Yield Of Cowpea Research Articles

Cultivation of Cowpea Challenges in West Africa for Food Security: Analysis of Factors Driving Yield Gap in Benin

Feeding the world in 2050 requires us to find ways to boost yields of the main local crops. Among those crops, cowpea is one of the grain legumes that is playing an important role in the livelihood of millions of people in West Africa, especially in Benin. Unfortunately, cowpea on-farm yields are very low. In order to understand the main factors explaining cowpea yield gaps, we collected and analyzed detailed survey data from 298 cowpea fields in Benin during the 2017, 2018 and 2019′s rainy seasons, respectively. Composite soil samples were collected from cowpea fields and analyzed in the laboratory. Data on farm field management practices and field conditions were recorded through interviews with 606 farmers. Average cowpea grain yields were low and seldom surpassed 700 kg ha−1 on farmer’s fields. Significant differences were observed between cowpea grain yields from northern to southern Benin (p < 0.05), and the lowest yields were observed in northern Benin. These low yields are related to crop management practices, soil nutrient contents, and the interaction of both. According to the model of regression tree from northern to southern Benin, the use of mineral fertilizer, insecticide sprays to control pests, and the improvement of phosphorus, nitrogen, potassium (P, N, K) and cation sum content in the topsoil would increase cowpea grain yields. Insect pests, diseases, and soil fertility decline are the largest constraints limiting grain yield in Benin. Future research should focus on formulating site-specific fertilizer recommendations for effective cowpea cultivation in Benin, as well as the control of insect pests and diseases.

Modeling of Cowpea (Vigna unguiculata) Yield and Control Insecticide Exposure in a Semi-Arid Region.

The aim of this study was to evaluate the adaptability of different genotypes of cowpea (Vigna unguiculata L. Walp.) in the edaphoclimatic conditions of a semi-arid region. In the experimental design, a completely randomized split-plot (2 × 8), with 3 repetitions (blocks) was used. The experiment comprised 7 new genotypes and 1 local genotype as the first main factor and application of insecticide as a secondary factor. Two-factor analysis of variance (two-way ANOVA) determined the differences between the treated and untreated plots. The results obtained in the experiment showed that the introduced genotypes V3 (IT07K-181-55), V7 (H4), and V5 (IT97K-556-4M) adapted well to the edaphoclimatic conditions of the study area and their yields were respectively 1019, 1015, and 841 kg/ha of grains in treated plots and 278, 517 and 383 kg/ha in untreated plots. Multivariate analysis revealed that the most important parameter was the germination rate. Finally, the best yield was obtained with the genotype V3 (IT07K-181-55), subjected to the use of insecticide, and with the V7 (H4) genotype in untreated plants. The findings presented in this research should be useful in crop system agricultural programs, particularly in the terms of selection of cultivating systems suitable for high-yielding cowpea.

Productivity and Profitability of Fodder Cowpea Cultivars under Various Zinc Management Practices in IGP of India

Background: Soils of North-Western Indo-Gangetic plains (IGP) are deficient in zinc content which may lead to lower forage yield of cowpea. Henceforth, the adequate supply of zinc either through soil or foliar spray and selection of suitable cultivar of cowpea could enhance the fodder productivity.Methods: A field experiment was laid out in factorial randomized block design during Kharif season, 2019 to assess the effect of different zinc management practices (control; 10 kg ZnSO4; 20 kg ZnSO4; 0.5% ZnSO4 foliar spray at 20 DAS; 0.5% ZnSO4 foliar spray at 20 and 40 DAS) on productivity and profitability of cowpea cultivars (C-152; MFC-08-14; MFC-09-1) and post-harvest fertility status of soil.Result: Cowpea cv. C-152 showed the highest growth attributes, green fodder yield, nutrient content as well as uptake and net returns. Among different zinc management practices, the application of 20 kg ZnSO4 as basal application or 0.5% ZnSO4 foliar spray at 20 and 40 DAS recorded significantly highest growth, green fodder yield, nutrient content as well as uptake and net returns. Significantly highest soil OC, available N, K and Zn were also noted under these treatments. It is inferred that cowpea cv. C-152 and application of either 20 kg ZnSO4 as basal or 0.5% ZnSO4 as foliar spray at 20 and 40 DAS were found the most productive and profitable approach and sustained the soil fertility status.

Integrated Effect of Deficit Irrigation and Sowing Methods on Weed Dynamics and System Productivity of Maize–Cowpea Sequence on Vertisols

The aim of this study was to explore the effect of sowing methods and deficit irrigation on weed dynamics, yield and water-use efficiency (WUE) of the maize–cowpea system during the summer and monsoon seasons, respectively. The field experiment was carried out for two years (2015 and 2016) using a split design with three replicates under irrigated (maize) and rainfed (cowpea) conditions on vertisols of a semi-arid region. Treatments included three sowing methods [i.e., broad bed and furrow (BBF), corrugated furrow (CF) and ridges and furrow (RF)] and four irrigation levels [i.e., irrigation once in 10 days (I10D), irrigation at 40% (I40), at 50% (I50) and at 60% (I60) depletion]. The results indicated that, regardless of weed flora (monocots, dicots and sedges), the RF method produced higher weed density (2.09–2.98 No. m−2) compared to CF (2.00–2.80 No. m−2) and BBF (1.85–2.64 No. m−2) in maize at 30 and 60 days after sowing (DAS). The RF method with irrigation at I40 and I50 recorded significantly higher weed density, followed by the CF and BBF method. A similar trend was also observed with dry weight of weeds (monocot; 24.19%, dicot; 25.52%, and sedges; 29.80%) in maize at 30 and 60 DAS. Higher weed density and dry weight of weeds in the RF method with I40 was due to higher soil moisture availability and higher nutrient uptake due to larger lateral wetting of the soil and greater water use (29.27%). However, the BBF method favoured the growth of weeds (9.33–16.60%) in cowpea at 55 DAS and coped under rain-fed situation over CF and RF. The CF with moderate depletion (I50) method produced significantly higher maize equivalent yield (MEY) of cowpea (10,000 kg ha−1) with considerable reduction in the total water usage (19.33%). Therefore, under a water scarcity situation, growers can practice CF and I50 for higher yield and WUE of maize–cowpea sequence cropping.

A case study of fly ash utilization for enhancement of growth and yield of cowpea (Vigna unguiculata L.) to sustainable agriculture

Fly ash (FA) is a coal combustion by-product of brick kiln, thermal power and incineration plants operated either based on coal and biomass or industrial solid waste. It creates environmental problems attached with their unfair utilization and problems of disposal. The growing of environmental awareness and increasing energy and material requirement will foster recycling. The Ministry of Environment, Forest and Climate Change (MoEF&CC) and Pollution Control Board (CPCB) have prepared guidelines for utilization of FA in agriculture as soil ameliorant and modifier. Recycling will promote reuse of precious materials which would otherwise be wasted and alleviate energy consumption and greenhouse gas emissions from extraction and processing. FA has potential to serve as fertilizer for improving the soil textures at optimum amount. The main purpose of this work was to use the pollutant as fertilizer. Present work was done to study the effect of FA on some biochemical and morpho-physiological properties and yield of V. unguiculata. From the obtained results after statistical analysis of data, it can be evinced that the use of FA in lower amount (25 g/m2) has sufficient quantity of macro- and micro-nutrients, which appear to be useful for the plant growth and yield of V. unguiculata, but higher amount (50, 100 g/m2) of FA showed detrimental impact on plant. The low concentration of FA improves the structure, texture of the soil which enhances the fertility of soil. So, FA can be used as a fertilizer for the enhancement of growth and yield of cow pea.

The crucial role of mulch to enhance the stability and resilience of cropping systems in southern Africa

Conservation agriculture has been promoted to sustainably intensify food production in smallholder farming systems in southern Africa. However, farmers have rarely fully implemented all its components, resulting in different combinations of no-tillage, crop rotation, and permanent soil cover being practiced, thus resulting in variable yield responses depending on climatic and soil conditions. Therefore, it is crucial to assess the effect of conservation agriculture components on yield stability. We hypothesized that the use of all three conservation agriculture components would perform the best, resulting in more stable production in all environments. We evaluated at, eight trial locations across southern Africa, how partial and full implementation of these components affected crop yield and yield stability compared with conventional tillage alone or combined with mulching and/or crop rotation. Grain yield and shoot biomass of maize and cowpea were recorded along with precipitation for 2 to 5 years. Across different environments, the addition of crop rotation and mulch to no-tillage increased maize grain by 6%, and the same practices added to conventional tillage led to 13% yield increase. Conversely, adding only mulch or crop rotation to no-tillage or conventional tillage led to lower or equal maize yield. Stability analyses based on Shukla’s index showed for the first time that the most stable systems are those in which mulch is added without crop rotation. Moreover, the highest yielding systems were the least stable. Finally, additive main effects and multiplicative interaction analysis allowed clarifying that mulch added to no-tillage gives stable yields on sandy soil with high rainfall. Similarly, mulch added to conventional tillage gives stable yield on sandy soil, but under low rainfall. This is the first study that highlighted the crucial role of mulch to enhance the stability and resilience of cropping systems in southern Africa, supporting their adaptability to climate change.

English

This research was conducted to study the effects of climate variables such as rainfall, temperature, and relative humidity on cowpea yield, and evaluated in Gombe State, Nigeria, during the period of 2009 to 2018 (one decade). The ex-post facto research design was adopted for the study, utilizing secondary data obtained from meteorological and agronomic data collected from the Metrological Office and agronomic data from the Ministry of Agriculture, Gombe State. Both data were collected and analysed using analysis of variance (ANOVA), Pearson Product Moment Correlation and Simple Linear regression. The study found that there is a negative relationship between rainfall, relative humidity and area of land/ha, while a positive relationship existed for temperature and cowpea yield over the period under study decade. The study revealed that all the parameters-rainfall temperature, relative humidity contributes 61% to climate variation in the study area. The study among others recommended that cowpea farmers should adopt new measures such as early planting, use of resistant varieties, contour farming to conserve water and supplementary irrigation to cope with the negative effects of climate change on cowpea yield and increases cowpea production in Gombe State, Nigeria. Key word: Climate variation, yield, cowpea. 

Parameterization of the AquaCrop model for cowpea and assessing the impact of sowing dates normally used on yield

The AquaCrop model was evaluated considering a data set from a cowpea (BR3-Tracuateua cultivar) cultivation in Castanhal/Brazil under different irrigations during the reproductive phase, which is sensitive to water deficit. Data on leaf area index (LAI), soil water content (SWC), biomass, and final yield of two harvests were used for model calibration (2013) and validation (2014). LAI data were used for parameterization of canopy cover (CC), and some crop parameters obtained in the field. The model was also used to evaluate the impacts of sowing dates, as well as the strategy of using an economical irrigation threshold (60% of Readily Available Water) on the water use and crop yield. Regarding the results after parameterization of the canopy cover curve, the model efficiency index (EF) presented a satisfactory performance (0.98), which is due to the high correlation coefficient (R2 = 0.99) between the simulated and observed values and the low values of normalized root mean square error (NRMSE < 6.33%). For model performance in simulating SWC, there was high efficiency (EF > 0.70) for all treatments, with low estimated errors and NRMSE representing 8.12% of mean SWC observations during validation, indicating high precision for simulation of biomass and cowpea yield. The model performance index ranged from 0.92 to 0.94 for biomass and from 0.92 to 0.99 for final yield. These results showed that AquaCrop is suitable for simulating biomass production and yield of cowpea. Additionally, sowing in early April is appropriate for better water use and productivity and the tested irrigation threshold can be indicated to significantly improve final crop yields.

Effect of Water Deficit at different Stages of Development on Forage Yield of Cowpea (Vigna unguiculata L.) Genotypes

The present study was evaluated fourteen populations of cowpea at Farm of Agriculture Research Station Ismailia, Ismailia Governorate, Egypt. These populations were collected from different regions including one check variety. These were investigated under three levels of watering (100%, 75% and 50% of field capacity), for forage yield, genetic variability and association characters during two successive summer seasons 2017 and 2018 using a Randomized Complete Block Design in a split plot. Analysis of variance was revealed significant variation (P < 0.05) among cowpea genotypes for plant length, number of shoots/plant, dry matter percent, forage fresh and dry yields/plot, expected forage fresh and dry yields/fad and water use efficiency. The irrigation levels had non-significant effects on remain traits {i.e.: plant length, number of shoots/plant in the second season, leaf/stem ratio, dry matter percent, forage fresh and dry yields/plot, expected forage dry yield/fad and water use efficiency}. Moreover, the irrigation levels and cowpea genotypes-interaction had highly significant differences for the studied traits, excepting of number of shoots/plant. Among the fourteen cowpea genotypes through the three irrigation levels, over two seasons (2017 & 2018); the Kenyan genotype named KF-122 was produced significant more crude protein (24.20%) and crude fiber (27.60%), whilst, this genotype; IN-1-14 was produced significant less crude protein (12.20%) and crude fiber (13.90%), furthermore the, the cheek Egyptian genotype named Buff was recorded, approximately, average aforementioned value over two seasons. The phenotypic variance (d2p) and phenotypic coefficient of variation (PCV %) were slightly higher than corresponding genotypic variance (d2g) and genotypic coefficient of variation (GCV %) for the quantitative forage characters of cowpea indicated the presence of less environmental effect (d2e and ECV %) upon the concerned characters. Heritability in broad sense estimates was moderate to high for all studied traits

Effects of continous cropping and NPK fertilizer on growth and yield of cowpea (Vigna unguiculata (L) Walp) grown on soils from different management systems

Studies were conducted to investigate the effect of continuous cropping and NPK fertilizer on the growth and yield of cowpea (Vigna unguiculata (L) Walp) grown on soils from different management systems. The investigations were carried out in two parts. The first dealt with the effect of continuous cropping while the other focused on the effect of NPK fertilizer on cowpea. Representative soil samples were obtained at 0-15 cm depth from land which had been continuously cropped, under forest tree fallow, and secondary bush fallow. These were bulked, processed, and analyzed. Six (6) kg of each type of soil were weighed into 25 x 22 cm polybag of 500 gauge. The continuous cropping experiment involved three cropping cycles of 35days each of cowpea on the same soils from 3 cropping systems. In the second experiment, a 2 x 3 factorial involving 2 levels of fertilizers (0, 40 kg NPK/ha) and 3 sources of soil were carried out to test their effects on cowpea. The growth parameters measured were plant height, number of leaves/plant and number of branches/plant. Number of nodules/plant, number of pods/plant, dry matter and grain yield were also estimated. Successive cropping of soils significantly reduced cowpea growth. Cowpea plants grown on soils from continuously cropped land had the least growth performance. Number of nodules/plant increased with successive cropping. Higher dry matter yield was obtained from the continuously cropped land. A significant (r = +0.55) positive correlation was found between soil P and dry matter yield of cowpea. NPK fertilization had only significant effect on plant height at 10 WAP but not on other growth parameters measured. The highest grain yield was obtained from unfertilized secondary bush fallow soil. Sources of soil (soil management system) had significant effect on some of the agronomic characters of cowpea.

Differential response of cowpea towards the CuO nanoparticles under Meloidogyne incognita stress

The application of nanoparticles as potent nematicides along with the plant growth-promoting effects is quite intriguing to meet the need for an alternative management strategy for nematode management. Here we reported the nematicidal effects of synthesized Copper oxide nanoparticles (CuO) against Meloidogyne incognita second-stage juveniles (J2S) under in vitro and in planta conditions at different concentrations. Scanning Electron Micrograph of CuO nanoparticles treated J₂S revealed the distorted, crinkled cuticle in comparison to control J₂S. CuO nanoparticles in graded concentrations (50, 100 and 200 ppm) applied concomitantly, three days before and after the nematode inoculation was assessed in terms of morphology, yield and biochemical attributes of infected Cowpea (Vigna unguiculata L. Gomti.). In planta, trials revealed that the application of CuO nanoparticles before the nematode inoculation at 100 ppm concentration exhibited healthier growth attributes besides concurrent reduction in nematode parameters in comparison to plants treated with M. incognita.

Seeds enriched with molybdenum improve cowpea yield in sub‐humid tropical regions of Brazil

AbstractThe possible benefits of molybdenum (Mo)‐enriched seeds for grain legumes have yet to be addressed in sub‐humid tropical areas, where cowpea (Vigna unguiculata L.) is an important crop. In 2016, seeds with 0.014 (low), 0.674, or 1.987 (high) μg seed−1 of Mo were harvested from plants sprayed with 0, 250, or 850 g ha–1 of Mo, respectively. These seeds were combined with either Bradyrhizobium inoculation (with or without) in 2017 or nitrogen (0 or 60 kg ha−1) in 2018 and evaluated under small farmer management in Maranhão State, Brazil. Maximum nodules plant−1 in these trials was 5.2. In 2017, inoculation acted synergistically with Mo‐enriched seeds by increasing nodule weight. Averaged across inoculation levels, plants originated from high‐Mo seeds had 36% higher leaf N concentration than those raised from low‐Mo seeds. Inoculation did not affect yield, but plants grown from high‐Mo seeds yielded 42% more than those raised from low‐Mo seeds. In 2018, seed Mo content did not affect nodule and yield where urea was applied. However, without urea, plants raised from high‐Mo seeds had 3.5‐fold greater values for nodule number and weight and yielded 70% more than those grown from low‐Mo seeds. We conclude that using Mo‐enriched seeds associated with Bradyrhizobium inoculation would improve cowpea N nutrition and yield in a sustainable way.

Agronomic biofortification of cowpea with zinc: Variation in primary metabolism responses and grain nutritional quality among 29 diverse genotypes

Dietary zinc (Zn) deficiency is widespread globally, and is particularly prevalent in low- and middle-income countries (LMICs). Cowpea (Vigna unguiculata (L.) Walp) is consumed widely in LMICs due to its high protein content, and has potential for use in agronomic biofortification strategies using Zn. This study aimed to evaluate the effect of Zn biofortification on grain nutritional quality of 29 cowpea genotypes. Zn application did not increase cowpea yield. In 11 genotypes sucrose concentration, in 12 genotypes total sugar concentration, and in 27 genotypes storage protein concentration increased in response to Zn supply. Fifteen genotypes had lower concentrations of amino acids under Zn application, which are likely to have been converted into storage proteins, mostly comprised of albumin. Phytic acid (PA) concentration and PA/Zn molar ratio were decreased under Zn application. Six genotypes increased shoot ureides concentration in response to Zn fertilization, indicating potential improvements to biological nitrogen fixation. This study provides valuable information on the potential for Zn application to increase cowpea grain nutritional quality by increasing Zn and soluble storage protein and decreasing PA concentration. These results might be useful for future breeding programs aiming to increase cowpea grain Zn concentrations through biofortification.

Leafy Vegetables under Shade? Performance, Consumer Acceptance, and Nutritional Contribution of Cowpea (Vigna unguiculata (L.) Walp.) Leaves in the Yayu Coffee Forest Biosphere Reserve in Southwest Ethiopia

In rural Ethiopia, people consume mainly cereals and pulses. Integrating vegetables into the multi-storey cropping system of the Yayu Coffee Forest Biosphere Reserve could improve nutritional health while reducing pressure on natural habitats in the biodiversity hotspot. The aim of the study was to assess the performance of cowpea under shade and its consumer acceptance as leafy vegetables. Trials compared continuous harvesting with uprooting, and food preference was tested. A baseline survey was conducted in four villages and revealed that cropping of vegetables in coffee plantations would be adoptable by 17% of farmers. The cumulatively harvested mean leaf yield (18.15 t ha−1) was significantly higher than the leaf yield of the uprooted cowpea (6.56 t ha−1). As many as 41% (52%) of participants liked cowpea dishes (very much). Based on the trial yields and the RDA, a 25 m2 cowpea plot could produce sufficient vitamin A for 2.1–4.6 adults, iron for 0.8–1.7, and vitamin C for 1.3–2.9 adults during six months. Cowpea was successfully cultivated below coffee, yielded most when repeatedly harvested and showed a high acceptance among consumers. The consumption of cowpea leaves from coffee forests could contribute to a balanced diet and improved nutrition.

Physical and chemical assessment of charcoalized soil on the field performance of maize (Zea mays)

This study investigated the effects of charcoalized soil on maize and cowpea which was conducted in the Green House of the Science Laboratory Technology in The Oke-Ogun Polytechnic. The treated seeds of maize was planted in plastic containers containing 4.2g of charcoalized soil in the Green House. The result obtained showed that sample E with manure had the highest stem height (40.69) while sample E with manure has the lowest value (8.97). It further revealed that the leaf length ranged from 60.14 to 24.52, Sample E with manure has 60.14 while sample B without manure had the 24.52 which is the lowest leaf length among the samples. Number of leaves ranged from 9.04 to 5.42mm, sample E with manure has the highest values while sample A without manure had was the lowest value. It revealed that there was no significance difference in cadmium and cobalt contents. It further reveled that Sodium ranged from 0.69 to 0.007, Sample B with manure having the highest sodium contents while Sample B without manure having the lowest sodium contents. Calcium ranged from 19.0 to 0.007, Sample B without manure having the highest calcium contents while sample E without manure having the lowest calcium contents among the samples. However, the efficiency of biomass conversion into charcoal was important in conjunction with a newly proposed opportunity to use charcoal as a soil conditioner that improves soil quality on very acid and highly weathered soils. It is hereby recommended that in other to improved nutrient contents, particularly in C+, resulted in a significant cowpea yield increase and further field-testing of charcoalized soil should be continued for three or more growing seasons to see the trends in yield, so as to ascertain the long-term effects of charcoal production on the fertility of tropical soils.

Growth and Yield of Pulses as Influenced by Intercropping with Finger Millet [Eleusine coracana (L.) Gaertn.] in the Southern Laterites of Kerala

Background: In the recent years, the yield plateau of the major cereals together with the climate change concerns, the potential of millets and pulses have been identified as pivotal for addressing the agrarian and nutritional challenges. The present study was conducted to assess the feasibility of intercropping green gram, black gram and cowpea in finger millet.Methods: A field experiment was conducted during summer 2019-2020 (February to May, 2020) to assess the variation in the growth and yield of pulses, viz., green gram, black gram and cowpea on intercropping with finger millet, along with and without AMF inoculation.Result: Pulses were observed to be significantly taller when intercropped with finger millet in the presence of AMF. Leaf area index (LAI), dry matter production, seed yield and haulm yield were higher for sole crops. Between the intercropping treatments, with and without AMF, LAI, dry matter production and seed yield were superior when pulses where intercropped in finger millet inoculated with AMF. Intercropping finger millet with cowpea recorded the highest finger millet equivalent yield (FMEY) followed by black gram and green gram. The treatment, T6 (finger millet with AMF + cowpea) registered the highest FMEY (3388 kg ha-1) followed by T5 (3234 kg ha-1). Intercropping finger millet (with AMF) with black gram (T4) and green gram (T2) recorded FMEY of 2708 kg ha-1 and 2497 kg ha-1 respectively.

Estimation of Yield Loss of Cowpea, [Vigna unguiculata (L.) Walp.] with Reaction Response of Few Genotypes against Root Knot Nematode, Meloidogyne incognita (Kofoid and White), Chitwood

Background: Root knot nematode, Meloidogyne incognita is one of the main biotic constraints in reducing the quantity and quality of the cowpea crop in most of the growing areas of the world. The nematode produces galls on roots and disrupt the physiology of the plant by reducing crop yield and product quality and are therefore of great economic importance.Methods: Studies were conducted to estimate the yield loss of cowpea in field condition along with evaluation of few genotypes under net house condition against root knot nematode based on gall index, reaction response and number of egg masses/ 5 g of root at Directorate of Research, BCKV, West Bengal. Estimation of cowpea yield loss was conducted with the parameter of mean yield, percentage avoidable and increase in yield, Root Knot Index (RKI in 1-5 scale) and final nematode population reduction. Result: Under treated condition, cowpea yield was significantly increased ranging from 10.93 to 14.58% with 37.19 to 38.17% reduction of nematode population. The range of avoidable yield loss was 9.85 to 12.72%. In response reaction, 28 genotypes were found as moderately resistant. Local cowpea cultivar, Kashikanchan may be avoided at nematode infection area due to its high susceptibility and the moderately resistant genotypes may be suggested for the use in future breeding studies as a parental material to develop the root knot nematode resistant cultivars.

Cowpea production constraints on smallholders’ farms in Maradi and Zinder regions, Niger

Cowpea production in Niger is constrained by biotic and abiotic factors that lead to lower yields and incomes for smallholder farmers. For decades now, efforts have been made to improve cowpea production, including the development and release of improved varieties that are high yielding and resistant or tolerant to pests and diseases. The present study assessed cowpea production constraints on 584 smallholders’ farms in Maradi and Zinder regions of Niger. Estimated parameters consisted of farm size, varieties used and pests and disease prevalence. We found that the average farm size for both regions was 2.10 ha. Local varieties (63%) and IT90K 372-1-2 (30.5%), an improved variety released 25 years ago, were the most-cultivated cowpea varieties. Two recently introduced varieties were planted on less than 4% of fields. Cowpea was grown in association with millet and sorghum on 96.6% of fields. Average cowpea yield for both regions was 253.4 kg ha−1. Five major insect pests and the plant parasite Striga, identified as major production constraints, were negatively correlated with cowpea yields. Diseases were significantly and negatively associated with cowpea yields. To increase cowpea productivity, there is a need to develop and/or promote adapted high-yielding varieties, and to disseminate good agricultural practices to minimize the incidence of pests and diseases.

&amp;lt;i&amp;gt;Zai&amp;lt;/i&amp;gt; Pit Effects on Selected Soil Properties and Cowpea (&amp;lt;i&amp;gt;Vigna unguiculata&amp;lt;/i&amp;gt;) Growth and Grain Yield in Two Selected Dryland Regions of Kenya

Erratic rainfall and temperature regimes, strongly affect agricultural productivity. To address the reduction in production, this study assessed the effect of Zai pit depths on selected soil properties and cowpea growth and grain yield. Zai pit technology was tested in two locations falling under Agroecological Zone IV (relatively dry areas) i.e. Machakos in Machakos County and Naivasha in Nakuru County, Kenya, aiming to determine the combined effect of four Zai pit depths and two levels of manure (plots with manure and plots without manure) on selected soil properties, growth and yield of cowpea. Experiment was laid out in split plot arrangement, with manure levels as the main plot factor and Zai pit depths (Flat: Z0, 30 cm: Z30, 45 cm: Z45 and 60 cm: Z60) as subplot factor, replicated four times. Cowpea (M66 variety) was used as the test crop. Inorganic nitrogen (Nin) and extractable phosphorus (Pex) were significantly (P ·kg−1 for Nin and 80.4 mg·kg−1 for Pex in Zai pits compared to flat plots which were at 0.91 mg·kg−1 for Nin and 47.1 mg·kg−1 for Pex. The values of Nin and Pex also varied depending on depths, with Z45 having highest Nin at 1.17 against the least, at 0.89 in the Z0, while Pex was highest in Z30 at 102.3 mg·kg−1 while Z0 having the least Pex of 89.7 mg·kg−1. Generally, crops in Zai pitted plots were larger in diameter (0.46 cm) and height (34.20 cm) than crops in flat plots at (0.42 cm) and (18.11 cm) diameter and height respectively. Better performance was observed in yield, with Z45 yielding 853.33 kg·Ha−1 against 685.0 kg·Ha−1 in Flat plots in Machakos while 931.66 kg·Ha−1 in Z45 against 563.33 kg·Ha−1 from Flat plots in Naivasha. This study demonstrated great potential of Zai pit technology on crop production, as reflected on improved growth and yield of cowpeas. Combining Zai pits with manure increases soil Nin, Pex and is a guarantee of great crop performance in terms of high final yields.

Effect of treated effluent from beverage industry irrigation on growth and yield of cowpea [Vigna unguiculata (L.)] in maize: Cowpea cropping sequence

A field experiment was conducted in the premises of coca cola Pvt. Ltd., near Bidadi, Ramanagara district of Karnataka during 2017-18 to study the effect of beverage industry effluent on soil properties, growth and yield of maize with ten treatments replicated thrice using RCBD design. The beverage industry effluent was slightly alkaline in pH (8.21 ±0.20). Electrical conductivity was medium (1.75± 0.14 dS m-1), BOD (5.23± 0.36 mg L-1) and COD (20.44 ± 1.07 mg L-1) and TSS (152.90 ± 0.21 mg L-1) but low in plant nutrient content. Among the plant parameters in residual cowpea crop higher plant height (45.44 cm), No of branches plant-1 (10.00), seed and haulm yield (1023.33 kg ha-1and 2411.86 kg ha-1, respectively) were significantly higher in the treatment receiving irrigation with beverage industry effluent + RDF + gypsum (T7) compared to all other treatments. Significantly lower plant height (38.91 cm), No of branches plant-1 (8.56), seed and haulm yield (876.14 kg ha-1and 2064.95 kg ha-1, respectively) were recorded in treatment received irrigation with beverage industry effluent + RDF without gypsum (T2).