Improving nutrient and economic efficiency of dairy intensification depends on intensive use of scattered cropland

Dairy farms located in villages constitute an important sub-sector of milk production in China, and need to intensify to meet growing milk demand. There has been little attempt to quantify the nutrient use efficiency of these dairy farms and their effects of integrated livestock-crop systems (ILCS) bounded by the village. We undertook a detailed study of eight ILCS, differentiated into three mixed systems in which dairy farms use scattered cropland for grass production, and five specialized systems where forage is imported from outside village boundaries. Nitrogen and phosphorus use efficiency (NUE and PUE), water consumption and economic performance were evaluated using monitoring data from eight dairy farms and their 200 neighboring smallholders. Compared with specialized systems, mixed systems exhibited 111% higher total milk productivity (3.8 vs 1.8 x 10 6 kg yr -1 ) and lower water consumption (15 vs 31 m 3 kg -1 protein). NUE and PUE were 27.6% and 17.9% higher at the ILCS system level for mixed systems compared with specialized systems. Intensive use of local (village) scattered cropland for grass production within mixed ILCS improved system-level feed self-sufficiency and increased local recycling of manure nutrients in crop production, reducing chemical fertilizer requirements. Crop production within mixed ILCS had similar grain yield but exhibited a benefit to cost ratio twice as high, a labor productivity ratio six times higher and a land productivity ratio 1.5-2 times higher than specialized systems. Development of village-based mixed ILCS therefore shows promise as a sustainable intensification strategy for milk production in China. The efficiency of mixed ILCS could be further enhanced through breeding strategies to improve the yield and feed conversion efficiency of dairy cows, further increasing the proportion of dairy feed demand met by local cropland, and improving access to efficient manure spreading equipment.(c) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.