Thirty years of growing cereal without P and K fertilization

Over thirty years a significant depletion of P and K in soil occured when the were not given in fertilizers. This caused a reduction in crop yield. An abundant P application exceeding the crop uptake very clearly prevented the yield reduction but did not raise the extractable P concentration in the soil. Severe K deficiency did not start to appear until 20 years of growing cereal without fertilizer K. K application compensating for the uptake by the crop did not prevent the decrease of its extractable concentration in this soil, but this decrease did not affect crop yield

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

ESTIMATING CORN YIELD RESPONSE MODELS TO PREDICT IMPACTS OF CLIMATE CHANGE

Projections of the impacts of climate change on agriculture require flexible and accurate yield response models. Typically, estimated yield response models have used fixed calendar intervals to measure weather variables and omitted observations on solar radiation, an essential determinant of crop yield. A corn yield response model for Illinois crop reporting districts is estimated using field data. Weather variables are time to crop growth stages to allow use of the model if climate change shifts dates of the crop growing season. Solar radiation is included. Results show this model is superior to conventionally specified models in explaining yield variation in Illinois corn.Crop Production/Industries,

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

Is tillering efficiency a relevant trait in selecting for high yield potential in rice?

Improving yield potential in rice implies the characterization of particular crop traits that may be used by breeders in their breeding programs. The rice crop is known to initiate and develop many tillers; a significant part of this may be higher than 50%, do not produce any grain. Recent breeding programs for yield potential have selected genotypes with high tillering efficiency (low tiller mortality) such as new plant types to reduce dry matter loss (Schnier et al 1990) and respiration cost (Dingkuhn et al 1990), but they did not produce the expected high yield in experimental fields. A positive correlation of grain yield with tillering efficiency would also imply a detrimental effect of non-productive tillers. We reviewed here a number of our recent field works to characterize the correlation between grain yield and tillering efficiency across genotypes of the same crop duration grown in similar favorable conditions and across crop managements for the same genotype. (Résumé d'auteur

Spatial Patterns of Crop Yields in Latin America and the Caribbean

Because of the apparent slowdown in the growth of crop yield potential, the increasing share of farmers already using modern crop varieties, and the accelerating flow of knowledge on agricultural technology, one would expect to find gradual convergence inLatin america, crop yield, convergence, spillover, weather variability

Evaluating Dryland Crop/Livestock System Alternatives for Risk Management under Declining Irrigation in the Texas Panhandle

Production budgets for dryland crop and crop/livestock systems are developed to estimate yields, costs and returns for dryland wheat and sorghum and for alternative dryland crop/livestock systems. A crop simulation model aids yield estimation. The yield and return distributions are used to estimate risk and relative risk for included alternatives.Relative Risk, Ogallala Aquifer, Crop-Livestock Systems, Wheat, Sorghum, Crop Production/Industries, Farm Management, Livestock Production/Industries, Production Economics, Productivity Analysis,

Crop status evaluations and yield predictions

A model was developed for predicting the day 50 percent of the wheat crop is planted in North Dakota. This model incorporates location as an independent variable. The Julian date when 50 percent of the crop was planted for the nine divisions of North Dakota for seven years was regressed on the 49 variables through the step-down multiple regression procedure. This procedure begins with all of the independent variables and sequentially removes variables that are below a predetermined level of significance after each step. The prediction equation was tested on daily data. The accuracy of the model is considered satisfactory for finding the historic dates on which to initiate yield prediction model. Growth prediction models were also developed for spring wheat