Concern about potential increases in weed populations without the use of herbicides has limited the uptake of organic farming. However, as both public demands for organic produce and the profile of organic farming have increased in recent years, so too has the range of weed control options. Progress in cultural methods of weed control has included the use of novel weed-suppressing cover crops, and the identification of specific crop traits for weed suppression. Direct weed control has also seen developments, with new implements appearing on the market that could benefit in the future from sophisticated machine guidance and weed detection technology. Advances in novel techniques such as steaming have also been made. Many weed control operations in organic systems present the grower with conflicts, and both these and many of the most recent developments in organic weed control are reviewed. An increase in our understanding of weed biology and population dynamics underpins long-term improvements in sustainable weed control. The outcome of these studies will benefit conventional and organic growers alike. Emphasis is given to the need for flexibility and a combination of weed biology knowledge, cultural methods and direct weed control to maintain weed populations at manageable levels.

Non‐chemical weed management in organic farming systems

Chenopodium quinoa - an Indian perspective

Cogongrass is considered to be one of the ten most troublesome and problematic weedy species in the world. This species is found throughout tropical and subtropical regions, generally in areas dist...

Cogongrass (Imperata cylindrica)—Biology, Ecology, and Management

This review focuses on updated information about α-galactosides, their chemical structure, biosynthesis, plant physiological functions, occurrence in foods, positive and negative physiological effe...

Alpha-Galactosides : Antinutritional Factors or Functional Ingrédients?

P.A. IJI and D.R. TIVEYDepartment of Animal Science, University of Adelaide, Waite Campus,Glen Osmond 5064, AustraliaThis review presents findings on the influence of natural raffinose seriesoligosaccharides and .synthetic (industrial) products on the productivity ofbroiler chicken. There is evidence of negative effects on animal health andproductivity from the use of raffinose series 01igosaccharides, but beneficialeffects from synthetic oligosaccharides. Part of this contradiction may be due todifferences in the chemical nature of the supplements, the level of supple-mentation or the duration of feeding. The future for synthetic oligosaccharidesis bright, but further adoption of natural sources requires a greater under-standing of their chemistry to facilitate the production of beneficial com-pounds and the elimination of detrimental fractions. Most current literaturefavours the inclusion of various oligosaccharides in the diet. The cost ofproduction could be minimised by the use of natural ingredients which containoligosaccharides, or by cheap syntlietic products, sources of which arehighlighted in this review.Keywords: Broiler chicken; growth; health; non-starch polysaccharides; oligo-saccharides; raffinose

Natural and synthetic oligosaccharides in broiler chicken diets

Comparison of chickpea cultivars: chemical composition, nutritional evaluation, and oligosaccharide content

Drought, heat stress, and unfavorable soil conditions are key abiotic factors affecting quinoa’s growth and development. The aim of this research was to examine the effect of progressive drought and N-fertilization reduction on short-cycle varieties of quinoa (c.v. Titicaca) for different sowing dates during the dry season (from October to December). A two-year experimentation (2017–2018 and 2018–2019) was carried out in Burkina Faso with four levels of irrigation (full irrigation—FI, progressive drought—PD, deficit irrigation—DI and extreme deficit irrigation—EDI) and four levels of N-fertilization (100, 50, 25, and 0 kg N ha−1). Plant phenology and development, just like crop outputs in the form of yield, biomass, and quality of the seeds were evaluated for different sowing dates having different temperature ranges and photoperiodicity. Crop water productivity (CWP) function was used for examining plant’s water use efficiency under drought stress conditions. Emerging findings have shown that CWP was highest under DI and PD (0.683 and 0.576 kg m−3, respectively), while highest yields were observed in 2017–2018 under PD and its interaction with 25 to 50 kg N ha−1 (1356 and 1110 kg ha−1, respectively). Mean temperatures close to 25 °C were suitable for optimal plant growth, while extreme temperatures at anthesis limited the production of grains. Small changes in photoperiodicity from different sowing dates were not critical for plant growth.

https://www.mdpi.com/2073-4395/9/10/607/pdf

Effect of Drought, Nitrogen Fertilization, Temperature and Photoperiodicity on Quinoa Plant Growth and Development in the Sahel

The effects of four aqueous extracts (0, 1.0, 2.0, and 3.0% w/v) of itchgrass [Rottboellia cochinchinensis (Lour.) W. Clayton] and cogongrass (Imperata brasiliensis Trin.) on rice germination and the effects of residues (0, 1.0, 2.0, and 3.0% w/w) incorporated in the growth medium on early rice plant development, were tested. Allelochemicals present in weed extracts reduced germination of rice by 11-15% at the highest concentration of extracts. A different effect of residues on total dry matter of seedlings was observed. The lowest concentration of water extracts of weeds increased epicotyl length and reduced the germination index. Only itchgrass extracts had a negative effect on rice root elongation. Growth reduction of rice induced by residues of both weeds was similar and plant height and leaf number per plant were reduced by 22 and 43%, respectively. In contrast, rice radicle length was more sensitive to the itchgrass residues than to the cogongrass residues. Residues of both weeds at the highest level caused a decrease of 50% in N concentration of rice plants. Potassium content was unaffected by cogongrass while P was decreased only by the highest level of residues. The effects were dependent on levels of residues and on weed species. The results demonstrated the allelopathic potential of itchgrass and cogongrass residues on germination and the early development of rice.

Allelopathic interference of itchgrass and cogongrass: germination and early development of rice.

The traditional cropping system widespread in the Department of Pando (Bolivian Amazon) is the slash and burn methodology. The main crops sowed soon after the slash are maize, rice, cassava and common beans. Two separate field experiments (carried out in 2008-2009) were carried out to determine the agronomic responses of maize to sowing date, plant population and row width. For the first experiment a split-plot design was used. Maize cultivar (Bayo Blando and Perla Pandino) was considered as main plots and the date of sowing as subplots. For the second experiment a split-split-plot design was used. Row spacing (0.5, 0.7 and 0.9 m) was considered as main plot, maize cultivar (Cubano Amrarillo and Perla Pandino) as subplots, and plant density (5.0, 7.5 and 10 plant m -2 ) as sub-subplots. A significant reduction of grain yield was observed as the date of sowing (DS) delayied. Yield reduction of the second DS compared to the first, was 85 and 45% for Perla Pandino and Bayo Blando. The importance of plant density as a function of the correct row spacing is clearly shown. With the row spacing in use in the considered area (0.9 m) and with the narrowest (0.5 m), the best yields were obtained with 10 plants m -2 (5.5 t ha -1 ). The following conclusions can be drawn from the present study: 1. A delay in the sowing date for maize by 15-20 days (compared to sowing ??immediately after the cutting of the virgin forest or the secondary forest) strongly reduces grain production. The cultivar Perla Pandino was the most susceptible with a reduction of 85%. Late sowing of maize ( mais de socorro ), is suitable only if intercropped with other crops in order to protect the soil from erosion. Traditionally, rice and cassava are intercropped with maize, even if common beans or a legume cover crop would be more advisable. 2. The density of maize may be increased up until 10 m -2 in order to achieve the most productive results by using row spacings of 0.5 e 0.9 m, respectively, depending on the genotypes used. For varieties, with a reduced height such as Perla Pandino, it is possible to use a more narrow row spacing, whilst for tall plants, over 2 m, such as Cubano Amarillo, a wider row spacing is recommended.

Maize production as affected by sowing date, plant density and row spacing in the Bolivian Amazon

The aim of this study was to determine the possibility of amaranth cultivation in Central Italy and to determine the optimum plant density. Field trials were carried out in 2011 and 2012 under non-irrigated conditions in Tuscany (43° 18’ N, 11° 47’ E). Twelve accessions of two amaranth species ( Amaranthus cruentus L. and A . hypochondriacus L.) were utilised. Genotypes were evaluated over a two-year period using a RCB design with three replicates. The effects of plant density were investigated in 2012. A with a split-plot design was used, where the A . cruentus accessions (AMES 5148, PI 511719 and PI 643045) constituted the main plots. Plant densities (7.5, 15, 30 and 60 plants m –2 ) constituted the subplots. Plants were transplanted at the 3-4 true leaf stage. Morphological traits were determined using 5 plants selected from the two central rows of the sampling area. Plots were hand-harvested and cleaned with a mechanical grid with appropriate sieve diameters. A . cruentus was shown to be more suitable to the Central Italy agro-ecological conditions than A . hypochondriacus . The accessions derived from Mexico (PI 477913, PI 576481, PI 643045, PI 643053, and PI 6495079), Guatemala (PI 511719) and Puerto Rico (AMES 5148), had both higher grain yields and a greater stability over the two-year period, with a mean grain production ranging from 2.8 to 3.2 t ha –1 . The severe climatic stress in 2012 (high temperatures and aridity), resulted in a 43-60% reduction in seed production compared to that of the previous year. Under these conditions, PI 511719, AMES 26015, AMES 5386, AMES 5148, PI 477913 yielded on average 1.9 t ha –1 . Yields of A . hypochondriacus were negligible in both years, probably attributable to greater photoperiod sensitivity, resulting in reduced flowering and delayed maturity. By increasing density up to 60 and 30 plants m –2 for PI 511719 and AMES 5148, respectively, grain production was increased by 55%. As the plant population increased, plant height, panicle length and diameter, basal stem diameter and branches per plant were reduced. AMES 5148 plants were composed of one single stem with apical panicles at a density of 30 plants m –2 , whilst the other two accessions were similar at the highest plant density. Branch number per plant was negatively correlated with grain production (r=–0.536**). Hence, A . cruentus may be grown in Central Italy even under arid conditions, using a density of either 30 or 60 plants m –2 according to the genotype used.

/pdf/amaranthus-cruentus-l-is-suitable-for-cultivation-in-central-2wcjkuwe6l.pdf

Paolo Casini

Papers

Comparison of chickpea cultivars: chemical composition, nutritional evaluation, and oligosaccharide content

Effect of Drought, Nitrogen Fertilization, Temperature and Photoperiodicity on Quinoa Plant Growth and Development in the Sahel

Allelopathic interference of itchgrass and cogongrass: germination and early development of rice.

Maize production as affected by sowing date, plant density and row spacing in the Bolivian Amazon

Amaranthus cruentus L. is suitable for cultivation in Central Italy: field evaluation and response to plant densities