Two field experiments were conducted at Ellembelle and Jomoro districts in the Western region of Ghana where rubber cultivation is a predominant farming activity. The objective of the study was to assess the effect of rubber and plantain intercropping systems on selected soil properties. The experiment was arranged in a randomized complete block design (RCBD) with 3 replications. The treatments were the sole crop rubber (R), sole crop plantain (P) and three intercrop systems comprising an additive series of plantain: one row of plantain to one row of rubber (PR), two rows of plantain to one row of rubber (PPR) and three rows of plantain to one row of rubber (PPPR). Generally, agroforestry systems improved the soil hydraulic properties considerably, with the highest cumulative infiltration rates of 5.16 and 8.68 cm/min observed under the PPPR systems at the Ellembelle and Jomoro sites, respectively. Microbial biomass C (Cmic), N (Nmic) and P (Pmic) was significantly improved (P < 0.05) under the agroforestry than the monocrop systems. The Cmic, Nmic and Pmic values were highest under the PPPR system at both Ellembelle (Cmic, = 139.9 mg/kg; Nmic = 36.26 mg/kg and Pmic = 87.6 mg/kg) and Jomoro (Cmic = 78.7 mg/kg; Nmic = 80.3 mg/kg and Pmic = 3.45 mg/kg) sites.

We report soil carbon stock (SCS) and nutrient characteristics of a pure stand of Senna siamea grove in comparison with adjacent cropland using t-test. This study was conducted in 2018 at the Kwame Nkrumah University of Science and Technology, Kumasi. Soil sampling up to 50 cm depth was carried out from five subplots in each ecosystem. The SCS of the grove at 0–15 cm depth was over 100% greater (30.78 Mg/ha) than that of the cropland (15.16 Mg/ha). Soil pH and total N content of the grove were 5.75 ± 1.22 and 0.10 ± 0.03% in the topsoil (0–15 cm) and 5.52 ± 0.80, 0.06 ± 0.01% and 5.03 ± 1.22, 0.04 ± 0.01% in the 15–30 and 30–50 cm depths, respectively. Although these values were greater in the grove than the cropland, the available phosphorus content was 3–4 fold greater in the latter soil. The two ecosystems affected soil organic carbon and total nitrogen contents significantly (p < 0.05) only in the topsoil, but had a significant influence on soil available phosphorus in both the topsoil and the subsoil. Sand content of the grove seemed to explain greater variability in its SCS (R2 = 0.81) than clay content. The greater SCS of the Senna grove demonstrates its role in soil carbon storage in tropical climate in the era of climate change.

Aims: Direct methods of measuring saturated hydraulic conductivity (K s ), either in situ or in the laboratory, are time consuming and very expensive. Several Pedotransfer functions (PTFs) are available for estimating K s , with each having its own limitations. In this study, the performances of four popular PTFs were evaluated on different soil classes in the semi deciduous zone of Ghana. The PTFs considered herein were Puckett et al. (1985), Campbell and Shiozawa (1994), Puckett (1994), andFerrer-Julià et al. (2004). In addition, five local data derived PTFs were used to study the possibility of using local datasets to validate PTF accuracy. Materials and Methods: A total of 450 undisturbed soil cores were collected from the 0 -15 cm depth from three benchmark soils, namely, Stagni-Dystric Gleysol (SDG), Plinthi Ferric Acrisol (PFA) and Plinthic Acrisol (PA). The K s of samples were measured by the falling-head permeameter method in the laboratory. Sand, silt and clay fractions, bulk density, organic matter content, and exchangeable calcium and sodium were measured and used as input parameters for the newly derived PTFs. Accuracy and reliability of the predictions were evaluated by the root mean square error (RMSE), coefficient of correlation (r), index of agreement (d), and the Nash-Sutcliffe efficiency (NSE) between the measured and predicted values from both tested and newly derived PTFs. The relative improvement (RI) of the newly derived PTFs from this study over the existing ones were also evaluated. Results: The newly derived PTFs in this study had higher prediction accuracy with r, d, RMSE and NSE ranging from 0.80 -0.99, 0.79 -0.94, 0.14 -1. 74 and 0.84 -0.98, respectively, compared with 0.32 -0.45, 0.27 -0.50, 4.00 -4.90 and 0.41 -0.47 for the tested PTFs. The relative improvement of the newly derived over the tested PTFs ranged from 56.50 -95.71% in the SDG, 70.73 -96.89% in the PFA, and 65.37 -95.81% in the PA. Generally, RI was observed to be highest for Model 1 in the SDG, and Model 4 in both PFA and PA, and lowest for Model 5 in all three soils. It was observed that the inclusion of exchangeable calcium and sodium as predictors increased the predictability of the newly derived PTFs.

Background Soil application of biochar and straw alone or their combinations with nitrogen (N) fertilizer are becoming increasingly common, but little is known about their agronomic and environmental performance in semiarid environments. This study was conducted to investigate the effect(s) of these amendments on soil properties, nitrous oxide (N2O) and methane (CH4) emissions and grain and biomass yield of spring wheat (Triticum aestivum L.), and to produce background dataset that may be used to inform nutrient management guidelines for semiarid environments. Methods The experiment involved the application of biochar, straw or urea (46% nitrogen [N]) alone or their combinations. The treatments were: CN0–control (zero-amendment), CN50 –50 kg ha–1 N, CN100–100 kg ha–1 N, BN0 –15 t ha–1 biochar, BN50–15 t ha–1 biochar + 50 kg ha–1 N, BN100–15 t ha–1 biochar + 100 kg ha–1 N, SN0 –4.5 t ha–1 straw, SN50 –4.5 t ha–1 straw + 50 kg ha–1 N and SN100–4.5 t ha–1 straw + 100 kg ha–1 N. Fluxes of N2O, CH4 and grain yield were monitored over three consecutive cropping seasons between 2014 and 2016 using the static chamber-gas chromatography method. Results On average, BN100reported the highest grain yield (2054 kg ha–1), which was between 25.04% and 38.34% higher than all other treatments. In addition, biomass yield was much higher under biochar treated plots relative to the other treatments. These findings are supported by the increased in soil organic C by 17.14% and 21.65% in biochar amended soils (at 0–10 cm) compared to straw treated soils and soils without carbon respectively. The BN100treatment also improved bulk density and hydraulic properties (P < 0.05), which supported the above results. The greatest N2O emissions and CH4 sink were recorded under the highest rate of N fertilization (100 kg N ha–1). Cumulative N2O emissions were 39.02% and 48.23% lower in BN100 compared with CN0 and CN100, respectively. There was also a ≈ 37.53% reduction in CH4 uptake under BN100compared with CN0–control and CN50. The mean cumulative N2O emission from biochar treated soils had a significant decrease of 10.93% and 38.61% compared to straw treated soils and soils without carbon treatment, respectively. However, differences between mean cumulative N2O emission between straw treated soils and soils without carbon were not significant. These results indicate the dependency of crop yield, N2O and CH4 emissions on soil quality and imply that crop productivity could be increased without compromising on environmental quality when biochar is applied in combination with N-fertilizer. The practice of applying biochar with N fertilizer at 100 kg ha−1 N resulted in increases in crop productivity and reduced N2O and CH4soil emissions under dryland cropping systems.

A three-year field trial was conducted between 2014 and 2017 in the Ellembelle and Jomoro districts of the Western region of Ghana where rubber production is common to determine the optimum population density of plantain when grown in combination with immature rubber tree crops. The trials were arranged in a Randomized Complete Block Design with 3 replications. The treatments were sole rubber, sole plantain, and three intercrops of one row of plantain in between two rows of rubber, two rows of plantain in between two rows of rubber, and three rows of plantain in between two rows of rubber. The rubber clone used was GT1 while the variety of plantain used was false horn. The results showed that population density of plantain had significant effect on the growth of the associated rubber. Growing plantain at closer spacing of 1.5 m under the high-density plantain treatment significantly increased plantain yield compared to the other cropping systems. There was a significant positive relationship between population density of plantain and the rubber tree growth and development. The optimum population density of plantain when intercropped with rubber was 1,666/ha. The study showed intercropping was advantageous over sole cropping for both crops.

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Ghana’s agricultural economy is largely dominated by the crop subsector with much focus on the production of tree, arable and vegetable crops. Nevertheless, Phytophthora spp. are major threat to the production of these crops contributing significantly to yield reduction. In this review, the main focus will be to look at the threats the pathogen poses to production, economic importance of Phytophthora diseases, highlights some Phytophthora diseases with limited research in the country but have the potential of affecting crop production, management options and the prospect of developing and deploying biological control strategies considered environmentally friendlier and devoid of human health risks to reduce the effect of this pathogen on crop production as well as reducing the dependency on chemical control option.