Beans are considered a very important commodity in the world. It is eaten in the form of seeds (fruit vegetables) and leaves (leafy vegetables). Bean seeds can be eaten green and are preferred almost anywhere in the world. At this state, they contain a lot of vitamins. Beans are grown for food in parts of Africa and Latin America. In developed countries, alongside the limited production of home gardens for home consumption, this crop has grown in open fields over large areas while constituting a source of capital and a pillar of development [1]

Bean is a grain legume which is very nutritious and rich in protein. The leaves, green pods, young and mature seeds are edible. The crop residues are good feed for livestock and also form a good basis for compost manure. Vegetable bean crops mainly provide carbohydrates, sources of metabolic energy (starch), and proteins, but also varied panoply of other elements: lipids, fibers, minerals and vitamins [3].Besides their role in the nitrogen cycle, vegetable production interacts with other plants in the biotechnical cycle such as phosphorus, etc. They participate in increasing the functional diversity of ecosystems, which is favorable to biodiversity within agro systems [3].

Beans are one of the main crops in eastern DR Congo [4].In Kabare territory, it is seen along with soybeans, as an important component of the cropping system through restoring soil fertility and providing protein to small farmers. With the appearance of bacterial banana wilt in the area, which has had disastrous consequences on the economy of agricultural households, it seems more important to intensify this crop given the nutritional and agronomic advantages it offers [5]. 

Despite genetic progress, the optimum production potential is rarely expressed by cultivated bean varieties because of the biotic and abiotic constraints involved in the development of the yield components [6].In addition, there are poor land management practices leading to nutrient depletion of the soil, but also increasing population pressure leading to a drastic reduction in cultivable land [7].

Over the past 30 years, there has been a dramatic increase in population in Kabare. Arable land has become scarce. Day for day, there are land issues between peasants. Some wealthy people who acquired large plantations during the period of Belgian settlers pursuing their own interests do not exploit them for the benefit of the peasant population in the annual report of the Bushumba area (2014). Climate change and its serious consequences mean that rains are becoming rare in many areas, including our own. All this results in the scarcity of cultivable land, land conflicts between neighbors, the drop in production and yield, the overexploitation of land with numerous consequences such as famine, rural exodus, malnutrition, lack of employment, juvenile delinquency, sexual immorality,…[4,8].

With all these constraints, it seems important to study and promote bean production techniques adapted to local conditions. Depending on how the varieties grow, beans are subdivided into bush and climbing. Climbing beans are also more resistant to fungal and root rot diseases [9] and have a better potential to fix nitrogen[10,11,12]. Although climbing beans produce more than bush beans, it is the latter that are preferred in field crops. However, several authors [2] van der [13,5]  show that staking increases the production of twining bean from 29 to 100%. To tie 2, 3 or 4 long stakes together or tripod increases in doubles or triples the climbing beans production of than that of bush beans for the same unit of area.

In Kabare territory preciously in the Bushumba area, the main constraint to the extension of climbing bean remains the availability of stakes. This low availability is the result of the deforestation that accompanied the massive arrival of Rwandan refugees in 1994. The finding is that when the stakes are used, they rarely exceed 1.5 m. In most cases, they broadcast beans and / or on small mounds, rarely in rows. Do the different staking methods have a significant impact on climbing bean production? What would be the best method to popularize for climbing bean staking? However, the application of 3 m stakes or other staking methods combined with good cultural practices and practices would improve the yield of climbing beans.

The main aim is to contribute to the improvement of the production of climbing beans in Kabare territory South Kivu province by evaluating the effect of the various techniques of stakes on the growth and the yield of climbing bean and offer the most efficient and economically profitable staking method.

 Study area 

The test was conducted in  Bushumba area Kabare territory at the Mushweshwe experimental site. This site is located between 28 ° 33 ’32’ ’ longitude and 2 ° 18’ 58 ’’ latitude at an altitude of 1538 m. It is separated from Katana by 15 km and from Birava by 7 km. It is bounded to the north by Luhihi area to the south by Lugendo area and  village of Buhehe and to the west by  village Nyabulongwe, to the east by  village of de Buhehe. The agricultural domain of Mushweshwe is located in the village of Buhehe and separated from it by neighboring trees planted by the Belgian Congolese and German cooperation.

The Bushumba area is 97 km. It is part of 14 groups (Bushumba, Luhihi, Lugendo, Ishungu, Bugorhe, Bugobe, Irambi-Katana, Miti, Mudaka, Mudusa, Mumosho, Kagabi and Cirunga) which make up the Kabare chiefdom collectivity which bears the same name of the territory. The territory of Kabare is located between 27 ° 45 ’and 28 ° 55’ longitude and 2 ° 30 ’and 2 ° 50’ latitude. It includes two communities (chiefdom); the chiefdom community of Kabare and the chiefdom community of Nindja. Bushumba is located about 30 km from Bukavu, the capital of South Kivu province. The Bushumba area is administratively made up of six villages Murama, Muganzo, Cishoke 1 et 2, Lwangoma, Nyabulongwe, Buhehe in the report of the Bushumba area (2010).

The vegetation consists of savannah varying from wooded savannah to grassy savannah under the multiple effects of agriculture. Thus the forest is replaced by this, the original Albizia grandibactectera forest has disappeared[14]. Today the vegetation consists of trees, shrubs and grasses. The grass usually or mostly consists of grasses (Hyparhenia spp) which are used as pasture for cattle. The latter are much threatened by farmers who lack arable fields.

We can add to this plant flora, afforestation trees like Eucalyptus grandis, Leucaena gloca and L. Leucocephala, Grevelea robusta, Cedrela serrata, Maesopsis emini, Markhamia lutea, and some endangered species since the advent of Rwandan shelters. The latter taught the populations to exploit and to exploit wood (manufacture of embers) almost all large trees and even the means to small trees have been decimated and many hills remain bare and should be reforested in order to bypass them. Heavy consequences on crops. We cannot but cite bananas despite the presence of bacterial wilt and industrial crops coffee, tea, sugar cane, cinchona, etc. which are distributed in different corners in Kabare, but the largest plantations are those of coffee trees than fruit trees and fields of vegetable crops (food crops etc.).The fodder species observed are mainly grasses such as Hyparhenia diplandre, H. filipendula, etc. and legumes such as Leucaena spp, etc.

Mushweshwe soil would be ultisol according to the American classification. It is similar to that of ISDR / Bukavu. It is poor soil but can be alleviated with farmyard manure, compost and good soil conservation and protection methods. Mushweshwe soil has two origins volcanic and forest. Its pH would be variable from acidic soil to basic soil from 4.1 to 7[15]. This soil is neutral (pH = 7) and alkaline (4.1) in the bottom. The result of the soil analyzes of the soil samples carried out at the UCB / Kalambo soil laboratory is in table 1.

Table 1. Chemical composition and texture of the soil sample from the experimental site at the UCB / Kalambo soil analysis laboratory on January 28, 2017.

The area benefits from a humid tropical climate characterized by two seasons including  3 months of  dry season (June to August ) and  9 months of rainy season( September to May) . A small dry season begins from mid-January to mid-February, lasting 3 to 4 weeks. The mean annual temperature of the area varies between 19 and 20 ° C. Relative humidity ranges from 68 to 75% and annual rainfall is 1,500 mm Long periods of drought (dry season) are observed in our environments and disrupt the agricultural calendar and the crop cycle. The dry season has become long 3 to 4 months or sometimes even 5 months compared to the rainy which has become 7 months instead of 9 months. There is a significant increase in temperature following this global warming.

This hydrography is dominated by Lake Kivu which makes its natural limit towards the eastern part. Then there are large rivers which take their sources in the PNKB and flow into the lake –Kivu. We mention Mushweshwe, Karhungulu, Karhanywa, Mpugwe, Cindrier, Langa, Lwiro, Bidagarha, Cirhagabwa, and Nyabarongo form the natural boundary of Kabare and Kalehe territory. Mushweshwe, Karhungulu rivers and Lake Kivu surround the Mushweshwe Agricultural domain. The ITAV / Mushweshwe contains several water sources in village of Buhehe  3 sources of drinking water in the planned plots of the ITAV (10, 6, 8 and 20 and 22) and in Buhehe the sources of Lyamuzungu towards Lake Kivu are Lukondogolo, Kamabale, Lya method, Lyabamba I, Lyabamba II, etc. in the lower Karhungule.

Climbing bean variety HV / Namulenga

The characteristics of this climbing bean variety HV / Namulenga are presented in table 2. This variety was purchased from INERA/ Mulungu for the test

Table 2. Characteristics of the variety HV / Namulenga (PNL/INERA Mulungu, 2018)

Device: Complete Random Block 

The field experimentation method was used and carried out in growing season A, from November 2^nd, 2020 to February 15^th, 2021. The experiment took place in the agricultural field of Mushweshwe at the ITAV/ Mushweshwe, an expanse of land located at the bottom of the guest house (Guest house) of senior executives and Administrative staff of the ISEAV, next to the Kanyenye Primary School. The experimental field is located between 02 ° 18 ’04’ 7’’ S latitude and 028 ° 53 ’03 7’’ E longitude on an elevation of 1508 m.

The experimental set-up was a complete random block (Figure 1). This device was subdivided into 5 blocks and each block into 5 plots, for a total of 25 (5 blocks x 5 treatments / block). Each plot has a dimension of 2 m x 1.75 m or 3.5 m², at a distance of 50 cm between the lines. The length of 11 m and the width of 9 m is the total surface of 99 m² with a useful surface of 87 m². Each treatment is repeated once and only once per block. All the treatments were monitored at the same time and staking was carried out on November 20^th, 2020. Figure 1 shows the experimental design below.

Figure 1. Experimental design

Legend

P1 = stake of the tripod: Tie 3 long stakes together. Tying stakes together increases their strength. 

P2 = Outside T stakes + string + spike or a rope or stake is tied horizontally between 2 strong single stakes. Our ropes are made from sisal.

P3 = Single stake of 3 m.

P4 = Crossed stakes 

C = Single stake of 1 m considered as control treatment 

Leaf area, plant height, diameter data were measured for a total of 15 plants. The diameter data was collected by the diagonal and median method at the rate of 5 plants per diagonal and 3 plants per median, a total of 10 plants (for 2 diagonals) and 6 plants (for 2 medians).It was measured using a caliper. The branches were counted per plant to get the number of ramifications. Plant height was measured using a decameter and leaf area using a graduated slat. We took the length of the sheet and the width and the regression coefficient. The bean correction index is 0.3. The number of seeds per pod was counted during the observations also the number of pods for each treatment. The yield was obtained by extrapolation of the plot production per hectare.

 Statistical analysis 

Data encoding was done on the laptop computer using Microsoft Office Excel 2010 [16] and statistical analyzes using SigmaPlot 12.0 software. SYSTAT Software Inc., San Jose, CA, USA, 2007 [17] Analysis consisted of examining single-endpoint variance (ANOVA I) and comparing means by the Smallest Significant Difference method (PPDS or LSD) at the 5% significance level [18,19]

Collar diameter 

Figure 1 shows the collar diameter of climbing bean following all treatments bellow. Indeed, the outside T stakes + string + spike or a rope (P2) has a large diameter at the collar with 0.109 cm than the following: (P1) stake of the tripod (0.084 cm), (P3) single stake of 3 m (0.055 cm), (P4) crossed stakes (0.084 cm) as well as (C) single stake of 1 m (0.0545 cm). Then stake of the tripod (P1) and crossed stakes (P4) have the same diameter 0.08 cm respectively and the single stake of 3 m  and  of 1 m than too (0.05 cm). 

Figure Image is available at PDF file

Figure 1. Collar diameter of different systems of staking of climbing bean (cm)

One way analysis of variance shows a significant difference of collar diameter (F = 13.585; p <0.001) i.e. the vigor of climbing bean plants differs into systems of staking using. Comparison of means using the Smallest Significant Difference method (or Fisher LSD Method) shows that (P4) crossed stakes and (P3) single stake of 3 m are so vigorous than (P2) rope, (P1) stake of the tripod and single stake of 1 m (C). (P1) stake of the tripod, (P2) rope and (C) single stake of 1 m have the same collar diameter so these plants have the same vigor.

Plant height 

The crossed stake plants (P4) have an 8.185 cm of height than the other of the remaining treatments following with the rope (P2) which has 7.334 cm of height than the stake of the tripod (P1), single stake of 3 m (P3) and single stake of 1m (C). Stake of the tripod (P1) are tall with 5.319 cm than those single stake of 3 m (P3) and single stake of 1m (C). Also, single stake of 3 m (P3) are tall with 3.535 cm than single stake of 1m (C) which has 0.744 cm. Figure 2 illustrates the height of climbing bean plants per treatment.

Figure Image is available at PDF file

Figure 2. Plant height of different systems of staking climbing bean (cm)

 The ANOVA summary shows a significant difference in the height of the plants (F = 409.868; p <0.001) that is the heights of the plants differ from each other. Comparison using the method of the Smallest Significant Difference (Fisher LSD Method) shows the following: crossed stake plants (P4) are taller or giants than single stake of 3 m (P3), rope (P2), stake of the tripod (P1) and single stake of 1m (C). Single stake of 3 m (P3) are giant than rope (P2), stake of the tripod (P1) and single stake of 1m (C). Stake of the tripod (P1) and rope (P2) have the same height so these plants have the same size but are large compared to single stake of 1m stake or Control (C)

Number of ramifications

Figure 3 shows the number of climbing bean branches of the different treatments. The treatment of crossed stakes (P4) has 40 ramifications than the other treatments. Single stake of 3 m (P3) has 32 ramifications, followed of rope (P2) with 26 ramifications and stake of the tripod (P1) with 24 ramifications and at the end single stake of 1m (C) with 8 ramifications. 

Figure Image is available at PDF file

Figure 3. Number of ramifications of climbing bean

One way analysis of variance shows a significant difference between the number of ramifications (F = 13,567.023; p <0.001) i.e. the ramification of climbing bean plants differs with staking systems. Comparison of means  using the method of the Smallest Significant Difference (or Fisher LSD Method) shows crossed stakes (P4) have more branching than single stake of 3m (P3), rope (P2), stake of the tripod (P1) and single stake of 1m (C). Single stake of 3 m (P3) has more ramification than rope (P2), stake of the tripod (P1) and single stake of 1m (C). Rope (P2) has more ramification than stake of the tripod (P1) and single stake of 1m (C). Stake of the tripod (P1) has more ramification than single stake of 1m (C).

 Leaf area (cm²)

In figure 4 below, the leaf area differ between treatments, the crossed stakes (P4) has broad leaves with 13.476 cm², single stake of 3 m (P3) with 13.238 cm² respectively the rope (P2) and stake of the tripod (P1) have 12.441cm² and finally single stake of 1m (C) with 11.782 cm².

Figure Image is available at PDF file

Figure 4. Variation of leaf area of ​​ climbing bean

The analysis of variance shows no significant difference between the leaf areas of staking treatments (F = 2.023; p = 0.118).The leaf area of climbing bean is the same for all applied stake systems.

Number of seeds per pod

Figure 5 shows the number of seeds per pod according to the different treatments. The crossed stakes (P4) has 8 seeds per pod than the other treatments. Then, the rope (P2) has 7 seeds per pod and single stake of 3 m (P3) and stake of the tripod (P1) have respectively 6 seeds. The control or single stake of 1 m (C) has 4 seeds per pod. 

Figure Image is available at PDF file

Figure 5. Number of seeds per pod of climbing bean

The ANOVA shows a significant difference in the number of seeds per pod (F = 6.044; p = 0.002): the number of seeds per pod differs from each other. Comparison of means using the method of the Smallest Significant Difference (Fisher LSD Method) shows crossed stakes (P4) have a higher number of seeds per pod than single stake of 3 m (P3), stake of the tripod (P1) and single stake of 1m (C). While they have the same number of seeds per pod as those outside T stakes + string + spike (P2). Then, stake of the tripod (P1) respectively have the same number of seeds per pod as crossed stakes (P4) which have a higher number than control or stake of 1m (C).

Number of pods per treatment

Figure 6 illustrates the number of pods per climbing bean treatment. However, the number of pods per crossed stake (P4) was high (505) than the rest of the remaining treatments. Then, single stake of 3 m (P3) also has a higher number of pods (451) than stake of the tripod (P1), rope (T2) and control (C). A rope (P2) has a higher number (377) than stake of the tripod (P1) and stake of 1m (C). Also, that stake of the tripod (P1) has a high number (374) than control (C) which has 112 pods per treatment.

Figure Image is available at PDF file

Figure 6. Number of pods per treatment

The ANOVA shows that a significant difference in the number of pods per treatment (F = 50.792; p <0.001), the number of seeds per pod differed between them. Comparison of means using the method of the Smallest Significant Difference (Fisher LSD Method) shows that crossed stakes (T4) has a higher number of pods than the others (T0, T1 and T2) but equal single stake of 3 m (T3). The outside T stakes + string + spike (T2) stakes has the same number of pods per treatment as the stake of the tripod (T1) which have a large number than the control.

Yield 

Figure 7 shows deference in treatments of the yield of climbing beans. Single stake of 3 m  (P3) has a higher yield (5.072 t / ha) than the other treatments. Then, the outside T stakes + string + spike (P2) raised (4.744 t / ha) and crossed stake (P4) with 2.852 t/ ha, t stake of the tripod (P1) with 2.486 t / ha and single stake of 1 m (C) has a yield of 0.968 t / ha. 

Figure Image is available at PDF file

Figure 7. Yield (tons/hectare) of climbing bean 

The ANOVA shows a significant difference in climbing bean yield (F = 108.608; p <0.001); climbing bean yields differ from each other. Comparison of means using the method of the Smallest Significant Difference (Fisher LSD Method) was already revealed that planting practices on the single stake of 3 m (P3) has the same yield as outside T stakes + string + spike (P2) which has a high performance than stake of the tripod (P1), crossed stakes (P4) and, single stake of 1m (C). Stake of the tripod (P1) and crossed stake (P4) have the same yield which is high compared to the control.

Crossed stakes (P4) and single stake of 3 m (P3) are so vigorous than rope (P2), stake of the tripod (P1) and single stake of 1 m (C). Stake of the tripod (P1), rope (P2) and single stake of 1 m(C) have the same collar diameter so these plants have the same vigor. The length of the stakes explained these. [2] shows that the ideal stake length is 2 m.

Crossed stake plants (P4) are taller or giants than single stake of 3 m (P3), rope (P2), stake of the tripod (P1) and single stake of 1m (C). Single stake of 3 m (P3) are giant than rope (P2), stake of the tripod (P1) and single stake of 1m (C). Stake of the tripod (P1) and rope (P2) have the same height so these plants have the same size but are large compared to single stake of 1m stake or Control (C).Our results are the same with those of [2] and [20] which shows that the climbing bean must be well staked (density and length of the stakes) to produce well. Additionally, climbing beans show their full production potential, they must be staked before tendrils form.

The leaf area of climbing bean is the same for all applied stake systems. It is a hereditary varietal trait[20].

Crossed stakes (P4) have a higher number of seeds per pod than single stake of 3 m (P3), stake of the tripod (P1) and single stake of 1m (C). While they have the same number of seeds per pod as those outside T stakes + string + spike (P2). Then, stake of the tripod (P1) respectively have the same number of seeds per pod as crossed stakes (P4) which have a higher number than control or stake of 1m (C).These could be explained by the staking method used [20,2]

Crossed stakes (T4) has a higher number of pods than the others (T0, T1 and T2) but equal single stake of 3 m (T3). The outside T stakes + string + spike (T2) stakes has the same number of pods per treatment as the stake of the tripod (T1) which have a large number than the control. Our results are similar to those obtained by [2] and [20] These could be explained by the staking method used too.

Single stake of 3 m (P3) has the same yield as outside T stakes + string + spike (P2) which has a high performance(4-5 t / ha) than stake of the tripod (P1), crossed stakes (P4) and, single stake of 1m (C). Stake of the tripod (P1) and crossed stake (P4) have the same yield which is high compared to the control. Our result joined of [21].Climbing beans offer potential to intensify bean production compared with bush beans, with yield potential being their greatest advantage: up to 4–5 t ha⁻¹ [21] versus 1 to 2 t ha⁻¹ for bush beans in Uganda [22]. 

The results of this work show that single stake of 3 m  has the same yield 4 to5t/ha as outside T stakes + string + spike . The following staking: crossed stakes and single stake of 3 m are so vigorous than rope or outside T stakes + string + spike, stake of the tripod and single stake of 1 m. Crossed stake plants are taller or giants and also a higher number of seeds per pod than single stake of 3 m, rope, stake of the tripod and single stake of 1m. The leaf area of climbing bean is the same for all applied stake systems. Single stake of 3 m (P3) has the same yield as outside T stakes + string + spike which has a high performance (4-5 t / ha) than stake of the tripod, crossed stake and, single stake of 1m .For a better future of our households, and also for a good economy and development, we recommend to the practice of climbing beans by sowing in rows and using the single stake of 3 m and the outside T stakes + string + spike or a rope. 

ACKNOWLEDGEMENTS

We would like to thank all the Authority of ISEAV/Mushweshwe. Thanks are also due to Agent of ISEAV/Mushweshwe for the collect data for this study.

COMPLIANCE WITH ETHICAL STANDARDS

Conflict of interest: We declare that there is no conflict of interest with the publication of this manuscript. No human/animal participants were involved in the preparation of this manuscript.

The authors declare that they have no conflict of interest

No funding sources

The study was approved by the Institut Supérieur d’études Agronomiques et Vétérinaires.

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