Herbage Production Research Articles

Prediction of fresh herbage yield using data mining techniques with limited plant quality parameters

The purpose of this study was to ascertain the fresh herbage yield, fertilizer dosage, and plant characteristics of the Sorghum-Sudangrass hybrid grown in arid and semi-arid regions, as well as their interrelationships. For this reason, data from the Sorghum-Sudangrass hybrid were used to assess the predictive performance of several data mining techniques, including CHAID, CART, MARS, and Bagging MARS. Plant traits were measured in Konya and Sanliurfa during 2021 and 2022. The descriptive statistical values were calculated as follows: plant height 306.27 cm, stem diameter 9.47 mm, fresh herbage yield 10852.51 kg/da, crude protein ratio 9.66%, acid detergent fiber 33.39%, neutral detergent fiber 51.85%, acid detergent lignin 9.76%, dry matter digestibility 62.88%, dry matter intake 2.34%, and relative feed value 114.68 (average values). The predictive capacities of the fitted models were assessed using model fit statistics such as the coefficient of determination (R²), adjusted R², root mean square error (RMSE), mean absolute percentage error (MAPE), standard deviation ratio (SD ratio), and Akaike Information Criterion (AIC). With the lowest values for RMSE, MAPE, SD ratio, and AIC (246, 1.926, 0.085, and 845, respectively), and the highest R² value (0.993) and adjusted R² value (0.989), the MARS algorithm was determined to be the best model for characterizing fresh herbage yield. As a solid alternative to other data mining techniques, the MARS algorithm was shown to be the most appropriate model for forecasting fresh herbage production.

Growth, yield, andrographolide content and total antioxidant activity of Kalmegh [Andrographis paniculata (Burm. f.) Wall. ex Nees] under variable nitrogen rates and organic manures application in Indo-Gangetic plains of India

Kalmegh is an important medicinal crop because of the most important biologically active phyto-chemical called andrographolide. Production of higher herbage yields with appropriate quality in terms of andrographolide is largely dependent upon efficient nutrient management. This study aimed to assess the effect of organic manures application and variable nitrogen rates on growth, yield, andrographolide content and total antioxidant activity of Kalmegh. The experiment was laid out in split plot design with three levels of organic manures [M1- Control, M2- vermicompost @ 5 t ha−1 and M3- poultry manure @ 5 t ha−1] and four fertility levels [F1- 0: 50: 50, F2- 50: 50: 50, F3- 75 (37.5 + 37.5): 50: 50 and F4- 75: 50: 50 kg ha−1 N, P2O5 and K2O, respectively] replicated thrice. The highest dry herbage yields and andrographolide content of kalmegh were recorded with vermicompost @ 5 t ha−1 + 75 (37.5 + 37.5): 50: 50 N, P2O5 and K2O kg ha−1 followed by poultry manure @ 5 t ha−1 + 75 (37.5 + 37.5): 50: 50 N, P2O5 and K2O kg ha−1 during both the years while, lower yields due to control. Dry herbage and andrographolide yield were found to be highest in M2×F3 compared with M1×F1. Our study concluded that the application of vermicompost @ 5 t ha−1 along with 75 kg ha−1 N in two splits and 50 kg ha−1of each P2O5 and K2O resulted higher yield and andrographolide content which, would provide better soil nutrient status in sustainable manner without affecting ecological balances.

Fertilization, irrigation and pasture sown to improve herbage production and quality in Nothofagus antarctica silvopastoral systems in southern Patagonia

Fertilization, irrigation and pasture sown to improve herbage production and quality in Nothofagus antarctica silvopastoral systems in southern Patagonia

Agronomic Biofortification of Fodder Maize (Zea mays L.) with Zn for Improving Herbage Productivity and Its Quality

Zinc (Zn) deficiency in soils not only reduces the productivity of forage crops, but also results in inadequate dietary zinc intake for livestock. The objective of this study was to evaluate the impact of different rates and methods of applying ZnSO4 to both soil and foliage on the yield and quality of fodder maize grown in a sandy loam soil testing low in DTPA-extractable Zn. A 2-year field experiment was conducted with six treatments including control, foliar application of 0.3% ZnSO4 at 30 days after sowing (DAS) (F1), foliar application of 0.3% ZnSO4 at 30 and 40 DAS (F2), soil application of 16 kg ha−1 ZnSO4 (S16) and a combination of both soil and foliar ZnSO4 application (S16 + F1 and S16 + F2). Increase in green herbage yield by 25%, dry matter yield by 47% and Zn content by 79% was observed under S16 + F2 treatment over the control. Zinc application improved N, K, Cu and crude protein content of herbage significantly over the control. Thus, the study shows that significant improvement in growth parameters, herbage yield and quality of maize can be achieved with soil Zn application + two foliar sprays of ZnSO4 at 30 and 40 DAS, thereby ensuring availability of improved fodder Zn to the livestock.

Cattle dry manure fertilization increases forage yield of grass‐legume mixtures, while maintaining the legume proportion and root‐associated microbiota

AbstractThe aim of this study was to find ways to improve the forage yield of grass‐legume mixtures without compromising soil biodiversity. In Argentinean Patagonia, the effects of applying cattle dry manure (M) and urea (U) (0, 60, 120, or 240 kg N ha−1 year−1) were assessed on herbage production of irrigated fescue‐lotus mixtures, as well as on the activity/abundance of autochthonous arbuscular mycorrhizal fungi and N‐fixing rhizobium bacteria. We hypothesised that manure has advantages over urea in increasing forage yields while maintaining the proportion of legumes and root‐associated microbiota. The 120 U, 240 U, and 240 M resulted in the greatest forage production; however, yield varied depending on the source applied. The high productivity of the 120 U and 240 U was probably due to the fast grass growth immediately after fertilization, which resulted in a depressed growth of the legume. The high yield of the swards fertilized with 240 M was probably due to slight and delayed growth of grass without legume yield decline. The highest radiation interception was found in swards with a low legume proportion, suggesting a light competition from grass fertilized with the highest urea doses, which were also consistent with the highest N and P nutritional status. The microbial activity/abundance were not affected by fertilization, but the final number of nodules was positively associated with the legume proportion. In conclusion, manure fertilization increased forage yield of the mixtures, while preserving the legume proportion and the root‐associated microbiota. Our findings aid in reducing synthetic‐N fertilizers applied in pasture‐based livestock systems.

Sweet specificities of the root extracellular trap of perennial ryegrass (Lolium perenne), a fructan accumulating plant

Perennial ryegrass (Lolium perenne) is a fructan-accumulating plant constituting one of the most important grassland species with high herbage production, nutritive value and digestibility for grazing cattle. Although fructans were reported to be involved in plant defense acting as antioxidants or stress signals, their contribution in root protection is still to be explored. In roots, atypical defense is provided by the “Root Extracellular Trap” or “RET” at the root-soil interface. The molecular composition and structural organization of the RET are essential to provide root defense against pathogen attacks and abiotic stresses. The RET was reported to be mainly composed of polysaccharides (homogalacturonan, xylogalacturonan, xyloglucan) and proteoglycans such as arabinogalactan proteins (AGPs). Our aim is to characterize the RET composition of L. perenne using cell imaging techniques and a wide range of monoclonal antibodies directed against epitopes from cell wall glycomolecules and to investigate the potential presence of fructans. Interestingly, we found that both mucilage and cell wall surface of border cells were enriched in AGP epitopes. An increased amount of the AGP-containing mucilage was produced by L. perenne root tip in response to both elicitor and osmotic stress. Fructan epitopes were also detected in root cap cells and appeared to be released in the RET under stress conditions. Taken together our findings suggest that AGPs together with fructans are involved in root response of L. perenne to environmental stresses.

The soil microbiome of Lolium perenne L. depends on host genotype, is modified by nitrogen level and varies across season

Genotype by environment interactions (G × E) are frequently observed in herbage production. Understanding the underlying biological mechanisms is important for achieving stable and predictive outputs across production environments. The microbiome is gaining increasing attention as a significant contributing factor to G × E. Here, we focused on the soil microbiome of perennial ryegrass (Lolium perenne L.) grown under field conditions and investigated the soil microbiome variation across different ryegrass varieties to assess whether environmental factors, such as seasonality and nitrogen levels, affect the microbial community. We identified bacteria, archaea, and fungi operational taxonomic units (OTUs) and showed that seasonality and ryegrass variety were the two factors explaining the largest fraction of the soil microbiome diversity. The strong and significant variety-by-treatment-by-seasonal cut interaction for ryegrass dry matter was associated with the number of unique OTUs within each sample. We identified seven OTUs associated with ryegrass dry matter variation. An OTU belonging to the Solirubrobacterales (Thermoleophilales) order was associated with increased plant biomass, supporting the possibility of developing engineered microbiomes for increased plant yield. Our results indicate the importance of incorporating different layers of biological data, such as genomic and soil microbiome data to improve the prediction accuracy of plant phenotypes grown across heterogeneous environments.

Herbage and sheep production from simple, diverse, and legume pastures established in an agrivoltaic production system

AbstractAgrivoltaic systems combine solar energy and agriculture, promoting dual land use. Although grazing sheep in these systems is common, research on intentionally designed pastures to increase production is lacking. This study seeks to compare the herbage growth and lamb production in simple, diverse, and legume pastures in an agrivoltaic system over 2 years in Oregon. Annual herbage production in diverse pastures (4583 kg DM ha−1) was comparable to simple pastures (4457 kg DM ha−1), but higher than legume pastures (p < .05; 4023 kg DM ha−1) for the 2020/2021 growing season. In the 2021/2022 growing season, diverse pastures had a higher yield (4660 kg DM ha−1, p < .05) than simple pastures (4052 kg DM ha−1), which were similar to legume pastures (3955 kg DM ha−1). Liveweight gain (LWG; g head−1 d−1) tended (p = .06) to be higher from lambs in diverse and legume pastures compared to simple pastures in spring 2021. Liveweight production (LWP; kg ha−1 d−1) of legume pasture were greater (P < 0.05) than other pasture types, while simple pastures had the lowest LWP during this period. In summer 2021, LWG tended to be greater in lambs grazing diverse versus simple pastures. No difference was detected (all p > .05) in LWG or LWP at any grazing period in 2022. Overall, efficiency of pasture production was greatly reduced by lower light availability in all pasture types. Diversification of pastures using forbs in agrivoltaics was a good strategy for greater herbage production, while the legume pastures had poor persistence.

The effect of nitrogen and phosphorus fertiliser application rate and strategy on herbage production and nitrogen response in spring

Maximising herbage yield while reducing nitrogen (N) fertiliser input, particularly in spring, is essential to ensure environmental and economic sustainability on grassland farms. A plot experiment was conducted over 2 yr, comparing three different spring N application rates of 30 (30N), 60 (60N) and 90 (90N) kg N/ha using three different spring application strategies: 0:100 (S1), 50:50 (S2) or a 33:66 (S3) split across February and March, respectively. Half of the plots also received phosphorus (P) fertiliser with the first application of N at a rate of 13 kg P/ha. Nitrogen fertiliser application for the remainder of the year (April–September) was the same for all plots (23 kg N/ha/application). Both spring and cumulative herbage yields were significantly affected (P < 0.05) by N application rate; 90N had the greatest spring and cumulative herbage yield compared to 30N and 60N (10,925, 9,834 and 10,499 kg DM/ha, respectively); however, N response reduced as N application rate increased. Nitrogen application strategy had a significant effect (P < 0.05) on spring herbage yield, with S1 significantly lower than S2 and S3. Applying 13 kg P/ha in spring increased herbage yield at defoliations 2 (23 April) and 3 (15 May) (+133 and 56 kg DM/ha, respectively), relative to no application of P fertiliser, as well as increasing cumulative herbage yield (+241 kg DM/ha). The results of the current study indicate that N should be applied in early February and the strategic application of N and P during spring can increase spring and cumulative herbage yield.

Perennial grasses in the south of Primorsky kray

Timothy grass (Phleum pratense L.) and cocksfoot (Dactylis glomerata L.) are among essential perennial fodder crops in the monsoon conditions of Primorsky kray. The paper presents the results of a study on hybrid specimens of timothy grass and cocksfoot. It was discovered that the herbage productivity of the timothy grass hybrids ranged from 317 (Morshanskaya 69 х Primorskaya mestnaya) to 372 g per plant (Primorskaya mestnaya х Narymskaya). The herbage productivity of the cocksfoot hybrids varied within 333-374 g per plant (Pushkinskaya х Dikorastushchaya and Dikorastushchaya х Aukshtuole, respectively). The following hybrids had the highest seed productivity per plant: Primorskaya mestnaya х Morshanskaya 69 (4.8 g, timothy grass) and Dikorastushchaya х Aukshtuole (3.5 g, cocksfoot). Hybrids Primorskaya mestnaya х Narymskaya and Dikorastushchaya х Aukshtuole stood out for the complex of economically important traits.

Integrated crop and livestock systems increase both climate change adaptation and mitigation capacities

Integrated crop-livestock systems (ICLS) are proposed as key solutions to the various challenges posed to present-day agriculture which must guarantee high and stable yields while minimizing its impacts on the environment. Yet the complex relationships between crops, grasslands and animals on which they rely demand careful and precise management. In this study, from a 18-year ICLS field experiment in Brazil, that consists in annual no-till soybean-pastures grazed by beef cattle, we investigated the impacts of contrasted pastures grazing intensities (defined by sward heights of 10, 20, 30 and 40 cm, plus an ungrazed treatment) on the agroecosystem productivity and soil organic carbon (SOC) under both historical and future (2040–2070, RCP8.5) climatic conditions. We used an innovative methodology to model the ICLS with the STICS soil-crop model, which was validated with field observations. Results showed that the total system production increased along with grazing intensity because of higher stocking rates and subsequent live weight gains. Moderate and light grazing intensities (30 and 40 cm sward heights) resulted in the largest increase in SOC over the 18-year period, with all ICLS treatments leading to greater SOC contents than the ungrazed treatment. When facing climate change under future conditions, all treatments increased in productivity due to the CO2 fertilization effect and the increases in organic amendments that result from the larger stocking rate allowed by the increased pasture carrying capacity. Moderate grazing resulted in the most significant enhancements in productivity and SOC levels. These improvements were accompanied by increased resistance to both moderate and extreme climatic events, benefiting herbage production and live weight gain. Globally, our results show that adding a trophic level (i.e. herbivores) into cropping systems, provided that their carrying capacities are respected, proved to increase their ability to withstand climate change and to contribute to its mitigation.

Adjusting nitrogen fertilization to spatial variations in growth conditions in silvopastoral systems for improved nitrogen use efficiency

Grass swards in silvopastoral systems have a lower herbage production near trees than open grassland. This is related to a lower nitrogen (N) uptake in an area close to the tree lines. The N use efficiency for the whole field can then be improved when N input is spatially adjusted and the overall amount reduced. We performed a 2-year field experiment to gain insights into this idea for making savings on N inputs by studying the response of the grass sward to fertilizer N input in relation to the distance from trees. We hypothesized an interaction between N input rate and position to the tree line on grassland herbage production and N uptake and, accordingly, N use efficiency. The field trial was carried out in a silvopastoral system in Germany consisting of the factors year (2019 and 2020), position (2.5, 6.5 and 24.5 m distances to tree line), annual N application rate (0, 15 and 30 g N m−2) and harvest date (four harvests per year). We found significant interactions between position × N rate for all target variables, and usually also in interactions with the harvest date or year. The N application close to trees at a distance < 6.5 m had in most cases no significant influence on herbage production but significantly increased herbage production by up to 35% at positions further away. Omitting the N fertilization in a corridor of 6.5 m near the trees would contribute directly to the saving of fertilizer N without a negative trade-off in herbage production.

Nitrogen offset potential in a multiyear farmlet-scale study: Milk and herbage production from grazed perennial ryegrass–white clover swards

The objective of this study was to quantify the farm gate nitrogen (N) offset potential of perennial ryegrass (Lolium perenne L.; PRG) white clover (Trifolium repens L.; WC) swards by comparing the herbage and milk production from dairy farmlets that were simulations of full farming systems. A study was established where 120 cows were randomly assigned to 4 farmlets of 10.9 ha (stocking rate: 2.75 cow/ha), composed of 20 paddocks each. Cows were fed 526 kg of DM of concentrate on average each year. The 4 grazing treatments were PRG-only at 150 or 250 kg of N/ha and PRG-WC at 150 or 250 kg of N/ha. Cows remained in their treatment group for an entire grazing season and were re-randomized as they calved across treatments each year. As cows calved in the spring as standard practice in Ireland, they were rotationally grazed from early February both day and night (weather permitting) to mid-November, to a target postgrazing sward height of 4.0 cm. Mean sward WC content was 18.1% and 15.4% for the 150 and 250 kg of N/ha PRG-WC treatments, respectively over the 3-yr period. When WC was included, lowering the N rate did not reduce pregrazing yield, pregrazing height, or herbage removed, but those factors decreased significantly when WC was absent. Total annual herbage DM production was 13,771, 15,242, 14,721, and 15,667 kg of DM/ha for PRG-only swards receiving 150 or 250 kg of N/ha and PRG-WC swards receiving 150 or 250 kg of N/ha, respectively. In addition, when WC was present, compressed postgrazing sward heights were lower (4.10 vs. 4.21 cm) and herbage allowance (approximately 17 kg/cow feed allocation per cow per day) higher than the high-N control (+ 0.7 kg of DM/cow per day). There was a significant increase in milk production, both per cow and per hectare, when WC was included in PRG swards. Over the 3-yr study, cows grazing PRG-WC had greater milk (+304 kg) and milk solids (+31 kg of fat + protein) yields than cows grazing PRG-only swards. This significant increase in milk production suggests that the inclusion of WC in grazing systems can be effectively used to increase milk production per cow and per hectare and help offset nitrogen use. This result shows the potential to increase farm gate N use efficiency and reduce the N surplus compared with PRG-dominant sward grazing systems receiving 250 kg of N/ha, without negatively affecting milk solids yield or herbage production, thus increasing farm profit by €478/ha.

Longer cutting intervals on the characteristics of Guinea grass: morphogenetic, productive, and nutritional traits

The aim of this study was to examine the effect of longer cutting intervals on morphogenetic and structural traits, herbage production, nutritional value, and in vitro digestibility of Guinea grass cv. Mombaça (Mombaça grass). Four cutting intervals (49, 63, 77, and 91 days) were evaluated in two crop years (2015-2016 and 2016-2017) during the rainy season, in two replicates. Cutting intervals influenced structural and morphogenetic traits, except for number of live leaves (4.35 leaves tiller-1) and final leaf length (72.94 cm) in the 2015-2016 crop year. As the cutting intervals increased, dry matter yield and stem percentage increased, whereas leaf percentage and leaf-to-stem ratio declined. Regardless of the evaluated crop year, the dry matter, acid detergent fiber, and lignin contents increased linearly; however, the neutral detergent fiber content was unaffected. Cutting intervals affected the crude protein content and in vitro digestibility. Considering leaf appearance rate, stem appearance rate, and leaf-to-stem ratio, the recommended harvest age for Mombaça grass for optimum yield and nutritional value is 77 days.

Shoot nitrogen concentrations required for optimal herbage growth of multiple perennial ryegrass (Lolium perenne L.) cultivars relative to modern summer‐active cocksfoot (Dactylis glomerata L.) and tall fescue (Festuca arundinacea Schreb.) cultivars

AbstractOne possible approach for improving the nitrogen (N)‐use efficiency of perennial ryegrass (Lolium perenne L.) pastures and reducing environmental N losses is to select cultivars or incorporate alternative pasture species with lower shoot N concentrations. Viability of this strategy depends on herbage production not being unduly compromised. A pot experiment compared the shoot N concentration requirements of a diverse range of perennial ryegrass cultivars to achieve 90% and 99% of the herbage yield maxima achievable within a 20 day regrowth cycle. This research was undertaken to quantify if and what effect Australasian breeding programs have had on the N nutrition of perennial ryegrass. Our experiment found minimal genetic variation in the shoot N concentration requirements for vegetative perennial ryegrass swards to achieve near‐maximum herbage yields of living biomass. Across evaluated cultivars, swards achieving 90% and 99% of herbage yield maxima required minimum shoot N concentrations (on a dry matter basis) of 2.56% and 2.87%, respectively. Our experiment also evaluated the shoot N concentration requirements of modern summer‐active cocksfoot (syn. orchardgrass; Dactylis glomerata L.) and tall fescue (Festuca arundinacea Schreb.) ecotypes. We found their shoot N concentration requirements to achieve optimal herbage growth to be similar to those of perennial ryegrass. Taken together, our results suggest that within the perennial ryegrass genome, and among similar high yielding temperate perennial grasses, there may be limited scope for selecting plants with lower shoot N concentration requirements.

Bahiagrass (Paspalum notatum CV. Inia Sepé) responses to defoliation intensities

AbstractDefoliation management is determinant of forage production and plant persistence. The objective of this study was to identify grazing suitability and stability of herbage production of INIA Sepé subjected to four intensities of defoliation (represented for sward canopies of 3, 10, 17 and 24 cm maintained constant through weekly cuts) and two rates of nitrogen fertilization (100 and 300 kg ha−1). The response variables studied were: botanical/morphological composition of the herbage mass, herbage accumulation, nutritive value, tiller population density (TPD), tiller weight (TW), leaf area index (LAI) and nitrogen nutrition index (NNI) and calculations performed relative to the tiller size × density compensation mechanism (SDC). Taller swards had smaller population of large tillers, with greater individual leaf area, showing a tiller × size density compensation response. Calculations indicated that the regression coefficient for the linear regression between TW and TPD in a log scale was close to −2.5, in agreement with the −5/2 self‐thinning rule, with variable LAI and R (ratio between tiller leaf area and volume). The exception was during year 1 for the 100 kg N ha−1, when the regression coefficient was close to −1.5. During year 2 only one replication of the 3 cm and 100 kg N ha−1 did not follow the SDC line. LAI and herbage accumulation were positively correlated with the distance between points of log(TW) × log(TPD) and an hypothetical −3/2 SDC line (p &lt; .0001). Paspalum notatum cv. INIA Sepé shows stability of herbage accumulation and ability to adjust tiller size and population density.

Effects of grazing platform stocking rate on productivity and profitability of pasture-based dairying in a fragmented farm scenario

The area adjacent to the milking parlor, accessible for grazing by lactating dairy cows (i.e., the grazing platform [GP]), can be limited on fragmented pasture-based dairy farms. Such farms, with a moderate overall farm stocking rate, typically have a much higher stocking rate of dairy cows on the grazing platform This study quantified the effects of farm fragmentation on milk and herbage production and profitability in a whole-farm systems-scale study over 3 years (2017-2019). Four systems, each with an overall farm stocking rate of 2.5 cows/ha but with different grazing platform stocking rates (GPSR), were examined. The proportions of the overall farm area within the GP were 100%, 83%, 71%, and 63% in each of the 4 systems, respectively. Hence, the 4 systems had GPSR of 2.5, 3.0, 3.5, and 4.0 cows/ha. The GP was used for grazing and silage (ensiled herbage) production, and the non-GP portion of each GPSR system was used solely for silage production. Concentrate supplementation per cow was the same across all GPSR systems; approximately 10% of the annual feed budget. All systems were compact spring-calving with 24 cows per system. We discovered a lower proportion of grazed herbage in the diet with higher GPSR. All silage produced on the non-GP areas was required to support higher GPSR on each of the systems. Annual herbage production and milk production per cow were not different between GPSR systems, resulting in similar milk production per hectare of the overall system area. The economic implications of different GPSR on fragmented farms were modeled in 2 scenarios: (1) quantifying the cost associated with different levels of farm area fragmentation; (2) investigating the optimum GPSR on pasture-based dairy farms, depending on variable criteria. A greater level of farm fragmentation lowered the profitability of pasture-based dairy production. Costs of production increased with higher GPSR and longer distances between GP and non-GP areas. At a fixed GP area, it was most profitable to increase GPSR up to 4 cows/ha on the GP when milk price was high, land rental price was low, and shorter distance existed between GP and non-GP areas.

The influence of soil potassium status on the productivity of docks (Rumex obtusifolius L.) in intensively managed temperate grassland

AbstractDocks are a widespread problem in grassland, necessitating novel management solutions as pesticides become increasingly regulated. The objective was to investigate the role of soil test Potassium (K) concentrations (Morgan's solution; Na acetate + acetic acid, pH 4.8; STK) on competitiveness of docks in grassland. The experimental site (52°21 N, 7°18 W) was reseeded with perennial ryegrass in October 2009. A plot experiment was laid down in a randomised complete block design with seven rates of fertiliser K (0, 50, 100, 150, 200, 250 and 300 kg ha−1) and eight replicates. Dock numbers were measured over 6 years (2010–2015) and herbage production over 5 years (2012–2016). There was poor alignment between fertiliser K and STK in the early years of the study, however this alignment improved over time. While fertiliser K had no effect on dock numbers, there were positive correlations between STK early in the study and dock numbers m−2 throughout the study. Dock numbers m−2 were relatively static between 2010 and 2012 and increased substantially between 2013 and 2015. Between 2013 and 2016 there were strong inverse relationships (r &gt; −.765; p &lt; .001) between dock and grass herbage production. Towards the end of the study the lower annual fertiliser K inputs (0 and 50 kg ha−1) resulted in lower (p &lt; .01) dock root and herbage production with an associated increase (p &lt; .05) in grass herbage production. It is evident there is a threshold STK for permanent grassland infested with docks at which grass is more competitive for plant‐available soil K than the docks to the detriment of the dock component of the sward.

Grazing intensity effects on sward responses of UF Riata Bahiagrass

AbstractBahiagrass (Paspalum notatum Flüggé) is a rhizomatous, perennial, warm‐season forage widely grown in the southeastern United States "UF Riata" bahiagrass is more upright growing with greater herbage production when days are shorter compared with most other cultivars. Lesser daylength sensitivity extends the grazing season, but in combination with more upright growth may negatively affect persistence under grazing, especially if out‐of‐season herbage production interferes with normal reserve storage. This 3‐year study investigated above and belowground sward responses of UF Riata bahiagrass to three levels of post‐grazing herbage mass (HM) (500 [heavy grazing, HG], 1500 [moderate grazing], or 2500 [light grazing, LG] kg DM ha−1, where DM is dry matter) imposed by mob stocking every 14 days. Total herbage accumulation (HA) and HA rate were not affected by treatment. Crude protein (CP) was affected by treatment × grazing cycle × year, whereas in vitro digestible organic matter concentrations were affected by treatment × year and grazing cycle × year. Root–rhizome biomass (12,940–9230 kg OM ha−1, where OM is organic matter) and soil cover percentage (97%–93%) decreased linearly as grazing intensity increased from LG to HG. Proportion of non‐planted grasses was 34% and 17% in HG and LG swards, respectively. Proportion of non‐grass weeds increased across treatments from 2% to 22% over the years. Moderate grazing could maintain similar CP to HG, and similar root–rhizome biomass to LG. Thus, considering both sward persistence and forage nutritive value, a target post‐grazing HM of ≈1500 kg DM ha−1 is recommended when UF Riata pastures are grazed every 2 weeks.

Эколого-биологические аспекты кустарниковой мелиорации деградированных пастбищ на бугристо-увалистых комплексах песчаных земель Прикаспия

The article presents the results of studies of the effectiveness of shrub reclamation on pastures of the Caspian Sea. Introduction. As a result of the outbreak of deflationary desertification of lands that occurred on the territory of the Russian Caspian Sea in the 70-80-ies of the XX century, it became necessary to develop methods for large-scale shrub reclamation of degraded lands. One of the problematic areas where these works were carried out is pastures on light soils of the Astrakhan Volga region. Materials and methods. The study is based on biomonitoring materials and field experiments using standard methods of forest taxation, soil science and geo-botany. Results and discussion. Thanks to the microclimate, the best conditions for the growth of herbaceous vegetation are formed in the spaces between pasture-protective strips with a width of 30 m. The yield of herbage phyto mass on them, both in spring and autumn, is higher by 0.06–0.13 t/ha. With severe damage or destruction of shrub plantations, areas with productive herbage degrade. Reclamation and forage plantations, depending on the age, increase the yield of pastures by 41–85%. The productivity of herbage is everywhere higher on pastures with a complex of pasture-protective and reclamation-forage plantations with teresken at the age of 20-25 years. Сonclusion. It has been established that pasture protection strips from haloxylon, reclamation and fodder plantations from krascheninnikovia and calligonum in the Astrakhan Volga region have been functioning for more than 45 years. It was determined that in forested areas, depending on age, the preservation of saxaul is 14–45% with an average plant height of 2.0–3.2 m. It is shown that the plantings of krascheninnikovia and calligonum on hollow-bumpy and withered plains with light soils at the age of 30–40 years have a safety of 45–70%, have a positive effect on the restorative succession of herbage between rows of shrubs and in the wind-shade zones of strip and backstage plantings. It was revealed that the addition to the pasture forage in the form of an available twig-leaf mass of shrubs in May – August can reach 0.5–4.0 t/ha in dry form. The hay yield of natural forage vegetation under the protection of shrub plantations on improved pastures is 1.2–1.5 times higher compared to unprotected lands and amounts to 0.70–1.60 t/ha. The results of the research can be useful in the phyto-melioration of degraded pastures located on bumpy sandy lands. Suggestions for practical application and direction of future research. The results of the research can be useful in the phytomelioration of degraded pastures located on bumpy sandy lands. An urgent problem remains the development of a system of measures for the care, repair and reconstruction of shrub plantations that can increase their productivity and durability on functioning pastures.