Yield photosynthesis and leaf anatomy of maize in inter- and mono-cropping systems at varying plant densities

Allelochemicals representing numerous chemical groups have been isolated from over 30 families of terrestrial and aquatic plants. Some of the compounds also have been isolated from soil in quantities sufficient to reduce plant growth. Although selected allelochemicals are believed to influence plant densities and distributions, none isolated from higher plants have been considered active enough for development as commercial herbicidal products. Almost all herbicidal allelochemicals exist in plants in nontoxic, conjugated forms. The toxic moiety may be released upon exposure to stress or upon death of the tissue. The most successful use of allelochemicals in weed control has been management of selectively toxic plant residues. For example, rye residues have controlled weeds effectively in a variety of cropping systems. Several weed species may interfere with crop growth through chemicals released from their residues. A number of noxious perennial species appear to exploit allelochemicals in their interference processes. This review focuses on the more recent chemical discoveries and how they might be exploited for weed control.

Download Full-text

Review: Winged bean (Psophocarpus tetragonolobus) cropping systems

Biodiversitas Journal of Biological Diversity ◽

10.13057/biodiv/d211258 ◽

2020 ◽

Vol 21 (12) ◽

Author(s):

Graham Eagleton

Keyword(s):

Crop Production ◽

Cropping Systems ◽

New Guinea ◽

Winged Bean ◽

Gene Pools ◽

Psophocarpus Tetragonolobus ◽

Forage Crops ◽

Growing Period ◽

Plant Densities ◽

Tuber Crop

Abstract. Eagleton GE. 2020. Review: Winged bean (Psophocarpus tetragonolobus) cropping systems. Biodiversitas 21: 5927-5946. Winged bean (Psophocarpus tetragonolobus (L.) DC.) is a rambling, nitrogen-rich, leguminous crop of the Old-World tropics. This review of winged bean (WB) within cropping systems of Southeast Asia and Melanesia revisited four traditional roles that the crop has played: as a minor courtyard vegetable of villages and suburbs throughout the region; as a popular tuber crop in the irrigated plains of Tada-U township in Central Myanmar; as a companion crop in the mixed garden fields of Wamena in Indonesian New Guinea; and as a niche tuber crop in rotation with sweet potato near Goroka in Papua New Guinea (PNG). Drawing upon such traditions, researchers since the 1970s have identified potential new roles for winged bean. In Malaysia, vegetable pod yields up to 35 t ha-1 over a 25-week growing period have been obtained from solidly trellised, branching cultivars. Ratooning the crop through a further two cycles covers the cost of the trellising. Tubers from un-trellised field crops in Myanmar, and of staked, pruned garden crops in highland PNG have been estimated to produce crude protein yields of at least 300 kg ha-1 and 600 kg ha-1, respectively. Synergies between the gene-pools and cultural traditions would be expected to expand the range, raise the yield and stabilize the quality of tuber crop production. Researchers in Sri Lanka intercropped maize with winged bean. At optimal plant densities, they recorded a corn cob yield of 5 t ha-1 together with a cumulative winged bean fresh pod yield of 27 t ha-1. In Kentucky (380N), the combination of maize with winged bean to produce silage resulted in 11-18% greater biomass with 39-67% greater nitrogen per hectare than maize monocrop control plots. Branching winged bean cultivars have significant potential for benign, high-nitrogen cover and forage crops. Promiscuous nodulation and the development of storage root-systems compensate for slow initial top growth which then accelerates to produce a substantial yield of highly digestible leaf protein and vitamins. Hard-seededness and daylength-sensitive phenology are significant, surmountable, barriers to an expanded role for winged beans.

Download Full-text

Optimizing plant density of promising Rice genotypes in northwest Bangladesh

Bangladesh Rice Journal ◽

10.3329/brj.v18i1-2.22993 ◽

2015 ◽

Vol 18 (1-2) ◽

pp. 1-7

Author(s):

B Karmakar ◽

MA R Sarkar ◽

MA Ali ◽

SM Haefele

Keyword(s):

Grain Yield ◽

Plant Density ◽

Cropping Systems ◽

Planting Density ◽

Growth Duration ◽

Grain Yields ◽

Plant Densities ◽

Biological Yield ◽

Rice Genotypes ◽

Rice Cropping Systems

A study was conducted at the Bangladesh Rice Research Institute, regional station farm, Rajshahi, Bangladesh, during 2010 and 2011 wet seasons to determine the effect of plant density on the performance of different genotypes. Three plant densities (20- × 15-, 20- × 20- and 25- × 15-cm spacing) and six genotypes (BRRI dhan56, BRRI dhan57, IR83377-B-B-93-3, IRRI 123, IR83381-B-B-6-1 and Binadhan-7) were tested in a strip-plot design with three replications, placing planting densities in the vertical plots and genotypes in the horizontal plots. Planting density × genotype produced significant effect on grain yield in 2011 but not in 2010. BRRI dhan56, BRRI dhan57 and IR83381-B-B-6-1 produced the highest grain yield in 20- × 15-cm spacing, while the other genotypes (IR83377-B-B-93-3, IRRI 123 and Binadhan-7) produced the higher yields in 25- × 15- or 20- × 20-cm spacing. In both years, genotypes had significant effects on grain yield, all yield components, growth duration, plant height, tillers hill-1 and tillers m-2, but not on straw and biological yield. Among the genotypes, IR83377-B-B-93-3 gave the highest mean grain yield (5.11 t ha-1) followed by IRRI 123 (4.97 t ha-1). The lowest mean yield (4.04 t ha-1) was found in BRRI dhan57 followed by IR83381-B-B-6-1 (4.14 t ha-1). Planting density had significant effects on grain yield, panicles hill-1, panicles m-2, tillers hill-1 and tillers m-2, and closer spacing reduced the number of days to flowering and maturity. Short duration rice genotypes achieved higher grain yields in closer spacing while longer duration genotypes produced higher grain yields in wider spacing. Results of this investigation suggest that the optimal plant density is dependent on varietal characteristics, and that current fixed planting densities used in many rice cropping systems are probably not adequate.Bangladesh Rice j. 2014, 18(1&2): 1-7

Download Full-text

Water use of pulse crops at various plant densities under fallow and stubble conditions in a semiarid environment

Canadian Journal of Plant Science ◽

10.4141/p06-117 ◽

2007 ◽

Vol 87 (4) ◽

pp. 719-722 ◽

Cited By ~ 5

Author(s):

Y. T. Gan ◽

J. Wang ◽

D. J. Bing ◽

P. R. Miller ◽

C. L. McDonald

Keyword(s):

Pisum Sativum ◽

Water Use Efficiency ◽

Cicer Arietinum ◽

Water Use ◽

Cropping Systems ◽

Rooting Depth ◽

Residual Soil ◽

Semiarid Environment ◽

Plant Densities ◽

Use Efficiency

Understanding water use characteristics of crops is essential for optimizing crop productivity in semiarid environments. This study determined water use (WU), water use efficiency (WUE), and postharvest residual soil water (PHRSW) of dry pea (Pisum sativum L.) and desi and kabuli chickpea (Cicer arietinum L.) at four plant densities under fallow and stubble cropping systems in a semiarid environment. Crops were grown in southwest Saskatchewan from 1998 to 2000. Chickpea used 28% more water than dry pea, while kabuli chickpea used 14% more water than desi chickpea only when grown on fallow at one of the sites. Pulses grown on fallow used 66% more water than when grown on stubble, with largest difference (48%) in WU between the two cropping systems being in the 60- to 90-cm soil depths. Overall, dry pea had the greatest WUE (12.9 kg ha-1 mm-1), followed by desi chickpea (7.3 kg ha-1 mm-1) and kabuli chickpea (6.6 kg ha-1 mm-1). Water use efficiency increased with increasing plant density for all the pulses, with dry pea showing a stronger response than chickpea. The PHRSW below the 60-cm depth differed significantly among pulses. Dry pea left an average of 33 mm available water at harvest, the desi left 20 mm, and the kabuli 13 mm. A deeper rooting crop grown after dry pea may benefit more from water conservation in the soil profile than when grown after chickpea under semiarid environmental conditions. Key words: Cicer arietinum, Pisum sativum, water use efficiency, rooting depth

Download Full-text