1Animal Production Systems Group,Wageningen University & Research,PO Box 338,6700 AH,Wageningen,the Netherlands.
2Plant Production Systems Group,Wageningen University & Research,PO Box 430,6700 AK,Wageningen,the Netherlands.
Animal. 2018 Aug;12(8):1755-1765. doi: 10.1017/S1751731118001039. Epub 2018 May 21.
Mineral phosphorus (P) used to fertilise crops is derived from phosphate rock, which is a finite resource. Preventing and recycling mineral P waste in the food system, therefore, are essential to sustain future food security and long-term availability of mineral P. The aim of our modelling exercise was to assess the potential of preventing and recycling P waste in a food system, in order to reduce the dependency on phosphate rock. To this end, we modelled a hypothetical food system designed to produce sufficient food for a fixed population with a minimum input requirement of mineral P. This model included representative crop and animal production systems, and was parameterised using data from the Netherlands. We assumed no import or export of feed and food. We furthermore assumed small P soil losses and no net P accumulation in soils, which is typical for northwest European conditions. We first assessed the minimum P requirement in a baseline situation, that is 42% of crop waste is recycled, and humans derived 60% of their dietary protein from animals (PA). Results showed that about 60% of the P waste in this food system resulted from wasting P in human excreta. We subsequently evaluated P input for alternative situations to assess the (combined) effect of: (1) preventing waste of crop and animal products, (2) fully recycling waste of crop products, (3) fully recycling waste of animal products and (4) fully recycling human excreta and industrial processing water. Recycling of human excreta showed most potential to reduce P waste from the food system, followed by prevention and finally recycling of agricultural waste. Fully recycling P could reduce mineral P input by 90%. Finally, for each situation, we studied the impact of consumption of PA in the human diet from 0% to 80%. The optimal amount of animal protein in the diet depended on whether P waste from animal products was prevented or fully recycled: if it was, then a small amount of animal protein in the human diet resulted in the most sustainable use of P; but if it was not, then the most sustainable use of P would result from a complete absence of animal protein in the human diet. Our results apply to our hypothetical situation. The principles included in our model however, also hold for food systems with, for example, different climatic and soil conditions, farming practices, representative types of crops and animals and population densities.
用于施肥的矿物磷 (P) 来自磷矿，而磷矿是一种有限的资源。因此，防止食品系统中矿物 P 的浪费和回收利用对于维持未来粮食安全和长期矿物 P 供应至关重要。我们建模的目的是评估在食品系统中防止和回收 P 废物的潜力，以减少对磷矿的依赖。为此，我们模拟了一个假设的食品系统，该系统旨在为固定人口生产足够的食物，对矿物 P 的最低投入要求。该模型包括代表性的作物和动物生产系统，并使用来自荷兰的数据进行参数化。我们假设没有饲料和食物的进出口。我们还假设 P 土壤损失很小，土壤中没有净 P 积累，这是西北欧条件的典型特征。我们首先评估了基线情况下的最低 P 需求，即 42%的作物废物被回收，人类从动物中获得 60%的膳食蛋白质 (PA)。结果表明，该食品系统中约 60%的 P 废物来自人类排泄物中 P 的浪费。随后，我们评估了替代情况下的 P 投入，以评估以下因素的（综合）影响：(1) 防止作物和动物产品浪费，(2) 完全回收作物产品废物，(3) 完全回收动物产品废物和 (4) 完全回收人类排泄物和工业加工水。回收人类排泄物显示出最大的潜力，可以减少食品系统中的 P 废物，其次是预防，最后是农业废物的回收。完全回收 P 可以减少 90%的矿物 P 投入。最后，对于每种情况，我们研究了人类饮食中 PA 消费从 0%到 80%的影响。饮食中动物蛋白的最佳量取决于动物产品的 P 废物是否得到预防或完全回收：如果得到预防，则人类饮食中少量的动物蛋白会导致 P 的最可持续利用；但如果没有得到预防，则人类饮食中完全没有动物蛋白会导致 P 的最可持续利用。我们的结果适用于我们的假设情况。但是，我们模型中包含的原则也适用于具有不同气候和土壤条件、耕作实践、代表性作物和动物类型以及人口密度的食品系统。
