Pavlů Klára, Kassahun Teowdroes, Pavlů Vilém V, Pavlů Lenka, Blažek Petr, Homolka Petr
Department of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences, Praha, Czechia.
Department of Nutrition and Feeding of Farm Animals, Institute of Animal Science, Praha, Czechia.
PLoS One. 2021 Mar 30;16(3):e0248804. doi: 10.1371/journal.pone.0248804. eCollection 2021.
Semi-natural grasslands occupy large parts of the European landscape but little information exists about seasonal variations in their nutritive value during the growing season. This paper presents results of novel data showing the effect of 13 years of previous contrasting management intensities on herbage nutritional value in relation to different dates of first defoliation (by grazing or haymaking). The treatments were: extensive management and intensive management from previous years (1998-2011). Both treatments were cut in June followed by intensive/extensive grazing for the rest of the grazing season (July-October). To evaluate forage quality in the first defoliation date, biomass sampling was performed in the year 2012 for 23 weeks from May to mid-October, and in 2013 for seven weeks from May to mid-June. Sampling was performed from plots that were not under management during the sampling year. Previous extensive management was associated with significantly reduced forage quality for in vitro organic matter digestibility (IVOMD), crude protein, neutral detergent fibre, acid detergent fibre and reduced divalent cations (Ca, Mg) and Na during the first seven weeks of the grazing season and the forage was suitable only for beef cattle. Due to low forage IVOMD, the forage is suitable only for cattle maintenance or for low quality hay when the start of grazing was postponed from seven weeks of vegetative growth to 13 weeks, regardless of the previous intensity. Herbage harvested after 13 weeks of the grazing season was of very low quality and was unsuitable as a forage for cattle when it was the only source of feed. Agri-environmental payments are necessary to help agricultural utilisation to maintain semi-natural grasslands by compensating for deterioration of forage quality, not only for the postponement of the first defoliation (either as cutting or grazing) after mid-June, but also when extensive management is required.
半天然草地占据了欧洲大片土地，但关于其生长季节营养价值的季节性变化的信息却很少。本文展示了新数据的结果，这些数据表明过去13年不同管理强度对比对牧草营养价值的影响，该影响与首次刈割（通过放牧或干草制作）的不同日期相关。处理方式为：过去年份（1998 - 2011年）的粗放管理和集约管理。两种处理方式均在6月进行刈割，随后在剩余放牧季节（7月至10月）进行集约/粗放放牧。为评估首次刈割日期的饲草质量，2012年从5月至10月中旬的23周以及2013年从5月至6月中旬的7周进行了生物量采样。采样在采样年份未进行管理的地块上进行。过去的粗放管理与放牧季节前七周体外有机物消化率（IVOMD）、粗蛋白、中性洗涤纤维、酸性洗涤纤维显著降低以及二价阳离子（钙、镁）和钠减少有关，此时牧草仅适合肉牛。由于饲草IVOMD较低，无论之前的强度如何，当放牧开始从营养生长7周推迟到13周时，该牧草仅适合维持牛的生存或制作低质量干草。放牧季节13周后收获的牧草质量极低，当它是唯一的饲料来源时，不适合作为牛的饲料。农业环境补贴是必要的，以帮助农业利用通过补偿饲草质量的恶化来维持半天然草地，不仅是为了补偿6月中旬后首次刈割（无论是刈割还是放牧）的推迟，也是为了补偿需要粗放管理的情况。
