The agronomic value of annual plant diversity in crop-weed systems

2006 ◽  
Vol 86 (3) ◽  
pp. 865-874 ◽  
Author(s):  
Anthony R. Szumigalski ◽  
Rene C. Van Acker

Enhanced crop or cultivar diversity within annual cropping systems could provide important ecological and agronomic benefits. The agronomic effects of annual plant diversity from mixtures of crop species and barley (Hordeum vulgare L.) cultivar types were compared using richness levels of 1, 2, 5 or 10 randomly selected taxa in a greenhouse experiment. Increasing crop richness increased overall crop dry matter production, production stability (i.e., decreased CV for dry matter production) and weed suppression. These agronomic variables tended to level off after a richness of five to six crop species, suggesting that further increases in crop diversity are redundant. Increasing barley cultivar richness increased crop production in one of two experimental runs, but no effects were observed for weed suppression. Increased light interception related to greater plant canopy height variation in diverse mixtures of species could have contributed to increased productivity in the crop richness experiment. The results of this study suggest that the ecological functions of diversity provide productivity, yield stability and weed suppression benefits for mixtures of crop species, and even perhaps for mixtures of cultivars within a given crop species. Key words: Diversity (crop), suppression (weed), stability (yield), intercropping, cultivars (barley), oat (wild)

1996 ◽  
Vol 5 (3) ◽  
pp. 299-310 ◽  
Author(s):  
Jouko Kleemola ◽  
Tuomo Karvonen

According to current scenarios, atmospheric CO2 -concentration ([CO2]) and average air temperature will rise in the future. The predicted longer growing season in Finland would imply that more productive cultivars and even new crop species could be grown. Moreover, higher [CO2] is also likely to increase dry matter production of crops. This study analyzed the growth of spring barley (Hordeum vulgare L.) under ambient and suggested future conditions, and its response to N fertilization. Model simulations of soil temperature and of snow accumulation and melting were also studied. The calibration and validation results showed that the model performed well in simulating snow dynamics, soil temperature, the growth of barley, and the response of crop growth to N fertilization under present conditions. According to the simulation runs, if a cultivar was adapted to the length of the growing period, the increase in dry matter production was 23% in a low estimate scenario of climate change, and 56% in a high estimate scenario under a high level of nitrogen fertilization. The simulation study showed that the shoot dry weight increased by 43%, on average, under high N fertilization (150-200 kg N/ha), but by less (20%) under a low level of N (25-50 kg N/ha) when the conditions under a central scenario for the year 2050 were compared with the present ones.


2014 ◽  
Vol 11 (1) ◽  
pp. 7-22 ◽  
Author(s):  
S Marimuthu ◽  
P Subbian

Field experiments were conducted at the farm of Tamil Nadu Agricultural University, Coimbatore, India during 2007 and 2008 to assess the weed population, dry matter production, weed smothering efficiency and yield of seed cotton in a cotton based cropping system with conjunctive use of NPK and bioinoculants. Cotton intercropped with Sesbania along with application of Azospirillum and Pseudomonas recorded the lowest weed population and weed dry matter production. The maximum weed suppression of 54.5 and 44% was observed in cotton + Sesbania system as compared to pure crop of cotton during both the years. The maximum cotton equivalent yield of 2052 and 1895 kg ha-1 was recorded in cotton + onion system which was at par with cotton + Sesbania system with cotton equivalent yield of 2010 and 1894 kg ha-1 during 2007 and 2008, respectively. Combined application of 100 % recommended dose of NPK and bioinoculants recorded maximum cotton equivalent yield of 2460 and 2190 kg ha-1 during 2007 and 2008, respectively. DOI: http://dx.doi.org/10.3329/sja.v11i1.18371 SAARC J. Agri., 11(1): 7-22 (2013)


2019 ◽  
Vol 11 (5) ◽  
pp. 152 ◽  
Author(s):  
Daiane Conceição de Sousa ◽  
João Carlos Medeiros ◽  
Julian Junio de Jesus Lacerda ◽  
Jaqueline Dalla Rosa ◽  
Cácio Luiz Boechat ◽  
...  

The use of cover crops is an important strategy for soil management in the Brazilian Cerrado to improve no-tillage (NT) systems. For this, it is necessary know the potential of cover crop species for biomass production, nutrient cycling, and persistence of residues on the soil surface in soils and climatic conditions of this biome. Thus, the experiment was developed to evaluate the agronomic potential of cover crops cultivated on an Oxisol (Latossolo Amarelo) in the Cerrado of Piauí, Brazil. The experiment was conducted from January 2015 to July 2016. The experimental design was in randomized blocks with 11 treatments and four replicates. The treatments consisted of single and intercropped cover species. The evaluations were: dry mass production, nutritional composition of the plants, nutrient accumulation by dry mass produced and decomposition rate of the dry mass produced for each treatment. The higher dry matter production was obtained with Crotalaria juncea, Cajanus cajan (cv. IAC-Fava larga), Pennisetum glaucum and Brachiaria ruziziensis. The lower dry matter production was obtained with Mucuna aterrima, and mix of Crotalaria spectabilis + Pennisetum glaucum. The higher nutrients accumulation in the plants occurred for Cajanus cajan (cv. IAC-Fava larga), Crotalaria juncea and Crotalaria spectabilis. The cover plants studied presented good potential for soil conservation, due to the permanence of residues on the surface, except for Mucuna aterrima and Crotalaria spectabilis.


1997 ◽  
Vol 37 (3) ◽  
pp. 359 ◽  
Author(s):  
R. D. Armstrong ◽  
K. Walsh ◽  
K. J. McCosker ◽  
G. R. Millar ◽  
M. E. Probert ◽  
...  

Summary. The growth and ability of 12 summer-growing annual and perennial legumes to fix nitrogen and the response of a subsequent wheat crop was examined in a field trial on a deep cracking clay soil in the Central Highlands of Queensland. Twelve legumes [Lablab purpureus cv. Highworth, Vigna radiata cv. Satin, Macroptilium atropurpureum cv. Siratro, Medicago sativa cv. Trifecta, Vigna trilobata (CPI 13671), Macroptilium bracteatum (CPI 27404), Glycine latifolia (CQ 3368), Desmanthus virgatus cv. Marc, Desmanthus virgatus cv. Bayamo, Stylosanthes sp. aff scabra (104710), Clitoria ternatea cv. Milgarra, Cajanus cajan cv. Quest)] and grain sorghum (Sorghum bicolor cv. Tulloch) as a non-legume control were established in November 1994 and their growth monitored until March 1995. The legumes averaged greater than 5 t/ha dry matter production and 77 kg N/ha (above-ground only). Dry matter production ranged from less than 2 t/ha for G. latifolia and M. sativa to greater than 9 t/ha for D. virgatus cv. Bayamo and C. cajan. Annual legumes initially had much higher relative growth rates than the perennial legumes but they rapidily exhausted all the plant available water content of the soil thus allowing the well-established perennials to eventually match this production. The proportion of plant nitrogen (above ground) derived from N2 fixation was generally low, reflecting high soil NO3, but varied widely between species ranging from less than 20% for D. virgatus cv. Marc and G. latifolia to over 45% for C. ternatea, S. scabra and V. trilobata. The quantity of nitrogen derived from fixation was correlated with above-ground dry matter and nitrogen content. There was a significant (P<0.05) growth response by wheat following legumes compared with that following sorghum in the increasing order V. radiata = M. atropurpureum = L. purpureus > C. cajan = M. sativa = V. trilobata = M. bracteatum = G. latifolia > S. scabra = D. virgatus = C. ternatea. Previous legume growth had no significant (P>0.05) effect on yield or nitrogen concentration in a second ‘plant-back’ crop (sorghum). It was concluded that a wide range of pasture-ley legumes have the potential to improve cereal crop production in this region.


2020 ◽  
Vol 10 (7) ◽  
pp. 708
Author(s):  
Loubna Azariz ◽  
Mohamed Fekhaoui ◽  
Souad Elblidi ◽  
Ahmed Yahyaoui

the increasing number of cases of soil contamination by trace elements have affected crop production, and represents a risk threatening the quality of our food products. Some of these contaminants, such as trivalent chromium Cr (NO<sub>3</sub>)<sub>3,</sub> which is similar to micronutrients, can, therefore, be absorbed by plants and whose phytotoxicity has long been considered negligible, and largely underestimated. The purpose of this work was to study the transfer of trivalent chromium from nutrient solution to green beans <em>Phaseolus vulgaris L</em> grown on bioponics; the contamination responses were determined in terms of growth parameters, yield, and dry matter production; at various concentrations (5, 10 and 20 ppm). Chromium trivalent effects have also been studied in tissues plant. Results showed that the absorption of trivalent chromium from the nutrient solution and its translocation to the aerial tissues plants had no adverse effects on growth parameters, and also on beans yield. Results also showed that chromium accumulates in roots rather than in the other tissues, and did not reduce the dry matter production, in terms of translocation and bioconcentration. The transfer factor is low and green beans cannot be defined as a hyperaccumulator of chromium.


Weed Science ◽  
1979 ◽  
Vol 27 (5) ◽  
pp. 549-553 ◽  
Author(s):  
David T. Patterson

The effects of shade on the growth and photosynthetic capacity of the exotic noxious weed itchgrass (Rottboellia exaltataL. f.) were determined under controlled environment conditions. The plants were grown at day/night temperatures of 29/23 C under 100, 60, 25, and 2% sunlight in a climate-controlled greenhouse. Mathematical growth analysis techniques were used to evaluate the effects of shading on dry matter production and leaf area production. Infrared gas analysis and diffusion porometry techniques were used to evaluate the effects of shading on photosynthesis and stomatal resistance. Shading markedly reduced dry matter production. At 40 days after planting, plants grown in 2, 25, and 60% sunlight had 0.3, 16, and 55%, respectively, of the dry weight of the plants grown at 100% sunlight. Leaf area production was less severely retarded by shading; the plants grown at 2, 25, and 60% sunlight had, respectively, 1.7, 42, and 99% of the leaf area of the plants grown at 100% sunlight. Ambient photosynthetic rates of recently expanded, single, fully exposed leaves were 22.5, 51.6, and 65.5 mg CO2dm-2h-1in the 25, 60, and 100% sunlight treatments, respectively. Photosynthetic rates at saturating irradiance did not differ significantly in plants grown at 25, 60, or 100% sunlight and ranged from 76.4 to 78.0 mg CO2dm-2h-1. Stomatal resistances, ranging from 6.0 to 7.5 s cm-1, also did not differ significantly among these plants. In terms of dry matter production, itchgrass is a shade-intolerant plant. However, even when grown in shade, itchgrass maintains the capacity for high photosynthetic rates and high growth rates when subsequently exposed to high irradiance. These characteristics help explain its competitiveness with crop species.


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