Maize grain and straw yields over 14 consecutive years in burned and mulched Mucuna pruriens var. utilis and Pueraria phaseoloides relay cropping systems

The cover crops Mucuna pruriens var. utilis and Pueraria phaseoloides were introduced to African farmers to improve crop production on degraded soils, yet they appear not to be adopted at scale. In the humid forest zone of West and Central Africa, the dominant Acrisols and Nitisols are inherently poor even when not degraded through agriculture. In this zone, sole maize cropping and vegetable production systems are gaining importance, yet both suffer from nutrient deficiencies. Cover crops were often introduced along with a system change, requiring biomass retention, mainly for nutrient retention reasons. Farmers in the zone commonly use slash and burn systems due to added weed control and ease of operations on clean fields. This study evaluated mucuna and pueraria with and without burning the fallow biomass in an annual sole maize crop relay system against the burned and retained natural fallow. Over 14 consecutive years, biomass burning did not cause lower maize grain yields in any of the fallow types, on the contrary, the economically important marketable cob yields were higher when biomass was burned (mulched 2.10 cobs m−2 vs. 2.26 cobs m−2 when burned, p < 0.07). After cover crop fallow, maize grain yields were significantly higher than after natural fallow (1.92 Mg ha−1) over the 14 years, with maize yields in the pueraria treatment (2.63 Mg ha−1) out yielding those in the mucuna treatment (2.28 Mg ha−1). Maize produced 1.92 cobs m−2 in natural fallow, significantly less than in the mucuna (2.23 m−2, p < 0.013) and the pueraria (2.39 m−2, p < 0.001) fallow. Introducing mucuna or pueraria cover crops into slash and burn systems appears as a suitable measure to increase yields without changing the land preparation approach.

Adoption of Agro-Forestry among Farmers in Onigambari area of Oyo State, Nigeria

This study was carried out in the Onigambari area of Oyo state to determine the choice of farmers to practice Ago-forestry in the area. The χ2 test result revealed that the educational level of the respondents correlated highly with the respondents major occupation (p<0.01). χ2 test shows that there was significant relationship (p<0.01) between the respondents’ level of education and awareness of agroforestry systems. This shows that farmers with a better educational background can accept agro forestry easily than those will lower education. Farmers’ awareness of Agroforestry systems, willingness to plant trees, purpose of planting trees and desired tree species were evaluated. It was observed that 74% of the respondents are not willing to practice agroforestry while 24% shows interest. 64% confirmed they are aware of the practice while 32% had never heard of such practice. The t-test result shows a significant difference with respect to the willingness of the respondents to practice agroforestry. Of those that areaware, 38% practice agroforestry for the purpose of fuel wood, 36% as source of income while only 2% practice for the purpose of wind breaking. Eucalyptus calmuldulensis, Magnifera indica, Gmelina aboreal are some of the tress used for this practice in the study area. Lack of seed and scarcity of land were identified as limiting factors that prevent farmers from practicing agroforestry. In summary it was observed that the respondent’s level of education correlated significantly to the level of education, also the level of education determines respondent’s willingness to practice agroforestry. It is recommended that Seeds, Seedlings and land be made available to encourage the practice among farmers. Extension workers are encouraged to engage farmers more on the benefits of agroforestry. Keyword: Farmers, Agroforestry, Climate change, Land degradation, Natural Fallow

Effects of Fallowing and Nitrogen Application on Striga Infestation, Soil Fertility and Maize Performance

Striga possesses an ominous obstacle to the African continent that is struggling with food security as it affects the livelihood of more than 300 million people. The control of Striga has proved exceptionally difficult. Two fallows, namely natural fallow (NF) and A. histrix fallow (AF) were maintained in 2012, such that the field was divided into two parts and each part was further divided into three replicates. Each part was separated from one another by a strip of 2 m width and the fallow factor was randomly assigned to each part which constituted the main plot. In 2013, the inorganic N fertilizer levels (0, 60, 90 and 120 kg ha-1) were applied to the fallow plots and assigned to the sub-plot. These treatments were laid out in a split plot arrangement fitted to a randomized complete block design with three replicates. The two fallows significantly (P < 0.05) reduced Striga infestation similar to application of N at 60 – 120 kg N ha-1. The two fallows significantly (P< 0.05) increased SOC. Only natural fallow significantly (P<0.05) increased the STN by 36 %. Maize grain yield after natural fallow (1527 kg ha-1) was not significantly (P>0.05) different from that after A. histrix (1943 kg ha-1). Inorganic N application had highly significant (P<0.05) effect on grain yield. Lowest grain yield of 1253 kg ha-1 was obtained without inorganic N application, which was significantly different from those fertilized with inorganic N. Inorganic N fertilizer rate of 60 kg ha-1 seems to be optimum for maize. The Nitrogen Fertilizer Replacement Value of A. histrix was low, 13 kg N ha-1. The effect of both fallows on grain yield was due mainly to increased SOC content.

Effect of Maize –Legume Intercrop and Fertilizer on Weed Suppression and Maize Performance in South Eastern, Nigeria

Maize is one of the most commonly cultivated arable crops in the rain forest zone of South Eastern Nigeria. Globally soil fertility and weed pressure are the most important constraints limiting increase productivity of Maize especially in Sub Saharan Africa (SSA). Unavailability and cost of inorganic fertilizer as well as cost of labour for weeding have engendered low productivity of maize. Hence this trial was conducted to evaluate the efficacy of maize-legume systems on weed suppression and maize performance. The trial was carried out at the Teaching and Research Farm of Faculty of Agriculture, University of Port Harcourt, Nigeria located within latitude 04°54’N and longitude 6°55’ E). The trial was conducted between April 4th and July 5th, 2017. The experiment was a 3 x 3 factorial arrangement fitted into a randomized complete block design (RCBD) consisting of 3 types of legume systems (Mucuna pruriens, Lablab purpurens and No legume) and three levels of NPK 15:15:15 fertilizer (0, 15, and 30 kg NPK/ha). The 9 treatment combinations were replicated thrice to give 27 plots. Data collected were on maize yield and yield components, weed and legume parameters at 4, 8 and 16 weeks after sowing (WAS). Result showed that legume significantly reduced weed biomass when compared to the natural fallow. The effect of weed biomass reduction was Mucuna 34.8% >Lablab 29.2%. The legume system significantly suppressed weed compared to natural fallow and the weed suppression ability average 56% and 30% respectively for Mucuna and Lablab whether or not they received NPK. Result of this trial also revealed that within 8 weeks after sowing legumes (8 WASL) 26% N and 22% N can be harvested by integrating this legume cover in cropping system and that NPK application has little or no effect in the performance of these legumes. Mucuna was not sensitive to fertilizer application while Lablab responded to fertilizer application. Maize was sensitive to Mucuna due to early integration; hence, it is recommended that these legumes be integrated at six weeks after sowing maize.

Maize and Weed Response to Legume Cover Short Fallow and Fertilizer in Port Harcourt South Eastern Nigeria

Field experiment was conducted in Faculty of Agriculture Teaching and Research Farm University of Port Harcourt, Port Harcourt, Rivers State, South Eastern Region of Nigeria between March and September 2017; to evaluate the effect of planted short fallow legume cover crop on maize performance and weed growth. The experimental design was a 5 x 2 factorial in randomized complete block design (RCBD) in a plot size of 4 m x 4 m with four replicates. The treatments consisted of four different legumes cover species fallow and a natural fallow as follows: Mucuna [Velvet bean (Mucuna pruriens (L.) DC var. utilis), Lablab (Lablab purpureus (L.) Sweet), Pigeon pea (Cajanus cajan (L.) Mill spp)], Centrosema (Centrosema pascuorum (L.) and a natural fallow (No Legume Cover) and two levels of inorganic fertilizer as NPK 15: 15: 15 (0 and 15 Kg ha-1 NPK). All legume cover growth characteristics were negatively correlated with weed cover and weed dry weight (r = -0.58 and r = -0.59 at P=0.0001). Legume dry weight had a positive correlation with all maize parameter (r =0.64 at P=0.0001) except for stem diameter (r = -0.43 at P=0.0051). Similarly, all weed attributes were negatively correlated to maize parameters. Maize height was better in plots that received short fallow legumes than natural fallow. There was increase in soil Nitrogen level after 10 weeks of fallow. Legume cover crop short fallow has the potentials for weed suppression, soil fertility and productivity improvement in maize culture.

Nematicidal Properties of Moringa oleifera, Chromolaena odorata and Panicum maximum and their Control Effects on Pathogenic Nematodes of Yam

A field study was conducted at Atonsu, Sekyere Central District, Ghana from 2013 to 2014, to (i) determine the effects of Moringa oleifera, Chromolaena odorata and Panicum maximum as ex-situ mulches, on soil nematodes population after two years of yam cropping and (ii) assess the effects of the soil nematodes on the yield and physical tuber quality of yam. The field experiment was a 3x3 factorial arrangement in a randomized complete block design with three replications. The first factor was ex-situ mulch types at three levels; Panicum maximum (farmers’ choice), Chromolaena odorata and Moringa oleifera. The second factor was natural fallow aged systems at three levels: 3, 5, and 7 years old. Data collected included nematode population changes, total tuber yield of yam and tuber physical quality assessment. Generally, Meloidogyne spp., Pratylenchus spp., and Scutellonema spp. were the nematode genera identified. However, Scutellonema spp. was found to be the most pathogenic nematode affecting yam tuber yield and physical quality. Chromolaena and Moringa mulches suppressed Scutellonema spp. populations by 80.7% and 76.2% respectively as compared to the Panicum maximum mulch. The suppressed Scutellonema spp. population significantly contributed to higher tuber yields and good tuber physical quality under the M. oleifera and C. odorata mulches in comparison to the P. maximum mulch.

Screening Cover Crops for Soil Macrofauna Abundance and Diversity in Conservation Agriculture

Soil health is important for sustainable crop production. Frequent soil cultivation has a negative impact on soil health, resulting in loss of soil macrofauna. Conservation agriculture can be practiced to improve soil health by improving the abundance of soil macrofauna. Three leguminous cover crops were tested for soil macrofauna abundance Vigna unguiculata, (cowpea) Lablab purpureus L. (dolichos lablab) and Mucuna pruriens (L.) DC (velvet bean). The experiment was done in two contrasting experimental sites of KwaZulu-Natal (Ukulinga and Bergville) in a randomised complete block design replicated three times. Bare plot and herbicide treatments served as controls. Natural fallow was used to make a comparison to all the other treatments. Cowpea (39 species) had the highest soil macrofauna abundance in Bergville. Lablab (57 species) had the highest soil macrofauna in Ukulinga. Cowpea (0.75 species) and lablab (0.61 species) improved soil macrofauna diversity respectively in Bergville. Natural fallow (0.46 species) had the lowest soil macrofauna diversity in Bergville. Lablab (0.56 species) and velvet bean (0.74 species) had high soil macrofauna species diversity in Ukulinga. Bare plot (0.3 species) had the lowest soil macrofauna species diversity respectively. It can be concluded that cowpea and lablab can be recommended for improving soil macrofauna abundance in conservation agriculture.

Nitrogen oxides and CO2 from an Oxisol cultivated with corn in succession to cover crops

The objective of this work was to evaluate the effect of two legumes (Crotalaria juncea and Mucuna pruriens), as cover crops, and of natural fallow, as a control treatment, on the emissions of NOx, N2O, and CO2 from an Oxisol cultivated with corn, under conventional and no-tillage systems, in the Cerrado region, in Central Brazil. Variations of CO2 fluxes in the soil were explained mainly by soil humidity and, in the legumes, under conventional system, by soil NH4+-N concentration. Plots with legumes under no-tillage system had higher annual emissions of CO2, NOx, and N2O than natural fallow. Results show that the use of legumes as cover crops favors the emissions of NOx-N + N2O-N and CO2-C. However, when considering the potential for mitigation of CO2 and nitrogen oxide emissions from the soil, it is important to evaluate changes in soil carbon and nitrogen stocks.