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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #398289

Research Project: Developing Resilient Irrigated Cropping Systems in Concentrated Dairy Production Areas of the Semi-arid West

Location: Northwest Irrigation and Soils Research

Title: Potential of winter cover crops and tillage for managing manure-based nutrient loading

item Baxter, Abigail
item Leytem, April
item Dungan, Robert - Rob
item Bjorneberg, David - Dave

Submitted to: International Journal of Plant and Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2023
Publication Date: 6/12/2023
Citation: Baxter, A.E., Leytem, A.B., Dungan, R.S., Bjorneberg, D.L. 2023. Potential of winter cover crops and tillage for managing manure-based nutrient loading. International Journal of Plant and Soil Science. June 2023: 1-18.

Interpretive Summary: As of 2020, Idaho is the third largest dairy producing state in the country, housing 645,000 head of cattle. Based on a 1000 lb liveweight, dairy cows produce an average of 82 lbs of manure daily (Fischer, 1998), meaning that Idaho’s dairy operations generated approximately 9 million tons of manure a year. One of the primary agricultural uses of manure is to act as a nutrient source and a soil conditioner, providing key nutrients such as N and P. Nutrients from manure can take up to 3 years to be fully used by crops, meaning that repeated applications can lead to nutrient buildup which can result in harmful side effects to the surrounding environment. This study tested the combined ability of winter triticale and tillage practice to counteract nutrient accumulations from repeated manure applications. We also took a deeper look at the potential impacts to crop yield, nutrient content, and overall forage quality. Our results show that winter cover crops has a strong potential to significantly add to annual nutrient removal rates, but not enough to significantly compete with nutrient additions at standard manure application rates. Tillage practice did not seem to have any prominent effects on the crops themselves but may have a more significant role in soil nutrient available. For farmers who hope to use a cover crop for producing forages for animal feed, our results showed that triticale grown in manured and non-manured soil were of good quality and could be successfully incorporated in animal feed rations.

Technical Abstract: Increased utilization of manure resulting from the expansion of the dairy industry has culminated in a soil nutrient surplus in southern Idaho. The objective of this study was to investigate the combined effect of winter cover crops and tillage practice on nutrient cycling, yield, and overall forage quality under annual manure applications. The 2 x 4 split plot study (2015 -2021) consisted of main treatments of conventional (ConTill) vs minimal (MinTill) tillage, and secondary treatment combinations of (1) manure (M) vs no manure (NM) and (2) winter triticale ( X Triticosecale) (CC) vs fallow (NCC) for each tillage type. Corn (Zea mays) and triticale whole plant tissue were collected for annual yield, tissue concentrations, nutrient removal rates, and forge quality. CC reduced corn yields (-1.65 M/ha) while M increased triticale yield (+13.6 Mg/ha). For both forages, M had greater tissue P (+0.483 and +2.21 g/kg) and K (+4.18 and +19.91 g/kg) and reduced Ca (-0.60 and -0.54 g/kg). Corn with M had smaller Mg (-0.43 g/kg) and triticale had greater Mg (+0.22 g/kg). Forages with M removed greater N (+39.93 and +109.84 kg/ha), P (+12.98 and +21.18 kg/ha), and K (+99.81 and +187.48 kg/ha). Corn with M removed less Mg (-7.85 kg/ha) and Ca (-11.24 kg/ha) and triticale removed greater Mg (+6.06 kg/ha) and Ca (+10.00 kg/ha). For both forages, M removed greater Zn and Na. M had greater corn CP (+0.89%), EE (+0.16%), and ash (+0.41%), and less ADF (-0.84%) and starch (-0.74%). CC had greater corn ADF (+0.50%) and less starch (-0.76%). M had greater triticale DM (+0.23%), CP (+4.21%), ADF (+4.27%), aNDFom (+6.46%), and lignin (+0.68), but smaller starch (-0.13%) and WSC (-9.46%). Use of triticale as a winter cover crop has strong potential for adding significantly to annual nutrient removal rates but may require nutrient additions for adequate plant growth. Producers should carefully consider the trade-offs in soils with high nutrient status. Triticale may exhibit increased risk of excess tissue concentrations that can be detrimental to animal health when grown on manured soils, but can be mitigated through well-balance feed rationing.