Integrated farm management systems to improve nutrient management using semi-virtual Farmlets: agronomic responses

Abstract

With increasing demand for land and food, there is growing interest in sustainable intensification of agricultural production. Here we investigated sustainable intensification of grass and corn production for dairy farms using a system of semi-virtual farmlets that combine replicated field research plots with feed modelling. We improved manure N capture by spreading separated liquid fraction with a low emission sliding shoe applicator on grass, and manure P capture by precision injecting separated sludge into corn. Reducing the number of annual harvests (5 to 3) increased grass yield and inter-seeding Italian ryegrass in early maturing corn increased fall growth of the cover crop, thus helping to protect soil over winter and providing additional high quality herbage in spring. Irrigation improved yield and potentially yield stability of corn and grass, and adding a nitrification inhibitor to reduce N2O emission may help reduce pollution swapping especially from injected manure. Overall, allocating more land to corn than grass will increase farm productivity but effectiveness of measures to reduce pollution and pollution swapping need to be evaluated. Results show that good practices ensuring vigorous crops are challenging to implement but critical for achieving sustainable intensification. The semi-virtual farmlet system is very helpful for developing and evaluating sustainable production measures for corn and grass.