Efficiency Of Intercropping Research Articles

Integrated management approaches reduced yield loss, and increased productivity in faba bean, due to gall disease in northwestern Ethiopia

A field study was conducted to determine the effects of gall disease on yield and yield components of faba bean at Farta, Ethiopia, in 2019 and 2020. Bayleton spray and/or seed dressing, moderately resistant varieties, and intercropping as treatments were arranged in a split-split plot design with three replications. Results revealed significant (P < 0.01) differences among treatments in disease severity, yield and yield components of faba bean. Highly significant and negative correlations between agronomic and disease parameters were established. Gall disease pressure caused yield losses of 60, 67.61 and 68.61% on Bulga 70-wheat, Bulga 70-mustard intercropping and sole Bulga 70 in untreated plots, respectively. Integration of varieties Degaga and Tumsa with fungicide treatments reduced yield losses and gall disease epidemics, and also increased efficiency of intercropping by 20% over respective sole cropping in both years; and thus, such treatments could be recommended in the study areas and other related agro-ecologies.

Providing Alternative Hosts and Nectar to Aphid Parasitoids in a Plum Orchard to Determine Resource Complementarity and Distance Range Effect on Biological Control

There are many different practices that contribute to conservation biological control, but little is known about their complementarity. We tested the effects of providing food and alternative hosts to parasitoids by intercropping a plum orchard with companion plants. Oats and vetch were intercropped into the orchard either as single-species (oats or vetch) or two-species (oats and vetch combined) intercrops within an inter-row. The trophic resources provided by these intercrops were assessed, along with the incidences of aphids and their parasitoids in plum trees. We found up to ten alternative host species provided by oats and vetch, and extrafloral nectar was available from the vetch and mixed strips. An effect of intercrop type and distance to plum trees was observed on aphid incidence during one sampling period. Parasitism rates in exclusion cages were affected by intercrop type, reaching almost 60% close to the mixed intercrop. However, no general tendency was observed upon whether oats, vetch or their mixture was associated with a lower incidence of aphids. We found no evidence that providing effective sources of food and alternative hosts for parasitoids increased aphid mortality in this study. The context-dependent efficiency of intercropping is discussed.

Modelling soybean and maize growth and grain yield in strip intercropping systems with different row configurations

Abstract Intercropping of two or more crop species increases the efficiency of resource use and often produces a greater yield per unit land area. The relative efficiency of intercropping depends on row configuration, but there is a shortage of modelling-based evaluation of alternative intercropping options due to the inadequacy of standard process-based crop models to simulate resource capture, growth and yield formation when the canopy is spatially structured in strips. We implemented a light interception model for strip crops into the APSIM Classic model and combined it with a quasi-Bayesian approach to derive the model parameters to simulate crop growth and grain yield in maize-soybean strip intercropping. We used 4 years of field data for 5 different row configurations to derive key model parameters for simulation of light interception, LAI dynamics, biomass growth and grain yield of maize and soybean intercrops. Key model parameters (e.g. RUE, k etc.) were found to change with row-spacing and configuration, posing challenges to simulate different configurations with a single parameter set. The potential ranges of these key parameters were derived by constraining the model to observed data. The model can be potentially used to evaluate impact of planting configurations on productivity of strip intercropping systems, but the variability of key model parameters among configuration treatments calls for further in-depth research to improve modelling physiology of strip intercrops.

Effect of Irrigation on Intercropping Systems of Wheat (Triticum aestivum L.) with Pea (Pisum sativum L.)

Intercropping is an old and commonly used agricultural practice and involves the cultivation of two or more crops in the same area of land at the same time and may improve yield, the use of the environmental resources, product quality, and soil health. The objective of the present study was to study the effect of water availability of wheat-pea intercrops using agronomic and physiological characteristics. The experiment was conducted at the farm of Aristotle University of Thessaloniki, Greece during two growing seasons 2017–2018 and 2018–2019 using two different cultivars from pea (Isard and Olympos) and wheat (Yecora E and Elissavet) and two irrigation regimes. The availability of water increased grain yield and affected most of the characteristics that were studied. In terms of total Land Equivalent Ratio (LER) there was a yield advantage of intercrops over monocrops, which indicates the efficiency of intercropping for using the environmental resources. Both wheat cultivars, the pea cultivar Olympos and their intercrops indicated high adaptation capacity to rainfed conditions, whereas Isard and its intercrops performed better under irrigation. Therefore, the intercropping of wheat with pea uses the water resources of the environment more efficiently and can be used in dry land conditions for higher yield.

Abiotic Soil Health Indicators that Respond to Sustainable Management Practices in Sugarcane Cultivation

Soil quality (SQ) assessments are fundamental to design more sustainable land uses and management practices. However, SQ is a complex concept and there is not a universal approach to evaluate SQ across different conditions of climate, soil, and cropping system. Large-scale sugarcane production in Brazil is predominantly based on conventional tillage and high mechanization intensity, leading to SQ degradation. Thus through this study, we aim to assess the impact of sustainable management practices, including cover crops and less intensive tillage systems, in relation to the conventional system, using a soil quality index composed of abiotic indicators. Additionally, we developed a decision tree model to predict SQ using a minimum set of variables. The study was conducted in the municipality of Ibitinga, São Paulo, Brazil. The experimental design used was in strips, with four cover crops and three tillage systems. We evaluated three sugarcane cultivation cycles (2015/16, 2016/17, and 2017/18 crops). To calculate the SQ index, we selected five abiotic indicators: macroporosity, potassium content, calcium content, bulk density, and mean weight-diameter of soil aggregates. Based on our SQ index, our findings indicated that the soil quality was driven by the production cycle of sugarcane. Although a reduction of soil quality occurs between the plant cane and first ratoon cane cycles, from the second ratoon cane there is a trend of the gradual restoration of soil quality due to the recovery of both the soil’s physical and chemical attributes. Our study also demonstrated that the cultivation of sunn hemp and millet as cover crops, during the implementation of sugarcane plantation, enhanced soil quality. Due to the advantages provided by the use of these two cover crops, we encourage more detailed and long-term studies, aiming to test the efficiency of intercropping involving sunn hemp and millet during the re-planting of sugarcane.

EFFECT OF POPULATION DENSITY OF SWEET POTATO ON THE YIELD OF MAIZE-SWEET POTATO INTERCROP FOR WEEDS SUPPRESSION IN SOUTHERN GUINEA SAVANNAH NIGERIA

ABSTRACT Maize–sweet potato intercropping often results in weed suppression and increased crop productivity. This study was designed to determine the appropriate planting time and optimal density of sweet potato in a maize-sweet potato intercropping system that will minimize weed infestation and improve yield of the component crops in a drought-prone southern Guinea savanna of Nigeria. The experiment was laid as a randomized complete block design with a split-plot arrangement and 3 replications in 2018 and 2019 growing seasons. The main plots were planting time (May, June and July) while the sub-plots consisted of 3 maize-sweet potato intercropping populations(maize at 53,333 plants/ha + 33,333 plants/ha of sweet potato, maize at 53,333 plants/ha + 66,666 plants/ha of sweet potato and maize at 53,333 plants/ha +99,999plants/ha of sweet potato), sole maize at 53,333 plants/ha and sole sweet potato at 33,333 plants/ha. The results revealed that, 7 weed species were the most prevalent and there was inconsistent effect of planting date on weed flushes while weed smothering efficiency of intercropping was between 31 to 49 % and 48 to 73% for weed density and weed biomass, respectively. Intercropping resulted in land equivalent ratios (LER) of 1.29 to 1.74 while the competitive ability of maize was increased with an increase in sweet potato density. Planting in the month of June had significantly higher tuber yield of 9.56 t/ha of sweet potato and maize grain yield of 3.28 t/ha while intercropping 33,333 plants/ha of sweet potato (1 vine of sweet potato planted at 0.40m apart on the ridge and 0.75m between ridges) and maize at 53,333 plants/ha (0.25m x 0.75m) gave an intercrop yield of 7.32 t/ha tubers and 3.46 t/ha grain yield with highest LER of 1.74, a net profit of ₦566,435.00 and benefit cost ratio of 1.44 was relatively similar to sole sweet potato. Therefore, the above intercropping pattern established in the month of June will minimize weed infestation and improve productivity of maize and sweet potato in the southern Guinea savanna of Nigeria.

EFFECTS OF INTERCROPPING SYSTEM AND NITROGEN FERTILIZATION ON LAND EQUIVALENT RATIO, YIELD AND MINERAL CONTENT OF BROCCOLI

To determine effects of intercropping broccoli with onion and their correspondence to different nitrogen concentrations on growth, yield and nutrient contents, field studies were conducted for two years. In intercropping plots, onion sets were planted between broccoli rows. Broccoli and onion plants were also grown as monocrops. Nitrogen was applied at three different rates (160, 200 and 240 kg ha–1) in both mono and intercrop plots of broccoli. The overall efficiency of intercropping was evaluated by employing land equivalent ratios (LERs). Cropping systems significantly did not affect chlorophyll reading value, yield and other parameters observed. However, nitrogen application rate had significant effect on these parameters. The highest values of these parameters were generally observed in 240 kg ha–1 nitrogen application. Macro and microelement content of broccoli leaves was affected neither by cropping systems nor by nitrogen fertilization except for N, Mn, Zn and NO3. Intercropping increased plant height but decreased the plant diameter of onion. There wasn’t significant decrease in plant weight of intercropped onion at 240 kg ha–1 nitrogen treatment when compared to monocropping. Broccoli intercropped with onion at 240 kg ha–1 nitrogen had the highest LER values, showing that intercropping practice could be more productive than monocropping especially in case of 240 kg ha–1 nitrogen application.

Ecosystem service provision of grain legume and cereal intercropping in Africa

Achieving food security is challenging in Africa, a continent beset by low crop yield and soil quality, climate adversities, pests, weed infestations, and crop disease outbreaks. In this context, it is important to re-visit the resource-use efficiency and ecosystem service values of intercropping of grain legumes and cereals, a practice that has long been used by small-scale producers to mitigate the risk of crop failure and to safeguard household food availability. Despite its historical use, there are significant knowledge gaps regarding multiple aspects of intercropping, including examination of the different crop combinations on ecosystem services from agriculture. Using meta-analysis approach of land equivalent ratio (LER), a widely-accepted index to assess the efficiency of intercropping production systems, we found that intercropping of cereals with legumes resulted in an elevated LER (i.e., 1.31), regardless of species combination. A significantly greater LER than the overall LER (P < .05) was observed with the combination of maize-pigeon pea (LER = 1.57) and maize-groundnut (LER = 1.52). Increasing LER with intercropping was constant across rainfall variability, as well as in the absence of nitrogen fertilizer, which are the hallmark properties of intercropping in resource-deprived Africa. Intercropping could also reduce soil erosion, pest/weed incidence, and increase carbon sequestration by about ~46%, ~20–30%, and ~15%, respectively, compared to its sole crop control. In this comprehensive quantitative assessment of intercropping benefits across the African continent, we highlighted the provision of different ecosystem services from agroecosystems, a crucial foundation to achieving sustainable agricultural production.

Efikasnost združivanja mrkve i crnog luka na njihova morfološka i nutritivna svojstva

A trial involving intercropped and pure stands of carrots 'Nantes' and onions 'Kupusinski jabucar' was conducted on a certified organic farm in Futog. The yield, morphological and nutritional properties of the crops analyzed were determined in the study. Furthermore, the biological efficiency of intercropping was assessed using the relative yield (RYT) and the land use efficiency index (LER). The mixture of crops had influenced the morphological properties examined. In both experimental plant species, the nutritional properties of onions and carrots exhibited a higher content of dry matter (DM) in the double-row growing system without maize gluten meal (onions - 11.42 %, carrots - 10.45 %) compared to single crops. The highest content of β-carotene was determined by alternating single rows of onions and carrots in a plot without the use of gluten (68.94 μg/g DM). The relative yield and the land use efficiency index have shown that there is a biological efficiency of combining carrots and onion as the values obtained are higher than 1. Carrots and black onions are favorable for intercropping because they are complementary, thus interactively contribute to increasing the yield per unit area and improving the nutritional properties.

Agronomic and Economic Feasibility of Tomato and Lettuce Intercropping in a Soilless System as a Function of the Electrical Conductivity of the Nutrient Solution

An intercrop is studied here as a new way of farming in soilless systems within a protected environment. To estimate the efficiency of intercropping in this cultivation system, an experiment was conducted to evaluate the effect of the electrical conductivity (EC) of the nutrient solution (2.0, 2.5, and 3.0 dS·m−1) on lettuce and tomato plants and on the agronomic and economic feasibility of the intercrop compared with monoculture. The results indicated that a moderate increase in EC from 2.0 to 3.0 dS·m−1 did not exert any important effect on tomato plant production or quality but did cause a decrease in lettuce yield in both the first and second crops. Intercropping was only feasible for lettuce when the tomato and lettuce plants were transplanted on the same day. The highest tomato (G class) and lettuce yields were achieved at an EC of 2.5 dS·m−1; this condition resulted in the highest intercrop profitability (0.53 €·m−2 more) when compared with tomato monoculture.

Water use and crop coefficient of the wheat–maize strip intercropping system for an arid region in northwestern China

Relay strip intercropping of spring wheat and maize is practiced on a large scale in arid regions of northwestern China. In this study, a field experiment was carried out during 2012 and 2013 growing seasons to examine water use and crop coefficient of this system in an arid environment. The experiment comprised three treatments: sole-cropped wheat, sole-cropped maize, and wheat–maize intercropping. The grain yields of both intercropped wheat and maize were enhanced by intercropping. The gross economic profit for wheat–maize intercropping was 16.4% lower than that of sole maize and 95.4% higher than that of sole wheat. The overall land use efficiency was improved by intercropping. The time course of leaf area index in intercropping had the similar trends to those in sole crops with relatively low values, which never exceeded 3.0m2m−2 throughout both growing seasons. Compared to weighted means of the sole-cropping systems, wheat–maize intercropping used 26% and 24% more water in 2012 and 2013, respectively. The water-use efficiency of intercropping was nearly the same as the weighted means of the sole crops. Due to the incomplete groundcover in intercropping plots, more water was consumed as soil evaporation. Averaged over two seasons, the ratio of soil evaporation to actual evapotranspiration was 33.4, 20.7 and 24.1% for intercropping system, sole-cropped wheat and sole-cropped maize, respectively. Crop coefficient (Kc) of sole-cropped wheat was 0.19±0.02, 1.05±0.07, and 0.42±0.09 at the initial, mid and late season in two seasons, respectively. Kc value of the sole-cropped maize was 0.22±0.03, 1.10±0.06 and 0.60±0.02 at the initial, mid and late season, respectively. The Kc values of the wheat–maize intercropping system varied in 0.21±0.03, 0.89±0.05, and 0.78±0.06 at the initial, middle and late wheat growing season, and in 0.85±0.03 and 0.61±0.01 at the middle and late maize growing season, respectively. Therefore, longer growing season and incomplete ground cover are the main factors that resulted in higher water use for wheat–maize intercropping compared to sole crops. Results of this study can help to improve the irrigation efficiency for the wheat–maize strip intercropping system.

Drip irrigated sunflower intercropping

One of the difficulties in the implementation of agroenergy’s cropping is the growing area competition with subsistence crops. Few studies have been conducted to show the efficiency of intercropping between plants of energy’s potential with cultures of economic sustainability. The objective of this study was to evaluate the effectiveness of intercropping sunflower cultivars with corn and beans, in the initial growth under localized irrigation. The experiment was conducted at the end of the year 2012, in an area of 950 m2, located in the Campus II-UEPB, Lagoa Seca, Paraiba. The irrigation system was managed based on the Reference Evapotranspiration (ETo), calculated by the Penmann-Monteith Method with data obtained locally. The experimental design was a randomized blocks factorial (2 × 4) × 3, with treatments combining two varieties of sunflower in four plantation systems: single or isolated, intercropped with maize, with bean and with caupi. Each plot consisted of four rows of sunflowers in spacing 0.3 × 0.7 m and length of 5 m, interspersed with rows of beans or corn, except in the isolated system. The central rows of sunflowers were used to measure the following growth characteristics: plant height, stem diameter, number of leaves and leaf area. Data were subjected to analysis of variance by F test and the means compared by Tukey test at 5% probability. The diversification of sunflower varieties promoted differences in initial growth, regardless of the cropping system. There was significant effect at 15 DAS, where the sunflower variety “Advanta CF101” had higher plants than the variety “Helio 253” at 40 DAS; the variety “Helio 253” had a stem diameter greater than the “Advanta CF101”.

Intercropping of marcela (Achyrocline satureioides (Lam.) DC.) and carrot (Daucus carota L.): crop yields and concentrations of phenolic compounds and flavonoids

SummaryThe objective of this study was to evaluate the productivity and gross yield of marcela (Achyrocline satureioides (Lam.) DC.) when monocropped or intercropped with carrot (Daucus carota L.) under the growing conditions in Dourados-MS, Brazil. Treatments were arranged in a randomised block design with four replications. The characteristics evaluated were the fresh weights (FWs) and dry weights (DWs) of whole plants and inflorescences of marcela, and the FW of marketable and non-marketable carrot roots and the FWs of carrot leaves. Also evaluated were the concentrations of phenolic compounds and flavonoids present in the inflorescences of marcela.The efficiency of intercropping was evaluated using the equivalent area index (EAI) which indicates the area of land required in a monoculture to produce the same yield as 1.0 ha of polyculture using the same plant population with the same management practices. For marcela, higher levels of inflorescence production, phenolic compounds and flavonoids were confirmed by intercropping. There were no significant differences in the characteristics of carrot among the planting arrangements. The EAI for the marcela-carrot intercropped system was 2.95. Therefore, intercropping was considered more effective than a monoculture.

Early interspecific interference in the wheat/faba bean (Triticum aestivum/ Vicia faba ssp. minor) and rapeseed/squarrosum clover (Brassica napus var. oleifera/Trifolium squarrosum) intercrops

Most of research on intercrops evaluate performances and interference between species on the basis of final yield, while little knowledge is available on the interference in early stages and at the root level, at least for cultivated intercrops. In fact, in the few studies on this subject species are often combined minding at experimental needs ( e.g. common substrate, temperature and water requirements, easy root separation) more than at their actual use in the farm. The present work evaluates interspecific interference during early developmental stages for two intercrops of agricultural interest: soft wheat-faba bean and rapeseed-squarrosum clover. Improving this knowledge would help intercrop growth modelling and rational cultivation. The experiments were carried out on soft wheat ( Triticum aestivum ), faba bean ( Vicia faba var. minor ), rapeseed ( Brassica napus var. oleifera ) and squarrosum clover ( Trifolium squarrosum ), germinated and grown until 32 days after sowing (DAS) as one-species stands or as wheat/faba bean and rapeseed/squarrosum clover intercrops, with different densities and proportions for the two species in each couple. Germination was studied in controlled-temperature chamber, plantlet growth was studied on pots in the greenhouse. During germination no interspecific interference was observed for both wheat/faba bean and rapeseed/squarrosum clover intercrops. During plantlet growth, interspecific interference occurred in both intercrops causing variations in whole plant and root dry matter accumulation. In the wheat/faba bean intercrop each species suffered from the competitive effect of the companion species and faba bean was the dominant species when present in lower proportion than wheat. The unexpectedly high aggressivity of faba bean may be explained either with the greater seed size that could have represented an initial advantage within the short duration of the experiment or with the competition towards wheat for substrate N which is not usual in the open field for a N fixing species. In the rapeseed/squarrosum clover intercrop, rapeseed was facilitated by squarrosum clover, while squarrosum clover suffered from the competitive effect of rapeseed, which was the dominant species. The resource use efficiency of intercrops as compared to that of one-species crops was lower in the wheat/faba bean couple, not much different in the rapeseed/squarrosum clover one. In both couples, the best performance was observed when the ratio of the dominant species was lower than that of the companion species (number of plants in the ratio 1:3).

The Effects of Nitrogen Fertilization on Intercropped Strawberry and Broad Bean

ABSTRACT To determine different aspects of intercropping strawberry (Fragaria xananassa L. Duch.) with broad bean (Vicia faba L. cv. Lara) and their similarities to different nitrogen concentrations, this field study was conducted for three years. The overall efficiency of intercropping was measured by using Land Equivalent Ratios (LERs). In intercropping plots, broad bean seeds were sown in the middle of strawberry rows. Meanwhile strawberries and broad beans were also grown as sole crops based on identical experimental design. Nitrogen was applied at three different rates (0, 80, and 160 kg/ha) in both sole and intercrop plots of strawberry. Sole cropping broad beans grown with no fertilizer-N application were considered the control. As a result of these studies, it was reported that the chemical characteristics such as ascorbic acid, total soluble solid, and titratable acidity of strawberry fruits were not significantly affected by either intercropping or nitrogen fertilization. While cropping system did not have any negative effects on fruit weight, fruit weight per plant, and yield of strawberry, nitrogen application rate did significantly affect these parameters. The 80 kg/ha nitrogen application gave maximum amount of marketable fruits for strawberry in both sole cropping and intercropping. Cropping system interaction with nitrogen application showed significant differences in fruit weight per plant and total fruit weight of strawberry. Intercropping caused some phenotypic alteration such as increasing height and growth habits of broad bean. However, there were no significant reductions in pod numbers, pod weight per plants and total yield of intercropped broad bean at 80 kg/ha nitrogen application as compared with sole cropping. Strawberry intercropped with broad bean at 80 kg/ha nitrogen gave the best LER values, indicating that intercropping might be more productive than sole cropping especially in case of 80 kg/ha nitrogen application.

EFFECT OF VARYING MAIZE DENSITIES ON INTERCROPPED MAIZE AND SOYBEAN IN NEPAL

Maize and soybean are commonly intercropped in the drier zones of the western mid-hills in Nepal, but farmers report that productivity of soybean has been declining in recent years. Two researcher managed on-farm field experiments were conducted in the mid-hills environment of Nepal during 2001 and 2002, and one glasshouse experiment at the University of Wales, Bangor during 2003, to determine whether varying densities of maize and soybean influenced productivity of the system and to what extent soybean exhibited adaptation to shade. In neither season was maize yield affected by the presence of soybean, but grain yield of soybean was reduced in mixture by means of 59 and 53% during 2001 and 2002 respectively. Biomass and grain yield of maize were greatest at 53×103 plants ha−1 and least at the lowest density, whilst conversely biomass and grain yield of soybean increased. With increasing maize density, rates of accumulation of dry matter and leaf area index also increased, the latter resulting in decreasing transmission of light to the intercropped soybean. Soybean exhibited no photosynthetic adaptation to shade, but the specific leaf area was greater in artificially shaded and intercropped plants. Land equivalent ratios of all intercrops were greater than unity (1.30 to 1.45), indicating higher efficiency of intercropping compared to sole crops. Given the low plasticity in response of the maize canopy to variations in density, it is suggested that soybean could be better grown under maize by increasing between-row spacing of maize from 0.75 to 1.0 m to improve light transmission to the understorey, resulting in higher overall productivity of the intercropping system, and also that soybean germplasm be screened for adaptation to shade.

Análise econômica de cultivos consorciados de alface americana x rabanete: um estudo de caso

O trabalho foi realizado para verificar se cultivos consorciados de alface e de rabanete são economicamente viáveis. Foram elaborados os custos de produção das culturas em monocultivo e em consorciação. Alguns indicadores agroeconômicos foram usados para avaliar a eficiência dos sistemas consorciados: índice de uso eficiente da terra, receita bruta, receita líquida, vantagem monetária, vantagem monetária corrigida, taxa de retorno e índice de lucratividade. A associação das culturas da alface e rabanete permitiu um melhor aproveitamento dos fatores de produção, com aumento na produção por unidade de área. Os consórcios estabelecidos ao zero (espaçamento entrelinha 0,30 x 0,30 m) e aos 14 dias após o transplantio da alface (espaçamento entrelinhas de 0,40 x 0,30m) tiveram os melhores indicadores agroeconômicos, com índices de uso eficiente da terra de 1,76 e 1,61, taxas de retorno de 4,13 e 4,53, e índices de lucratividade de 75,77 e 77,94%, respectivamente.

Effects of plant population and nitrogen fertilizer on yield and efficiency of maize-bean intercropping

Nitrogen supply and plant population are basic parameters for cereal-legume intercropping. In order to study plant population and nitrogen fertilizer effects on yield and yield efficiency of maize-bean intercropping, a field experiment was established. Three bean plant populations and three nitrogen levels were used. Maize dry matter accumulation decreased with increases in bean plant population. Competitive effect of intercrop beans on maize yields was high at higher plant populations, being decreased by nitrogen fertilizer; application of 50 kg ha-1 N was very efficient in increasing maize cob yield. Intercropping significantly decreased harvest index of beans in all plant population and nitrogen fertilizer situations. The efficiency of intercropping, compared to sole cropping, was evidenced by the values obtained for Land Equivalent Ratio (LER) for biomass, cob and pod yields that increased with increases in bean plant populations and nitrogen fertilizer levels.

Effect of intercropping maize and solanum potato on yield of the component crops in Central Uganda

Three potato (Solunum tuberosum) varieties and one maize variety were intercropped in six spatial arrangements, viz., sole crops, 2:1, 2:2, 1:1, 1:2 potato: maize row arrangements and one additive mixture. Intercropping influenced some growth parameters of potato but not of maize. For instance, the rate of potato stem extension and leaf formation rates were hastened by intercropping. Branching in potato influenced leaf area development, especially during the second season when the additive mixture supported the least leaf area. Potato yield differed significantly among the spatial arrangements with the highest yield in the sole crop followed closely by the 2:1 and 2:2 potato: maize mixtures. However, these yield differences depended on potato variety, with Kisoro being the most responsive to changes in spatial arrangement. Assessment of biological efficiency of intercropping using the Land Equivalent Ratio (LER) method, revealed that yield advantages increased slightly with increase in the proportion of potato in the mixtures. However, it was only the additive mixture with a significant overall LER of 1.58, indicating a 58.2% yield advantage for intercropping. The contribution of maize to total LER was greatest in the 1:2 and additive mixtures. Key Words: Biological efficiency, inter-cropping, land equivalent ratio, Solanum tuberosum, spatial arrangement, yield advantage (African Crop Science Journal 2001 9(1): 83-96)

Yields and returns from strip intercropping on six Iowa farms

AbstractStrip intercropping seeks to capture the biological efficiency of intercropping in traditional agricultural systems and is compatible with agricultural equipment used in the U.S. This efficiency stems from complementary use of resources by constituent crops and is a function of crop selection, strip width and orientation, weed control, and other factors. Strip intercropping requires a high level of management; further, some reports suggest the gains and losses more-or-less balance in actual production situations. These questions are best addressed by the performance of strip intercropping as implemented by farmers in production situations.Practical Farmers of Iowa (PFI) members have worked with Iowa State University agronomists to evaluate strip intercropping. For three years six farmers compared strip intercropping to field blocks of individual crops. The strip intercrop systems employed three crops: corn, soybeans, and small grains with a forage legume underseeding. The comparison systems, crops grown in sole-crop blocks, consisted of the same three crops on four farms (planting pattern comparison) or, on two farms, just corn and soybeans in rotation (systems comparison). Yields and field operations were recorded and entered in the Iowa State University Crop Enterprise Record System (CER) to derive gross profit, total production cost, and net profit for each crop component and for each cropping system on every farm. Strip intercropping net profit was generally greater than that in field blocks, and intercropping compared favorably with CER results obtained from corn-soybean rotations on other farms around Iowa. Land equivalent ratios (LER) were usually greater than 1.0, indicating satisfactory biological efficiency. Despite occasional problems, in this set of 18 site-years strip intercropping was associated with greater stability of net profit.