Despite holding such great promise in human nutrition and soil fertility improvement, the productivity of mung bean worldwide including in Ethiopia is quite low. This low yield is attributed to numerous factors including cultivation on marginal lands making it prone to a number of abiotic stresses, growing low yielding varieties and inappropriate agronomic practices. Use of good yielding varieties and applying the best agronomic practices are the best ways to increase yield of any crops. Among the agronomic practices, optimum plant population is a prerequisite for obtaining higher productivity (Rafiei, 2009). The significance of using optimum inter and intrarow spacing has been recognized by several researchers. Kabir and Sarkar (2008) reported that highest seed yield of mung bean was obtained maintaining 30 cm × 10 cm spacing between rows and plants, respectively. Plant density of 40 plants m -2 at 25 cm x10 cm planting was the optimum fo achieving higher productivity (Singh et al., 2011). The
Results on seed oil ratio clearly showed the significant effects of intrarow spacing (P < 0.05), N doses and interactive effect of R × N (P < 0.01). Average oil ratio of two years ranged from 43.4 % to 46.0 % with maximum oil ratio obtained from 20 cm space. The positive effect of N doses was observed on seed oil ratio compared to control. Average seed oil ratio ranged from 40.9 % to 47.4 %. Maximum oil ratio was recorded from N3 and further increase of N doses resulted in slight incline in seed oil ratio. Results also revealed higher seed oil ratio during 2008 compared to 2007 irrespective of row spacing or N dose. The low oil ratio probably caused by the diversity of precipitation between two years. Özer et al., 2004 also reported that low rainfall during the vegetation stage of sunflower may lead to decline in oil concentration. Interactive effect of R × N was found significant and average seed oil ratio for two years ranged from 39. 7 % to 48.6 %. Maximum oil ratio was observed in the combination of R3 × N3. Contrarily, minimum oil was recorded from R3 × N0 . Our
The production of groundnut (Arachis hypogea L.) is limited by high weed infestation causing high yield losses in Nigeria. Field trials were, therefore, conducted to evaluate the effect of intra-row spacing and weed control methods on growth and yield of groundnut at the Teaching and Research Farm of the Federal University of Agriculture, Abeokuta in the forest-savannah transition zone of South west Nigeria during the cropping seasons of 2008 and 2009. Two intra-row spacings (15 and 25 cm) were evaluated which constituted the main plot treatments, while five weed control treatments (pre-emergence application of commercial formulation of metolachlor + prometryne (Codal) at 1.6 kg a.i/ha alone and the same treatment followed by supplementary hoe-weeding (SHW) at 6 weeks after sowing (WAS) and at 2.4 kg a.i/ha, 2 hoe-weedings at 3 and 6 WAS and weedy checks where weeds were not removed throughout the crop life cycle. All the treatments in different combinations were arranged in a split- plot design with four replicates. Intra-row spacing of 15 cm resulted in significant reduction in weed growth compared to the intrarow spacing of 25 cm as reflected in weed cover score, and dry weights at 9 and 12 WAS as well as cumulative weed dry matter production in both years. In addition, inter-row spacing of 50 cm caused significant improvement in crop growth as reflected in the crop vigour score, canopy height and canopy diameter and number of root nodules, with subsequent increase in pod yield per hectares. Similarly, All the weed control treatments caused significant reduction in weed cover score at 9 and 12 WAS, weed dry weights at 6, 9 and 12 WAS and cumulative weed dry matter production compared to the weedy check in both years The most effective treatments were the combination of intra-row spacing of 15 cm and the use of pre-emergence application of metolachlor + prometryne at 1.6 kg a.i./ha followed by one supplementary hoe-weeding at 6 WAS. Such treatments had effective weed control with consequent high groundnut pod yield comparable to those of two hoe-weedings. In this study, unchecked weed growth throughout the crop life cycle resulted in about 75.4 and 82.6% reductions in potential yield of groundnut in 2008 and 2009 seasons. Intra-row spacing of 15 cm and pre-emergence application of metolachlor + prometryn at 1.6 kg a.i/ha followed by supplementary hoe weeding at 6 WAS is therefore recommended for weed control alternative to frequent hoe weedings to can cut down on labour input particularly where labour is limiting and land under cultivation is large.
For field trials, we need to take account of any constraints on plot size and position within the field. Is there a minimum plot size that will be necessary for the realistic application of a treatment? This may differ between treatments, and may be much larger that it is realistic to assess, so that assessment will be of one or more sub-plots within each plot, or by selecting random or systematic quadrat positions. Both approaches have their place depending on what is being assessed – e.g. for intra-row cultivation it might be sensible to systematically position quadrats between rows, or to separately make within- and between-row assessments. Having selected the required plot size we then need to position the plots within the field. Are there features of the field that are likely to cause variability in the response? These might include the position relative to the field boundaries, slopes or the direction of prevailing winds, or even an observed variation in weed density or species composition. These sources of variation need to be accounted for in the blocking structure that is used. Note that blocks do not need to be contiguous – particularly where weed density is variable, it would be appropriate to allocate plots to blocks based on their weed density rather than their physical position.
The effects of spacing and nitrogen were however not significantly different (P≤0.05). Pearl millet variety did not also have any significant (P≤0.05) effect on number of panicles harvested. The number of pearl millet panicles harvested at 20 cm spacing was significantly (P≤0.001) higher than those harvested at 30 cm. Similarly, the number of panicles harvested when no fertilizer was applied was not significantly different from those that received fertilizer (Table 5). 100 –grain weight of TY was significantly (P≤0.05) higher than that of BSH. The effect of spacing and nitrogen fertilisation did not significantly affect 100 - grain weight of pearl millet varieties. TY produced the highest grain yield and Arrow the lowest. Both TY and BSH significantly (P≤0.05) out-yielded Arrow. The latter (Arrow), however produced the highest straw yield and Tongo Yellow the least (Table 5). Sowing at wider intra-row spacing (30 cm) produced longer panicles, relative to closer intrarow (20 cm) sowing. Grain and straw yields at closer spacing were also greater than for wider planting distance.
Plant height was significantly (P<0.05) affected by the application of nitrogen and intra-row spacing. Number of branches were significantly (P<0.05) affected due to nitrogen application, while there was no due to intra-row spacing. Application of nitrogen at 99 kg ha -1 increased plant height by 13.6% over no application of nitrogen. The maximum value of plant height was recorded at intra-row spacing of 40cm. Plant height increased with decreased spacing in tomato. Intra-row spacing of 35 and 40cm were statistically not different on plant height. Increasing nitrogen application from 0 to 99 kg ha -1 linearly increased tomato branches. The highest branches were recorded at nitrogen rate of 99 kg ha -1 , however, application of nitrogen at 39, 69 and 99 kg ha -1 statistically parity. Application of Nitrogen at 99 kg ha -1 increased tomato branches by about 28.9 % over no nitrogen (0 nitrogen) application. The result of current study was in line with who reported that as urea rate increased , plant height also increased. Increasing urea rate increased plant height and number of branches per plant. Similar to this study that the number of branches and leaves increased with increased rate of urea . Plots amended with urea fertilizer were significantly better than the control in terms of plant height and number of branches.
Combined mean analysis result showed that the main and interaction effects of intra and inter-row spacing were highly significant (P<0.0001) on seed yield (Table 1). This result is similar with Higgins (1968), who reported that under narrow intra-row spacing and higher population density smaller plants of Vernonia were crowded out and disappeared. This self-thinning effect is a result of increased interplant competition for space, light, moisture and nutrients at the higher populations. Hence, at wider spacing the final plant stand per meter square can be higher than that of narrow spacing. The highest seed yield (2491.3 kg ha -1 ) and lowest seed yield (1391.7 kg ha -1 ) were obtained from 60cm X 60cm and 30 cm X 70cm intra and inter row spacing combinations respectivel (Table 3). This result is close to the research finding in Zimbabwe that showed seed yields of Vernonia galamensis varied from 1822 to 2469 kg/ha (Teynor et al., 1992).
Treatments, Experimental Design and Cultural Management: The treatments consisted of three factors the seed age (year one and two), intrarow spacing (5, 10 and 15 cm) and varieties of soybean (TGX and Belesa-95). The size of each plot was 4x3m (12 m 2 ). The space between blocks was 1m and the space between rows in each plot was 60cm. 100kg of DAP was applied. The experiment was laid out as randomization complete block design (RCBD) in a factorial arrangement with three replications (3x2x2). TGX and Belesa-95 varieties released in 2003 and adaptable to several areas including Awassa, Gutin, Baco, Dedessa and Pawe etc. were used. It is one of the high yielding varieties and has been recommended and distributed to the farmers and state farms for large scale production in the country. These varieties need 150 days to maturity. Sowing was done on 21 th of June by placing the seeds at an appropriate distance as per the treatments with the help of tape meter and then covering it manually with the soil.
factors such as lack of improved variety, disease, insect and agronomic practices like in optimum row spac- ing and plant population per unit area. Proper method of sowing is among the important biotic factors that determine the proper plant population, which improves the performance and productivity of plants in the field. Plant population plays an important role as it is one of the most important yield contributing characters . Combinations of researches on inter- and intra-row spac- ing is lacking in boosting productivity of mung bean in northwestern Ethiopia. Therefore, the present study was conducted to investigate the optimum inter- and intra- row spacing of mung bean for maximum yield and yield components and to evaluate the economic feasibility of different inter- and intra-row spacing of mung bean.
Leaf Area Index: Transplanting date did not affect leaf area index (LAI) in the three years. Intra- row spacing had significant effect on LAI. At 10cm intra-row spacing, maximum LAI (4.2) was produced (Table 4) as against the minimum (1.7) at 25cm intra-row. The trend of increase in LAI at the various intra-rows showed 10cm intra-row spacing was significantly higher than 15cm intra-row spacing which was higher than 15cm intra-row spacing which was higher than 20cm, which was in turn higher than 25cm intra-row spacing. The findings were in line with Gautam, et al. (1982) and Shinggu, et al. (2009) who reported increased LAI in finger millet to be due to narrow spacing. Graybill, et al. (1991) reported that increase in LAI of maize and rice was due to increased plant density resulting from narrow spacing.
Cowpea (Vigna unguiculata L Walp) a member of the family fabaceae is one of the major pulses grown in Savanna region of Nigeria. Different species are cultivated in the Savanna ecological zone of Nigeria (Ng, 1995). The crop is can do well as sole crop or in crop mixtures, especially the local spreading cultivars that produce pods later after the harvest of other components crop in the mixture. Blade (2005) remarked that the crop is shade tolerant. The crop is a good source of protein. The grain composition reported by Davies et al. (1991) is; protein (24,8%), fat(1.9%) fiber(6.3%), carbohydrate (63.6%) thiamin (0.00074%) riboflavin (0.00042%) niacin (0.00281%). As a legume, the crop fixes atmospheric nitrogen and can reduce the depletion of the nutrient from the soil compared to fields that are under continuous cereal production (Bation et al 2002). Spacing has significant role in the performance of cowpea just like any other crop. It was observed by Ahmed et al. (2012) that increase in plant population of cowpea decreased plant height, number of branches per plant and stem girth. The spacing of 75 x 25cm has been recommended by Enwezor et al. (1989). However Anonymous (2011) recommended the spacing of 20 x 75cm for erect and semi-erect but 50 x 75cm for prostrate types. Amgad et al. (2010) noted that varying intra-row spacing of 50 – 125cm at the inter-row spacing of 60cm had no marked effect on growth attributes of cowpea, when they used three varieties.. Nevertheless they noted that the closest intra-row spacing of 50 x 60cm produced the highest grain yield. In contrast Malami and Samaila remarked that the widest spacing of 75 x 100cm spacing produced the highest grain yield when they used Kanannado which is a prostrate variety. In a guideline on cowpea production, it was remarked that prostrate varieties require wider spacing. Therefore it appears that there is no definite spacing for all varieties of cowpea, hence the need to undertake this study.
1000-seed weight was significantly (P<0.05) affected by interaction of variety, inter- and intra-row spacing (Table 1). The highest 1000 seed weight was recorded at interaction of variety WG-Hibiscus-Sudan, inter-row spacing of 90 cm and intra-row spacing of 90 cm; while, the lowest value was recorded at interaction of variety WG-Hibiscus-Jamaica, inter-row spacing of 60 cm and intra-row spacing of 60 cm (Table 8). 1000-seed weight increased at lowest plant population density in WG-Hibiscus-Sudan due to the fact that reduced competition of plants for light, water and nutrient could able to produce highest 1000-seed weight. But in case of WG-Hibiscus- Jamaica, 1000 seed weight increased at the prescribed spacing. This could be due to favorable growth conditions of the spacing for maximum seed weight. Contrasting results were reported by Jakusko et al. (2013) on sesame and Yayeh et al. (2014) on field pea.
The interaction effect intrarow spacing and year had a significant (p < 0.05) effect on number of ears per plant. The highest number of ears per plant (1.85) was produced where plants were sown at a widest intrarow spacing (35 cm) in 2016 cropping season, while the lowest number of ears per plant (1.44) was produced in the same intrarow spacing in 2015 cropping season (Table 5). The result showed that number of ears per plant revealed increasing trend as intrarow spacing increased from 25 to 35 cm in 2016 cropping season but in 2015 cropping season this trend did not occur (Table 5). The higher number of ears at the widest intra-row spacing in 2016 cropping season might be due to ade- quate rainfall (was it high or the distribution was good? or both) that resulted in higher number of ears per plant at wider intrarow spacing. Similarly,  and.  reported that wider-spaced maize plants obtained more soil moisture and nutrients than narrower plants that led to having a high number of ears per plant than narrow spacing.  also reported that with decreasing of plant spacing from 30 cm to 15 cm, the number of ears per plant was significantly re- duced from 1.42 to 1.21 possibly due to more competition for light, aeration and nutrients and consequently enabling the plants in closer spacing to undergo less reproductive growth.
Working machines for intra-row weed control can differ according to their constructional and functional typology, as well as according to the function of the different working depths. The availability of a simulation model to evaluate in advance their performances can help the machine manufacturer to design and develop new solutions, also by taking into account a given planting layout. The construction typology directly influences also the kinematic chain and the overall complexity of the identified working system. Different types of driving power can provide for different solutions, going from the mechanical to the hydraulic power, to the electric power, mainly depending on the required power level. Most modern tractors show enough potential in all these modalities. Even the electric drive would not require significant integrations in most of the available electrical systems.
automatic, “non-chemical” systems for the effective elimination of weeds in the intra-row area are not available. One way to eliminate intra-row weeds without the use of chemical agents could be to destroy the germination capacity of the weed seeds under the rows by heating a narrow band of soil around the rows to about 70–90°C before seeding. As only a very few weed species will germinate from deep soil layers (White et al., 1999), only the topmost 5 cm of the soil will need to be heated. By heating only a narrow band of 6–8 cm around the rows to a depth of 5 cm, energy savings of more than 90% can be anticipated, compared with a full steaming of the entire soil surface. In practice, the system may be combined with a computer-controlled sowing machine for the subsequent sowing of plants in the centre of the treated bands. The system will result in the crop growing in rows free of plant competition. This also provides favourable conditions for the functional capacity of a subsequent operation involving vision-based row guidance.
Hand weeding is still widely used in Northern Europe as the primary method for controlling weeds growing between the crop plants in the row (intra-row) in organic vegetables, such as seeded onions and leek, and carrots. Weeds between the crop rows (inter-row) can normally be controlled satisfactorily by inter-row cultivations.
The results revealed a significant difference in both seasons due to row width. The increases in those yield components contributed to the higher productivity presented by narrowing sown maize. Therefore, the larger availability of solar radiation probably allowed plants to set more grains per ear and to produce heavier grains. These results in good accordance with those reported by [2,17,20,21,27]. The difference among four yellow maize hybrids i.e. SC 3084, SC 3062, SC 2055 and SC 2066 on number of ear/plant, ear length, ear diameter, number of rows/ear, number of grains/row, ear grains weight, shelling percentage, 100-grain weight and grain yield/ha. The differences in yield and yield components due maize hybrids may be due to the genetic factors. These results in good agreement with those reported by [2,4,11,12,13,14,16,27,]. Hill spacing significantly affected number of ear/plant, ear length, ear diameter, number of rows/ear, number of grains/row, ear grains weight, shelling percentage, 100-grain weight and grain yield/ha. The increases in grain yield when plants were sown at lowest hill spacing (15 cm) may be due to increase in number of rows/ear and number of grains/ear. These results in good agreement with those reported [4,26]. This may be due to more approach uniformity by sown at 15 cm hill spacing. Therefore, the higher yields obtained with the use of narrow spacing cannot be attributed to a different pattern of leaf area development or a larger leaf surface area to intercept solar radiation. A similar conclusion was reported by those reported by [1,24]. The effective interaction between maize hybrids and row width on the 100 grain weight and grain yield/ha significant effected on these traits in both seasons. There were varietal differences in response to intra-row spacing. Grain yield is the product of crop dry matter accumulation and the proportion of the dry matter allocated to the grain and harvest index in corn declines when plant density increases above the critical plant density. Highest grain yield/ha from sown S.C. 3084 at narrow row width (60 Cm) in 20 cm hill spacing i.e. 59.999 plants/ha reduced competition between, which will be more approached to uniformity which helps sun radiation penetration within plants then increase net photosynthesis, consequently increase grain yield per unite area.
In both harvesting seasons and pooled mean analysis result showed that, Above ground biomass and Leaf fresh weight were highly significantly (p>0.01) influenced by intra-row, inter-row spacing and their interaction. These indicate that the effects of different levels of intra-row spacing were affected by different levels of inter-row spacing. The maximum above ground biomass 72605 gm and leaf fresh weight 9510 gm were observed at 40*60cm and the minimum above ground biomass 15726.17 gm and leaf fresh weight 3162.39 gm were observed at 100*120 intra and inter-row spacing. The increasing trend of above ground biomass and leaf fresh weight per hectare observed in this study is in agreement with the result of Rao (2002) on rose scented geranium, Zewdinesh (2010) on A. annua. Similarly, the current investigation supports the previous research findings conducted by (Abebe Terefe, 2007) on Vernonia galamensis. Highest herbage resulted by the highest population (narrow spacing) and the lowest ones resulted by the lowest population (wider spacing). This is probably due to the occurrence of higher number of branch and leaves contributed from greater number of plants per unit area; resulted in higher use of light in that experiment.
By utilizing more advanced computer vision navigation, a row band width of 5 cm is considered for the boundary between inter and intra-row weeding area (2.5 cm on each side of the row center defined by plant positions). Thus, in this scenario it is expected that 87.5% of the total area are covered with the inter-row area and the inter-row weeding, leaving 12.5% for the intra-row area for intra-row weeding. A strategy consisting of 6 to 8 post-emergence treatments with 1 to 2 weeks apart are considered as recommended by Graglia et al. (2004, 2006). A 60-95% weed control is expected for the intra-row area (Bernaerts, 2004, www.mechanischschoon.nl) and 62-90% weed control (all species) is expected for the inter-row area (Graglia et al., 2004, Pullen and Cowell, 1997).