Intercropping Treatments Research Articles

Evaluation of intercropped switchgrass establishment under a range of experimental site preparation treatments in a forested setting on the Lower Coastal Plain of North Carolina, U.S.A.

There is growing interest in using switchgrass (Panicum virgatum L.) as a biofuel crop and for its potential to sequester carbon. However, there are limited data on the establishment success of this species when grown as a forest intercrop in coastal plain settings of the U.S. Southeast. Therefore, we studied establishment success of switchgrass within experimental intercropped plots and in pure switchgrass plots in an intensively managed loblolly pine (Pinus taeda) plantation in eastern North Carolina. Pine trees were planted in the winter of 2008, and switchgrass was planted in the summer of 2009. Establishment success of switchgrass was measured over the growing season from May to October 2010, and quantified in terms of percent cover, height (cm), tiller density (number of tillers m−2), leaf area index and biomass (Mg ha−1). At the end of the growing season, pure switchgrass plots were taller than the intercropped treatments (114 ± 2 cm versus 98 ± 1 cm, respectively), but no significant treatment effects were evident in the other variables measured. Switchgrass biomass across all treatments increased from 2.65 ± 0.81 Mg ha−1 in 2009 to 4.14 ± 0.45 Mg ha−1 in 2010. There was no significant effect of distance from the pine row on any switchgrass growth parameters. However, we anticipate a shading effect over time that may limit switchgrass growth as the pines approach stand closure.

Study on Intercropping Carrot with Groundnut Under Different Row Arrangements

Burirhat, Rangpur during two consecutive seasons of 2004-05 and 2005-06, respectively, to find out suitable row arrangement of carrot with groundnut for higher yield and economic return. There were six treatments, such as sole groundnut, sole carrot, one row of carrot in between two normal rows of groundnut, two rows of carrot in between two normal rows of groundnut, two rows of groundnut alternated with two rows of carrot and three rows of groundnut alternated with three rows of carrot. Results showed that monoculture produced the highest yields of individual crops but in intercropping system the highest groundnut equivalent yield (10.63 t/h and 11.10 t/ha) was obtained from two rows of carrot in between two rows of groundnut. The maximum land equivalent ratio (1.67 and 1.74), the highest gross return (Tk.212600/ha and Tk. 248400/ha) and net return (Tk.184881/ha and Tk.211680) were also obtained from the intercropping treatment with two rows carrot in between two normal rows of groundnut. But due to higher cost in this treatment, maximum benefit cost ratio (7.09 and 7.01) was obtained from the intercropping treatment with one row carrot in between two normal rows of groundnut in both the years. DOI: http://dx.doi.org/10.3329/bjar.v37i2.11223 Bangladesh J. Agril. Res. 37(2): 215-223, June 2012

Repellent and attractive effects of herbs on insects in pear orchards intercropped with aromatic plants

There is increasing interest in the use of vegetation such as aromatic plants as intercrops to biologically control insect pests in agroecosystems and orchard ecosystems. Understanding the mechanisms underlying the repellent effects of aromatic plants on orchard pests (e.g., scarabaeid pests) can lead to improved application of intercropping cultivation practices in orchards. We tested eight intercropping treatments, each containing a different species of aromatic plant, in a pear orchard, along with a natural grass treatment and a clean tillage (control) treatment. The results showed that intercropping reduced the annual cumulative number and abundance of scarab beetles relative to the control. The annual dynamics of scarab populations were also significantly altered where intercrops were used. However, with the exception of Ichneunmonidae, the natural parasites of scarabs showed no preference for the aromatic plants. A correlation analysis indicated that the reduction in some of the scarab beetle species was related to the abundance of certain specific natural enemy species. In addition, the diversity, evenness and degree of dominance of natural enemy species may have contributed to the decrease in scarab populations. This study shows that intercropped aromatic plants can be applied to control the scarab beetles in orchard ecosystems, but that effects vary across aromatic plant species.

Effect of chemical fertilizers on yield and nutritive value of intercropped Sudan grass (Sorghum Sudanense) and cowpea (Vigna unguiculata L. Walp) forages grown in an adverse environment of western Saudi Arabi

A field experiment was carried out during 2009/2010 and 2010/2011 seasons at Hada Al-Sham experimental Farm of King A/Aziz University in Jeddah, Saudi Arabia. The objective was to evaluate the effect of some chemical fertilizers on productivity and nutritive value ofSorghum Sudanense Var. Panar intercropped with Cowpea (Vigna unguiculata L. Walp) in an adverse condition of soil and irrigation water. The chemical fertilizers applied were 50 kg/ha of urea (46%N), 50 kg/ha of triple superphosphate (46% P), 50 kg/ha of KNO3, 50 kg/ha of NPK (20:20:40) and a control for check. Sudan grass and Cowpea were sown as sole crops and as a mixture. Treatments were laid out in a split plot design with the fertilizer treatments in the main plots and the intercropping treatments in the subplots. Parameters measured were plant height and nutritive value for the Sudan grass, fresh and dry yields and the land equivalent ratio (LER). The chemical fertilizers had no significant (P ≤ 0.05) effect on productivity but significantly improved forage quality. Intercropping of Sudan grass and Cowpea significantly (P ≤ 0.05) increased forage productivity and improved forage quality and land equivalent ratio (LER). Cowpea was not a good competitor as it disappeared following the first cut in the first season. Key words: Chemical fertilization, intercropping, cowpea, sorghum forage, Sudan grass, salinity, land equivalent ratio (LER)

THE IMPACT OF SOYBEAN AND CORN INTERCROPPING SYSTEM AND SOIL FERTILITY MANAGEMENT ON SOYBEAN APHID POPULATIONS APHIS GLYCINES (HEMIPTERA: APHIDIDAE) AND SOYBEAN GROWTH PERFORMANCE

Agricultural management cropping systems play an important role in affecting a crop plant’s ability to tolerate or resist insect pests. Field studies were conducted to examine the effect of two strategies management systems: fertilizer treatment and intercropping soybean with corn on soybean aphid (Aphis glycines Matsumura) population and soybean growth and yield parameters. The intercropping treatments were: soybean alone; 2:1 soybean/corn intercrop; and 3:1 soybean/corn intercrop. While the soil fertility treatments were the combination of NPK (urea 100 kg ha-1 + SP-36 200 kg ha-1 + KCl 200 kg ha-1) levels, dolomite (4 ton ha-1), compost (10 ton ha-1), and chicken manure (10 ton ha-1). The results of the first study showed that the intercropping soybean with corn significantly reduced the population density of soybean aphids. However, there were no significant effects of intercropping systems on soybean growth (plant height) and yield (number seed per pod and thousand seed weight) performances except on the number of soybean pods per plant. Meanwhile, the result of the second study indicated that soil fertilizer treatments had a significant effect on the soybean plant characteristics: leaf numbers; pod numbers; and plant height. Combining intercropping methods and soil fertilizer management offer an opportunity to protect the soybean plants by natural and sustainable pest management.

接种AM真菌对玉米和油菜种间竞争及土壤无机磷组分的影响

在温室盆栽条件下,分别模拟单作、间作和尼龙网分隔种植,比较接种丛枝菌根(arbuscular mycorrhizal, AM)真菌<em>Glomus intraradices</em>和<em>Glomus mosseae</em>对菌根植物玉米和非菌根植物油菜生长和磷吸收状况的影响,并分析土壤中各无机磷组分的变化。结果发现,接种AM真菌可以促进土壤中难溶性磷(Ca₁₀-P和O-P)向有效态磷转化,并显著降低总无机磷含量 (<em>P</em><0.05),显著提高菌根植物玉米的生物量和磷吸收量(<em>P</em><0.05),特别是在间作体系中使玉米的磷营养竞争比率显著提高了45.0%-104.1% (<em>P</em><0.05),显著降低了油菜的生物量和磷吸收量(<em>P</em><0.05),从而增强了了菌根植物的竞争优势,降低了非菌根植物与菌根植物的共存能力。揭示了石灰性土壤中AM真菌对植物物种多样性的影响,有助于更加全面地理解AM真菌在农业生态系统中的作用。;Arbuscular mycorrhizal fungi (AMF) form mutualistic associations with more than 85% of terrestrial plant species and play key roles in nutrient cycling and ecosystem functioning. Most plant individual stimulates nutrient availability through their fungal partner. Highly mycorrhizal-dependent plant species derive more benefits from AMF in comparison to low mycorrhizal dependency plant species. But the effects of AMF on the competition between mycorrhizal and non-mycorrhizal plants remained largely unclear, particularly in an environment with low phosphate bioavailability. The increased phosphate availability for host plants and enhanced plant phosphorus nutrition is a major outcome of the AM symbiosis and then AMF colonization could and consequently increase plant biomass. The larger plants are then expected to be successful competitors. <br> In our previous, AMF colonization significantly decreased phosphorus concentration and content of rape roots compared with non-inoculation treatments, while in contrast mycorrhizal association improved phosphorus nutrition of maize plants. The results clearly showed the beneficial effects of mycorrhizal associations on AMF host plants in competition with non-host plants. In this previous research, plants were cultivated in purple soil with higher phosphorus availability which is more important as this determined the effect of AMF inoculation on host plant P nutrition. Then in this research, calcareous fluvo-aquic soil with lower phosphorus availability was used and different form of inorganic phosphorus were measured to reveal the effect of AMF inoculation on competition between mycorrhizal plant and non-mycorrhizal plants species. Maize (<em>Zea mays </em>L.) and rape (<em>Brassica napus </em>L.) plants were cultivated in three different interaction patterns, namely intraspecific (monoculture), intespecific (intercropping) and no interaction (nylon net split). All plants were inoculated with <em>Glomus intraradices</em>, <em>Glomus mosseae</em> or remained uninoculated. The strength of competition was measured as the reduction in biomass caused by the presence of a competitor. The results showed that AMF inoculation decreased soil inorganic phosphate significantly and transformed more Ca₁₀-P and O-P into higher availability phosphorus form. In the intercropping treatment, the inoculation improved the plant growth and phosphorus uptake of maize, and meanwhile decreased the growth and phosphorus uptake of rape significantly. Our results clearly showed the strong competitive strength and phosphorus competitive strength of maize to rape., and the beneficial effects of mycorrhizal associations was due to the favorable growth of host plants over non-host plants. It reveals that AM fungus may play an important role in structuring plant community and needs a comprehensive insight to understand the effect of AM fungus on plant biodiversity in ecosystems.

Intercropping barley with pea for agronomic and economic considerations in northern Ontario

Intercropping, a mix of non-legume and legume crops, can improve crop yield and/or economic returns and reduce input costs. Field experiments (barley-pea intercrop) were conducted in 2008, 2010 and 2011 on an Oskondoga silt loam soil at Thunder Bay, Ontario, Canada, to determine the effect of intercropping barley (non-legume) and pea (legume) on grain yield, land equivalency ratio (LER), grain quality (protein concentration-PC), N uptake and economic returns. Barley and pea were grown as mono crops and in combinations as intercrops (both in the same row/and alternate rows). Nitrogen fertilizer was applied at 0, 40 and 80 kg·N·ha-1 to mono crop barley and at 0, 20 and 40 kg·N·ha-1 to barley-pea intercrop combinations. On an average of three years, application of 80 kg·N·ha-1 increased grain yield of barley by 846 kg·ha-1 as a sole crop and by 420 - 488 kg·ha-1 in the two intercropping combinations. Compared to barley and pea as sole crops, grain yield with barley-pea intercropping was greater by 266 kg·ha-1 with alternate row combination and by 223 kg·ha-1when both crops were grown in the same row. The LER values suggested 7% - 17% less land requirement for barley-pea intercropping than sole crops. Net returns from barley-pea intercropping without applied N greatly improved ($854 - $939 ha-1) compared to barley sole crop with 80 kg·N·ha-1($628 ha-1), although the net returns were highest for pea grown as a sole crop without applied N ($1141 ha-1). For barley as a sole crop, PC in grain increased with applied N. Compared to barley as sole crop with zero-N, PC in barley grain increased when barley was intercropped with pea. In barley-pea intercrop treatments, application of N fertilizer had no significant effect on PC in barley grain, although PC in pea grain was much higher than PC in barley grain. The response trends of total N uptake in grain were similar to grain yield. The findings suggest that pea or barley-pea intercropping could be an option for organic farming systems.

Relative Composition of Weeds and Integrated Weed Management in Mulberry Garden

Crop-weed competition is a limiting factor in the growth of mulberry plant and weed management practices had marked influence on weed density and weed dry matter production. Based on the weed survey in the farmers field and investigations compared to chemical weeding intercropping with cowpea had an increased weed control effect in mulberry plantations. The lowest density and dry matter of weeds were recorded in cowpea intercropping treatment. Reduced density and dry matter production of weeds resulted in increased production of mulberry growth and yield.

Legumes intercropped with spring barley contribute to increased biomass production and carry-over effects

SUMMARYIntercropping systems that include legumes can provide symbiotically fixed nitrogen (N) and potentially increase yield through improved resource use efficiency. The aims of the present study were: (a) to evaluate the effects of different legumes (species and varieties) and barley on grain yield, dry matter production and N uptake of the intercrop treatments compared with the associated cereal sole crop; (b) to assess the effects on the yields of the next grain crop and (c) to determine the accumulation of N in shoots of the crops in a low-input rotation. An experiment was established near Edinburgh, UK, consisting of 12 hydrologically isolated plots. Treatments were a spring barley (Hordeum vulgare cvar Westminster) sole crop and intercrops of barley/white clover (Trifolium repens cvar Alice) and barley/pea (Pisum sativum cvar Zero4 or cvar Nitouche) in 2006. All the plots were sown with spring oats (Avena sativa cvar Firth) in 2007 and perennial ryegrass in 2008. No fertilizers, herbicides or pesticides were used at any stage of the experiment. Above-ground biomass (barley, clover, pea, oat and ryegrass) and grain yields (barley, pea and oat) were measured at key stages during the growing seasons of 2006, 2007 and 2008; land equivalent ratio (LER) was measured only in 2006. At harvest, the total above-ground biomass of barley intercropped with clover (4·56 t biomass/ha) and barley intercropped with pea cvar Zero4 (4·49 t biomass/ha) were significantly different from the barley sole crop (3·05 t biomass/ha; P&lt;0·05). The grain yield of the barley (2006) intercropped with clover (3·36 t grain/ha) was significantly greater than that in the other treatments (P&lt;0·01). The accumulation of N in barley was low in 2006, but significantly higher (P&lt;0·05) in the oat grown the following year on the same plots. The present study demonstrates for the first time that intercrops can affect the grain yield and N uptake of the following crop (spring oats) in a rotation. Differences were also linked to the contrasting legume species and cultivars present in the previous year's intercrop. Legume choice is essential to optimize the plant productivity in intercropping designs. Cultivars chosen for intercropping purposes must take into account the effects upon the growth of the partner crop/s as well as to the following crop, including environmental factors.

Effect of intercropping, Bradyrhizobium inoculation and N, P fertilizers on yields, physical and chemical quality of cowpea seeds

The present study was aimed to determine the effects of inoculation with Bradyrhizobium strain, intercropping, nitrogen and phosphorus fertilization and their interaction on the yield, physical and chemical properties of cowpea seeds. The results showed that the seed yield of cowpea was significantly (P≤0.05) increased by Bradyrhizobium inoculation, nitrogen and phosphorus fertilizers, but not by intercropping. All treatments of intercropping, P, Bradyrhizobium plus N and Bradyrhizobium plus P treatments significantly (P≤0.05) increased the hydration coefficient and cookability of cowpea seeds compared to untreated plants in both seasons. For chemical composition, all treatments significantly (P≤0.05) increased the dry matter, ash, protein and fiber content of the seeds compared to the untreated plants for the two systems and in both seasons, whereas it significantly (P≤0.05) decreased carbohydrate content of the seeds. Fat content of the seeds was not increased by Bradyrhizobium inoculation and intercropping, but it was significantly increased by nitrogen and phosphorus fertilization. Intercropping, Bradyrhizobium inoculation and nitrogen and phosphorus fertilization significantly (P≤0.05) increased tannin content and in vitro protein digestibility of the seeds compared to untreated plants for both systems and in the two seasons.

Application of Rhizosphere Interaction of Hyperaccumulator Noccaea Caerulescens to Remediate Cadmium-Contaminated Agricultural Soil

There is an urgent requirement for selecting appropriate technologies to solve food safety problems due to soil contamination. In this study, the hyperaccumulator Noccaea caerulescens and a high Cd accumulator pakchoi cultivar (Brassica rapa L. spp. Chinenesis cv.) were grown in a moderately Cd-contaminated soil with three planting systems (mono-crop, inter-crop, and crop-rotation) and three growing durations (25, 50, and 75 days) to study the role of rhizosphere interaction of both species on the uptake of Cd. The Cd accumulations in the shoot of pakchoi were significantly reduced in the inter-crop treatment, also the decreased percentage increased with rhizosphere interaction between the two species. In the inter-crop systems of 75 days, the Cd concentration and amount in the shoot of pakchoi represented 54% and 83% reduction, respectively, while the total depletion of Cd decreased by approximate 19%. Although the Cd concentration and amount in the shoot of pakchoi were significantly reduced by 52% and 44%, respectively, in the crop-rotation treatment, the decreased percentage were markedly lower than in the inter-crop treatment. Therefore, the rhizosphere interaction of hyperaccumulator with non-hyperaccumulator may reduce the risk of vegetable contamination during making full use of or remediating the contaminated soil.

Efeito do consórcio de milho com Panicum maximum na comunidade infestante e na cultura da soja em rotação

Objetivou-se com este trabalho estudar os efeitos do consórcio de milho com colonião (Panicum maximum cv. Aruana) na infestação de plantas daninhas e na cultura da soja em rotação. O experimento foi realizado em campo, no período de dezembro de 2008 a abril de 2010, em área experimental da UNESP, campus de Jaboticabal-SP. Utilizou-se o delineamento em blocos ao acaso, com quatro repetições, em esquema de parcela subdividida. Foram estudadas duas formas de semeadura (a lanço e em linha) de colonião nas parcelas e quatro quantidades de sementes (200, 400, 600 e 800 pontos de valor cultural - PVC) nas subparcelas, além de três testemunhas, representadas pelo monocultivo das espécies, como tratamentos adicionais. O cultivo consorciado não afetou o desenvolvimento do milho, comparado ao milho solteiro. Embora na colheita do milho houvesse maior matéria seca e densidade de plantas de colonião com a semeadura de 800 PVC, antes da semeadura da soja o acúmulo de massa não diferiu entre os tratamentos de consórcio. Portanto, a semeadura de 200 PVC de sementes de colonião, a lanço ou em linha, foi suficiente para a manutenção de quantidade (9,1 t ha-1) adequada de palha sobre o solo. Antecedendo a semeadura da soja, a infestação de plantas daninhas na testemunha de milho solteiro foi maior do que nos tratamentos de consórcio e nas testemunhas da forrageira solteira (a lanço e em linha). O mesmo foi observado para densidade de plantas daninhas após a instalação da cultura. Os sistemas de consórcio de milho com colonião não interferiram em nenhuma característica avaliada na cultura da soja cultivada em rotação. Da mesma forma, não foi observada diferença entre os tratamentos de consórcios e a testemunha de milho em monocultivo para produção de grãos de soja.

Water use and yield of wheat/maize intercropping under alternate irrigation in the oasis field of northwest China

A field experiment was carried out to investigate the effects of alternate irrigation (AI) on the yield, water use and water use efficiency (WUE) of wheat ( Triticum aestivum L.)/maize ( Zea mays L.) intercropping system in an oasis region of northwest China in 2006–2008. Three planting patterns, i.e., sole wheat, sole maize and wheat/maize intercropping. Three irrigation levels were applied for each treatment during 3 years. Results showed that land use efficiency of wheat and maize was significantly enhanced by intercropping system; land equivalent ratio (LER) of wheat/maize intercropping system in different treatments was all greater than 1.0. Moreover, significant difference in grain yield was observed between intercropping treatment and sole cropping treatment, in which the yield of intercropped wheat was 55.37–74.88% of sole wheat, and intercropped maize was 66.63–78.87% of sole maize. Wheat/maize intercropping treatments increased water use by 1.8–16.4% than half of the total water use of sole-cropping wheat and maize. Compared to sole cropping wheat treatments, wheat/maize intercropping with alternate irrigation significantly improved water use efficiency (WUE) by 30.5–57.7%, 55.5–71.4% and 12.0–19.8%, and increased by 32.7–37.8%, 9.5–15.8% and 4.0–20.8% than sole cropping maize treatments in 2006–2008, respectively. Our results suggest that AI should be a useful water-saving irrigation method on wheat/maize intercropping in arid oasis field where intercropping planting is decreased because of limited water resource.

Effects of intercropping of garlic or lettuce with Chinese cabbage on the development of larvae and pupae of diamondback moth ( Plutella xylostella )

The effects of intercropping on the growth and development of the diamondback moth (DBM),Plutella xylostella (Lepidoptera: Plutellidae), were investigated over five generations in a laboratory in Fuzhou, China. The treatments included intercropping Chinese cabbage (Brassica chinensis) with garlic (Allium sativum) (CG) and lettuce (Lactuca sativa) (CL), and the monoculture of Chinese cabbage as control (CK). The larval stage was significantly longer for the intercropping treatments compared to CK. Intercropping affected pupal weight but not the percentage of successful larvae population. Pupae tended to be 10 to 15% larger in the intercropping treatments for three of the five generations. The increase in size, pupa mortality was significantly higher with intercropping. Our findings suggest that intercropping can suppress the DBM populations in a long period rather than in a short term. Key words: Plutella xylostella intercropping, diamondback moth, larval development, pupal mortality.

Effect of fertilizer in controlling weeds under intercropping of pearl millet and red bean in Sistan region, Iran

This experiment was conducted at the Agriculture Research Center of Zabol University during 2007 cropping season. The experimental design was split plot, using randomized complete block design with three replications. The factors included were, main factors: unfertilized (F 1 ), 100% fertilizer (F 2 ), 100% manure (F 3 ), 50% fertilizer + 50% manure (F 4 ) and five sub factors: sole crop of millet (I 1 ), 75% millet + 25% bean (I 2 ), 50% millet + 50% bean (I 3 ), 25% millet + 75% bean (I 4 ) and sole crop of bean (I 5 ). The plants were planted as replacement method. The results showed that the lowest dry matter for crops and total dry matter of weeds was achieved from 50% fertilizer + 50% manure treatment. Also, the highest total dry matter of millet and bean was obtained from this treatment. The highest dry matter of millet and bean was obtained from the sole crop of millet and bean. Further, the highest total dry matter of millet and bean was achieved from the intercropping treatments. The land equivalent ratio (LER) for most of the intercropping treatments was greater than one which indicated that intercropping had advantage over sole crop. Comparing the performance of sole crop and intercrop treatments, the results indicated that intercropping combinations were more advantageous in terms of weed control. Key words: Intercropping, pearl millet, red bean, weeds, land equivalent ratio, yield.

Producción y distribución de materia seca en lerén [Calathea allouia (Aubl.) Lindl

El lerén [Calathea allouia (Aubl.) Lindl] es un tubérculo tropical con potencial para procesamiento y como un sustituto para las castañas de agua. La sombra afecta la tasa fotosintética del cultivo por lo que el crecimiento y los rendimientos varían. Existe poca información en cuanto al mejoramiento agronómico de este cultivo. Este estudio se estableció para entender cómo, a través de la manipulación de la luz, densidad poblacional y factores nutricionales, la producción y distribución de los asimilatos afecta el rendimiento del cultivo. Al igual que para determinar si los rizomas del lerén son los verdaderos sumideros o si actúan como un filtro/almacenamiento para la tuberización. Se llevaron a cabo varios experimentos de invernadero y de campo durante un periodo de dos años en la Estación de Campo de la Universidad de Trinidad Tobago. Los tratamientos evaluados fueron luz [luz solar completa y sombra (50%)], densidad poblacional (20.8 y 27.7 mil plantas por hectárea), y fertilización [N-P2-O5-K2O (13:13:20)]a varios niveles (0.0 a 0.6 t/ha). Se midió el área foliar, materia seca, y rendimiento de los tubérculos. Los resultados indicaron que el índice de área foliar varió entre 1.38 (luz solar) y 3.08 (sombra) y que el mismo no estuvo afectado por la nutrición del cultivo. Tanto para los ensayos de invernadero como los de campo, la acumulación de material seca en los rizomas y su distribución en los tubérculos fue mayor en los tratamientos con sombra que en aquellos bajo luz solar. La aplicación de fertilizantes no influenció el crecimiento de las hojas ni la producción de materia seca (capacidad fotosintética) en los ensayos en el invernadero, pero hubo mayor distribución de asimilatos desde los rizomas hasta los tubérculos cuando se usó una menor densidad poblacional x intercalado. La distribución de asimilatos de los tallos a los rizomas, y de los rizomas a los tubérculos fue más eficiente en los tratamientos de sombra x intercalado. La aplicación de fertilizante a la dosis de 0.5 t/ha a la densidad de 20.8 mil plantas por hectárea produjo la mayor cantidad de materia seca (1,066 g/planta) y el mayor rendimiento de tubérculos (261.3 g/planta). El estudio sugiere que en el lerén, los rizomas y tubérculos son los sumideros primarios y secundarios, respectivamente, con una distribución de asimilatos de tallos a rizomas y de rizomas a tubérculos.

Forage yield and quality of intercropped corn and soybean in narrow strips

Maize-soybean intercropping can increase forage quality with no detrimental effect on dry matter (DM) yield. The objective of this study was to compare corn-soybean intercrop in narrow strips with corn as monocrop in terms of DM yield and forage quality. This study was conducted in Matamoros, Coahuila (Mexico) in 2006 and 2007. Intercrops were established in rows spaced 0.50 m apart, evaluating alternate corn-soybean strips with one, two, three, and four rows per crop, and a treatment using an alternate twin-row planting pattern per crop, with a 1.0-m row-spacing. As control treatments, monocrops of corn in rows 0.76 m apart and soybean in rows 0.50 m apart were evaluated. A randomized complete block design with four replications was employed. Corn-soybean intercrop produced DM yields similar to those of monocropped corn due to higher corn yields in border rows adjacent to soybean. Crude protein (CP) yields per hectare in intercrop treatments were higher (27.5 to 42.8%) than those of monocropped corn, due to greater CP concentrations in intercrops (16 to 21 g kg–1). When soybean was harvested at the beginning maturity stage (R7), neutral detergent fiber concentration was reduced by 60 to 63 g kg–1 in corn-soybean intercropping compared to corn monocrop. Acid detergent fiber was not altered by intercropping. Results indicate that maize-soybean intercrop in narrow strips can provide forage quality advantages without affecting yield.

Effects of some integrated management options on parthenium interference in sorghum

Parthenium is widely distributed across the uncropped areas of the tropics. It has slowly encroached into many crops and causes considerable yield loss. It heavily infests sorghum, which is widely cultivated by the resource‐poor farmers in Africa and Asia. Its interference and management in sorghum in these cropping systems is not well understood. Therefore, this experiment was undertaken to determine the appropriate parthenium management techniques to use in sorghum crops. All the studied weeds, in combination with parthenium, offered greater competition to sorghum than parthenium alone. Similarly, under a composite stand of weeds, parthenium was inferior in competitiveness to the other weeds until 60 days after sowing (DAS); by 90 DAS, it could accumulate a higher dry weight due to its consistent growth. A pre‐emergence treatment of atrazine (0.75 kg ha‐1) with wheat straw mulch (5.0 t ha−1) brought about a consistent and significant reduction in the parthenium growth and, consequently, increased the sorghum yield by 90.8%. Cowpea intercropping with and without pendimethalin (1.0 kg ha−1) as a pre‐emergence treatment could not control parthenium between 0 and 60 DAS, but could reduce the parthenium growth during the later period of 60–90 DAS, which resulted in a significant increase in sorghum growth. These intercropping treatments increased the sorghum grain yield by 156.2% and 142.4%, respectively, over the unweeded control and by 18.5% and 12.1%, respectively, over the weed‐free control. These treatments also promoted a higher uptake of N, P, and K by the sorghum crop. Thus, cowpea intercropping was the most effective method for parthenium management vis‐à‐vis sorghum yield improvement, followed by cowpea intercropping with pendimethalin and then by atrazine as a pre‐emergence treatment with wheat straw mulch.

Contribution of runoff to incomplete off season soil water refilling in a Mediterranean vineyard

Abstract The dynamics of soil water was investigated in a Mediterranean vineyard during the 2003–2007 period in order to identify the inter-seasonal modification of water storage due to intercropping. The intercrop was a mixture of tall fescue and rye grass. Soil water content was measured on 3 m soil profiles (plus one 5 m profile) as was runoff from local stands. Great variations in soil refilling were observed over the years, for both the bare soil and intercrop treatments. The complete refilling occurred once and it was associated with a rise of the water table up to less than 2 m from the soil surface in the low part of the field. During the other years, the wetting front was identified between 1 m and 2.3 m at spring in the bare soil treatment, deeper in the lowest part of the field. The available soil water content at bud-break was influenced by the topography. A higher infiltration was observed in the intercropped treatment. Runoff kinetics was compared to rainfall kinetics in a selection of three rain events differing by duration and intensity. The curve number method was used to perform the analysis of runoff at a 1-day time-step rather than the quarter of an hour time-step of the registrations. With this method, the time limitation of water balance studies for Mediterranean vineyards would be partially removed.

Evaluation of the planting schedule of soyabean/cassava intercrop systems for optimum yields in the guinea savanna of Nigeria

Seven soyabean/cassava intercrop planting schedules were evaluated in a field trial at the National Cereal Research Institute, Badeggi during the 2005 and 2006 cropping seasons with a view to determining theplanting schedule that will result in optimum yields of the component crops. Experimental design was randomized complete block with three replicates. The soyabean variety TGX 1019 2EB was intercropped withcassava variety 92/0427 using the following planting schedules:- (1) Cassava planted at 28 Days Before Planting Soyabean (28 DBPS) (2) Cassava planted at 14 Days Before Planting Soyabean (14 DBPS) (3)Soyabean /Cassava Planted Same Day (PSD) (4) Cassava planted at 14 Days After plating Soyabean (14 DAPS) (5) Cassava planted at 28 Days After Planting Soyabean (28 DAPS) (6) Sole cassava (planted on the 30 of June ; recommended planting time in this agro-ecological zone) (7) sole soyabean (planted on the 28 of July; recommended planting time in this agro-ecological zone. Results obtained indicated that the planting of cassava at 28 Days Before Planting Soyabean (i.e. soy+cas 28 DBPS) resulted in the highest cassava yields of 41,700 and 42,182 kg/ha in 2005 and 2006 respectively. These yields were significantly higher (P=0.05) than the cassava yields obtained at the other intercrop treatments in both years. This treatment also resulted in the highest gross yields of the component crops as indicated by the LER in both years.Keywords: Cassava, Soyabean, Planting Schedule, GrossYields.