An alternative approach to the analysis of mixed cropping experiments. 2. Marketable yield.

1983 ◽  
Vol 31 (2) ◽  
pp. 143-155
Author(s):  
C.J.T. Spitters
Keyword(s):  
Harvest Index ◽  
Plant Biomass ◽  
Niche Differentiation ◽  
Individual Plant ◽  
Mixed Cropping ◽  
Resource Exploitation ◽  
Marketable Yield ◽  
Land Equivalent Ratio ◽  
Alternative Approach ◽  
Competition Effects

The effects of competition on marketable yield are derived from those on biomass by means of the relation between individual plant biomass and harvest index. A method is presented to estimate competition effects and advantage of mixed cropping directly from the data of marketable yield. The effect of spp. composition and population density on the advantage of mixed cropping, measured by the land equivalent ratio, is partitioned into an effect due to better resource exploitation (niche differentiation), a favourable influence of mixed cropping on harvest index and an effect due to density which can also be achieved by growing monocrops at a higher density. The approach is illustrated with the results of an experiment on mixed cropping of maize and groundnuts. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals An alternative approach to the analysis of mixed cropping experiments. 1. Estimation of competition effects.

1983 ◽  
Vol 31 (1) ◽  
pp. 1-11 ◽  
Author(s):  
C.J.T. Spitters
Keyword(s):  
Simple Model ◽  
Niche Differentiation ◽  
Total Density ◽  
Mixed Cropping ◽  
Alternative Approach ◽  
Competition Effects

A simple model is introduced to estimate the degree of intra-specific and inter-specific competition and niche differentiation from final biomass data of a set of populations varying in spp. composition and total density. Competition effects can be estimated using addition series. The model is illustrated with results from mixed cropping of maize and groundnut. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Acrolein Reduces Biomass and Seed Production of Potamogeton pectinatus in Irrigation Channels

2004 ◽  
Vol 18 (3) ◽  
pp. 605-610 ◽  
Author(s):  
Diego J. Bentivegna ◽  
Osvaldo A. Fernández ◽  
María A. Burgos
Keyword(s):  
Plant Growth ◽  
Field Experiments ◽  
Plant Biomass ◽  
Treatment Plant ◽  
Irrigation District ◽  
Potamogeton Pectinatus ◽  
Individual Plant ◽  
Plant Weight ◽  
The Third ◽  
Irrigation Channels

Chemical weed control with acrolein has been shown to be a lower cost method for reducing submerged plant biomass of sago pondweed in the irrigation district of the Lower Valley of Rio Colorado, Argentina (39°10′S–62°05′W). However, no experimental data exist on the effects of the herbicide on plant growth and its survival structures. Field experiments were conducted during 3 yr to evaluate the effect of acrolein on growth and biomass of sago pondweed and on the source of underground propagules (i.e., rhizomes, tubers, and seeds). Plant biomass samples were collected in irrigation channels before and after several herbicide treatments. The underground propagule bank was evaluated at the end of the third year. Within each treatment, plant biomass was significantly reduced by 40 to 60% in all three study years. Rapid new plant growth occurred after each application; however, it was less vigorous after repeated treatments. At the end of the third year at 3,000 m downstream from the application point, plant biomass at both channels ranged from 34 to 3% of control values. Individual plant weight and height were affected by acrolein treatments, flowering was poor, and seeds did not reach maturity. After 3 yr, acrolein did not reduce the number of tubers. However, they were significantly smaller and lighter. Rhizomes fresh weight decreased by 92%, and seed numbers decreased by 79%. After 3 yr of applications, operational functioning of the channels could be maintained with fewer treatments and lower concentrations of acrolein.

scholarly journals Effect of mixed cropping and plant extracts on the growth, yield and pest control of jute (Corchorus olitorius L.)

2013 ◽  
Vol 25 (1) ◽  
pp. 49-60 ◽  
Author(s):  
Adeyela I. Okunlola ◽  
Thomas I. Ofuya
Keyword(s):  
Plant Extracts ◽  
Growth And Yield ◽  
Total Biomass ◽  
Percentage Increase ◽  
Mixed Cropping ◽  
Corchorus Olitorius ◽  
Marketable Yield ◽  
Piper Guineense ◽  
Shoot Weight ◽  
Number Of Branches

ABSTRACT This study investigated the effect of plant extracts (Azadirachta indica and Piper guineense) on the growth and yield of jute (Corchorus olitorius L.) (Cor) under sole and mixed cropping with Amaranthus hybridus (Ama) and Celosia argentea (Cel). The highest percentage increase in plant height, number of leaves, number of branches and stem girth (130.6, 865.0, 220.4 and 114.0%, respectively) was found in untreated Cor + Cel, cypermethrin treated Cor + Ama, cypermethrin treated Cor and A. indica extract treated Cor + Ama, respectively. The highest percentage increase in shoot weight (71.0%), marketable yield (53.9%) and total biomass (51.5%) was in A. indica treated C. olitorius. Extract treatment had no effect on the number of branches at four, five and seven weeks after planting (WAP) in Cor + Ama + Cel; four, five and six WAP in Cor + Cel; four and six WAP in Cor + Ama; as well as four and five WAP in Cor. The highest percentage increase in leaf fresh weight was obtained in cypermethrin treated Cor (53.3%) and Cor + Ama + Cel (52.2%), while the smallest increase was in P. guineense treated Cor (1.1%) and Cor + Ama (2.5%). The activity of A. indica was independent of time of application while P. guineense was not. Among the extract treated groups, the highest percentage increase in shoot weight (71.0%), marketable yield (53.9%) and total biomass (51.5%) was in A. indica treated Cor. The activity of the extracts against insect pests of sole cropped Cor increased significantly (p < 0.05) with increasing extract concentration. The highest efficiency with the use of P. guineense was 250 g dm-3 at four, five and six WAP (94.0, 92.7 and 90.3%, respectively) and 200 mg dm-3 at seven WAP (81.7%). In the case of A. indica extract, the highest efficiency was found with the use of 200 g dm-3 at four, six and seven WAP (92.7, 85.3 and 100%, respectively). A. indica extract (250 g dm-3) treatment gave the highest efficiency at five WAP (100%).

Growth, photosynthesis and productivity of greenhouse tomato cultivated in open or closed rockwool systems

2002 ◽  
Vol 82 (4) ◽  
pp. 771-780 ◽  
Author(s):  
X. Hao ◽  
A. P. Papadopoulos
Keyword(s):  
Lycopersicon Esculentum ◽  
Plant Biomass ◽  
Alternative Methods ◽  
Marketable Yield ◽  
Tomato Production ◽  
Greenhouse Tomato ◽  
Tomato Yield ◽  
Nutrient Film Technique ◽  
Closed Systems ◽  
Environmentally Sound

Two full spring season tomato crops (Lycopersicon esculentum Mill. “Trust”) were grown in an open rockwool system with standard rockwool feeding formulae (O-R; conventional method), and in closed rockwool systems with standard rockwool (C-R) or Nutrient Film Technique (C-NFT) feeding formulae (modified in 1997) in 1996 and 1997 to examine the feasibility of a fully closed rockwool production system with appropriate feeding formulae. The closed rockwool system with optimized feeding formulae achieved high marketable yield, similar to that of the open rockwool system. There were no differences in early plant growth, plant biomass or biomass partitioning, and in total fruit yield, size and grades except for the closed rockwool system with the standard rockwool feeding formulae (C-R), which had lower yield than C-NFT in the last month of harvest in 1996. The photosynthesis of old foliage was higher and the root systems at the end of the experiments were rated healthier in plants grown in the closed (C-R and C-NFT) systems than in plants grown in the open (O-R) system. Over 30% of water and fertilizer was saved with the closed systems in comparison to the conventional open system. These results demonstrated that closed rockwool systems with optimized nutrient feedings are economically and environmentally sound alternative methods for greenhouse tomato production in Ontario. Key words: Lycopersicon esculentum, tomato, yield, recycling, rockwool, greenhouse

scholarly journals Effects of Drought Stress on Some Agronomic and Morpho-Physiological Traits in Durum Wheat Genotypes

2020 ◽  
Vol 12 (14) ◽  
pp. 5610
Author(s):  
Alireza Pour-Aboughadareh ◽  
Reza Mohammadi ◽  
Alireza Etminan ◽  
Lia Shooshtari ◽  
Neda Maleki-Tabrizi ◽  
...  
Keyword(s):  
Drought Stress ◽  
Grain Yield ◽  
Durum Wheat ◽  
Harvest Index ◽  
Plant Biomass ◽  
Geometric Mean ◽  
Grain Filling ◽  
Tolerance Index ◽  
Wheat Genotypes ◽  
Grain Filling Period

Durum wheat performance in the Mediterranean climate is limited when water scarcity occurs before and during anthesis. The present research was performed to determine the effect of drought stress on several physiological and agro-morphological traits in 17 durum wheat genotypes under two conditions (control and drought) over two years. The results of analysis of variance indicated that the various durum wheat genotypes responded differently to drought stress. Drought stress significantly reduced the grain filling period, plant height, peduncle length, number of spikes per plot, number of grains per spike, thousand grains weight, grain yield, biomass, and harvest index in all genotypes compared to the control condition. The heatmap-based correlation analysis indicated that grain yield was positively and significantly associated with phenological characters (days to heading, days to physiological maturity, and grain filling period), as well as number of spikes per plant, biomass, and harvest index under drought conditions. The yield-based drought and susceptible indices revealed that stress tolerance index (STI), geometric mean productivity (GMP), mean productivity (MP), and harmonic mean (HM) were positively and significantly correlated with grain yields in both conditions. Based on the average of the sum of ranks across all indices and a three-dimensional plot, two genotypes (G9 and G12) along with the control variety (G1) were identified as the most tolerant genotypes. Among the investigated genotypes, the new breeding genotype G12 showed a high drought tolerance and yield performance under both conditions. Hence, this genotype can be a candidate for further multi-years and locations test as recommended for cultivation under rainfed conditions in arid and semi-arid regions.

Alteration in plant spacing improves submergence tolerance in Sub1 and non-Sub1 rice (cv. IR64) by better light interception and effective carbohydrate utilisation under stress

2020 ◽  
Vol 47 (10) ◽  
pp. 891 ◽  
Author(s):  
Debarati Bhaduri ◽  
Koushik Chakraborty ◽  
A. K. Nayak ◽  
Mohammad Shahid ◽  
Rahul Tripathi ◽  
...  
Keyword(s):  
Leaf Senescence ◽  
Plant Biomass ◽  
Rice Cultivar ◽  
Antioxidant Enzyme Activities ◽  
Individual Plant ◽  
Submergence Tolerance ◽  
Light Penetration ◽  
Imaging Data ◽  
Seedling Vigour ◽  
Plant Plant

Besides genetic improvement for developing stress-tolerant cultivars, agronomic management may also add considerable tolerance against different abiotic stresses in crop plants. In the present study, we evaluated the effect of six different spacing treatments (S1: 10 × 10 cm; S2: 15 × 10 cm; S3:15 × 15 cm; S4:20 × 10 cm; S5: 20 × 15 cm; S6: 20 × 20 cm (row-row × plant-plant)) for improving submergence tolerance in rice. A high yielding submergence intolerant rice cultivar IR64 was tested against its SUB1 QTL introgressed counterpart (IR64-Sub1) for 12 days of complete submergence for different spacing treatments in field tanks. Relatively wider spaced plants showed higher individual plant biomass and early seedling vigour, which was particularly helpful for IR64 in increasing plant survival (by 150% in S6 over S1) under 12 days of submergence, whereas the improvement was less in IR64-Sub1 (13%). Underwater radiation inside the plant canopy, particularly beyond 40 cm water depth, was significantly greater in wider spacing treatments. Leaf senescence pattern captured by SPAD chlorophyll meter reading and chlorophyll fluorescence imaging data (Fm, Fv/Fm) taken at different time intervals after stress imposition suggested that there was lesser light penetration inside the canopy of closer spaced plants, and that it might hasten leaf senescence and damage to the photosynthetic system. The initial content of total non-structural carbohydrate (NSC) was higher in wider spaced plants of IR64, and also the rate of depletion of NSC was lesser compared with closer spaced plants. In contrast, there was not much difference in NSC depletion rate under different spacing in IR64-Sub1. Further, higher antioxidant enzyme activities in wider spaced plants (both IR64 and IR64-Sub1) after de-submergence indicated better stress recovery and improved tolerance. Taken together we found that wider spacing (row-row: 20 cm and plant-plant: 15 cm and more) can significantly improve submergence tolerance ability in rice, particularly in submergence intolerant non-Sub1 cultivar like IR64, perhaps due to better underwater light penetration, delayed leaf senescence and slower depletion of NSC reserve.

scholarly journals Niche Differentiation of Active Methane-Oxidizing Bacteria in Estuarine Mangrove Forest Soils in Taiwan

2020 ◽  
Vol 8 (8) ◽  
pp. 1248
Author(s):  
Yo-Jin Shiau ◽  
Chiao-Wen Lin ◽  
Yuanfeng Cai ◽  
Zhongjun Jia ◽  
Yu-Te Lin ◽  
...  
Keyword(s):  
Plant Biomass ◽  
Niche Differentiation ◽  
Stable Isotope Probing ◽  
Field Conditions ◽  
Type I ◽  
Mangrove Forests ◽  
Downstream Site ◽  
Upstream Site ◽  
Type Ia ◽  
Mangrove Soils

Mangrove forests are one of the important ecosystems in tropical coasts because of their high primary production, which they sustain by sequestering a substantial amount of CO2 into plant biomass. These forests often experience various levels of inundation and play an important role in CH4 emissions, but the taxonomy of methanotrophs in these systems remains poorly understood. In this study, DNA-based stable isotope probing showed significant niche differentiation in active aerobic methanotrophs in response to niche differentiation in upstream and downstream mangrove soils of the Tamsui estuary in northwestern Taiwan, in which salinity levels differ between winter and summer. Methylobacter and Methylomicrobium-like Type I methanotrophs dominated methane-oxidizing communities in the field conditions and were significantly 13C-labeled in both upstream and downstream sites, while Methylobacter were well adapted to high salinity and low temperature. The Type II methanotroph Methylocystis comprised only 10–15% of all the methane oxidizers in the upstream site but less than 5% at the downstream site under field conditions. 13C-DNA levels in Methylocystis were significantly lower than those in Type I methanotrophs, while phylogenetic analysis further revealed the presence of novel methane oxidizers that are phylogenetically distantly related to Type Ia in fresh and incubated soils at a downstream site. These results suggest that Type I methanotrophs display niche differentiation associated with environmental differences between upstream and downstream mangrove soils.

scholarly journals Effects of nitrogen fertilisation and irrigation on seed yield and yield components of signal grass (Urochloa decumbens)

2020 ◽  
Vol 71 (3) ◽  
pp. 294 ◽  
Author(s):  
M. W. Canto ◽  
E. J. Pancera ◽  
A. Barth Neto ◽  
C. Bremm ◽  
P. U. Vier ◽  
...  
Keyword(s):  
Seed Yield ◽  
Seed Weight ◽  
Harvest Index ◽  
Plant Biomass ◽  
Block Design ◽  
Application Rate ◽  
Nitrogen Fertilisation ◽  
Combined Application ◽  
Urochloa Decumbens ◽  
Signal Grass

The effects of nitrogen (N) fertiliser rate and irrigation on seed yield and its components were evaluated for signal grass (Urochloa decumbens (Stapf) R.D. Webster; syn. of Brachiaria decumbens Stapf) cv. Basilisk in a field experiment in Umuarama, Paraná, Brazil. Two water regimes (irrigated and non-irrigated) and four nitrogen (N) fertiliser rates (0, 25, 50 and 75 kg ha–1) were applied to perennial signal grass crops in a split-plot randomised complete block design with three replications. In two consecutive harvests, favourable rainfall resulted in irrigation having limited influence on most measurements, and the combined application of irrigation and N fertiliser did not improve seed yield. Compared with the nil N, the highest N application rate significantly increased seed yield for the first crop (266 vs 498 kg ha–1) and the second crop (104 vs 286 kg ha–1). Nitrogen fertilisation significantly increased number of seed per area, reproductive tiller density and plant biomass at harvest for the first and second crops. Harvest index, 1000-seed weight, reproductive tiller weight, number of spikelets per panicle and number of seeds per panicle were unaffected by N rate. Harvest index ranged from 1.10% to 3.63% and 1000-seed weight from 2.15 to 3.36 g. There were no treatment effects on number of days to flowering or anthesis. Fertilisation with 75 kg N ha–1 for the first crop and 50–75 kg N ha–1 for the second crop maximised signal grass seed yield.

scholarly journals Accumulation of trace metals by aquatic macrophytes and their possible use in phytoremediation techniques

2008 ◽  
Vol 56 (1) ◽  
pp. 97-104
Author(s):  
Michaela Hillermannová ◽  
Radovan Kopp ◽  
Ivo Sukop ◽  
Tomáš Vítek
Keyword(s):  
Surface Water ◽  
Trace Metals ◽  
Plant Species ◽  
Aquatic Plants ◽  
Aquatic Macrophytes ◽  
Plant Biomass ◽  
Water Current ◽  
Ecological Group ◽  
Individual Plant ◽  
The Individual

The aim of the performed research was to obtain knowledge on the ability of aquatic plants naturally growing at a site to absorb trace metals contained in bottom sediments and surface water. Furthermore, we compared differences in the accumulation of trace metals by the individual groups of aquatic plants (submerged and emergent) and assessed a possible use of the individual plant species in phytoremediation techniques. Representative samples of water, sediments and aquatic macrophytes were taken from three anthropogenically loaded streams in six monitoring cycles in several collection profiles differing in the distance from a source of contamination. The samples were analysed for the total content of selected trace metals (As, Cd, Pb, Al, Hg, Zn, Fe, Mn, Cr, Ni and Cu). For comparison, one profile at an unloaded site was sampled as well. The obtained results were subjected to multivariate statistical analysis of data. Increased contents of Fe, Al, Mn, Cr and Zn were detected in sediments and plant biomass at loaded sites, namely 2–3× higher than at the comparing site. The contents of metals in surface water samples were altogether below the detection limit of the analytical method. When evaluating the individual plant species, we can state that the lowest contents of metals were detected in shore species (reed canary grass Phalaroides arundinacea, wood club-rush Scirpus silvaticus and red dock Rumex aquaticus); plant species growing in the very water current (water star-wort Callitriche sp. and flote-grass Glyceria fluitans) exhibited mean contents of metals. In species forming mats (Fontinalis antipyretica and Cladophora sp.), these contents were several times higher as compared to the previous species. The results of the performed research show that one of important factors, which influence the accumulation of trace metals in plants, is their ecological group (emergent – submerged) affiliation and the species classification within this group. Based on the evaluated data, we can recommend species of moss and algae that form mats eventually species growing in the very water flow for the future use in phytoremediation techniques.

Sign in / Sign up

Export Citation Format

Share Document