Results of trials with poppy seed (Papaver somniferum) in organic and integrated production technology.

The influence of organic and integrated management practices on poppy yield, pests and disease incidence was assessed in field trials in 2009. Crop management based on mineral fertilisers application and chemosynthetic pesticides treatment significantly increased the yield of poppy compared to organic crop protection and organic management of fertilization. Integrated crop protection decreased harmfulness of pests as rate of infectious diseases observed on capsules during harvest

Airline Pricing under Different Market Conditions: Evidence from European Low-Cost Carriers

Traditional theories of airline pricing maintain that fares monotonically increase as fewer seats remain available on a flight. A fortiori, this implies a monotonically increasing temporal profile of fares. In this paper, we exploit the presence of drops in offered fares over time as an indicator of an active yield management intervention by two main European Low-Cost Carriers observed daily during the period June 2002 - June 2003. Our results indicate that yield management is effective in raising a flight's load factor. Furthermore, yield management interventions are more intense, and generate a stronger impact, on more competitive routes: one possible interpretation is that a reduction in competitive pressure allows the carriers to adopt a more standardized approach to pricing. Similarly, we find that yield management interventions are more effective in raising the load factor on routes where the customer mix is more heterogenous (i.e., it includes passengers traveling for leisure, business and for family matters). On markets with homogeneous customer base, no robust yield management effect was observed.Easyjet, Intertemporal Pricing, Panel Data, Ryanair, Yield Management

Effect of organic, low-input and conventional production systems on yield and diseases in winter barley

The effect of organic, low-input and conventional management practices on barley yield and disease incidence was assessed in field trials over two years. Conventional fertility management (based on mineral fertiliser applications) and conventional crop protection (based on chemosynthetic pesticides) significantly increased the yield of winter barley as compared to organic fertility and crop protection regimes. Severity of leaf blotch (Rhynchosporium secalis) was highest under organic fertility and crop protection management and was correlated inversely with yield. For mildew (Erysiphe graminis), an interaction between fertility management and crop protection was detected. Conventional crop protection reduced severity of the disease, only under conventional fertility management. Under organic fertility management, incidence of mildew was low and application of synthetic pesticides in “low input” production systems had no significant effect on disease severity

Some considerations concerning the panel management in rubber tapping (Hevea brasiliensis)

Research devoted to long term panel management deserved less efforts, mainly due to the long duration required for experimentation. The present study deals with the comparison of two panel management strategies on nine clones tapped in 1/2S, over a total period of nine years, in Côte d'Ivoire: annual panel changing and no panel changing. Four IRCA clones were.compared to PB 330, GT 1, PB 217 et PB 260. For all clones, panel management influenced the annual yield. During the first six years, panel changing was more favourable to yield. After nine years, however, the cumulative rubber yield did not vary with panel strategy. Only clone !RCA 111 showed a significant higher yield with no panel changing. Authors recommend a panel changing strategy based on physiological fatigue of the tapping panel. The aim is to sustain the yie1d potentia1 of the trunk and to reduce the tapping panel dryness occurrence during the downward tapping period. (Résumé d'auteur

Changes in Producers’ Perceptions of Within-field Yield Variability Following Adoption of Cotton Yield Monitors

Precision Farming, Risk, Yield Monitor, Yield Variability, Yield Perceptions, Spatial Yield Distributions, Within Field Variability, Farm Management, Production Economics, Risk and Uncertainty, Q12, Q16,

California Almond Yield Prediction at the Orchard Level With a Machine Learning Approach.

California's almond growers face challenges with nitrogen management as new legislatively mandated nitrogen management strategies for almond have been implemented. These regulations require that growers apply nitrogen to meet, but not exceed, the annual N demand for crop and tree growth and nut production. To accurately predict seasonal nitrogen demand, therefore, growers need to estimate block-level almond yield early in the growing season so that timely N management decisions can be made. However, methods to predict almond yield are not currently available. To fill this gap, we have developed statistical models using the Stochastic Gradient Boosting, a machine learning approach, for early season yield projection and mid-season yield update over individual orchard blocks. We collected yield records of 185 orchards, dating back to 2005, from the major almond growers in the Central Valley of California. A large set of variables were extracted as predictors, including weather and orchard characteristics from remote sensing imagery. Our results showed that the predicted orchard-level yield agreed well with the independent yield records. For both the early season (March) and mid-season (June) predictions, a coefficient of determination (R 2) of 0.71, and a ratio of performance to interquartile distance (RPIQ) of 2.6 were found on average. We also identified several key determinants of yield based on the modeling results. Almond yield increased dramatically with the orchard age until about 7 years old in general, and the higher long-term mean maximum temperature during April-June enhanced the yield in the southern orchards, while a larger amount of precipitation in March reduced the yield, especially in northern orchards. Remote sensing metrics such as annual maximum vegetation indices were also dominant variables for predicting the yield potential. While these results are promising, further refinement is needed; the availability of larger data sets and incorporation of additional variables and methodologies will be required for the model to be used as a fertilization decision support tool for growers. Our study has demonstrated the potential of automatic almond yield prediction to assist growers to manage N adaptively, comply with mandated requirements, and ensure industry sustainability

Yield gap and the shares of climate and crop management in yield and yield variability of staple crops in West Africa. [O-3330b-01]

" Yield gap " (Yg) is a key concept of agricultural science for identifying the room for improvement of yields through better management of the agroecosystem. in rainfed agriculture Yg is the difference between actual yield (Ya) and the theoretical water limited yield (Yw) that would be achieved if solar radiation, temperature and precipitations were the only factor limiting the crop's growth and yield. Changes in Yw over regions and years are due to climate-soil interactions that are not easily modified by crop management, whereas changes in Yg are due to limiting factors that are typically within the scope of crop management such as nutrient availability, weeds, and pests. We provide an example of yield gap estimates in semi-arid a frica, using yield and other agronomic data collected in famers' fields of Senegal in 1990 and 1991 and from 2006 to 2012. i t illustrates how contrarily to what most people would expect climate is not, on average, what most limits yields in that region: yet, actual yields are on average a quarter of water limited yield, and this is due to constraints whose reduction is technically possible albeit subject to the economic and environmental relevance of doing so. Most studies dealing with the impact of climate change on agriculture in West a frica compare Yw under present and future climate as predicted by climate models. t he magnitude of those predicted long term changes in Yw by 2050 is down to –20% in the worst scenario combining a +6°C change with a -20% rainfall change. s uch changes in water limited yields are certainly concerning, but they are remarkably small compared to the potential +390% increase that would result from closing the current yield gap. When considering yield variations observed across plots and years, and not anymore regional averages over a few years, what strikes is the stability of observed yields compared to variations of Yw. We used crop model simulations with historical series of 20 years of weather data to compare yield distributions over years of a crop grown using 3 contrasted levels of fertilisation and no incidence of weeds, pests or diseases. For each fertilisation level, the simulated yield reached a maximum value the 'best year' of the series. t he three fertilisation levels were chosen so that the maximum simulated yield reached 0.25 Yw, 0.5 Yw, and 0.75 Yw respectively. t he resulting simulated yield distributions show that even if management allows increasing the median yield, in many years the climate is the main limiting factor and fertilising has no or a slight impact only. i n other words, the way the current climate limits crop production in this region is by making uncertain the output of investing for high yields. Buying fertilizers or working hard for manure collection, transport and distribution do not translate, a certain number of years, into more production. For farmers struggling for the daily subsistence of their family, that kind of risk may not be justified while alternative use of family resources in cash and labour force provide less risky ways to produce subsistence means. Until recently, in many farming systems of West africa, the growth in food needs due to population growth in rural areas was matched thanks to increases in cultivated or pasted areas rather than increases in crop yields or livestock pressure on land (i.e extension rather than intensification of crop or livestock activities). When rural families reached the limits of this strategy, migrations of many kinds of distance and duration became the adjustment variable to the gap between resources available from farming and population needs. T his suggests that for many, it is less risky to leave home than to intensify cropping or livestock systems. Anyway, as job opportunities for migrants from the rural zones are currently low in West african cities and elsewhere, there are legitimate concerns about the way this strategy may soon reach its limit as well. i n terms of climate change, the worst scenario for farmers of that region would be if crop intensification became even more risky under future climate than at present. t here is thus an urgent need for joint agronomic and climate research to go beyond the prediction of Yw or of yield under unchanged crop management and determine whether or not the future climate will increase the yield risks associated with crop intensification in that region. But this should not divert from designing and implementing policies incentive to such intensification under present climate, as this might be much easier now than later. (Texte intégral

D4_2-D4_5-D3_2.Yearly report of crops yield and quality data as influenced by soil management 2019

Yearly reports on crops yield and quality as influenced by soil management (2018-2019

Impact of Simulated Insect Defoliation and Timing of Injury on Cabbage Yield in Minnesota

In 1992 and 1994, field studies were done to assess the tolerance of transplanted cabbage to simulated insect defoliation and to determine if the defoliation level and growth stage at which defoliation begins influences final yield. In both years, 6 defoliation levels ranging from 0-100% were applied to transplanted cabbage at 4 time intervals. The time intervals began at transplanting, pre-head and head stages and continued until either head stage or harvest. For both years, the only time interval with significantly higher yield than the trans- plant to harvest interval (longest interval) was the head to harvest interval (shortest interval) and significant yield loss occurred only when defoliation was \u3e12.5%. Results suggest that transplanted cabbage can withstand relatively low levels of defoliation before yield loss occurs but that yield loss is also related to the duration over which defoliation occurs. In early growth stages, to protect yield, pest management practices should focus on reducing the interval over which damage occurs. The use of cultural practices that delay the onset of defoliation or allow avoidance of pests could protect yield. These strategies may include using transplants to shorten the time from planting to harvest or using planting dates that allow significant plant growth (i.e., head stage) before defoliators are able to infest the crop and cause significant damage. In addition, management strategies that reduce pest populations can also protect yield but at the head stage should switch to managing pests to protect marketability by reducing aesthetic damage and head contaminants