scholarly journals Physiology of Weeds in Intraspecific Competition

2018 ◽  
Vol 10 (6) ◽  
pp. 334
Author(s):  
Caroline Hernke Thiel ◽  
Felipe Adelio de David ◽  
Leandro Galon ◽  
Sidnei Deuner ◽  
Cesar Tiago Forte ◽  
...  

When plants are subjected to competition, their physiological behavior changes. To understand the developmental physiology of weeds will subsidize the development of cropping systems which favor the crops plants in detriment of weeds. The objective of this work was to evaluate the physiological behavior of different weed species, growing under intraspecific competition. Greenhouse experiment was conducted in randomized complete block design arranged in factorial scheme 4 × 5 with four replications. Factor A was the weed species [Urochloa plantaginea (Alexandrergrass), Bidens pilosa (hairy beggarticks), Ipomoea indivisa (morningglory) and Conyza bonariensis (hairy fleabane)], and factor B was the plant density of these species (20, 40, 60, 80 or 100 plants m-2). The following variables were evaluated: sub-stomatal CO2 concentration, photosynthesis rate, consumed CO2, stomatal conductance, transpiration rate, water use efficiency, plant height, shoot diameter, leaf area, and shoot dry biomass. Alexandergrass relies on the superior control of stomatal opening and high water use efficiency. Hairy beggarticks efficiency in competition lies on its ability to remove water from soil to levels when the other surrounding plant species would undergo stress. Morning glory and hairy fleabane did not present detectable particular features in the study, and their importance as weeds is probably tied to other survival abilities but superior competition. In conclusion, the weed species studied present distinct competitive strategies.

2010 ◽  
Vol 28 (4) ◽  
pp. 699-703 ◽  
Author(s):  
I Aspiazú ◽  
T Sediyama ◽  
J.I Ribeiro Jr ◽  
A.A Silva ◽  
G Concenco ◽  
...  

The objective of this work was to evaluate characteristics associated with the photosynthetic activity of cassava plants in competition with weeds or not. The trial was performed on open environment conditions, with experimental units consisting of fiber glass vases with 150 dm³ filled with Red Yellow Latosol, previously fertilized. Treatments consisted in the cultivation of cassava plants isolated and associated to three weed species (Bidens pilosa, Commelina benghalensis and Brachiaria plantaginea). After cassava shooting, 15 days after planting, a removal of the weeds excess was performed, sown at the time of cassava planting, leaving six plants m-2 of B. pilosa and four plants m-2 of C. benghalensis and B. plantaginea. At 60 days after emergence (DAE), stomatal conductance (Gs), vapor pressure in the substomatal cavity (Ean), temperature gradient between leaf and air (ΔT), transpiration rate (E) and water use efficiency (WUE) were evaluated. B. pilosa showed greater capacity to affect growth of cassava plants. B. plantaginea is very efficient in using water, especially by presenting C4 metabolism, and remains competitive with cassava even under temporarily low water status. C. benghalensis, in turn, is not a good competitor for light and apparently is not the primary cause of water depletion in the soil. The effects of weeds, in this case, were more associated with the competition. However, they were found between moderate to low. This implies that the competition established at experimental level was low.


Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 313
Author(s):  
Guoqiang Zhang ◽  
Bo Ming ◽  
Dongping Shen ◽  
Ruizhi Xie ◽  
Peng Hou ◽  
...  

Achieving optimal balance between maize yield and water use efficiency is an important challenge for irrigation maize production in arid areas. In this study, we conducted an experiment in Xinjiang China in 2016 and 2017 to quantify the response of maize yield and water use to plant density and irrigation schedules. The treatments included four irrigation levels: 360 (W1), 480 (W2), 600 (W3), and 720 mm (W4), and five plant densities: 7.5 (D1), 9.0 (D2), 10.5 (D3), 12.0 (D4), and 13.5 plants m−2 (D5). The results showed that increasing the plant density and the irrigation level could both significantly increase the leaf area index (LAI). However, LAI expansion significantly increased evapotranspiration (ETa) under irrigation. The combination of irrigation level 600 mm (W3) and plant density 12.0 plants m−2 (D4) produced the highest maize yield (21.0–21.2 t ha−1), ETa (784.1–797.8 mm), and water use efficiency (WUE) (2.64–2.70 kg m−3), with an LAI of 8.5–8.7 at the silking stage. The relationship between LAI and grain yield and evapotranspiration were quantified, and, based on this, the relationship between water use and maize productivity was analyzed. Moreover, the optimal LAI was established to determine the reasonable irrigation level and coordinate the relationship between the increase in grain yield and the decrease in water use efficiency.


2016 ◽  
Vol 46 (7) ◽  
pp. 1145-1150 ◽  
Author(s):  
Daniel Fonseca de Carvalho ◽  
Dionizio Honório de Oliveira Neto ◽  
Luiz Fernando Felix ◽  
José Guilherme Marinho Guerra ◽  
Conan Ayade Salvador

ABSTRACT: The aim of the present study was to evaluate the effect of different irrigation depths on the yield, water use efficiency (WUE), and yield response factor (Ky) of carrot (cv. 'Brasília') in the edaphoclimatic conditions of Baixada Fluminense, RJ, Brazil. Field trials were conducted in a Red-Yellow Argisol in the 2010-2011period. A randomized block design was used, with 5 treatments (depths) and 4 replicates. Depths were applied by drippers with different flow rates, and the irrigation was managed by time domain reflectometry (TDR) technique. The reference (ETo) and crop (ETc) evapotranspiration depths reached 286.3 and 264.1mm in 2010, and 336.0 and 329.9mm in 2011, respectively. The root yield varied from 30.4 to 68.9t ha-1 as a response to treatments without irrigation and 100% replacement of the soil water depth, respectively. Values for WUE in the carrot crop varied from 15 to 31kg m-3 and the mean Ky value was 0.82. The mean values for Kc were obtained in the initial (0.76), intermediate (1.02), and final (0.96) stages. Carrot crop was influenced by different water depths (treatments) applied, and the highest value for WUE was obtained for 63.4% of soil water replacement.


Irriga ◽  
2015 ◽  
Vol 20 (3) ◽  
pp. 528-543 ◽  
Author(s):  
Marcelo Rossi Vicente ◽  
Everardo Chartuni Mantovani ◽  
ANDRÉ LUÍS TEIXEIRA FERNANDES ◽  
FÁBIO TEIXEIRA DELAZARI ◽  
EDMILSON MARQUES FIGUEREDO

EFEITO DE DIFERENTES LÂMINAS DE IRRIGAÇÃO NAS VARIÁVEIS DE DESENVOLVIMENTO E PRODUÇÃO DO CAFEEIRO IRRIGADO POR PIVÔ CENTRAL  MARCELO ROSSI VICENTE1; EVERARDO CHARTUNI MANTOVANI2; ANDRÉ LUÍS TEIXEIRA FERNANDES3; FÁBIO TEIXEIRA DELAZARI4 E EDMILSON MARQUES FIGUEREDO5 1 Instituto Federal do Norte de Minas Gerais, Salinas, MG, [email protected] Departamento de Engenharia Agrícola, Universidade Federal de Viçosa, Viçosa, MG, [email protected] Universidade de Uberaba, Uberaba, MG, Fábio Teixeira Delazari, [email protected] Departamento de Fitotecnia, Universidade Federal de Viçosa, Viçosa, MG, [email protected] Bahia Farm Show, Luís Eduardo Magalhães, BA, [email protected]  1      RESUMO O presente trabalho foi conduzido com objetivo de avaliar o efeito de diferentes lâminas de irrigação nas variáveis de produção, estádios maturação de frutos e eficiência no uso da água pela cultura do cafeeiro irrigado por pivô central equipado com emissores LEPA, na região Oeste da Bahia. Realizou-se o trabalho na fazenda Café do Rio Branco, localizada em Barreiras - BA em cafeeiros adultos da variedade Catuaí IAC 144. O experimento obedeceu ao delineamento de blocos casualizados, composto de cinco tratamentos correspondentes à 70, 85, 100, 125 e 150% da lâmina de irrigação determinada pelo software Irriplus. As produtividades, os estádios de maturação dos frutos e eficiência no uso da água do cafeeiro foram submetidos à análise de variância e regressão, em que os modelos foram escolhidos baseados na significância dos coeficientes de regressão utilizando-se o teste t de 1 a 10% de probabilidade. Diante dos resultados obtidos, pode-se concluir que, a produtividade da cultura do café foi expressivamente dependente da lâmina de água aplicada, sendo que a maior produtividade (60 sc ha-1) foi alcançada com a lâmina de irrigação acumulada de 661 mm ano-1, correspondente à 96% da lâmina de irrigação determinada pelo software Irriplus. A lâmina que proporcionou a máxima porcentagem de frutos cereja (44,1%) foi de 723 mm ano-1 (105%). A lâmina que proporcionou a maior eficiência no uso da água foi de 480 mm ano-1 (70%). Palavras-Chave: Coffea arabica, manejo da irrigação, emissor LEPA, uso eficiente da água.  VICENTE, M. R.; MANTOVANI, E. M.; FERNANDES, A. L. T.; DELAZARI, F. T.; FIGUEREDO, E. M.EFFECTS OF DIFFERENT LEVELS OF IRRIGATION DEPTHS   ON GROWTH AND PRODUCTION VARIABLES OF COFFEE UNDER CENTER PIVOT  IRRIGATION     2        ABSTRACT This study aimed to evaluate the effect of different irrigation depths on yield, ripening stages and water use efficiency by the   coffee crop irrigated by center pivot with LEPA emitters in western Bahia. The experiment was carried out at the Café Rio Branco farm, in Barreiras city, Bahia state, using  adult coffee trees of cv. Catuaí IAC 144. A completely randomized block design was used with five treatments consisting of 70, 85, 100, 125 and 150 % of ETc, determined by the Irriplus software.  Data of yield, fruit ripening stage and water use efficiency were evaluated   using analyses of variance  and regression. Models were chosen based on level of significance of   regression coefficients using the Student´s t-test, 1 to  10% probability.  Based on the results,  coffee crop yield was highly dependent on  the water depth applied. The highest yield (3.6 ton/ha) was achieved  using accumulated irrigation depth of 661 mm year -1 (96 % of Etc).  Water depths of   723 mm year-1 (105 %) and 480 mm year-1 (70% ETc)  provided the highest percentage of cherry fruit (44.1%) and the highest water use efficiency, respectively. Keywords: Coffea arábica, irrigation management, LEPA emitter, water use efficiency.


2020 ◽  
Author(s):  
Jay Jabro ◽  
Bart Stevens ◽  
bill Iversen ◽  
brett Allen ◽  
Upendra Sainju

<p>Better management practices have been used to increase soil water storage and reduce evaporation from the soil surface to optimize crop water use efficiency (WUE) in irrigated agriculture. A field study was conducted to evaluate the effect of  conventional tillage (CT), No-till (NT) and strip tillage (ST) practices on yield, water use (WU) and WUE of sugarbeet (Beta vulgaris L.) on a clay loam soil under over-head sprinkler irrigation system in the northern Great Plains. Tillage treatments were replicated five times in a randomized block design. Seasonal WU and WUE for sugarbeet root and sucrose yield were determined for the 2018 and 2019 growing seasons according to the water balance and WUE equations under three tillage practices. Results showed that no significant differences due to tillage treatment were found for crop WU, root yield, sucrose yield, and WUE for sugarbeet root and sucrose in 2018 and 2019 growing seasons. In 2019, the average value of WU across three tillage systems (616 mm) was significantly greater relative to 2018 (468 mm) due to atypical large rainfalls (218mm) occurred in September of 2019. Consequently, WUE values for both root and sucrose yield in 2019 under CT, NT, and ST were significantly greater than those in 2018. While NT and ST practices are promising alternative to CT for agricultural production in this region, further research is needed prior to making any recommendation.</p>


This study was carried out during the 2015 and 2016 dry cropping seasons at the Teaching and Research Farm of the University of Agriculture, Makurdi, Southern Guinea Savanna Agroecology of Nigeria. The objectives were to determine the consumptive use and water use efficiency of okra using the Lysimetric technique. This involved the use of twelve (12) locally fabricated minilysimeters housing three (3) irrigation treatments corresponding to 50, 75 and 100% of the soil available water capacity replicated four (4) times and laid out in a Randomized Complete Block Design (RCBD). The Blaney-Criddle formula which is latitude dependent derives its strength from a 5-year accumulated temperature, data was used to predict the potential evapotranspiration of okra. The crop evapotranspiration is equivalent to the crop water use. Results show that the consumptive use estimated varied from 263.52 – 1,944.90 mm, water use efficiency was from 22.73 – 2.28 kg/ha/mm and crop coefficients of 0.36 – 2.28 corresponding to 50 – 100% (Low to High) soil available water capacity (SAWC) respectively. Okra performed better under low soil available water capacity.


2022 ◽  
Vol 2022 ◽  
pp. 1-7
Author(s):  
Kamran Baksh Soomro ◽  
M. M. Shaikh ◽  
Sanyogita Andriyas ◽  
Muhammad Rizwan Shahid

Water shortage is a real problem in many parts of the world and finding alternative solutions such as the application of saline water in cropping systems is highly appreciated. Research on drip irrigation and soil salinity is still inadequate, and their effect on crop yield and water use efficiency (WUE) is a huge challenge for small farmers. The present study was conducted in Malir, a semiarid region in the Sindh province of Pakistan. The purpose was to estimate the effects of two different qualities of irrigation water including fresh quality water (IT1 0.56 dS m−1) and saline groundwater (IT2 2.89 dS m−1) on WUE using drip irrigation technology in 2018–19. The experimental design was complete randomized block design (RCBD) with two treatments of irrigation: (1) freshwater (IT1) with 0.56 dS m−1 electrical conductivity and (2) saline water (IT2) with 2.89 dS m−1 electrical conductivity. The average biomass and crop yield under IT1 were 10.2 t.ha−1 and 7.4 t.ha−1, respectively, and were found higher than those under IT2 (7.3 t−1 and 4.2 t.ha−1, respectively). Hence, both the treatments remained equally effective in season 1 as compared to season 2 ( p ≤ 0.05 ). The WUE of bitter melon under IT1 was 1.60 and 1.56 kg.m−3 in seasons 1 and 2, respectively, and was higher than those under IT2 which were observed 1.21 and 1.07 kg.m−3 in seasons 1 and 2, respectively.


Irriga ◽  
2018 ◽  
Vol 23 (3) ◽  
pp. 454-466
Author(s):  
Leonardo Chechi ◽  
Luan Junior Kuhn ◽  
Vanderléia Fortuna ◽  
Patricia Mara De Almeida ◽  
Maurício Albertoni Scariot ◽  
...  

As the water stress is one of the main causes for the low maize yield in Brazil, this study aimed to evaluate the yield components, grain yield and the water use efficiency of maize crop submitted to different methods of irrigation depth adjustment and validate the “Lâmina” spreadsheet to recommend irrigation depth in this crop. The treatments applied were: non-use of irrigation (control); irrigation depth adjustment provided by” Lâmina” spreadsheet (Lâmina); soil moisture equivalent to actual capacity of water in the soil at 55% of the total soil water capacity (55% RWC); and soil moisture equivalent to 100% of the field capacity (100% FC). The experimental design was a randomized block design with four replications, each experimental unit consists of a plot 3 meters wide and 3 meters long. The variables analyzed were total water applied, dry matter, ears per plant, kernel rows per ear, kernels per row, kernels per ear, one thousand kernels weight, grain yield and water use efficiency. Grain yields were similar between irrigated treatments, showing significant differences compared to the control. The Lâmina and 55% RWC showed the best results for water use efficiency and yield components. The Lâmina treatment used the least amount of water, with high yields, contributing to the rational water use in irrigated agricultural systems.


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