A Ph.D. thesis at the University of Basrah discusses the Preparation of  Protein Hydrolysates from Plant Pods and Animal by-Products and Studying their Effect on Growth and Yield of Lettuce (Lactuca sativa L. ) Planted under Salt Stress
The results showed that the spraying with protein hydrolysates improved of all characteristic of vegetative growth ,yield quality and chemical characteristics and low oxidative stress . protein hydrolysates gave highest total yield was 22.072 and 20.882 tone dounum-1 for both seasons .
The amin of the experiment was to study the effect of spraying of  hydrolysates plants and  animal protein hydrolysates in growth and yield lettuce under salt stress.
The study concluded that the spraying with protein hydrolysates improved of all characteristic of vegetative growth  and yield and tolerant to salt stress
The study recommended to used other types of plant and animal by products to Preparation of  Protein Hydrolysates as biofertilizer.