Influence of Cereal-Legume Rotation on Striga Control and Maize Grain Yield in Farmers’ Fields in the Northern Guinea Savanna of Nigeria

On-farm trials were conducted in 2001, 2002, and 2003 in the northern Guinea savanna of Nigeria to evaluate integrated Striga hermonthica control measures under farmermanaged conditions. These included intercropping a Striga-resistant maize variety with cowpea for 3 years and also cropping this maize in rotation with legume trap crops - soybean and cowpea for 1-2 two years. Intercropping Striga-tolerant maize variety, Acr. 97TZL Comp. 1-W, with cowpea (Vigna unguiculata L.) consistently reduced Striga infestation in maize relative to continuously cropped sole maize over the threeyear period. Maize grain yield was lower in the intercrop than in the sole maize plot probably due to competition from cowpea. However, because of the high value of cowpea in the intercrop, crop value for this system was higher than sole cropped maize. Legume-maize rotation reduced Striga infestation by 35% after one year of legumes in the rotation and by 76% after two years of legumes in the rotation. Soybean was more effective in reducing Striga infestation and also gave higher maize grain yield than cowpea. The rotation of these two legumes with maize had clear advantage over continuously cropped maize. Farmers should therefore be encouraged to adopt the introduction of grain legumes into the cereal cropping systems of the Nigerian savanna

Agronomic response of drought-tolerant and Striga-resistant maize cultivars to nitrogen fertilization in the Nigerian Guinea savannahs

In additon to drought and Striga hermonthica parasitism, nitrogen deficiency is a major constraint to maize pro¬duction in the Guinea savannahs of Nigeria. The use of mineral fertilizers is limited because of unavailability and high costs. The use of maize cultivars that perform well under sub-optimal N conditons is therefore desirable. Breeders at IITA have selected maize cultivars that combine tolerance to drought and Striga hermonthica parasit¬ism. This study evaluated six of these cultivars under a range of N application rates and compared these with a widely grown variety, TZB-SR. The study was conducted in Zaria and Samaru Kataf in Kaduna State of Nigeria. Results showed N application significantly reduced days to flowering and increased yield and yield components. Cultivars selected for combined tolerance to drought and Striga recorded lower number of days to flowering under N stress and higher dry matter, higher grain yield, higher number of grains m-2 and higher 500-seed weight at all N rates. This confirms earlier reports that maize cultivars selected for tolerance to drought will perform well under N-limited conditions. Grain yield was significantly associated with dry matter, number of grains m-2 and 500-seed weight at all N levels suggesting that these agronomic traits are significant determinants of maize yield at all N rates. Two cultivars (DT STR SYN-W/IWD C3 SYN and IWD C3 SYN/DT-SYN-1-W) were particularly outstanding at all added N levels probably due to long term improvement for drought tolerance. These two cultivars can be recommended for large-scale demonstration and release to the farmers in the West African savannas

Evaluation of multi-stress tolerant maize varieties for sustainable intensification in Northern Guinea Savanna of north eastern Nigeria

Maize productivity is limited by multiple stresses in the savannas of West and Central Africa. Field trials were conducted in northern Guinea savanna of Nigeria in 2011 and 2012 to evaluate the performance of multi-stress tolerant maize varieties. Thirteen varieties including Local Check replicated three times were tested in randomized complete block design. Plant and ear heights were significantly higher for LNTP x LNP-WC3 and 2004 TZE-W DT-STRC4 than POOL 18-SR, 2009 TZE-W POP-STR, EVDT 99-W STR; and EVDT 2000-Y STRQPM, respectively. Striga count was significantly lower for EVDT 99-W STR and LNTP x LNP-WC3 than all the other entries. Days to 50% tassel and 50% silk were each significantly earlier for EVDT 99STR W-STR QPM, DT-W STR SYN, EVDT-99W STR and 2009 TZEW DT STR than the Local Check. Anthesis Silk Interval (ASI) was significantly lower for TZE COMP3 DT-WC2, 2009 TZEW DT STR, and EVDT 99-W STR than Local Check. Number of ears plant-1 was sig¬nificantly higher for 2008 DTMA-Y STR than Local Check. Grain yield ha-1 was significantly superior for DT-Y STR SYN, 2008 DTMA-Y STR, 2004 TZE-W DTSTR C4, 2009 TZEW DT STR and EVDT 99-W STRQPM, respectively. Plant height was positively correlated with ASI and ear height, while ear height was positively associated with ears plant-1, days to 50% silk and 50% tassel. Grain yield ha-1 was positively correlated with ears plant-1, days to 50 % silk, days to 50% tassel and ear height, while ears plant-1 was negatively correlated with ear weight. Farmer selec¬tion criteria for acceptance of variety were in the order: Striga tolerance > nutrient value > drought tolerance > flour value > good taste > high yield > early maturity. The five varieties: DTY STR SYN, 2008 DTMA-Y STR, 2004 TZE-W DT STRC4, 2009 TZEW DT STR and EVDT 99-W STRQPM satisfied farmers criteria and were promising and thus nominated for on-farm demonstration and subsequent adoption in the region

Using a Participatory Approach and Legume Integration to Increase the Productivity of Early Maturing Maize in the Nigerian Sudan Savannas

Drought, infestation of cereal crops by the parasitic weed Striga hermonthica, and poor soil fertility are the major constraints to maize production by smallholder farmers in the Sudan savannas of northern Nigeria. Four innovation platforms (IPs) were therefore established in 2008 in the Sudan savanna (SS) agroecological zone of northern Nigeria to create a stakeholder forum to address these identified food production challenges in the target areas. )e IPs comprised researchers from Bayero University, Kano; Institute for Agricultural Research, Zaria; International Institute of Tropical Agriculture; state and local government extension programs in Kano and Katsina states; input and output dealers; community-based organisations; and media organisations in the two states. )e current study reports on the effects of legume integration on maize performance in farmer fields and the adoption of Striga management technologies introduced in the IPs over a four-year period. )e deployment of drought- Striga-tolerant and early-maturing maize varieties along with legume rotation reduced Striga infestation by 46–100% when cowpea was rotated with maize, 80–97% when groundnut was rotated with maize, and 59–94% when soybean was rotated with maize. Grain yield of maize increased by 63–88% when cowpea was rotated with maize, 69–128% when groundnut was rotated with maize, and 9–133% when soybean was rotated with maize. Participatory and detailed questionnaire-based adoption surveys showed high adoption of improved maize varieties, five years after program interventions. )e maize variety 99EVDT-W-STR C0 was the most popular among all the IPs because it is early maturing, Striga-resistant, and drought-tolerant. )e high maize yields and high adoption rates suggest that the IP approach was effective in disseminating maize technologies

Understanding the response of sorghum cultivars to nitrogen applications in the semi-arid Nigeria using the agricultural production systems simulator

The Agricultural Production Systems simulator (APSIM) model was calibrated and evaluated using two improved sorghum varieties conducted in an experiment designed in a randomized complete block, 2014–2016 at two research stations in Nigeria. The results show that the model replicated the observed yield accounting for yield differences and variations in phenological development between the two sorghum cultivars. For early-maturing cultivar (ICSV-400), the model indicated by low accuracy with root means square error (RMSE) for biomass and grain yields of 20.3% and 23.7%. Meanwhile, Improved-Deko (medium-maturing) cultivar shows the model was calibrated with low RMSE (11.1% for biomass and 13.9% for grain). Also, the model captured yield response to varying Nitrogen (N) fertilizer applications in the three agroecological zones simulated. The N-fertilizer increased simulated grain yield by 26–52% for ICSV-400 and 19–50% for Improved-Deko compared to unfertilized treatment in Sudano-Sahelian zone. The insignificant yield differences between N-fertilizer rates of 60 and 100 kgha−1 suggests 60 kgNha−1 as the optimal rate for Sudano-Sahelian zone. Similarly, grain yield increased by 23–57% for ICSV-400 and 19–59% for Improved Deko compared to unfertilized N-treatment while the optimal mean grain yield was simulated at 80 kgNha−1 in the Sudan savanna zone. In the northern Guinea savanna, mean simulated grain yield increased by 8–20% for ICSV-400 and 12–23% for Improved-Deko when N-fertilizer was applied compared to unfertilized treatment. Optimum grain yield was obtained at 40 kgha−1. Our study suggests a review of blanket recommended fertilizer rates across semi-arid environments for sorghum to maximize productivity and eliminate fertilizer losses, means of adaptation strategies to climate variability

Multi-level Access in Searchable Symmetric Encryption

Remote storage delivers a cost effective solution for data storage. If data is of a sensitive nature, it should be encrypted prior to outsourcing to ensure confidentiality; however, searching then becomes challenging. Searchable encryption is a well-studied solution to this problem. Many schemes only consider the scenario where users can search over the entirety of the encrypted data. In practice, sensitive data is likely to be classified according to an access control policy and different users should have different access rights. It is unlikely that all users have unrestricted access to the entire data set. Current schemes that consider multi-level access to searchable encryption are predominantly based on asymmetric primitives. We investigate symmetric solutions to multi-level access in searchable encryption where users have different access privileges to portions of the encrypted data and are not permitted to search over, or learn information about, data for which they are not authorised

Intensive Cereal–Legume–Livestock Systems in West African Dry Savannas

The dry savannas of West Africa are undergoing rapid transformation of agricultural practices owing to the rapid human and livestock population growth, increase in agricultural intensification and accelerated climate change which has increased the incidence and severity of diseases, pests and drought. The major constraints to agricultural production in the savanna include poor soil fertility, pests and diseases of crops and livestock, parasitic weeds such as Striga hermonthica, drought, and competition between crops and livestock for resources, Inadequate policies, weak institutional mechanisms, and poor linkages among farmers, and researchers prevent adoption of improved agricultural technologies that can combat these constraints. The risk of continuous cultivation on these poor and fragile soils is huge. Integrating crop and livestock production offers ways to increase production while protecting the environment. Over the years, research and development institutions have generated several agricultural technologies to alleviate the majority of the production constraints in the West African savannas. However, most development organizations use traditional extension methods that result in poor adoption of the improved technologies. The integration of crop and livestock production is particularly desirable in intensively farmed and densely populated areas with access to urban markets. Proper integration of these practices will diversify smallholder income and increase food security. Integrated genetic and natural resource management provides the keys improved eco-efficiency. This includes integrating pesticide use with cultural practices such as modified planting date and disease control; rotating/intercropping cereals and legumes; use of pest resistant\tolerant cultivars to increase the effectiveness of pest control and reduce the need for pesticides; and improving soil fertility restoration/maintenance. Government and national institutions in West Africa are encouraged to scale-out these technologies to wider areas for increased benefit to farmers through the use of proven extension methods

Structured Encryption and Leakage Suppression

Structured encryption (STE) schemes encrypt data structures in such a way that they can be privately queried. One aspect of STE that is still poorly understood is its leakage. In this work, we describe a general framework to design STE schemes that do not leak the query/search pattern (i.e., if and when a query was previously made). Our framework consists of two compilers. The first can be used to make any dynamic STE scheme rebuildable in the sense that the encrypted structures it produces can be rebuilt efficiently using only O(1) client storage. The second transforms any rebuildable scheme that leaks the query/search pattern into a new scheme that does not. Our second compiler is a generalization of Goldreich and Ostrovsky\u27s square root oblivious RAM (ORAM) solution but does not make use of black-box ORAM simulation. We show that our framework produces STE schemes with query complexity that is asymptotically better than ORAM simulation in certain (natural) settings and comparable to special-purpose oblivious data structures. We use our framework to design a new STE scheme that is ``almost zero-leakage in the sense that it reveals an, intuitively-speaking, small amount of information. We also show how the scheme can be used to achieve zero-leakage queries when one can tolerate a probabilistic guarantee of correctness. This construction results from applying our compilers to a new STE scheme we design called the piggyback scheme. This scheme is a general-purpose STE construction (in the sense that it can encrypt any data structure) that leaks the search/query pattern but hides the response length on non-repeating queries

Phosphorus And Nitrogen Fertilization Of Soybean In The Nigerian Savanna

Soybean (Glycine max) is a major cash crop in the savannas of Nigeria although productivity is typically constrained by poor soil fertility. The objective of this research was to determine the interactive effect of N and P on soybean productivity in the northern Guinea and Sudan savannas of northeast Nigeria. Experiments were conducted using locally adapted early and late maturing cultivars. Two rates of N and three rates of P fertilizer were also compared at both sites over two years. At both sites, pods plant−1 and seed yield were higher in 2006 than in 2007, possibly due to better rainfall distribution in 2006. Nitrogen fertilizer had no significant effect on seed yield or pods plant−1. Application of P fertilizer increased pods plant−1 by 40–66%. Averaged across site and year, seed yield with no P was 1057.2 kg ha−1 while yield with 20 and 40 kg ha−1 P were 1941.0 kg ha−1 and 2371.5 kg ha−1, respectively. No significant interaction effect between N and P fertilizer on seed yield and pods plant−1 was observed. The late maturing cultivar yielded less than the earlier maturity group cultivar in 2007 likely due to moisture stress. For optimum seed yield 40 kg of P fertilizer ha−1 is recommended for soybean production in both locations. Our results suggest that N fertilizer is not critical for soybean production in this area

Impact of the Mass Drug Administration for malaria in response to the Ebola outbreak in Sierra Leone

Background: As emergency response to the Ebola epidemic, the Government of Sierra Leone and its partners implemented a large-scale Mass Drug Administration (MDA) with artesunate–amodiaquine (ASAQ) covering >2.7 million people in the districts hardest hit by Ebola during December 2014–January 2015. The World Health Organization (WHO) and the National Malaria Control Programme (NMCP) evaluated the impact of the MDA on malaria morbidity at health facilities and the number of Ebola alerts received at District Ebola Command Centres. Methods: The coverage of the two rounds of MDA with ASAQ was estimated by relating the number anti-malarial medicines distributed to the estimated resident population. Segmented time-series analysis was applied to weekly data collected from 49 primary health units (PHUs) and 11 hospitals performing malaria parasitological testing during the study period, to evaluate trends of malaria cases and Ebola alerts during the post-MDA weeks compared to the pre-MDA weeks in MDA- and non-MDA-cheifdoms. Results: After two rounds of the MDA, the number of suspected cases tested with rapid diagnostic test (RDT) decreased significantly by 43 % (95 % CI 38–48 %) at week 1 and remained low at week 2 and 3 post-first MDA and at week 1 and 3 post-second MDA; RDT positive cases decreased significantly by 47 % (41–52 %) at week 1 post-first and remained lower throughout all post-MDA weeks; and the RDT test positivity rate (TPR) declined by 35 % (32–38 %) at week 2 and stayed low throughout all post-MDA weeks. The total malaria (clinical + confirmed) cases decreased significantly by 45 % (39–52 %) at week 1 and were lower at week 2 and 3 post-first MDA; and week 1 post-second MDA. The proportion of confirmed malaria cases (out of all-outpatients) fell by 33 % (29–38 %) at week 1 post-first MDA and were lower during all post-MDA weeks. On the contrary, the non-malaria outpatient cases (cases due to other health conditions) either remained unchanged or fluctuated insignificantly. The Ebola alerts decreased by 30 % (13–46 %) at week 1 post-first MDA and much lower during all the weeks post–second MDA. Conclusions: The MDA achieved its goals of reducing malaria morbidity and febrile cases that would have been potentially diagnosed as suspected Ebola cases with increased risk of nosocomial infections. The intervention also helped reduce patient case-load to the severely strained health services at the peak of the Ebola outbreak and malaria transmission. As expected, the effect of the MDA waned in a matter of few weeks and malaria intensity returned to the pre-MDA levels. Nevertheless, the approach was an appropriate public health intervention in the context of the Ebola epidemic even in high malaria transmission areas of Sierra Leone