Agri-Food and Biosciences Institute (AFBI), Newforge Lane, Belfast, United Kingdom.
Agri-Food and Biosciences Institute (AFBI), Newforge Lane, Belfast, United Kingdom.
Sci Total Environ. 2020 Apr 20;714:136690. doi: 10.1016/j.scitotenv.2020.136690. Epub 2020 Jan 16.
The dairy sector is an important sector in Northern Ireland being the single largest contributor to its agricultural economy. However, the sector contributes more to soil phosphorus (P) surplus compared to other agricultural sectors. Consequently, the goal of this research is to analyse the environmental technical efficiency of dairy farms making use of a novel parametric hyperbolic distance function approach. The model is able to internalise P surplus as undesirable output in the dairy production process by treating desirable and undesirable outputs asymmetrically. The stochastic production frontier model is analysed simultaneously with an inefficiency model to explain variability in efficiency scores assuming the existence of heteroskedasticity in the idiosyncratic error term. Additionally, we estimated the shadow price and pollution cost ratio of P surplus in dairy farms. This paper contributes to the existing literature as it provides the first attempt to empirically estimate the pollution abatement cost of P surplus in dairy farms. Besides, the hyperbolic environmental technology distance function methodology employed to achieve the study objectives is less restrictive compared to the radial output/input distance function approach employed in previous studies. This allows for the estimation of a more robust environmental efficiency measure and shadow price of P surplus that is consistent with public policy goals that seek to simultaneously reduce pollution and increase production of desirable outputs. Our results showed that the average environmental technical efficiency estimates for dairy farms in Northern Ireland is 0.93 and the shadow price (marginal abatement cost) of P surplus evaluated at the mean is £12.29/kg. Intensification resulting in increased use of concentrates feed was found to be negatively related to environmental technical efficiency. We also found that age of the farmer and share of milk output have a positive relationship with environmental technical efficiency.
奶制品行业是北爱尔兰的一个重要行业，是其农业经济的最大单一贡献者。然而，与其他农业部门相比，该部门对土壤磷（P）过剩的贡献更大。因此，本研究的目标是利用新颖的参数双曲线距离函数方法分析奶牛场的环境技术效率。该模型能够通过不对称地处理理想和不理想的产出，将 P 过剩纳入奶制品生产过程中的不良产出。随机生产前沿模型与无效模型同时进行分析，以解释效率得分的可变性，假设个体误差项中存在异方差。此外，我们估计了奶牛场 P 过剩的影子价格和污染成本比。本文为现有文献做出了贡献，因为它首次尝试在经验上估计奶牛场 P 过剩的减排成本。此外，与以前研究中使用的径向投入/产出距离函数方法相比，所采用的双曲线环境技术距离函数方法限制较少。这允许更稳健的环境效率衡量标准和 P 过剩的影子价格的估计，这与旨在同时减少污染和增加理想产出的公共政策目标一致。我们的结果表明，北爱尔兰奶牛场的平均环境技术效率估计值为 0.93，在平均值处评估的 P 过剩的影子价格（边际减排成本）为 12.29 英镑/公斤。发现集约化导致浓缩饲料使用增加与环境技术效率呈负相关。我们还发现，农民的年龄和牛奶产量份额与环境技术效率呈正相关。
