Short-term yield gains or long-term sustainability? – a synthesis of Conservation Agriculture long-term experiments in Southern Africa

2022 ◽  
Vol 326 ◽  
pp. 107812
Author(s):  
Christian Thierfelder ◽  
Blessing Mhlanga
Keyword(s):  
Southern Africa ◽  
Conservation Agriculture ◽  
Short Term ◽  
Long Term Experiments

scholarly journals Can Long-Term Experiments Predict Real Field N and P Balance and System Sustainability? Results from Maize, Winter Wheat, and Soybean Trials Using Mineral and Organic Fertilisers

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1472
Author(s):  
Ilaria Piccoli ◽  
Felice Sartori ◽  
Riccardo Polese ◽  
Maurizio Borin ◽  
Antonio Berti
Keyword(s):  
Winter Wheat ◽  
Nutrient Balance ◽  
Environmental Indicators ◽  
Nutrient Loss ◽  
Real Field ◽  
Short Term ◽  
Organic Fertiliser ◽  
Long Term Experiments ◽  
P Balance

Agri-environmental indicators such as nutrient balance may play a key role in soil and water quality monitoring, although short-term experiments might be unable to capture the sustainability of cropping systems. Therefore, the objectives of this study are: (i) to evaluate the reliability of long-term experimental N and P balance estimates to predict real field (RF) (i.e., short-term transitory) conditions; and (ii) to compare the sustainability of short- and long-term experiments. The LTE-based predictions showed that crops are generally over-fertilised in RF conditions, particularly maize. Nutrient balance predictions based on the LTE data tended to be more optimistic than those observed under RF conditions, which are often characterised by lower outputs; in particular, 13, 44, and 47% lower yields were observed for winter wheat, maize, and soybean, respectively, under organic management. The graphical evaluation of N and P use efficiency demonstrated the benefit of adopting crop rotation practices and the risk of nutrient loss when liquid organic fertiliser was applied on a long-term basis. In conclusion, LTE predictions may depend upon specific RF conditions, representing potential N and P use efficiencies that, in RF, may be reduced by crop yield-limiting factors and the specific implemented crop sequence.

The effect of phosphate and potash fertilizers on cut and grazed grassland

1970 ◽  
Vol 74 (2) ◽  
pp. 397-407 ◽  
Author(s):  
J. S. Brockman ◽  
P. G. Shaw ◽  
K. M. Wolton
Keyword(s):  
Short Term ◽  
Long Term Experiments ◽  
K Fertilizer ◽  
P Fertilizer ◽  
Cutting Management ◽  
Experimental Management ◽  
Almost All ◽  
Grazed Swards ◽  
Grazed Grassland

SUMMARYAn experiment was carried out over a 5-year period on a grass/clover sward at North Wyke to compare three methods of experimental management—individually grazed plots, communally grazed plots and cutting with removal of herbage. Responses to phosphate and potash fertilizers under each management were measured.P fertilizer increased grass yields in the first 4 years and decreased clover yields in the last 2. In almost all respects cut and grazed sward responded similarly to P. Fertilizer K had no effect on grass yield but markedly increased clover yield and raised herbage K content. Grazed swards developed a higher herbage K content than cut swards, and K fertilizer increased it more in the fourth and fifth years on the individually grazed than on the communally grazed plots. Thus communal grazing resulted in appreciable transfer of K from plot to plot in animal returns.It is concluded that whilst cutting management may be used for short-term experiments, its use in long-term experiments gives different results from grazing. Communal grazing can lead to the transfer of N and K effects from plot to plot, so that plots must be grazed individually except perhaps where P is the only variable nutrient.

A critical study of the failure of a long-term calcium and phosphorus balance experiment with laying hens

1960 ◽  
Vol 54 (1) ◽  
pp. 131-139 ◽  
Author(s):  
N. K. Jenkins ◽  
C. Tyler
Keyword(s):  
Laying Hens ◽  
Systematic Errors ◽  
Critical Study ◽  
Short Term ◽  
Phosphorus Balance ◽  
Long Term Experiments ◽  
Calcium And Phosphorus

A long-term calcium and phosphorus balance experiment with laying hens is described.The cumulative balances of calcium and phosphorus over a whole year were seen to be physiologically impossible.Results from other workers using short term balances could be equally impossible and a similar situation has recently been noted in balance experiments with ruminants.The techniques employed in the experiment were, therefore, investigated in detail.Only systematic errors could be responsible and it was found that the most likely source of such errors was (a) the spilling of food on to the floor or into the water bowl, and (b) failure to collect all the droppings.These errors only become apparent in long-term experiments and are more pronounced when diets containing high levels of calcium and/or phosphorus are fed.

MONOCLONAL ANTIBODY-MEDIATED ENHANCEMENT OF GROWTH HORMONE ACTIVITY IN VIVO

1985 ◽  
Vol 107 (3) ◽  
pp. R9-R12 ◽  
Author(s):  
A. T. Holder ◽  
R. Aston ◽  
M.A. Preece ◽  
J. Ivanyi
Keyword(s):  
Monoclonal Antibody ◽  
Hormone Activity ◽  
Short Term ◽  
Long Term Experiments ◽  
Snell Dwarf ◽  
New Perspective ◽  
Dwarf Mice ◽  
Dose Dependent

ABSTRACT This work demonstrates that complexing hGH with monoclonal antibody EBl (MAB-EBl) can produce a striking potentiation of the somatogenic actions of hGH in vivo in Snell dwarf mice. In short-term experiments significant increases in cartilage metabolism and body weight were noted; these responses were dose-dependent for both MAB-EBl and hGH concentration. Increased growth was also observed in long-term experiments. In marmosets where MAB-EBl cross-reacts with endogenous GH, MAB-EBl alone enhanced the actions of endogenous GH. A new perspective may be necessary to incorporate these results into the current concept of antibody action.

scholarly journals Long-term field experiment on the impacts of the neonicotinoid dinotefuran and the organophosphate fenitrothion on a honeybee colony

2015 ◽  
Author(s):  
Toshiro Yamada ◽  
Yasuhiro Yamada ◽  
Kazuko Yamada
Keyword(s):  
Field Experiment ◽  
Lethal Dose ◽  
Short Term ◽  
Long Period ◽  
Sugar Syrup ◽  
The World ◽  
Long Term Experiments ◽  
Honeybee Colony ◽  
Term Field

Neonicotinoides are persistent and highly toxic pesticides that have become popular instead of organophosphates, being suspected to be a trigger of massive disappearance of bees that raises concern in the world. The evaluation of the long-term influence for a whole colony in the natural environment is, however, not established yet. In this paper, we conducted a long-term field experiment and found different impacts on honeybee colonies (Apis mellifera) in an apiary between the neonicotinoid dinotefuran and the organophosphate fenitrothion even though whose concentrations in sugar syrup provided for bees were adjusted to have nearly equal short-term effects on a honeybee based on the median lethal dose (LD50) as well as the insecticidal activity to exterminate stinkbugs. The colony with administration of dinotefran (dinotefuran colony) became extinct in 26 days, while the colony with administration of fenitrothion (fenitrothion colony) survived the administration for the same period. Furthermore, the fenitrothion colony succeeded to be alive for more than 293 days after administration, and also succeeded an overwintering, which indicates that colonies exposed to fenitrothion can recover after the exposure. Meanwhile, the dinotefuran colony became extinct even though the intake of dinotefuran was estimated to be comparable with that of fenitrothion in terms of the LD50 of a honeybee. Moreover, the colonies in our previous long-term experiments where dinotefuran with higher concentration were administered only for first few days (Yamada et al., 2012) became extinct in 104 days and 162 days, respectively. From these results, we speculate that colonies exposed to dinotefuran hardly recover from the damage because dinotefuran is much more persistent than fenitrothion and toxic foods stored in cells can affect a colony in a long period.

A modified Munger cell for testing long-term effects of predator-induced stress on prey: an example using Tyrophagus putrescentiae (Acaridae) and its predator Neoseiulus cucumeris (Phytoseiidae)

2019 ◽  
Vol 24 (10) ◽  
pp. 2285-2289
Author(s):  
XIAOYING WEI ◽  
ZHI-QIANG ZHANG
Keyword(s):  
New Method ◽  
Tyrophagus Putrescentiae ◽  
Long Term Effects ◽  
Short Term ◽  
Neoseiulus Cucumeris ◽  
Induced Stress ◽  
Long Term Experiments

Predators can influence prey directly by consuming them, or indirectly by inducing stress to them. In previous studies, the exposure of leaves or containers to predators is short term and the replacement of such predator-exposed units for any long-term experiments is laborious. This study aims to establish a new method to enable continuous predator-induced stress to prey by using a modified Munger cell, with Tyrophagus putrescentiae and its predator predator Neoseiulus cucumeris as an example.

scholarly journals Study of the thermal release behaviour of mercury and thallium from liquid eutectic lead-bismuth alloy

2005 ◽  
Vol 93 (3) ◽  
Author(s):  
Jörg Neuhausen ◽  
B. Eichler
Keyword(s):  
Experimental Error ◽  
Short Term ◽  
Temperature Range ◽  
Thermal Release ◽  
Long Term Experiments ◽  
Bismuth Alloy

SummaryThe release of mercury and thallium from liquid eutectic lead-bismuth alloy (LBE) under a flowing Ar/7%-HDuring short-term experiments significant amounts of mercury begin to evaporate from liquid LBE at temperatures starting from about 475 K. 80% of the mercury present in the sample is released from samples of approximately 1.5–3 g within one hour at temperatures higher than 625 K. Thallium release in the temperature range investigated is below experimental error. Long-term experiments reveal that even at temperatures as low as 476 K about 25% of the mercury present in the samples is released per day under a flowing Ar/7%-H

Cross-induction of cell types in Dictyostelium: evidence that DIF-1 is made by prespore cells

Development ◽  
2001 ◽  
Vol 128 (24) ◽  
pp. 4959-4966
Author(s):  
Robert R. Kay ◽  
Christopher R. L. Thompson
Keyword(s):  
Enzyme Activity ◽  
Cyclic Amp ◽  
Cell Types ◽  
Cell Type ◽  
Short Term ◽  
Signal Molecule ◽  
Long Term Experiments

To investigate how cell type proportions are regulated during Dictyostelium development, we have attempted to find out which cell type produces DIF-1, a diffusible signal molecule inducing the differentiation of prestalk-O cells. DIF-1 is a chlorinated alkyl phenone that is synthesized from a C12 polyketide precursor by chlorination and methylation, with the final step catalysed by the dmtA methyltransferase. All our evidence points to the prespore cells as the major source of DIF-1. (1) dmtA mRNA and enzyme activity are greatly enriched in prespore compared with prestalk cells. The chlorinating activity is also somewhat prespore-enriched. (2) Expression of dmtA is induced by cyclic-AMP and this induction is inhibited by DIF-1. This regulatory behaviour is characteristic of prespore products. (3) Short-term labelling experiments, using the polyketide precursor, show that purified prespore cells produce DIF-1 at more than 20 times the rate of prestalk cells. (4) Although DIF-1 has little effect on its own synthesis in short-term labelling experiments, in long-term experiments, using 36Cl– as label, it is strongly inhibitory (IC50 about 5 nM), presumably because it represses expression of dmtA; this is again consistent with DIF-1 production by prespore cells. Inhibition takes about 1 hour to become effective. We propose that prespore cells cross-induce the differentiation of prestalk-O cells by making DIF-1, and that this is one of the regulatory loops that sets the proportion of prespore-to-prestalk cells in the aggregate.

scholarly journals Peluang dan Tantangan Implementasi Model Pertanian Konservasi di Lahan Kering

2020 ◽  
Vol 11 (2) ◽  
pp. 77
Author(s):  
Achmad Rachman
Keyword(s):  
Soil Quality ◽  
Agricultural Land ◽  
Organic Matter Content ◽  
Conservation Agriculture ◽  
Crop Productivity ◽  
Matter Content ◽  
Small Scale ◽  
Cropping Pattern ◽  
Short Term

<p><strong>Abstrak.</strong> Pertanian konservasi adalah salah satu alternatif model pada praktek pertanian di lahan kering yang dalam jangka panjang dapat meningkatkan produktivitas tanaman, efisiensi usahatani, dan kualitas lingkungan melalui perbaikan kualitas tanah. Tulisan ini membahas prospek penerapan pertanian konservasi untuk meningkatkan kualitas tanah dan produktivitas lahan kering. Model pertanian konservasi lebih menekankan pada perbaikan kandungan bahan organik tanah melalui kombinasi 3 pendekatan yaitu olah tanah minimum, pemulsaan, dan pengaturan pola tanam. Introduksi model pertanian konservasi di negara-negara berkembang seperti Indonesia, yang umumnya lahan pertaniannya berskala sempit (&lt;1 ha) dihadapkan pada masalah perkembangan gulma dan penurunan produktivitas pada fase awal implementasi, dan lahan yang tidak bersih sehingga berpotensi memicu munculnya hama dan penyakit tertentu. Namun demikian, model pertanian konservasi ini berpotensi untuk mengubah lahan kering terdegradasi atau tidak produktif menjadi lahan pertanian produktif dengan efisiensi usahatani yang tinggi. Dengan manfaat jangka panjang tersebut, maka implementasi pertanian konservasi di lahan kering, yang potensinya mencapai 29,4 juta ha, akan meningkatkan secara signifikan kontribusi lahan kering terhadap upaya mempertahankan swasembada pangan nasional dan meningkatkan kesejahteraan petani lahan kering. Diperlukan proses dan modifikasi untuk mengadaptasikan teknologi ini yang disesuaikan dengan karakteristik agroekosistem, konidisi sosial, dan ekonomi lokal setempat, sehingga berbagai kendala adopsi dapat diminimalisir dan manfaat dapat dioptimalkan baik jangka pendek maupun jangka panjang. Selain itu, diperlukan dukungan pemerintah dalam bentuk pelatihan, advokasi, dan bantuan input usahatani untuk meminimalisir resiko kerugian petani terutama pada tahap awal implementasi teknologi.</p><p><em><strong>Abstract.</strong></em> Conservation agriculture is an alternative model to agricultural practices in dryland which in the long term provides a number of benefits including an increase in crop productivity, farm input efficiency and environmental quality through the improvement of soil quality. This paper discusses the prospect for implementing conservation agricultural to improve soil quality and productivity of dryland. The conservation agriculture model emphasizes the improvement of soil organic matter content through a combination of 3 approaches, namely minimum tillage, mulching, and cropping pattern. Introduction of conservation agriculture into developing countries like Indonesia, which are generally small-scale farming (&lt;1 ha), will face a number of obstacles caused by short-term and immediate shortcomings of the technology. These shortcomings include weed development and productivity decline in the early phase of implementation, and the potential to trigger the emergence of certain pests and diseases due to unclean land. However, the practice has the potential to transform degraded or unproductive drylands into more efficient and productive agricultural land. With those long-term benefits of conservation agriculture, its implementation to 29.4 million ha of dryland of Indonesia will boost significantly the contribution of dryland agriculture in sustaining national food self sufficiency and improving the welfare of dryland farmers. Processes and modifications are needed to adapt this practice to suit local agroecosystem, social and local economic characteristics so that various adoption constraints can be minimized and short-term and long-term benefits can be optimized. In addition, government supports are needed in the form of training, advocacy and farm inputs subsidies to minimize the risk of loss of farmers especially in the early stages of technology implementation.</p>

Sign in / Sign up

Export Citation Format

Share Document