scholarly journals Weeds Cause Losses in Field Crops through Allelopathy

2016 ◽  
Vol 8 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Ali ZOHAIB ◽  
Tasawer ABBAS ◽  
Tahira TABASSUM
Keyword(s):  
Cropping Systems ◽  
Substantial Reduction ◽  
Growth Yield ◽  
Crop Plants ◽  
Economic Losses ◽  
Plant Residues ◽  
Potential Threat ◽  
Physiological Processes ◽  
Germination And Growth ◽  
Decomposition Of Plant Residues

A large number of weeds are known to be associated with crops and causing economic losses. Weeds interfere with crops through competition and allelopathy. They produce secondary metabolites known as allelochemicals, which belong to numerous chemical classes such as phenolics, alkaloids, fatty acids, indoles, terpens etc. However, phenolics are the predominant class of allelochemicals. The allelochemicals release from weed plants takes place through leaf leachates, decomposition of plant residues, volatilization and root exudates. Weeds leave huge quantities of their residues in field and affect the associated, as well as succeeding crops, in various cropping systems. Liberation of allelochemicals from weeds affects the germination, stand establishment, growth, yield and physiology of crop plants. They cause substantial reduction in germination and growth of the crop plants by altering various physiological processes such as enzyme activity, protein synthesis, photosynthesis, respiration, cell division and enlargement, which ultimately leads to a significant reduction in crop yield. In crux, allelopathic weeds represent a potential threat for crop plants and cause economic losses.

scholarly journals Is Agriculture Always a GHG Emitter? A Combination of Eddy Covariance and Life Cycle Assessment Approaches to Calculate C Intake and Uptake in a Kiwifruit Orchard

2021 ◽  
Vol 13 (12) ◽  
pp. 6906
Author(s):  
Federica Rossi ◽  
Camilla Chieco ◽  
Nicola Di Virgilio ◽  
Teodoro Georgiadis ◽  
Marianna Nardino
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Greenhouse Gases ◽  
Eddy Covariance ◽  
Large Scale ◽  
Cropping Systems ◽  
Substantial Reduction ◽  
Co2 Absorption ◽  
Positive Contribution ◽  
Efficiency Ratio

While a substantial reduction of GHG (greenhouse gases) is urged, large-scale mitigation implies a detailed and holistic knowledge on the role of specific cropping systems, including the effect of management choices and local factors on the final balance between emissions and removals, this last typical of cropping systems. Here, a conventionally managed irrigated kiwifruit orchard has been studied to assess its greenhouse gases emissions and removals to determine its potential action as a C sink or, alternately, as a C source. The paper integrates two independent approaches. Biological CO2 fluxes have been monitored during 2012 using the micrometeorological Eddy covariance technique, while life cycle assessment quantified emissions derived from the energy and material used. In a climatic-standard year, total GHG emitted as consequence of the management were 4.25 t CO2-eq−1 ha−1 yr−1 while the net uptake measured during the active vegetation phase was as high as 4.9 t CO2 ha−1 yr−1. This led to a positive contribution of the crop to CO2 absorption, with a 1.15 efficiency ratio (sink-source factor defined as t CO2 stored/t CO2 emitted). The mitigating activity, however, completely reversed under extremely unfavorable climatic conditions, such as those recorded in 2003, when the efficiency ratio became 0.91, demonstrating that the occurrence of hotter and drier conditions are able to compromise the capability of Actinidia to offset the GHG emissions, also under appropriate irrigation.

INHIBITION OF RESPIRATION, GERMINATION, AND GROWTH BY SUBSTANCES ARISING DURING THE DECOMPOSITION OF CERTAIN PLANT RESIDUES IN THE SOIL

1958 ◽  
Vol 36 (5) ◽  
pp. 621-647 ◽  
Author(s):  
Z. A. Patrick ◽  
L. W. Koch
Keyword(s):  
Plant Residues ◽  
Toxic Substances ◽  
Root Cells ◽  
Toxic Activity ◽  
Root Rots ◽  
High Soil Moisture ◽  
Heat Stable ◽  
Tobacco Seedlings ◽  
Ph Range ◽  
Germination And Growth

Substances capable of markedly inhibiting the respiration, germination, and growth of tobacco seedlings were obtained after residues from timothy, corn, rye, or tobacco plants had been allowed to decompose under appropriate conditions in the soil. Bio-assay tests, based on manometric methods, made it possible to determine some of the conditions under which the decomposition gave rise to phytotoxic by-products and to obtain rapidly an accurate measure of the degree of their toxicity. Among the factors influencing the production of the toxic products, the species and stage of maturity of plant material added, the water content and pH of the soil, and length of decomposition period seemed most important. Substances capable of reducing the respiration of tobacco seedlings by 50 to 90% were consistently obtained when any of the abovementioned plant residues had been decomposing for 15 to 25 days under conditions of high soil moisture and when the pH of the soil solution was below 5.5 throughout this period. Timothy gave rise to substances possessing the highest toxic activity, followed by corn, then rye, and finally tobacco. Aqueous extracts of unamended soil or of macerated plant tissues prepared either before decomposition had taken place or when decomposition was inhibited by autoclaving the soil were not toxic.The toxic substances, obtained by water extraction, exhibited an inhibiting effect on respiration of tobacco seedlings after an exposure of less than one hour and also induced darkening and necrosis of root cells. Some extracts affected the cells of the apical meristem most severely while others affected only the cells of the elongation region.While the toxic substances have not been identified, they were relatively nonspecific in their action, affecting tobacco, timothy, and barley in approximately the same manner and in many instances possessed also antifungal activity. They were soluble in water, insoluble in petroleum ether, stable in acid, and most active in the pH range 4.5 to 5.8. They were precipitated by alkali and the activity was markedly reduced when readjusted to the acid range. They were also heat stable and did not lose their activity in storage at 1°–3 °C. provided they were covered by a layer of toluene.Because of their rapid production and the marked injurious effects exerted on various plants it is believed that these toxins may perform a significant role in the field as the primary cause of some root rots and in predisposing plants to attack by organisms not normally regarded as pathogenic.

The influence of soil conditions on the decomposition of organic matter in the soil

1917 ◽  
Vol 8 (3) ◽  
pp. 385-417 ◽  
Author(s):  
E. J. Russell ◽  
A. Appleyard
Keyword(s):  
Organic Matter ◽  
Soil Fertility ◽  
Plant Nutrients ◽  
Fundamental Importance ◽  
Soil Conditions ◽  
Plant Residues ◽  
Beneficial Effects ◽  
Decomposition Of Organic Matter ◽  
Decomposition Of Plant Residues

The biochemical decomposition of plant residues and other organic matter in the soil is of fundamental importance for soil fertility. It causes the breaking down of coarse plant fragments which otherwise might open up the soil too much: it leads to the production of colloidal complexes known as humus which exert many beneficial effects both chemical and physical, and it brings about the formation of nitrates, the most important of the nitrogenous plant nutrients.

scholarly journals High-throughput phenotyping in cotton: a review

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Irish Lorraine B. PABUAYON ◽  
Yazhou SUN ◽  
Wenxuan GUO ◽  
Glen L. RITCHIE
Keyword(s):  
High Throughput ◽  
Cropping Systems ◽  
Three Dimensional ◽  
Growth Yield ◽  
Analytical Techniques ◽  
Phenotypic Traits ◽  
Technological Advances ◽  
Recent Developments ◽  
Potential Applications ◽  
High Throughput Phenotyping

Abstract Recent technological advances in cotton (Gossypium hirsutum L.) phenotyping have offered tools to improve the efficiency of data collection and analysis. High-throughput phenotyping (HTP) is a non-destructive and rapid approach of monitoring and measuring multiple phenotypic traits related to the growth, yield, and adaptation to biotic or abiotic stress. Researchers have conducted extensive experiments on HTP and developed techniques including spectral, fluorescence, thermal, and three-dimensional imaging to measure the morphological, physiological, and pathological resistance traits of cotton. In addition, ground-based and aerial-based platforms were also developed to aid in the implementation of these HTP systems. This review paper highlights the techniques and recent developments for HTP in cotton, reviews the potential applications according to morphological and physiological traits of cotton, and compares the advantages and limitations of these HTP systems when used in cotton cropping systems. Overall, the use of HTP has generated many opportunities to accurately and efficiently measure and analyze diverse traits of cotton. However, because of its relative novelty, HTP has some limitations that constrains the ability to take full advantage of what it can offer. These challenges need to be addressed to increase the accuracy and utility of HTP, which can be done by integrating analytical techniques for big data and continuous advances in imaging.

scholarly journals Extreme Weather Events in Agriculture: A Systematic Review

2019 ◽  
Vol 11 (9) ◽  
pp. 2547 ◽  
Author(s):  
Alessia Cogato ◽  
Franco Meggio ◽  
Massimiliano De Antoni Migliorati ◽  
Francesco Marinello
Keyword(s):  
Agricultural Sector ◽  
Current Knowledge ◽  
Cropping Systems ◽  
Extreme Weather ◽  
Mitigation Measures ◽  
Extreme Weather Events ◽  
Economic Losses ◽  
Research Gaps ◽  
Weather Events ◽  
Major Interest

Despite the increase of publications focusing on the consequences of extreme weather events (EWE) for the agricultural sector, a specific review of EWE related to agriculture is missing. This work aimed at assessing the interrelation between EWE and agriculture through a systematic quantitative review of current scientific literature. The review analysed 19 major cropping systems (cereals, legumes, viticulture, horticulture and pastures) across five continents. Documents were extracted from the Scopus database and examined with a text mining tool to appraise the trend of publications across the years, the specific EWE-related issues examined and the research gaps addressed. The results highlighted that food security and economic losses due to the EWE represent a major interest of the scientific community. Implementation of remote sensing and imagery techniques for monitoring and detecting the effects of EWE is still underdeveloped. Large research gaps still lie in the areas concerning the effects of EWE on major cash crops (grapevine and tomato) and the agronomic dynamics of EWE in developing countries. Current knowledge on the physiological dynamics regulating the responses of main crops to EWE appears to be well established, while more research is urgently needed in the fields of mitigation measures and governance systems.

scholarly journals Growth, yield, water use efficiency and competitive functions of intercropping system of maize (Zea mays L.) and mungbean (Vigna radiata L.) as influenced by irrigation

2016 ◽  
Vol 13 (2) ◽  
pp. 94-107 ◽  
Author(s):  
S Roy ◽  
M Barman ◽  
AM Puste ◽  
SK Gunri ◽  
K Jana
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Cropping Systems ◽  
Growth Yield ◽  
Land Equivalent Ratio ◽  
Sole Crop ◽  
Maximum Value ◽  
Main Plot ◽  
Use Efficiency ◽  
Plot Design

Field experiment was conducted at Instructional Farm, Jaguli (Mohanpur), Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India during two consecutive summer seasons of 2010-11, and 2011-12. The experiment was laid out in split-plot design having 4 levels of irrigation– rainfed without mulch, rainfed with mulch, irrigation at IW (depth of irrigation water) / CPE (Cumulative pan evaporation) ratios of 0.5 and 0.75 in main-plot and 4 inter cropping systems, sole maize, sole mungbean, maize + mungbean (1:1 row ratio) and maize + mungbean (3:2 row ratio) considered as sub-plot treatments replicated thrice. Results revealed that application of irrigation and intercropping systems markedly influenced the growth, yield and yield components (number of cobs/plant, number of grains/cob in case of maize and number of pods/plant and number of seeds/pod in case of mungbean) where the maximum value of these components were recorded with the application of irrigation at IW/CPE ratio 0.75 in sole crop. Maize-mungbean in 3:2 row ratio yielded higher than that of 1:1 intercropping system which might be due to less light interception and more competition for water and nutrition between both the crops. CU of water increased with the increasing levels of irrigation and the maximum value (17.75 kg ha-1 mm- 1) of WUE (water use efficiency) was observed with irrigation at IW: CPE ratio 0.75 under intercropping system of maize : mungbean in 3:2 row ratio followed by IW: CPE ratio 0.50. Among the sole crop, maximum WUE was with IW/CPE ratio 0.75 might be due to more consumption of water corresponding to production potential of maize, while, it was more under rainfed with mulch in mungbean. The relative crowding coefficient (RCC) also revealed both the intercropping systems were advantageous and the land equivalent ratio (LER) increased with the level of irrigation.Thus, maize grown in association with mungbean (3:2 row ratio) were found to be more profitable (B:C ratio of 2.58) with higher monetary advantage as compared to sole crop of maize (B:C ratio of 1.98) with the application of irrigation at IW: CPE ratio of 0.75 in new alluvial zone of West Bengal.SAARC J. Agri., 13(2): 94-107 (2015)

scholarly journals Redevelopment of biological activity in stripmine spoils: saprotrophic fungi – abstract

1988 ◽  
Vol 94 ◽  
pp. 85-85
Author(s):  
Suzanne Visser
Keyword(s):  
Fungal Community ◽  
Soil Disturbance ◽  
Plant Residues ◽  
Fungal Community Composition ◽  
Saprotrophic Fungi ◽  
Fungal Community Structure ◽  
Soil Fungal Community ◽  
And Function ◽  
The Impact ◽  
Decomposition Of Plant Residues

The impact of severe soil disturbance on soil fungal community composition and function and how this relates to the resultant decomposition/mineralisation process is very poorly understood. Consequently, research was conducted to determine: (a) to what degree fungal community structure and potential function are altered in a sub-alpine coal mine spoil (Luscar, Alberta), and (b) how do alterations in the fungal community affect patterns of fungal colonisation and decomposition of plant residues deposited on recently mined soil.

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