کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5759614 1623213 2017 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Variations in nitrogen utilisation on conventional and organic dairy farms in Norway
ترجمه فارسی عنوان
تغییرات در مصرف نیتروژن در مزارع دامپزشکی مرسوم و ارگ در نروژ
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم کشاورزی و بیولوژیک (عمومی)
چکیده انگلیسی


- Dairy farms depend on off-farm area for production of concentrates.
- N-surpluses were lower on organic than on conventional dairy farms.
- More fertilizer N and biological N-fixation increased N-surpluses.
- Increased milk yield per cow reduced N-surpluses on conventional farms.

Reduced N-surpluses in dairy farming is a strategy to reduce the environmental pollution from this production. This study was designed to analyse the important variables influencing nitrogen (N) surplus per hectare and per unit of N in produce for dairy farms and dairy systems across 10 certified organic and 10 conventional commercial dairy farms in Møre og Romsdal County, Norway, between 2010 and 2012. The N-surplus per hectare was calculated as N-input (net N-purchase and inputs from biological N-fixation, atmospheric deposition and free rangeland) minus N in produce (sold milk and meat gain), and the N-surplus per unit of N-produce as net N-input divided by N in produce. On average, the organic farms produced milk and meat with lower N-surplus per hectare (88 ± 25 kg N·ha− 1) than did conventional farms (220 ± 56 kg N·ha− 1). Also, the N-surplus per unit of N-produce was on average lower on organic than on conventional farms, 4.2 ± 1.2 kg N·kg N− 1 and 6.3 ± 0.9 kg N·kg N− 1, respectively. All farms included both fully-cultivated land and native grassland. N-surplus was found to be higher on the fully cultivated land than on native grassland. N-fertilizers (43%) and concentrates (30%) accounted for most of the N input on conventional farms. On organic farms, biological N-fixation and concentrates contributed to 32% and 36% of the N-input (43 ± 18 kg N·kg N− 1 and 48 ± 11 kg N·kg N− 1), respectively. An increase in N-input per hectare increased the amount of N-produce in milk and meat per hectare, but, on average for all farms, only 11% of the N-input was utilised as N-output; however, the N-surplus per unit of N in produce (delivered milk and meat gain) was not correlated to total N-input. This surplus was calculated for the dairy system, which also included the N-surplus on the off-farm area. Only 16% and 18% of this surplus on conventional and organic farms, respectively, was attributed to surplus derived from off-farm production of purchased feed and animals. Since the dairy farm area of conventional and organic farms comprised 52% and 60% of the dairy system area, respectively, it is crucial to relate production not only to dairy farm area but also to the dairy system area. On conventional dairy farms, the N-surplus per unit of N in produce decreased with increasing milk yield per cow. Organic farms tended to have lower N-surpluses than conventional farms with no correlation between the milk yield and the N-surplus. For both dairy farm and dairy system area, N-surpluses increased with increasing use of fertilizer N per hectare, biological N-fixation, imported concentrates and roughages and decreased with higher production per area. This highlights the importance of good agronomy that well utilize available nitrogen.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Agricultural Systems - Volume 157, October 2017, Pages 11-21
نویسندگان
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