Appropriate soil water and nitrogen (N) management strategies are critical for achieving sustainable agricultural development in drylands. Straw mulching has been used to improve crop yield and water use efficiency (WUE), but N management strategies may need to be adjusted from conventional practice. The current study investigated the interactive effects of N application rate (conventional and high N rate), N application frequencies (single, and split N in 2 – 3 applications) and seasonal conditions on wheat population density dynamics, yield, harvest index (HI), grain protein content, water- and N-use efficiency, and residual soil N under straw mulching on the Loess Plateau of China. Nitrogen rate had no effect on yield, HI, WUE and grain protein content, but high N rate resulted in lower grain weight and nitrogen partial factor productivity (PFPN), and higher soil N residue. Splitting N applications significantly improved grain yield (7%), HI (9%), grain protein content (5%), PFPN and N harvest index, along with a reduction in soil N residue, compared to single application. However, there was no difference in above traits between split-N in 2 and 3 applications. Conventional N rate (vs. high N rate) and split N application (vs. single application) both alleviated the negative correlation between grain yield and grain protein content, and split N application increased grain N removal per unit yield compared to single N application. It is concluded that conventional N rate combined with split application in two doses, is suitable for straw mulching in drylands of the Loess Plateau, China.

Studies on tillering dynamics are essential to understand the aspects underlying the persistence and adaptation pathways of grass communities, especially in more complex multispecific pastures. This study aimed to assess the tillering dynamics and population stability of Andropogon gayanus cv. Planaltina (PG), Megathyrsus maximus cv. Massai (MG) and Urochloa brizantha cv. BRS Piatã (PP) grown as monocultures and as a mixture. The treatments corresponded to three grasses described above. Sixteen 180 m2 plots were randomly assigned and managed intermittently under manual harvest at pre- and post-harvest heights of 35 and 17.5 cm, respectively, for two years. During autumn/winter/early spring, when resource availability is limited by abiotic factors, pasture population stability was ensured by the conservation strategy of all species, mainly through the high tiller survival rate (85.5 ± 0.32). In late spring and summer, the capture strategy was prioritized for all species, with stability ensured through high tiller appearance rates (30.3 ± 0.80 and 40.4 ± 1.47, respectively), which compensated for the high tiller death rate (28.7 ± 1.10) and resulted in greater species turnover during these both seasons. The association among PG, MG and PP in a mixture allows species to coexist with relatively stable populations and tillering dynamics, similar to their monocultures. These findings represent a step forward in our understanding of mixed swards stability and indicate that such associations could be viable alternatives to palisadegrass monocultures in tropical regions. Further research should test this mixed sward under grazing, during medium to long-term.

Ensiling tropical grasses presents a challenge in achieving an optimal fermentation profile, particularly when the grass possesses high nutritional value. Therefore, this study aimed to evaluate the use of additives during ensiling as a strategy to enhance the fermentation profile and nutritional quality of Zuri grass (Megathyrsus maximus cv. BRS Zuri) silage harvested at two regrowth ages. The tested additives were control (CT); Lactiplantibacillus pentosus strain AV 14.17 (LP); cellulase (CE); and LPCE (LP + CE). The regrowth ages were 60 and 90 days. Increased regrowth age of Zuri grass resulted in a higher fermentability coefficient but a reduced crude protein content in the fresh forage. The CE and LPCE silages exhibited lower fibre content. The crude protein content was higher and the ammonia content was lower in the CE and LPCE silages when the grass was harvested at 60 days. The pH was lower in CE and LPCE silages at both regrowth ages. Butyric acid was detected only in the CT and LP silages when the grass was harvested at 60 days. The CE and LPCE silages showed greater effective digestibility. The indigestible fraction of neutral detergent fibre was higher in silage harvested at 90 days. The addition of cellulase, alone or combined with the L. pentosus strain, effectively solubilised the fibre components, resulting in a lower pH and more effective control of undesirable microorganisms, thus improving the nutritional value. The most significant results were obtained when Zuri grass was harvested at 60 days of regrowth.

Field experiments enable researchers to investigate the impacts of both natural and anthropogenic crop production factors on soil respiration (SR), the largest contributor of CO2 emissions from terrestrial ecosystems to the atmosphere. The hypothesis of this study was that the influence of two key anthropogenic factors – applied fertilizers and cultivated crops – on the respiration rate of arable soils could be separated in a field experiment. The objective was therefore to quantify the influence of these factors on SR and assess its dependence on soil characteristics. The study was conducted on the territory of the long-term field experiment at the Timiryazev Academy (Moscow, Russia), where the use of plots of crop rotation involving rye, barley, potatoes and fallow, with liming and various fertilizer types applied, was considered. Measurements were taken using the closed chamber technique and a portable infrared gas analyser from May 2023 to November 2024. During the vegetation periods, SR varied significantly and was not statistically different for most plots (0.063–0.276 g C/(m2·h)), except for the NPK + manure variant (0.371–0.430 g C/(m2·h)). During the bare soil period, SR was similar between fertilizer variants and 10–20 times lower under snow cover than during the vegetation period (0.006–0.018 g C/(m2·h)). A direct dependence of respiration on soil organic carbon and particulate organic matter content was observed (R = 0.552–0.650). Two-way PERMANOVA revealed significant effects of fertilizers (17.2–24.0% of the variance) and crops (6.5–7.1%) on SR, although their interaction was insignificant. Our research could form the basis for developing carbon sequestration compensation measures in response to specific fertilizer doses.

This study was conducted to evaluate the supplementation of anionic salt products to pre-partum diets on dry matter (DM) intake, nutrient digestibility, blood metabolites and milk composition of cows during the transition period. Twenty-four Holstein cows [614 ± 21.3 kg body weight (BW) and 2.0 ± 0.9 parity number] were blocked by parity and expected calving date and randomly assigned to the following treatments: Animate (ANI), anionic salts (Animate, Phibro Animal Health, Teaneck, US) fed at 2.85 %DM; or Meganion (MEG), anionic salts (MegAnion, Barentz Animal Nutrition, Hoofddorp, The Netherlands) fed at 1.85 %DM. Treatments targeted -150 mEq/kg diet DM and were provided starting at 30 d of the expected calving date. Treatment effects were evaluated until 56 days in milk. Pre-partum diets presented -55.9 and -32.1 mEq/kg diet DM for ANI and MEG, respectively. Dry matter intake and BW were similar across treatment groups during the pre-partum and post-partum periods. Post-partum body condition score (BCS) tended to be greater for MEG. Pre-partum urine pH was similar between treatment groups (6.33 and 6.49 for ANI and MEG, respectively). Cows fed MEG had greater neutral detergent fibre digestibility on weeks 5 (53.2 vs. 49.8 %) and 6 (53.5 vs. 49.6 %) of lactation than ANI. Serum concentration of Mg was greater in cows fed MEG during the pre-partum. No treatment differences were found for blood concentrations of ionised Ca, non-esterified fatty acids, beta-hydroxybutyrate or insulin. Milk yield was not affected. Both anionic salts maintained adequate calcium metabolism during the transition period and resulted in similar performance.

Production efficiency of pasture-based livestock production systems is primarily driven by the level of pasture utilisation, and, as such, regular monitoring of herbage mass (HM) provides essential information to assist on-farm decision making. Unfortunately, this practice is seldom carried out on commercial farms, likely due to the time commitment required across the entire grass-growing season. Recent studies have shown, however, that even moderately inaccurate HM data can improve the system-side profitability compared to enterprises with no data, warranting further investigations into the trade-off between the accuracy and cost associated with HM measurements. Using a weekly multi-paddock dataset from the North Wyke Farm Platform research site in Devon, UK, this study evaluated the technical validity and labour-saving potential of a simplified ‘pasture walk’ protocol for rising plate meters, under which only data along the diagonal transect – rather than the industry-standard W-shaped pathways – of the paddock are collected. Across 234 temporal-paddock combinations, the mean absolute difference in HM estimates between diagonal and W-transects was 106 kg DM/ha, a scale far too small to alter sward or animal management. The presented statistical analysis, together with a supplementary spatial simulation experiment, supported the generality of the findings across the full grass-growing season. With a 51.2% reduction in labour time (1.2 min/ha rather than 2.5 min/ha) across paddocks of various sizes and shapes, the proposed method is likely to facilitate uptake of evidence-based grazing management amongst farmers who currently do not quantify HM at all.