Impact of Manure and Mineral Fertilizer Application on Soil Quality Under a Corn-Soybean Rotation in South Dakota.

Improving soil nutrients are essential for the sustainable agriculture. Manure is an excellent source of supplying nutrients such as organic matter that can help in enhanced production. Manure provides higher organic matter to the soil and hence impact soil quality in long-term. The present study was conducted to assess the impacts of manure application on soil quality under a corn (Zea mays L.)-Soybean (Glycine max L.) rotation system.  A range of soil quality indicators used in this study that include soil organic carbon (SOC), aggregate stability, bulk density, water infiltration rate (IR), soil water retention (SWR) and soil penetration resistance. The study treatments include three manure treatments ((P) phosphorus based recommended manure application rate, (N) nitrogen based recommended manure application rate, (2N) nitrogen based double of recommended manure application rate), two fertilizer treatments ((F) recommended fertilizer and (HF) high fertilizer) and a control (CK).The study was conducted in two different long-term sites located by following randomized complete block design with four replications at Beresford and Brookings in South Dakota. The soil test, P from the P manure treatment was used to calculate the manure needed for that treatment and similarly N from the N manure treatment was used to calculate the manure needed for that treatment. Two-time N-based manure treatment is exactly two times amount of recommended N-based manure application rate. Similarly, both the P and nitrate-N soil tests were used from the fertilizer treatments to make the P and N recommendations for the fertilizer treatment. The manure was incorporated with a disc in one to three days after application. Soil samples with the auger and intact core samples from 0-10 cm, 10-20 cm, 20-30 cm and 30-40 cm depths were collected to analyze different soil properties. Preliminary results from this study showed that addition of organic manure significantly improves the soil properties. Results from the study will be helpful for management practices by providing information about the impact of different manure and fertilizer application rates on soil quality.