Developing Nurse Crop Practice in Potato Cultivation System.

Over the past century, productive potato soils have been depleted due to short crop rotations, intensive tillage required for potato production, short growing seasons limiting cover crop options, and erosion from intensive rainfall.  Use small grain nurse cover crops with one-pass hilling as means to improve potato yield and quality; using these methods, growers will reduce tillage and soil erosion, retain nutrients, and increase microbial activity (a key component of soil health). Building soil structures and increase microbial activity using cover crop is a common practice but all this happens during mid/late summer. Because of spring rainfall there could be a major loss of nutrients in potato cultivation system through leaching and vitalization. The objective of this study is to keep nutrient close to surface and increase microbial activity to build soil structures as well as increase nitrogen through mineralization.  Winter rye (112 and 224 kg/ha), annual rye (17 and 34 kg/ha), green spirit (17 and 34 kg/ha), and oats (112 and 224 kg/ha) were used as a nurse crop. Seeds were broadcasted/planted a day before potato planting and then killed and hilled after twenty one days of planting. Two trials, Aroostook Research Farm Presque Isle and Rogers farm Orono, were designed as Randomized complete block design with four replications. Two sensors, Holland Crop Circle ACS-430 and Trimble GreenSeeker 505, were used to measure crop biomass and nurse crop health before nurse crop was killed or hilled. Soil samples will be taken on the day of nurse crop killing or hilling to measure soil nitrate levels and microbial activity. Winter Rye biomass was significantly higher than any other nurse crop. Plant height, root length, and leaf area index was found higher in Winter Rye. Minimum biomass was being found with Italian Rye Grass (Green Spirit) compared to all other nurse crops. higher microbial activity was observed in Winter Rye with 224kg/ha seed rate. High weed problem was observed in nurse crop plots than control plots.