Cereal-legume mixtures increase net CO₂ uptake in a forage system of the Eastern Pyrenees

Forage systems are the major land use, and provide essential resources for animal feeding. Assessing the influence of forage species on net ecosystem CO2 exchange (NEE) is key to develop management strategies that can help to mitigate climate change, while optimizing productivity of these systems. However, little is known about the effect of forage species on CO2 exchange fluxes and net biome production (NBP), considering: species ecophysiological responses; growth and fallow periods separately; and the management associated with the particular sown species. Our study assesses the influence of cereal monocultures vs. cereal legume mixtures on (1) ecosystem scale CO2 fluxes, for the whole crop season and separately for the two periods of growth and fallow; (2) potential sensitivities of CO2 exchange related to short-term variations in light, temperature and soil water content; and (3) NBP during the growth period; this being the first long term (seven years) ecosystem scale CO2 fluxes dataset of an intensively managed forage system in the Pyrenees region. Our results provide strong evidence that cereal-legume mixtures lead to higher net CO2 uptake than cereal monocultures, as a result of higher gross CO2 uptake, while respiratory fluxes did not significantly increase. Also, management associated with cereal legume mixtures favoured vegetation voluntary regrowth during the fallow period, which was decisive for the cumulative net CO2 uptake of the entire crop season. All cereal legume mixtures and some cereal monocultures had a negative NBP (net gain of C) during the growth period, indicating C input to the system, besides the yield. Overall, cereal legume mixtures enhanced net CO2 sink capacity of the forage system, while ensuring productivity and forage quality.

PSIII-29 Effects of late gestational tall fescue forage system on spring-calving beef cow performance, circulating metabolites, and colostrum quality

Multiparous cows [n = 56; 639 ± 73 (SD) kg initial BW; 5.3 ± 0.4 initial BCS; 5.9 ± 3.0 yr of age; February 16, 2016 average calving date] were allocated by BW, BCS, age, and expected calving date to strip-graze endophyte-infected stockpiled tall fescue (STF; n = 4 pastures; 12.5% CP, 59.5% NDF; DM basis) or consume ad libitum endophyte-infected tall fescue hay (n = 4 uncovered drylots; 7.5% CP, 65.3% NDF; DM basis) for the last 75.0 ± 11.9 d of gestation. At 13.5 ± 1.6 d pre-calving, STF cows were moved to drylots and fed tall fescue haylage (12.6% CP, 61.7% NDF; DM basis). Effects of forage system were included in the model with pen as experimental unit. For gestational metabolites, effects of forage system, day, and their interaction were included with day as a repeated measure. Forage system did not affect (P ≥ 0.35) cow BW. Cows fed STF had greater (P ≤ 0.06) BCS than hay-fed cows at d 32 and 62 of study. Forage system did not affect (P ≥ 0.12) gestational plasma glucose or triglycerides. Serum non-esterified fatty acids (NEFA) were greater (P ≤ 0.005) in hay-fed cows at d 32 and 82 of study and less (P = 0.02) at d 62 of study. After study initiation, serum urea N was greater (P ≤ 0.002) in STF-fed cows than hay-fed cows. At colostrum sampling (6.8 ± 0.9 h postpartum), forage system did not affect (P ≥ 0.10) circulating NEFA, glucose, or triglycerides. Cows fed STF had greater (P ≤ 0.002) serum and colostrum urea N than hay-fed cows. Forage system did not affect (P ≥ 0.17) colostrum protein, lactose, triglyceride, or immunoglobulin concentrations. In conclusion, grazing STF improved cow BCS and altered cow metabolic status but did not affect colostrum quality.

Effects of shading on the growth and leaf photosynthetic characteristics of three forages in an apple orchard on the Loess Plateau of eastern Gansu, China

Background Inclusion of forage into the orchard is of great help in promoting the use efficiency of resources, while shading from trees restricts forage growth and production in the Loess Plateau of China. This study was aimed to investigate how tree shading affected leaf trait, photosynthetic gas exchange and chlorophyll feature of forages under the tree in the orchard-forage system. Methods The shading treatments were set as partially cutting branches (reduced shading), normal fruit tree shading (normal shading) and normal tree shading plus sun-shading net (enhanced shading) in an apple orchard. Leaf trait, photosynthesis, chlorophyll component and fluorescence related parameters were measured with lucerne (Medicago sativa), white clover (Trifolium repens) and cocksfoot (Dactylis glomerata) which were sown under apple trees. Results Shading imposed significant impacts on the growth and leaf photosynthetic characteristics, while there were differences among species. Enhanced shading decreased leaf thickness, leaf dry matter content (LDMC) and leaf mass per unit area (LMA). Biomass accumulation decreased with enhanced shading in cocksfoot, but did not change in white clover and lucerne which had much lower biomass accumulation than cocksfoot. Enhanced shading reduced net photosynthetic rate (Pn) of white clover and lucerne, but rarely affected cocksfoot, while it decreased instantaneous water use efficiency (WUEi) of cocksfoot but had few effects on the other forages. Enhanced shading reduced leaf dark respiration rate (Rd), light compensation point (LCP) and maximum assimilation rate. The Rd and LCP of cocksfoot were much lower than those of white clover and lucerne. Chlorophyll contents and chlorophyll a/b changed little with shading. Cocksfoot had the highest contents but lowest ratio. Maximum photochemical rate of photosystem II increased and non-photochemical quenching decreased with enhanced shading in cocksfoot, while did not change in the other forages. Discussion Leaf trait, photosynthetic gas exchange and chlorophyll feature were variously affected by species, shading and their interaction. Cocksfoot was more efficient than the other two forages in use of weakened light and more tolerant to tree shading. In the apple orchard, we recommend that reducing the density of apple tree or partially cutting branches together with selecting some shading-tolerant forages, i.e., cocksfoot, would be a practical option for the orchard-forage system in the Loess Plateau of China.

SIMULASI PRODUKSI HIJAUAN PADA TIPE UNIT SISTEM TIGA STRATA YANG BERBEDA

Nowadays, availability of forage for cattle and other animal protein resources getting less and less due to land changing functions. This will lead to increase in land price, decrease in animal productivities the will end on sustainability of the animal husbandry business. In Bali, farmers applied a Three Strata Forage System to provide forage along dry and rainy seasons. This study purpose was to find out forage production from four types but similar size of land (1 ha) which applied in that system, that were Type A (rectangle: 200 m x 50 m), Type B (L Form: 4 x (50 x 50 m), Type C (rectangle: 125 m x 80 m) and Type D (squares: 100 m x 100 m). This simulation showed that the forage production of the land was 14.533,805 ton DM/year for type A and B; 14.301,434 ton DM/year for Type C : and 14.276,171 ton/DM/year for Type D. It can be concluded that the land in similar size but differ in shape or type produce different quantity of forages. And addition forage production and carrying capacity were estimated below of recommended the three strata forage system. Keywords: Forages, production, three strata forage system