Abstract In traditional row and strip cowpea-sorghum intercropping systems, cowpea forage yield reduces significantly due to intense competition and dominance of sorghum in acquiring growth resources. This field study evaluated novel mixed strip intercropping systems of forage cowpea and sorghum having different number of crops rows arranged under different spatial arrangements. Cowpea was intercropped with sorghum in 8, 12 and 16 rows strips with row-row spacing of 30, 45 and 60 cm. In each strip, equal number of rows of cowpea and sorghum were maintained. Factorial arrangement of randomized complete block design with three replicates was used to execute the field trials during summer seasons of 2013 and 2014. Strips having 12 rows and 60 cm row-row spacing positively affected all agronomic variables of cowpea which led to maximum forage yield (22.2 and 23.7 t ha-1 during 2013 and 2014 respectively) and dry matter biomass (6.63 and 6.94 t ha-1 during 2013 and 2014 respectively). In contrast, 8-rows strips having line spacing of 30 cm outperformed other intercropping systems by yielding the maximum herbage yield and dry matter biomass of sorghum. The intercropping system comprising of 12-rows strips with 60 cm row-row spacing remained superior in recording the maximum crude protein, fats and total ash along with the minimum fiber content of cowpea. In addition, this intercropping system under rest of spatial arrangements also remained unmatched, while 16-rows strips under all planting geometries remained inferior to other intercropping systems. Thus, cowpea intercropping with sorghum in 12-rows strips having 60 cm spacing offers biologically viable solution to improve biomass and forage quality of cowpea in intercropping with sorghum.

Resumen En los sistemas tradicionales de cultivo intercalado de frijol caupí y sorgo en franjas y filas, el rendimiento de forraje del frijol caupí se reduce significativamente debido a la intensa competencia y al dominio del sorgo en la adquisición de recursos para el cultivo. Este estudio de campo evaluó novedosos sistemas de cultivo intercalado en franjas mixtas de frijol caupí forrajero y sorgo con diferente número de filas de cultivo en diferentes disposiciones espaciales. El frijol caupí se intercaló con el sorgo en franjas de 8, 12 y 16 filas con un espaciamiento de 30, 45 y 60 cm entre las filas. En cada franja se mantuvo igual número de filas de frijol caupí y sorgo. Para la ejecución de los ensayos de campo durante las temporadas de verano de 2013 y 2014 se utilizó un diseño factorial en bloques completos aleatorizados con tres repeticiones. Las franjas con 12 filas y un espaciamiento de 60 cm entre las filas afectaron positivamente a todas las variables agronómicas del frijol caupí que condujeron al máximo rendimiento forrajero (22.2 y 23.7 t/ha en 2013 y 2014, respectivamente) y de biomasa de materia seca (6.63 y 6.94 t/ha en 2013 y 2014, respectivamente). En cambio, las franjas de 8 filas con un espaciamiento de 30 cm superaron a otros sistemas de cultivo intercalado al obtener el rendimiento máximo de hierba y de biomasa de materia seca del sorgo. El sistema de cultivo intercalado compuesto por franjas de 12 filas con un espaciamiento de 60 cm entre las filas siguió siendo superior, al registrar el contenido máximo de proteína bruta, grasas y cenizas junto con el mínimo contenido de fibra de frijol caupí. Además, este sistema de cultivo intercalado bajo el resto de las disposiciones espaciales también permaneció incomparable, mientras que las franjas de 16 filas bajo todas las geometrías de siembra permanecieron inferiores a otros sistemas de cultivo intercalado. Por lo tanto, el cultivo intercalado de frijol caupí con sorgo en franjas de 12 filas con un espaciado de 60 cm ofrece una solución biológicamente viable para mejorar la biomasa y la calidad del forraje del caupí en cultivo intercalado con sorgo.

Abstract Background: Weeds are unwanted and undesirable plants which deteriorate the quality of agricultural products and interfere with farming activities. Most of the weeds (indigenous and invasive) seeds get preserved in soil horizons as weed seed bank which ensure their survival leading to the spoilage of quantitative and qualitative functioning of agricultural farms. Objective: To keep weeds below threshold level, elimination of weeds seed before germination can be a viable and pro-ecological approach. To achieve this objective, weed seeds reserved in the soil which serve as an effective pool to ensure their survival necessitate weed-seed bank management. Thus the ultimate goal was to synthesize and analyze research findings on weed seed bank management leading to formulating the most effective strategy encompassing viable control of weeds in maize. Methods: This study reviewed and analyzed the characteristics which impart botanical superiority to weeds and impact of all prevalent weed control strategies on weed seed bank, weeds density and maize yield. The research findings pertaining to different agronomic practices and technological packages were critically analyzed to sort out the most effective and eco-friendly approach to control weed-seed bank and weeds density in maize crop. Results: The synthesis and critical evaluation of research findings pertaining to weed control methods revealed that manual and mechanical methods were eco-friendly but involved expensive labor, while the chemical approach involving the use of herbicides led to serious deterioration of agro-environmental resources. Two or more techniques used in coherence which encompassed deep tillage to burry weeds seed and prevented their germination through mulches of biotic and synthetic materials along with optimizing sowing method especially raised bed technique reduced weed seed bank and weeds density in maize. Conclusions: It is inferred that integrated approach entailing cultural, manual, mechanical and chemical control can be developed as a pro-environmental and farmer friendly approach for weed control by reducing weed seed reserves which can potentially lead to higher economic returns through higher maize yield.

ABSTRACT Soybean suffers a serious blow to forage yield and quality while in intercropping with cereal forages like sorghum. The aim of this field investigation was to optimize planting time and spatial arrangement for boosting yield, quality and profitability of intercropped soybean. Treatments included soybean sown 20 days before and after sorghum under different spatial arrangements (3-1, 1-3, 2-3, 3-2 and 3-3 row proportions). The factorial arrangement was used to employ randomized complete block design (RCBD) for experimental execution with four replicates. Soybean sown 20 days prior to sorghum in 2-3 row replacement series was effective in yielding the highest yield attributes of soybean, which led to the highest green forage yield and dry matter biomass. The same intercropping system proved to be superior in generating the highest net income and benefit-cost ratio (BCR) (4.31). Correlation analysis revealed a positive correlation between agronomic variables under study and forage yield of soybean. Better quality forage with significantly higher crude protein, ether extractable fat and ash along with the lowest crude fiber content was given by soybean planted 20 days before sorghum in 3-2 row proportion. Soybean sown 20 days after sorghum under all spatial arrangements did not perform at par with soybean sown 20 days before sorghum. Thus, in order to avoid the drastic effects of sorghum on soybean forage yield and quality in soybean-sorghum intercropping systems, deferred sowing of sorghum might be considered keeping in view the availability of irrigation water and available time with respect of next crop.