Inter-row Spacing Research Articles

Utilization of harvested rainwater for ensuring green-fodder availability in arid Rajasthan

The efficient use and management of natural resources are important factors for success in agricultural farming. An experiment was conducted on round the year fodder production at ICAR-Central Arid Zone Research Institute, Jodhpur, Rajasthan during 2017–18 to 2019–20 by harvesting rainwater from the rooftop of buildings and irrigating crops using a solar operated water pump though drips and micro-sprinklers for efficient use of harvested water. In the 3 m inter-row spaces of bajra napier hybrid (BNH) variety CO 4, three legumes Vigna unguiculata (cowpea), Clitoria ternatea (butterfly pea) and Lablab purpureus (sem) received 40 and 60 kg P/ha, grown as intercrops during the rainy (kharif) season and lucerne in succession on residual P during winter (rabi) season. Among three kharif legumes, significantly higher green (11.19 t/ha) and dry (1.60 t/ha) fodder yields were recorded with cowpea that received 60 kg P/ha. An average 243.97 t/ha green and 37.55 t/ha dry fodder yields was recorded from the system in which share of BNH in green and dry fodder yield was 67.57 and 61.81% respectively. BNH gave 164.85 and 23.21 t/ha green and dry fodder from six cuts, kharif legumes contributed 7.43 t/ha in the green fodder and 1.12 t/ha in dry fodder from a single cut and lucerne produced 71.53 t/ha green and 10.32 t/ha dry fodder from the seven cuts in a year. This system has the capacity to meet out the green fodder requirement of 4–5 adult cattle unit (ACU) round the year from the land unit of 0.1 ha.

Effects of seed rate and inter row spacing on yield and yield components of food barley in Semen Ari Woreda, Ethiopia

A field experiment was carried out for two successive cropping seasons in 2017 and 2018 at Shama Bulket, Semen Ari Woreda, South Omo Zone, Southern Ethiopia, to determine optimum seed rate and inter-row spacing for food barley production. The experiment involved a factorial combination of three seed rates (80, 100 and 120 kg ha-1) and three inter-row spacing (20, 30 and 40 cm). The experiment was conducted using a randomized complete block design with three replications. The results indicated the treatments had significant effect in all parameters except plant height and spike length. Based on the result of this study, use of 30 cm inter-row spacing and 120 kg ha-1 seed rate is superior in grain yield (4481 kg ha-1) and total biomass (14.6 t ha-1). Therefore, use of 30 cm inter row spacing with seeding rate of 120 kg ha-1 can be recommended for food barley production at Shama Bulket kebele and its vicinity. Int. J. Agril. Res. Innov. Tech. 12(1): 34-38, June 2022

Identification of tolerance to high density and lodging in short petiolate germplasm M657 and the effect of density on yield-related phenotypes of soybean

Soybean yield has traditionally been increased through high planting density, but investigating plant height and petiole traits to select for compact architecture, lodging resistance, and high yield varieties is an underexplored option for further improving yield. We compared the relationships between yield-related traits, lodging resistance, and petiole-associated phenotypes in the short petiole germplasm M657 with three control accessions during 2017–2018 in four locations in the Huang–Huai region, China. The results showed that M657 exhibited stable and high tolerance to high planting density and resistance to lodging, especially at the highest density (8×105 plants ha−1). The regression analysis indicated that a shorter petiole length was significantly associated with increased lodging resistance. The yield analysis showed that M657 achieved higher yields under higher densities, especially in the northern part of the Huang–Huai region. Among the varieties, there were markedly different responses to intra- and inter-row spacing designs with respect to both lodging and yield that were related to location and density. Lodging was positively correlated with planting density, plant height, petiole length, and number of effective branches, but negatively correlated with stem diameter, seed number per plant, and seed weight per plant. The yield of soybean was increased by appropriately increasing the planting density on the basis of the current soybean varieties in the Huang–Huai region. This study provides a valuable new germplasm resource for the introgression of compact architecture traits that are amenable to providing a high yield in high density planting systems, and it establishes a high-yield model of soybean in the Huang–Huai region.

DO CROTALARIA PLANT HEIGHT AND MAIZE INTER-ROW SPACING AFFECT INTERCROPPED MAIZE YIELD?

Intercropping with Crotalaria species may reduce maize yield; thus, evaluations must understand and explain competition in an intercropped system. The aim was to evaluate the effects of Crotalaria species and inter-row maize spacing on the growth and yield of intercropped maize. A randomized block design in a split-plot scheme was used. Plots comprised maize inter-row spacings of 0.45 and 0.90 m. Subplots consisted of four cropping systems: maize monoculture and three systems of maize intercropped with C. juncea, C. spectabilis, and C. ochroleuca. Plant heights of maize and Crotalaria species throughout the cycle, maize yield, and Crotalaria dry mass were evaluated. The critical plant height of Crotalaria that reduced maize yield ranged from 0.32 to 0.75 m, that is, the more advanced the maize cycle, the greater the critical plant height of Crotalaria. Intercropping with C. juncea was the only one that reduced maize yield (21%) compared to its monoculture, and inter-row maize spacing did not affect the variables. These results were due to the greater plant height (more than 100% higher) and final dry mass (more than 80% higher) of C. juncea compared to the other Crotalaria species, promoting competition with maize for water, light, and nutrients. The choice of Crotalaria species is essential for management in maize intercropped systems, associating the ecosystem benefits of the intercropping without reducing the cereal yield.

Influences of inter- and intra-row spacing on the growth and head yield of cabbage (Brassica oleracea var. capitata) in western Amhara, Ethiopia

Abstract Plant population of 40,000 ha−1 with the respective inter- and intra-row spacing of 50 cm × 50 cm is the blanket recommendation for the production of head cabbage in Ethiopia. However, producers complain that this spacing produces too large head size, which is not the market's preference for household consumption instead for hotels and big institutions like universities. This two-season field experiment was conducted to optimize the head cabbage yield with appropriate head size by adjusting inter- and intra-row spacing. The result of the combined analysis over location and season revealed that all tested parameters were significantly (P < 0.05) influenced by the interaction effect of inter- and intra-row spacing. The combinations of 35 cm × 30 cm, 35 cm × 50 cm, and 50 cm × 30 cm inter- and intra-row spacing gave the highest head yield of 45, 43 significantly, and 42 t ha−1, respectively as compared to other treatment combinations. The interaction of the lowest inter- and intra-row spacing of 35 cm × 30 cm gave the lowest average head weight of 923 g of cabbage. The result showed that as intra-row spacing increased from 30 to 50 cm with all possible combinations of inter-row spacing, head-sized cabbage increased linearly. The current study identified that blanket recommendation of 50 cm × 50 cm inter-and intra-row spacing which assures a plant population of 40,000 ha−1 produced more than 1.4 kg individual head weight with a yield penalty of 10.70 t ha−1 compared to 50 cm × 30 cm inter- and intra-row spacing combination which assures a plant population of 66,667 ha−1. The current study confirmed that the earlier blanket recommendation of 40,000 plants ha−1 should be enhanced to a plant population of 66,667 ha−1 with a yield advantage of 131%. Concretely the manifested plant population difference gives an opportunity to producers to harvest a maximum yield with an acceptable head size of 1.2 kg. Therefore, it is concluded that the combination of 50 cm × 30 cm inter- and intra-row spacing assures that a plant population of 66,667 ha−1 is optimum for the production of head cabbage in the study and similar agro-ecologies.

Minimizing the Utilized Area of PV Systems by Generating the Optimal Inter-Row Spacing Factor

In mounted photovoltaic (PV) facilities, energy output losses due to inter-row shading are unavoidable. In order to limit the shadow cast by one module row on another, sufficient inter-row space must be planned. However, it is not uncommon to see PV plants with such close row spacing that energy losses occur owing to row-to-row shading effects. Low module prices and high ground costs lead to such configurations, so the maximum energy output per available surface area is prioritized over optimum energy production per peak power. For any applications where the plant power output needs to be calculated, an exact analysis of the influence of inter-row shading on power generation is required. In this paper, an effective methodology is proposed and discussed in detail, ultimately, to enable PV system designers to identify the optimal inter-row spacing between arrays by generating a multiplier factor. The spacing multiplier factor is mathematically formulated and is generated to be a general formula for any geographical location including flat and non-flat terrains. The developed model is implemented using two case studies with two different terrains, to provide a wider context. The first one is in the Kingdome of Saudi Arabia (KSA) provinces, giving a flat terrain case study; the inter-row spacing multiplier factor is estimated for the direct use of a systems designer. The second one is the water pump for agricultural watering using renewable energy sources, giving a non-flat terrain case study in Dhamar, Al-Hada, Yemen. In this case study, the optimal inter-row spacing factor is estimated for limited-area applications. Therefore, the effective area using the proposed formula is minimized so that the shading of PV arrays on each other is avoided, with a simple design using the spacing factor methodology.

Simulating rooftop solar arrays with varying design parameters to study effect of mutual shading

Rooftop solar arrays are a way of harvesting the energy from sun rays falling on the roof of buildings. These arrays can help buildings to generate power for themselves, either completely or partially fulfilling their energy needs. These systems however have their own sets of factors that can cause losses in them and reduce their power output. In this research work, the effect of mutual shading and design parameters are studied. The rooftop solar arrays with different parameters are simulated that help to estimate results closely agreeable with practical outcomes. The software ‘DIVA for Rhino’ was used to perform the simulations. The effect of various parameters such as the inclination of the roof surface, inter-row spacing of the panels, and their inclination, were studied. The degree of mutual shading was observed by varying these parameters. The power outputs and payback periods of the simulated systems were compared and their trends were observed to give a better understanding of how these factors affect rooftop solar arrays. The shading loss was high for higher panel inclination values coupled with smaller inter-row spacing. A higher roof inclination reduced the level of shading loss as it reduced the panel inclination with respect to the roof surface. The roof surface area increases with its inclination, which means more space for solar panels and hence a higher array power output. The results of the simulations will help in better decision-making during the construction of rooftop solar arrays as it helps to see the extent to which each of these parameters affects them.

Using spatially-explicit plant competition models to optimise crop productivity in intercropped systems

Intercropping, by capitalizing on positive biodiversity–productivity relationships, represents a promising option to increase agricultural sustainability. However, the complexity and context-dependency of plant–plant interactions can make it challenging for farmers to find suitable crop combinations. Furthermore, intercropping is usually implemented with standard inter-row spacing and plant densities based on monoculture practices, which might not be the ideal configuration to maximize yield.Here we present a spatially-explicit yield analysis method based on plant ecological interaction models that allowed to optimize crop species combinations and spatial configurations for maximal yield in intercropped systems. We tested this method with three crop species, namely oat, lupine, and camelina. In a first step, field experiments in which crop density and adjacent crop type were varied provided us with indications on which species would compete more with each other. The results showed us that oat and camelina strongly competed with each other. In addition, the distance experiments allowed us to understand how the changes in yield associated with the presence of neighbors vary with distance. This allowed us to find the sets of parameters (identity of neighbors, sowing density, distances between individuals) that optimise intercrop yield (measured as Land Equivalent Ratio [LER]) for the three considered species. Specifically, we show that alternating rows of species led to higher LERs than a homogeneous species mixing, and that 3-species combinations are not necessarily more performant than the best 2-species combinations. In addition, we show that increasing the density of oat is generally beneficial for LER, while increasing the density of lupine is not.By modelling crop yield from simple and reproducible density and distance experiments, our results allow to optimize crop mixtures in terms of species combinations and spatial configurations, for maximal crop yield.

Crop-local CO2 enrichment improves strawberry yield and fuel use efficiency in protected cultivations

In protected strawberry (Fragaria × ananassa Duch.) cultivation, CO2 enrichment is essential to enhance both fruit quality and yield. Fuel burning generators are commonly used to supply CO2 to entire commercial greenhouse space. However, methods that are less fuel-based are desired for contemporary agricultural practices. A new crop-local CO2 enrichment system using a modified fuel-burning generator has been developed to increase yields and decrease the fuel required for CO2 enrichment in greenhouse strawberry production. This crop-local CO2 enrichment (CLC) method directly supplies CO2 from perforated tubes set in the interrow space of the plant canopy. The effects of this technique on fruit quality, fruit yield, and fuel use efficiency have been examined in comparison with conventional CO2 enrichment (CC) practices. The CLC method increased CO2 concentration inside the plant canopy by 100–200 μmol mol–1 when compared with CC under the ventilating conditions by a roof window. This resulted in significant increases of approximately 10–26% in the average fruit weight, 13% in the cumulative fruit number, and 22% in cumulative marketable yield when compared to CC. Furthermore, cumulative fuel consumption was approximately 27% lower with the CLC method when compared to CC. These results indicate that CLC improves fuel use efficiency when compared with CC as it increased yields and decreased fuel consumption.

Plant Density and Time of White Lupine (Lupinus Albus L.) Relay Cropping with Tef (Eragrostis tef (Zucc.) Trotter) in Additive Design in the Highlands of Northwest Ethiopia

Agronomic strategies such as choosing the optimal row ratio and planting legume crops at the right time are crucial for enhancing crop productivity. A field experiment was conducted in 2016 and 2017 to assess the influence of plant density and lupine intercropping time on tef field productivity. The treatments were as follows: tef was planted at a 20 cm inter-row spacing, lupine was sown at 20 and 40 cm inter-row spacing (row ratio of 1 tef: 1 lupine and 2 tef: 1 lupine) and lupine intercropped three times (1, 2, and 3 weeks after tef planting). Randomized complete block design (RCBD) with 3 replications were used. Two sole tef and lupine were planted. The results revealed 40 cm inter-row spacing and delayed lupine intercropping (3 weeks after tef planting) provided the maximum tef grain yield of 1.80 t ha−1. The sole cropping of lupine produced the highest lupine grain yield (2.63 t ha−1). Lupine intercropping at 40 cm inter-row spacing and two weeks after tef planting resulted in the highest land equivalent ratio (1.54), tef equivalent yield (2.45 t ha−1), area time equivalent ratio (1.11), system productivity index (2.5), monetary advantage index (15206 birr ha−1), net benefit (65109 birr ha−1), and marginal rate of return (602%). Therefore, farmers in the northwest Ethiopian highlands should consider intercropping lupine two weeks after tef planting in-between two rows of tef as an effective intercropping system.

Improving upon the interrow hoed cereal system: the effects of crop density and row spacing on intrarow weeds and crop parameters in spring barley

AbstractAutomated guidance systems have advanced precise interrow hoeing in narrowly spaced cereals. Compared with other direct mechanical strategies, hoeing provides superior weed control and improved yields. However, weeds in the uncultivated intrarow zone may survive and compete intensely with the crop, causing yield loss. Therefore, improved intrarow weed management strategies in hoed cereals must be investigated. In spring barley (Hordeum vulgare L.), the effect of crop density was assessed at four levels (200, 300, 400, and 500 plants m−2); interrow spacing at two levels (15 and 20 cm), relevant to the abilities of current automated equipment to hoe between narrowly spaced rows; and weed management treatment at three levels (no additional controls, herbicide, and preemergence tine harrowing). All treatments received interrow hoeing, and a surrogate weed (white mustard, Sinapis alba L.) was sown and monitored throughout experiments. The manipulation of crop density was a reliable method for suppressing the growth of intrarow weeds. As barley density increased from the target 200 to 500 plants m−2, percent reduction in intrarow surrogate and ambient weed biomass (g m−2) increased from 49% to 82% and 53% to 99%, respectively. Increasing crop density caused a decrease in grain bulk density (kg hl−1) both years, and grain protein (%) and 1,000-kernel weight (g) in one year; whether these changes constitute a loss in grain quality depends upon end use. While row spacing had no effect on intrarow weeds, crop yields were 7% to 8% lower at 20 cm compared with 15 cm, incentivizing narrow row sowing. Barley yields were unaffected by increasing crop density, and the effect of preemergence tine harrowing was inconsistent. In one year, harrowing reduced surrogate and ambient weed biomass and increased barley yield; however, in another year, ambient weed biomass increased, and harrowing did not affect yield or surrogate weed biomass.

Framework for Mapping and Optimizing the Solar Rooftop Potential of Buildings in Urban Systems

The accurate prediction of the solar energy that can be generated using the rooftops of buildings is an essential tool for many researchers, decision makers, and investors for creating sustainable cities and societies. This study is focused on the development of an automated method to extract the useable areas of rooftops and optimize the solar PV panel layout based on the given electricity loading of a building. In this context, the authors of this article developed two crucial methods. First, a special pixel-based rooftop recognition methodology was developed to analyze detailed and complex rooftop types while avoiding the challenges associated with the nature of the particular building rooftops. Second, a multi-objective enveloped min–max optimization algorithm was developed to maximize solar energy generation and minimize energy cost in terms of payback based on the marginal price signals. This optimization algorithm facilitates the optimal integration of three controlled variables—tilt angle, azimuth angle, and inter-row spacing—under a non-linear optimization space. The performance of proposed algorithms is demonstrated using three campus buildings at the University of Alberta, Edmonton, Alberta, Canada as case studies. It is shown that the proposed algorithms can be used to optimize PV panel distribution while effectively maintaining system constraints.

Boosting Chickpea Production by Optimizing Inter-Row and Intrarow Spacing at Central Highlands of Ethiopia

A field experiment was conducted to determine optimum inter-row and intrarow spacing for a higher and economic yield of different chickpea varieties during 2016–2017 cropping season at Debre Zeit and Minjar. The experiment was carried out in a split-plot design replicated three times. The two varieties (Habru and Arerti) were assigned as a main plot and factorial of three inter-row spacing (20 cm, 30 cm, and 40 cm) and three intrarow spacing (5, 10, and 15 cm) as subplot treatments. The result indicated that variety and inter-row and intrarow spacing had a significant effect on yield and yield components of chickpea at both locations. Habru variety gave higher seed and biomass yield than Arerti. The highest seed and biomass yield were recorded for the intrarow and inter-row spacing range of 5–15 × 30–40 cm, respectively. Results of the partial budget analysis showed that the highest net benefit with acceptable marginal rate of return (>100%) was obtained from 10 cm × 30 cm intrarow and inter-row spacing. Therefore, 10 cm × 30 cm intrarow and inter-row spacing (330, 000 plants ha−1) can be recommended for a higher and economically optimum yield of chickpea at central highlands of Ethiopia.

Reduction of interrow spacing in cassava (Manihot esculenta Crantz) production

The interrow spacing commonly used in cassava cultivation in Brazil, especially in the Agreste region of Alagoas, ranges from 100 to 120cm. However, the reduction in row spacing can provide agronomic and environmental benefits in cassava cropping systems. Thus, this work aimed to evaluate the performance of two cassava varieties cultivated with reduced interrow spacing. Two experiments were conducted in the field, one in 2015/16 and another in 2017/18. A Split Plot design with four replications was used in both experiments. Four interrow spacing were evaluated in the main plot: 60, 80, 100 and 120cm, with plants spaced 60cm apart within rows, giving populations of 27,778, 20,833, 16,667 and 13,889 plants per hectare, respectively. In the subplots, two cassava varieties were evaluated: Caravela and Pretinha. An increase in interrow spacing promoted a linear reduction in the stem green mass of cassava. Plant height, leaf green mass, main stem diameter, root yield, tuberous root length, tuberous root diameter, flour percentage, flour yield, and starch content were not influenced by changes in interrow spacing. The Pretinha variety was superior to Caravela in the following evaluated traits: stem green mass, the diameter of tuberous roots, root yield, plant height, and flour yield. The results indicate the possibility of altering the interrow spacing in cassava to assist in the cultural management, without impacting crop yield.

Effect of slope position on soil properties and soil moisture regime of Stagnosol in the vineyard

Abstract Hillslope hydrology in agricultural landscapes is complex due to a variety of hydropedological processes and field management possibilities. The aim was to test if there are any differences in soil properties and water regime along the hillslope and to compare vineyard rows (vine) with inter-rows (grass) area for those properties. The study determined that there are significant differences in the contents of soil particle fractions, pH, and humus content along the slope (P < 0.0001), with lower confidence level in bulk density (P < 0.05). Differences between row and inter-row space were significant for the pH, humus, and silt content, but for sand and clay content, and bulk density differences were not determined. The study determined differences in soil water content among five slope positions (P < 0.0001), and between row and inter-row vineyard space (all with P < 0.05). Where in the upper slope positions (e. g., P1) soil water content was higher than on lower slope positions. Higher soil water content was observed at higher slope positions, associated with clay content. However, it can be concluded that the retention of moisture on the slope is more influenced by local-scale soil properties (primarily soil texture) and variability of the crop (row/inter-row) than the position on the slope.

Dependence of the Yield of Organic Potatoes on the Variable Composition of Technological Operations

The paper presents the results of experimental studies of the influence of the level of mineral nutrition and the variant composition of technological methods of care on the productivity of organic potatoes. The studies were carried out at the Experimental Station of the Institute for Engineering and Environmental Problems in Agricultural Production - Branch of Federal State Budgetary Scientific Institution “Federal Scientific AgroEngineering Center VIM near St. Petersburg. The soil of experimental plots is sod-podzolic light loamy gleyic on residual carbonate moraine loam. Soil resistance was measured with a Penetrologger. The use of deep loosening of the inter-row spacings during inter-row cultivation reduced the soil resistance in the inter-row spacing by about 20% and in the root formation zone by 13%. Deep loosening of the row spacings reduced the soil resistance in the experiment both with direct measurement after the technological operation to a depth of 60 cm, and within two months of measurements. With the combined use of compost and deep loosening, the yield increase was from 1.46% to 6.04% when comparing comparable doses. The maximum potato yield of 23.6 t /ha was obtained with deep loosening of row spacings and a poultry compost dose of 8 t /ha

Improving Yield of Non-Perennial Crops in the Conditions of Yakutia Using Different Doses of Mineral Fertilizers

Providing sustainable feed supplies is the main condition for the high productivity of the livestock industry. Feed supplies shall meet the needs of farm animals. The application effectiveness of mineral fertilizers is one of the most important factors of technology ensuring the improvement of yield, chemical composition, and nutritional value of feed. The article presents the results of research on the effectiveness of different doses of mineral fertilizers used to improve the yield of non-perennial fodder crops in the conditions of Yakutia. Experiments were held in 2015–2016 in the Moydoch plot of the Khangalassky District. Non-perennial fodder crops were sown on June 1. Sowing was done by drilling with 46 cm inter-row spacing for corn and sunflower, 30 cm for oil radish and sudangrass, and 15 cm for millet. The sowing depth was 4–6 cm for non-perennial fodder crops, and 2–3 cm for oil radish. The experience of application of mineral fertilizers to improve the yield of non-perennial crops has shown to primary affecting factors: the first factor — non-perennial crops variety (corn, sunflower, millet, sudangrass, oil radish), the second factor — mineral fertilizer dose (reference, (NPK)90 kg/ha, (NPK)120 kg/ha of primary nutrient). On average during two years of studies, corn crops have shown the highest fresh yield with mineral fertilizers applied at an NPK120 kg/ha dose of 9.7 t/ha; sunflower — 14.6 t/ha, millet — 6.1 t/ha, oil radish — 12.2 t/ha, and sudangrass — 7.6 t/ha with fertilizers applied at an NPK90 kg/ha dose. NPK120 kg/ha dose of mineral fertilizers ensured high nutrient content in the crops of corn, millet, oil radish, and sudangrass, and NPK90 kg/ha for sunflower. Sunflower and oil radish have shown the best nutritional value from all the studied species of non-perennial fodder crops.

Designing and Energy Estimation of Photovoltaic Energy Generation System and Prediction of Plant Performance with the Variation of Tilt Angle and Interrow Spacing

The focus of this research is to design a ground-mounted photovoltaic system at optimal tilt angle and interrow space to meet high demand of electrical energy. The Department of Electrical Engineering and Technology, GC University Faisalabad has been considered to perform the simulation test. This study is conducted using Meteonorm software for solar resource assessment. Furthermore, HelioScope software is used for modeling of a ground-mounted photovoltaic system, study of PV system’s performance in terms of annual generation, system losses and performance ratio and analysis of photovoltaic module’s performance, current-voltage and power-voltage curves for different irradiance levels. From SLD, it is seen that 11 strings are connected to each inverter and inverters output power are combined by using 20.0 A circuit interconnects. The performance of photovoltaic systems is impacted by tilt angle and interrow spacing. From simulation results of all cases, it is concluded that the PV system installed at 15° tilt angle with 4 feet interrow spacing are more efficient than the other installed PV systems, because total collector irradiance is maximum (1725.0 kWh/m2) as compared to other tilt angles. At 15° tilt angle, the annual production of photovoltaic system is 2.265 GWh and performance ratio of PV system is 82.0%. It is envisioned that this work will provide the guidance to energy system designers, planners and investors to formulate strategies for the installation of photovoltaic energy systems in Pakistan and all over the world.

Effects of Spacing on Growth and Green Cob Yield of Maize Under Supplementary Irrigation in Eastern Ethiopia

Maize (Zea mays L.) is an important grain crop of the world and it ranks second, after wheat in area cultivated and first in total production and productivity. In Ethiopia, maize has increasingly become a popular crop with steady growth in production area and yield. However, green cob maize production packages, including its appropriate spacing, are not yet determined. Evidences on effects of inter and intra-row spacing on growth and green cob yield of maize are not well explored. Therefore, this study was conducted at 9° 26' N latitude and 42° 03' E longitude, at an altitude of 1980 m a. s. l), Ethiopia from October 2020 to January 2021 to determine the effects of inter and intra-row spacing on growth, green cob number and biomass yield of maize (melkesa-II maize variety) under supplementary irrigation. The experiment was laid out in a randomized complete block design with factorial combination of four inter-row (55 cm, 65 cm, 75 cm, and 85 cm) spacing and three intra-row spacing (20 cm, 25 cm and 30 cm) with three replications. Data were collected on growth, green cob number and biomass yield and analyzed using SAS, (2002). The experiment result revealed that leaf area index, number of cobs per plant, cob length, number of cobs harvested per hectare and above ground fresh biomass yield and their interactions were highly significantly (P<0.01) affected by inter and intra-row spacing while cob diameter was significantly (P<0.05) affected by inter and intra-row spacing. The highest cob number harvested (90313 ha^-1) was recorded at narrowest inter and intra-row spacing of 55 cm x 20 cm while the lowest cob number harvested p (45098 ha^-1) was recorded from at widest inter and intra-row spacing of 85 cm x 30 cm (Table 8). Similarly, the highest fresh biomass yield of 31.27 and 28.66 ton ha^-1 was obtained at 55 cm and 65 cm inter-row spacing respectively. In general, significantly higher number of marketable green cobs and above ground fresh biomass yield were obtained at closer inter-and intra-row spacing for melkesa-II maize variety tested in the study area. Therefore, it can be concluded that spacing combination of 55 cm x 20 cm favored attaining of higher green cob number and above ground fresh biomass yield of melkesa-II maize variety in the area under irrigation.

ЗАСОРЕННОСТЬ И УРОЖАЙНОСТЬ САХАРНОЙ СВЕКЛЫ ПРИ РАЗЛИЧНЫХ СПОСОБАХ УХОДА ЗА ПОСЕВАМИ

In field experiments carried out in the conditions of the forest-steppe of the Middle Volga region, the influence of various methods of caring for crops on the productivity of sugar beet was studied. For the period from 1998 to 2018.weed infestation of sugar beet crops increased from 52.5% to 55.3%, while the number of all root weeds increased from 1.1 to 6.1 pcs/m2, and sow thistles and plume thistles - from 3.20 to 7.05 pcs/m2. It was noted that at the beginning of the growing season, the number of weeds increased sharply (by 2.8 times) from the phase of mass shoots of the crop to the beginning of the closing of leaves in the inter-row spaces, then the rate of emergence of new weeds decreased, and starting from the phase of opening the rows of sugar beet it increased again (by 1, 3 times).Сounting the number of weeds made it possible to establish that the implementation of three chemical treatments leads to an increase in the number of weeds by the time sugar beets are harvested. If in the initial period of sugar beet growth the number of weeds in the variant with three inter-row treatments was more than 90 pcs/m2, in the case of chemical treatments it was more than 60 pcs/m2, then the opposite was observed during the harvesting period. As a result of the research, it was found that the highest yield of root crops was obtained during three herbicidal treatments.