The results from this study indicated that some crops are less sensitive and can grow where the metal loading rates are higher which confirmed that different plant species have different capacity and capability to accumulate the heavy metals . The levels of copper in sugarcane were significantly different at New Farm and Chilumba . The relatively high levels of copper in sugarcane stalk stem at New Farm in Mufulira can be attributed to domestic wastewater laden with copper from copper processing and higher natural copper back- ground levels in the soils. The findings from this study indicated that there was heavy metal contamination of food crops at the two study sites were similar to the results from other studies in developing countries. The study on wastewater irrigation farming in Varanasi, India which indicated that there were seasonal differences in the heavy metal concentrations in the edible portion of Beta vulgaris . The results from this study confirmed the findings from the study on heavy metals uptake by vegetable crops from metal contamination in Tehran, Iran . It can be argued that there are potential health risks for the urban population who consume these vegetables and other food crops which have high levels of heavy metals that above the maximum recommended values by relevant authorities.

Modeling weight gain or growth of livestock is an important tool for optimizing management decisions and production systems hydroponic nft channel . Amongst considered livestock were cattle, sheep, chicken,ducks or turkeys . Several hundred papers deal with growth curves for fisheries.There exist also studies dealing with the growth patterns of intensive piglet production or a pig breed used as laboratory animal . But organic livestock farming differs from intensive livestock farming in many respects. Animal husbandry, feeding, weaning age and drug administration are the main aspects of that difference. Thus piglets from organic farming are kept under different rearing conditions than piglets in intensive production systems. Therefore, the aim of this study is the analysis of weight gain of piglets from organic farming.There are two types of growth models: models with a rather mathematical motivation, such as data fitting,and models with a biological motivatio.The latter models explain growth e.g. from balancing anabolism and catabolism.Intermediates between these types are unified approaches, which in essence describe the biologically motivated models by differential equations that generalize the logistic growth model.As the models differ by the number of parameters,with more parameters enabling a better fit, the model selection is based on the Akaike Information Criterion AIC , which combines the good fit with a penalty for the number of parameters.

Amongst the considered models, only two fitted the piglet data properly: the initial growth phase with only minimal human influence could best be described by the biologically motivated Bertalanffy model, while the long term growth with different phases of human interaction was best described by the two-linear model. The von Bertalanffy model describes weight gain of piglets in the first weeks of live until weaning best. Considering the whole piglet rearing the most natural nutrition is given during the suckling period. Provided that the piglets remain with the sow the ingested amounts of milk as well as the frequency of suckling are not influenced by the animal owner.The biologist von Bertalanffy developed his model for all animal species under natural living and nutritional conditions. The model concept is based on physiological processes that are responsible for growth. Growth is defined as a consequence of anabolism and catabolism and will take place as long as building processes outweigh degradation processes. In young animals the primary function of the ingested food is rapid growth, thus it can be seen as a natural limitation of growing capabilities. In this sense the model concept is suited to describe growth development in this early period of live. This model is based on the idea of growth as a biological process until achieving a species-specific weight in adult age.

By contrast, during the fattening period the hogs are supplied with much more energy than they would need for natural growth in order to reach as high weight gain as possible in a minimum of time. Thus,nft growing system the results of the paper confirm that this model appears to be optimal for close to natural conditions.Among the thirteen growth models the two-linear model describes the weight gain of piglets from organic farming best. This model aims at two different growth periods which actually are caused by the general conditions of the piglets’ rearing. At the age of about 40 days the piglets are weaned. From this moment on the piglets have no longer the opportunity to suckle milk. This implies that solid feed is the only food source and likewise water is the only source of liquid. Due to the loss of the familiar surroundings the piglets furthermore have to cope with new drinking and feeding troughs, new stable mates, new climate control and also a new germ flora.In addition to the stress attributable to weaning the immune protection of the maternal antibodies that were ingested with the colostrum directly after birth decrease and the piglets’ own immune system is still under development.