg−1 K. Conclusions: QUEFTS can be used for site-specific estimates of cassava yield responses to fertilizers under rain-fed conditions in West Africa, provided that yield is primarily constrained by N, P and K supplies, and not by drought or other nutrients.</p