Zadnjih godina poljoprivrednici se sve više susreću s polaganim rastom temperatura zraka, a koje tijekom ljetnih mjeseci najčešće prati i nedostatak oborina. U Hrvatskoj nedovoljnu opskrbu vodom ...najlakše opažamo za kasne jarine poput kukuruza i soje jer se njihova aktivna vegetacija najvećim dijelom odvija tijekom najtoplijeg i najsušnijeg dijela godine (srpnja i kolovoza). Općenito se može reći da sa sve dužim razdobljem nedostatka vode tijekom vegetacije dolazi do sve većih šteta u usjevu jer biljke zaostaju u rastu, imaju manju veličinu lisne površine, a time će na kraju i njihov prirod odnosno prinos biti značajno umanjen. Suša koja nastupi za vrijeme kritičnog perioda za vodu najviše smanjuje prirod odnosno prinos uzgajane kulture, a u ekstremnim slučajevima mogu nastati i potpune štete. No, suša ima prvenstveno jako negativan utjecaj na prinos, dok je njen učinak na kakvoću prinosa odnosno priroda relativno malen. U stručnom radu se iznosi negativan učinak visokih temperatura zraka i nedostatka vode na prinos i kakvoću kukuruza i soje, dvije naše najraširenije jare kulture.
This study investigated the effects of supplementing diets consisting of two dent corn hybrids (soft- and hard-type) with different amounts of rapeseed oil (2, 3, and 4%) and with (0.05%) or without ...emulsifier (Lysoforte Extended, Kemin) on the content and deposition of carotenoids in egg yolk. The feeding trial was conducted with 216 Lohmann Brown laying hens which were by 3 located in 72 cages. The cages were randomly assigned to 12 dietary treatments (2 hybrids × 3 rapeseed oil levels × 2 emulsifier levels), resulting in 6 cages (replicates) per each dietary treatment. After depletion, hens were fed treatment diets without added pigment for 7 wk. After stabilization of the carotenoid profile (lutein, zeaxanthin, α- and β-cryptoxanthin and β-carotene and total carotenoids), eggs were collected once a week until the end of the experiment and deposition efficiency was calculated based on carotenoid content in yolk and diets, yolk weight, egg production and diet intake. Corn hybrid and rapeseed oil affected (P < 0.05) the yolk content and deposition efficiency of most carotenoids. Moreover, a significant (P < 0.05) hybrid × rapeseed oil level interaction for all carotenoids indicated hybrid-specific responses to rapeseed oil supplementation. In the soft-type hybrid, the addition of 3% rapeseed oil enhanced the carotenoid content compared to 2% of rapeseed oil, whereas for the hard-type hybrid, 2 and 3% of rapeseed oil resulted in similar contents. Supplementation of 4% rapeseed oil reduced the content regardless of the hybrid. Emulsifier addition positively affected (P < 0.05) the deposition efficiency of all carotenoids except β-carotene. In conclusion, supplementing corn diets with rapeseed oil and emulsifier affected carotenoid utilization and these responses varied in hybrids differing in grain hardness, which should be considered when using corn as the sole source of carotenoids in hen diets.
Yolk carotenoid profile reflects the hen diet when corn grain is the only source of carotenoids, but corn origin and processing may affect carotenoid utilization. In the present study, 2 commercial ...dent corn hybrids differing in grain hardness (soft- and hard-type) were dried at low (40°C) and high (85°C) temperature and ground through a 5- and 9-mm sieve to investigate their effects on carotenoid bioavailability in laying hens. With 3 hens per cage, 168 Lohmann Brown laying hens were allocated to 8 dietary treatments (2 hybrids × 2 drying temperatures × 2 grinding sieves) in a completely randomized design (8 treatments × 7 cages). The trial lasted 8 wk, during which eggs were collected for analysis every 3 d until carotenoid content stabilized, and then once a week until the end of the experiment. The carotenoid profile of the experimental diets and yolks was analyzed using an HPLC method and deposition efficiency was calculated based on carotenoid contents, yolk weight, egg production and diet intake. The deposition efficiency for lutein, zeaxanthin, α- and β-cryptoxanthin, and β-carotene averaged 27.37, 18.67, 6.29, 3,32, and 0.94%, respectively. As expected, the tested hybrids highly affected the carotenoid content in egg yolk due to their differences in carotenoid profile. Interestingly, hard- and soft-type hybrids differed in the deposition efficiency for all individual carotenoids but not for the total carotenoids. High grain drying temperature tended to increase the bioavailability of lutein and zeaxanthin in both hybrids. For the hard-type hybrid, the content of β-carotene in egg yolk was higher when grains were dried at a high temperature, while the opposite response was found in the soft-type hybrid. The effect of grinding sieve size was important for the zeaxanthin bioavailability in the soft-type hybrid only. In conclusion, our findings showed that corn hybrid had a primary influence on the carotenoid content in the yolks of laying hens, but grain processing may change the bioavailability of carotenoids.
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•Kernel properties and carotenoid in vitro digestion were analysed in 103 commercial dent hybrids.•Tested hybrids characterized higher zeaxanthin than lutein content.•Kernel hardness ...traits are related to the extent of the amount of digested carotenoids.•Fiber, protein and amylose correlated with the release of carotenoids during digestion.
The objective of study was to investigate the relationships between maize kernel properties and carotenoid release during simulated gastrointestinal digestion of 103 hybrids of dent type. Commercial maize hybrids significantly differed in kernel hardness, chemical composition and carotenoid profile. Across all hybrids, the amount of digestible individual carotenoids increased as follows: β-carotene < α-cryptoxanthin < β-cryptoxanthin < lutein < zeaxanthin. The amount of digested carotenoids correlated negatively with amylose content and amylose-to-amylopectin ratio, while it correlated positively with the content of neutral detergent fibres and amylopectin as well as the Stenvert index. However, the content of endosperm lipids could not be related to carotenoid digestibility. Findings clearly indicate that the carotenoid release from the kernel during digestion is related to specific physical and chemical properties, leading to a better understanding of the effects of kernel matrix structure on carotenoid digestibility in dent-type maize hybrids.
Sweet sorghum (Sorghum bicolor L.) is an important silage crop and has an increasing popularity because of the need for relatively smaller quantities of water per unit dry matter production compared ...to maize. Regarding to high feed costs of protein supplementations, legumes can be used in livestock nutrition for their high protein content and, thus, providing cost savings. Since legumes have low dry matter yield, acceptable forage yield and quality can be obtained from intercropping cereals and legumes, compared to their sole crops. In this study, sweet sorghum (Sorghum bicolor L.) and climbing bean (Phaseolus vulgaris L.) intercropped in different sowing densities and pure sweet sorghum crops were evaluated to the best intercropping system with respect to yield and quality of fodder. Sweet sorghum was sown alone (18.0 seeds/m2) and intercropped with climbing bean as follows: 18.0 seeds/m2 of sweet sorghum and 3.7 seeds/m2 of climbing bean, 18.0 seeds/m2 of sweet sorghum and 5.0 seeds/m2 of climbing bean and 18.0 seeds/m2 of sweet sorghum and 7.5 seeds/m2 of climbing bean. The highest dry matter yield was produced by 18.0 plants/m2 of sweet sorghum and 7.5 plants/m2 of climbing bean (20.7 t/ha), and the lowest by solo sweet sorghum (18.2 t/ha). Intercropping of sweet sorghum with climbing bean reduced neutral detergent fiber content, which in turn, results in increased forage digestibility. Based on forage yield and quality, this study showed that among all intercropped forages, of 18.0 plants/m2 of sweet sorghum and 7.5 plants/m2 of climbing bean treatment were better performing than other intercrops.
Echinochloa crus-galli (L.) P. Beauv. is the most common monocotyledonous weed in maize crops in Croatia. Crop–weed interference is influenced by weed emergence patterns, and knowledge of the timing ...of weed emergence is crucial for the development of an efficient integrated weed-management program. Therefore, two-year field experiments were conducted in a maize crop sown in early May in continental Croatia to determine the emergence pattern of E. crus-galli from natural seedbank. In laboratory studies, the estimated base temperature and base water potential for the Croatian ecotype of E. crus-galli were 10.8 °C and −0.97 MPa, respectively. Then, the estimated germination parameters were compared with the values embedded in the AlertInf model from Italy (Veneto) to calibrate this hydrothermal model. The estimated hydrothermal units were around 28 for the onset (10%) and 93 for the middle (50%) emergence of E. crus-galli. Our findings showed that the AlertInf model satisfactorily simulated the emergence of E. crus-galli in maize crop in Croatia (EF = 0.97 in 2019 and 0.98 in 2020), indicating its potential use in other geographical areas
The nutritional value of maize grain can be influenced by its genetic background, which can lead to differences that could affect laying hens due to the high proportion of maize hybrids in the ...complete feed. This study aimed to investigate the effects of modern maize hybrids on hen production and egg quality. Dietary treatments differed only in a grain of 15 high-yielding maize hybrids, added at a fixed proportion of 600 g kg−1 and without additional pigments. By 3 in each cage, 225 Lohmann Brown hens were allocated to 15 dietary treatments in a completely randomized block design (15 treatments × 5 cages). The experiment lasted 10 weeks, during which the number and weight of eggs were recorded daily, and diet intake was recorded weekly. Eggs for quality analysis were collected once per week during the last five weeks of the experiment. Dietary treatments differed (p < 0.05) in complete feed intake (119.7–123.1 g), egg weight (58.02–61.51 g), daily egg mass (56.17–60.16 g), and feed conversion ratio (2.01–2.19). As expected, dietary treatments did not affect egg traits such as shape index, albumen height, Haugh units, shell strength, thickness, and weight, but differed (p < 0.05) in yolk color (6.28–8.76) and yolk (14.74–16.03 g) and albumen (34.39–39.29 g) weights. The findings suggest that using different maize hybrids in complete feeds used in egg production systems may lead to small but significant differences in some hen production and egg quality traits, which in turn affect farmers’ income.
Little is known about the best management systems for seed production of Italian ryegrass. The main objective of this study was to determine the influence of management systems on the first-year seed ...crop grown under various nitrogen fertilization (0, 60, 120 and 180 kg ha−1). Management systems of single-purpose crops were with (SeedPGR-crop) and without (Seed-crop) plant growth regulator application. The dual-purpose crops incorporated early spring forage cut during stem elongation (EF-seed-crop) and late cut at the onset of heading (LF-seed-crop) followed by seed harvest. Compared to the single-purpose crops, the dual purpose-crops shattered much less seeds but still yielded less because their plants had lower number of visible nodes on stems, shorter ears, fewer spikelets per ear, fewer flowers per spikelet in various ear sections and lighter seeds. Despite similar lodging incidence, the SeedPGR-crop produced relatively small, but significantly larger seed yield than the Seed-crop because plants in the SeedPGR-crop had shorter stems with fewer vegetative tillers, and shattered seeds slightly less. Nitrogen fertilization consistently improved seed yields in all management systems regardless of associated increases in lodging and seed shedding. These yield increments were mainly associated with the increased number of early- and late-formed reproductive tillers, and partly due to improved number of florets per spikelet and slightly heavier seed in early-formed reproductive ears. In spite of larger seed losses through shattering, the single-purpose crops largely out-yielded and had higher seed germination than the dual-purpose crops at all nitrogen fertilization rates, with maximized yields produced in the SeedPGR-crop.
Variations in soil pH have been shown to affect mesotrione adsorption, which in turn, may have an impact on crop susceptibility. Therefore, a greenhouse experiment was conducted to evaluate the ...effect of simulated mesotrione residues on pea crop grown in the typical agricultural soil (gleysol) of north-western Croatia. The soil pH was manipulated to obtain neutral (pH 7.0) and acidic (pH 5.0) values. Simulated mesotrione residues were 1.1, 2.3, 4.5, 9.0, 18, 36 and 72 g a.i. ha−1. Crop visual injuries as well as reductions in chlorophyll fluorescence and aboveground dry biomass were higher at pH 7.0 than at pH 5.0. With increasing mesotrione residues, the reductions in chlorophyll fluorescence ranged from 38.8% to 89.7% at pH 5.0 and from 63.7% to 99.3% at pH 7.0. Compared to chlorophyll fluorescence, the reductions in dry biomass were smaller and ranged from 49.2% to 96.8% at pH 7.0 and from 32.0% to 82.6% at pH 5.0 for the mesotrione residues from 1.1 to 72 g a.i. ha−1. These results indicate that soil pH is an important factor determining the susceptibility of pea crop to simulated mesotrione residues.
Huds. is an important pinoxaden-resistant grass weed in many countries of Europe. Recently, the low efficacy of pinoxaden was reported in winter cereals in Croatia, but a preliminary dose-response ...trial showed no herbicide resistance for the investigated weed population. Therefore, a two-year experiment was conducted under greenhouse conditions to determine the efficacy of various pinoxaden doses (20, 40 and 80 g a.i. ha
) on weed visual injuries and biomass reduction after herbicide application at different growth stages. As expected, the maximum weed biomass reduction (97.3%) was achieved by applying the highest dose (80 g a.i. ha
) at the earliest growth stage (ZCK 12-14). A pinoxaden dose of 20 g a.i. ha
resulted in satisfactory weed biomass reduction (88.9%) only when applied at ZCK 12-14. The recommended dose (40 g a.i. ha
) also provided sufficient weed control up to the growth stage ZCK 21-25. Slightly delayed (ZCK 31-32) application of the recommended dose brought about a low weed biomass reduction (60.1%). Double than the recommended dose also failed to provide satisfactory weed control at the advanced weed growth stages (ZCK 31-32 and ZCK 37-39). Thus, reported low efficacy of pinoxaden is most likely because of delayed herbicide application when
is overgrown.
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