Search Results (11)

Growing cover crop mixtures is a sustainable agriculture tool that helps to reduce fertilizer use and, at the same time, ensures lower environmental pollution. The aim of this research is to assess the biomass of the aboveground part of cover crop mixtures and the nutrients accumulated in it and to determine their influence on the soil properties and productivity of spring oats (Avena sativa L.). The biomass of the aboveground part of cover crop mixtures of different botanical compositions varied from 2.33 to 2.67 Mg ha⁻¹. As the diversity of plant species in cover crop mixtures increased, the accumulation of nutrients in the aboveground part biomass increased, and the risk of nutrient leaching was reduced. The post-harvest cover crop mixture TGS GYVA 365, consisting of eight short-lived and two perennial plant species, significantly reduced the mineral nitrogen content in the soil in spring and had the strongest positive effect on organic carbon content. Post-harvest cover crop mixtures TGS GYVA 365 and TGS D STRUKT 1 did not affect the content of available potassium in the soil but significantly reduced the content of available phosphorus. All tested cover crop mixtures, including the undersown TGS BIOM 1 and the post-harvest mixtures TGS D STRUKT 1 and TGS GYVA 365, reduced soil shear strength and improved soil structure, although the reduction was not statistically significant for TGS D STRUKT 1. Cover crop mixtures left on the soil surface as mulch had a positive effect on the chlorophyll concentration in oat leaves, number of grains per panicle, and oat grain yield. A significant positive correlation was found between oat grain yield and several yield components, including crop density, plant height, number of grains per panicle, and grain mass per panicle. These findings highlight the potential of diverse cover crop mixtures to reduce fertilizer dependency and improve oat productivity under temperate climate conditions. Full article

Undersown cover crops are an important tool for weed control in organic farming. The hypothesis of this research was that undersown crimson (incarnate) clover (Trifolium incarnatum Broth.), hairy (winter) vetch (Vicia villosa Roth.), perennial ryegrass (Lolium perenne L.), and winter rye (Secale cereale L.) in combination with bio-preparations inhibit the spread of weeds and influence the seed yield of spring oilseed rape in organic farming. The dry biomass of undersown cover crops, as well as the number and dry biomass of weeds, were determined before harvesting spring oilseed rape (Brassica napus L. spp. oleifera biennis Metzg.) (main crop) to identify the underlying influences on seed yield. We summarized that hairy vetch was distinguished by its rapid growth and by the fact that it produced an aboveground dry biomass that was significantly higher (1.9 to 12.4 times) compared with other cover crops, while crimson clover grown as a cover crop had a significantly higher aboveground dry biomass (by a factor of 3.2 to 4.9) compared with that of perennial ryegrass and winter rye. During the spring oilseed growing season, undersown cover crops did not suppress early emerging weeds that had not been controlled by inter-row loosening. During the spring growing season, weeds were best suppressed using bio-preparation-treated perennial ryegrass. The highest oilseed rape seed yield was obtained in 2020 after the application of bio-preparations in plots without any cover crops. Perennial ryegrass as a cover crop in combination with bio-preparations produced the highest reduction in oilseed rape seed yield. Further research should be directed toward determining the long-term effects of cover crops and bio-preparations on plant community formation in organic farming. Full article

Due to short post-harvest seasons, it is not always possible to grow worthy cover crops (CCs). This research aims to clarify the impact of undersown red clover (Trifolium pratense L., RC) and post-sown white mustard (Sinapis alba L., WM) management on their biomass, accumulated nitrogen (N), phosphorus (P), and potassium (K) content and the nutrient release to subsequent main crops. During the study period, RC mass yields varied from 220 to 6590 kg ha⁻¹ DM and those of WM from 210 to 5119 kg ha⁻¹ DM. WM shoot biomass increased with the increase in rainfall in August and the average daily temperature of the post-harvest period. CC productivity and efficiency were higher when growing short-season spring barley than winter wheat. In the warm and rainy post-harvest period, undersown WM after winter wheat increased the biomass by 34.1% compared to post-harvest sowing. The application of straw (+N) increased the accumulation of nutrients in WM biomass. The intensive fertilization of the main crop had a negative effect on RC yield and NPK accumulation. RC shoot biomass was characterized by a higher N content and WM by a higher P concentration. Well-developed CCs could reduce soil mineral nitrogen content by 28.5–58.8% compared to a plot without CCs. Nutrient transfer to spring barley was dependent on the N content of CC biomass and the carbon and nitrogen ratio (C:N < 20). We conclude that CC growth and efficiency were enhanced by the investigated measures, and in interaction with meteorological conditions. Full article

Farmers may promote the cultivation of under-sown cover crops (CCs) in various ways without jeopardizing the yield of a cash crop. With this survey, we aimed to understand how Finnish farmers manage possible challenges with under-sown CCs. A farmer survey was carried out in 2021. We invited 6493 farmers who had selected CCs as a registered measure to answer a questionnaire with 20 statements (a Likert scale), and 1130 responded (17.4%). A Cochran–Mantel–Haenszel test was used to measure the strength of the association between 11 farm/farmer characteristics of the respondents and 20 statements. Responses indicated that farmers often took under-sown CCs into account during the growing season. Sowing was considered an especially critical measure and the CC seeding rate was often assessed with a test run before sowing. Thirty-nine per cent of the respondents had made investments, most often to facilitate sowing. The farmers usually adjusted the fertilizer rate only according to the cash crop. Early harvesting of a cash crop was considered important by 58% of farmers to ensure that the CCs do not hamper the harvest. Farmers harvested cash crops as soon as they matured and were harvestable, though they had mixed views on whether CCs impacted the quality of the cash crop. Subsidized, investing farmers were likely to be oriented towards the benefits from the ecosystem services provided by CCs. Their experiences should be shared among the farming community to support the large-scale implementation of CCs. Full article

Above-ground biomass cover under Coffea arabica on sloping land is beneficial but difficult to sustain. Interplanting annual and perennial legumes can sustain the above-ground biomass cover, and improve soil fertility, yield, and profitability. This was tested on 26 sloping farms in a four-growing season experiment on undersowing C. arabica with new crop combinations: Mucuna pruriens var. utilis (T1); Millettia dura Dunn (T2); a combination of M. pruriens and M. dura (T3); and the control with a no-cover legume (T4). On each farm, all treatments followed a randomized single-block design. T3 produced 8.7 mt/ha/yr above-ground biomass that was significantly (p < 0.01) higher than other treatments and was increasing with the seasons. Under T3, plant-available nitrogen (N) and potassium (K) increased more than in other treatments. During the fourth season, coffee yield in T3 was 54%, 22%, and 11% higher than in T4, T2, and T1, respectively. The gross profit under T3 was 86% higher than in T4 in the fourth season. This indicates that interplanting a combination of M. pruriens and M. dura under C. arabica on sloping land can sustainably increase above-ground biomass cover, soil’s plant-available N and K, coffee yield, and profitability. Based on the results, the combination of M. pruriens and M. dura is recommended to optimize coffee production under the described conditions. Full article

Cover crops could provide environmental benefits in spring-grain systems through diversification, reduced nitrate leaching, and carbon sequestration. However, few farmers apply the technique, partly as they believe the cover crops will compete with the main crop and cause yield losses. Cover crops can either be sown together with the grain (undersown) or in autumn and establish after grain harvest. The current study uses a mixed-method approach combining field trials, interviews, and literature synthesis. The field trials focused on perennial ryegrass (Lolium perenne L.), Italian ryegrass (Lolium multiflorum Lam.), and meadow fescue (Festuca pratensis L.) that were undersown with 15 kg ha⁻¹ but with different seeding dates in spring wheat and barley. The interviews focused on gathering practical experiences from farmers in Norway and the literature synthesis gathered results from other studies. For carbon sequestration, nine studies were judged relevant for our target climate and included in our synthesis. They showed a median value at 264 kg C ha⁻¹ year⁻¹. In our field trials, 300–900 kg DM ha⁻¹ year⁻¹ was produced, with Italian ryegrass sown at the same date as the grain on top. Our trials showed no significant grain yield reduction due to the use of cover crops. However, our synthesis of the literature showed a 5–10% yield reduction with Italian ryegrass that was sown at the same time as the grain. One- or two-weeks delay in the sowing of Italian ryegrass, or reduced seeding rates, could reduce the problem. The interviews showed that farmers do not prefer undersown species, especially not perennial species, as they have experienced that such species may come up again in the following years and cause a weed problem. We recommend farmers to use cover crops and for undersowing, we recommend Italian ryegrass that is sown one or two weeks after the grain. Perennial ryegrass can also be recommended, as long as the growth is properly terminated. Full article

The inclusion of undersown cover crops in crop rotations and the use of biopesticides are essential for the long-term sustainability of the agroecosystem in organic farming. We hypothesized that biopesticides and undersown cover crops (crimson (incarnate) clover (Trifolium incarnatum Broth.), hairy (winter) vetch (Vicia villosa Roth.), perennial ryegrass (Lolium perenne L.), and winter rye (Secale cereale L.)) are likely to have a positive impact on soil agrophysical and biological properties. Soil shear strength, soil aggregate–size distribution, plant root dry biomass and number and biomass of earthworms were determined at the end of the plant growing season. We concluded that the application of biopesticides and growing of undersown cover crops decreased soil shear strength and increased the percentage of macro-aggregates (0.25–10 mm) in the plough layer. In the plots with cover crops, plant root biomass was found to be significantly higher by a factor of 1.9 to 3.5, compared to the plots without cover crops. The application of biopesticides and undersown cover crops did not significantly affect the number and biomass of earthworms in the soil. The abundance of earthworms was more influenced by meteorological conditions. Full article

Early adopter-farmers form a living lab of farms that have a great deal of hidden knowledge about the cultivation of cover crops (CCs). Understanding of how early adopters use and value CCs provides valuable knowhow to be shared with other farmers. This study gathered information about the most common under-sown CCs in Finland. A structured survey was used to collect farmers’ experiences considering CCs’ regional suitability, growth, competition, and impacts on soil and cash crop yields. The respondents were both conventional and organic farmers who cultivated CCs in 2020. One thousand one hundred and thirty farmers answered the survey. Four hundred and ten times they shared knowhow about the use of under-sown CCs. They were mostly familiar with clovers, ryegrasses, and timothy as CCs. They answered 27 specific statements on CC (a Likert scale, five answer choices). Farmers’ experiences were well in line with the understanding gained from field experiments. Farmers had experienced positive impacts of CCs on soil health. Organic farmers were slightly more positive than conventional farmers. This is attributable to a longer period of having CCs in organic farms, and general differences in means to control weeds and manage crop nutrition. Gained experience with common species used in grassland mixtures had strengthened farmers’ trust in their use of CCs. Farmers having high cereal areas are an important target group for sharing the early adopters’ experiences, as cereal farmers were more challenged to use even common CCs. Future research and on-farm experiments should focus on CCs with other cash crops instead of cereals (grain legumes, rapeseed, and other minor crops). Full article

Soil microbes play a key role in the nutrient cycling by decomposing the organic material into plant-available elements and also by maintaining the soil health. The study of soil microbial hydrolytic activity (SMA) was carried out in a long-term crop rotation (barley undersown (us) with red clover, red clover, winter wheat, pea and potato) experiment in five different farming systems during 2014–2018. There were two conventional systems, with chemical plant protection and mineral fertilizers, and three organic systems, which included winter cover crops and composted manure. The aim of the present study was to evaluate the effect of the (i) cropping system and (ii) precrops in rotation on the soil SMA. The soil microbial hydrolytic activity was significantly affected by yearly weather conditions, farming system, and crops. In all farming systems, the SMA was the lowest after dry and cold conditions during early spring in 2018. In unfertilized conventional systems, the considerably lower SMA is explained by the side effects of pesticides and low organic residuals, and we can conclude that the conventional system with no added fertilizer or organic matter is not sustainable, considering soil health. In each year, the SMA of organic systems with cover crops and composted manure was 7.3–14.0% higher compared to all farming systems. On average, for both farming systems, the SMA of all the rotation crops was positively correlated with the SMA values of precrops. However, in conventional farming systems, the effect of undersowing on the SMA of the precrop was smaller compared to organic systems. Full article

The stability of the soil aggregates is an important soil quality indicator, as it affects the soil’s overall functionality. As the soil aggregates are highly affected by agricultural practices, it is essential to know how crops interact with the aggregation process. Therefore, for obtaining more knowledge, this research was conducted in Estonia in an organic crop rotation field experiment from 2012/2013 through 2015/2016 to study the effects of crops (potato → spring barley undersown with red clover → red clover → winter wheat → pea) under different treatments (T_C—control; T_W—winter cover crops; T_W+M—T_W with farmyard manure 40 Mg ha⁻¹ per crop rotation). The results showed that in the topsoil (5–10 cm), the soil water-stable aggregate (WSA) content (determined by the wet sieving method) from highest to lowest was following: pea (61.7%), winter wheat (61.6%), spring barley (61.5%), red clover (59.3%), potato (57.1%); whereas in the subsoil (30–35 cm): potato (50.6%), pea (48.5%), red clover (47.9%), spring barley (47.7%), winter wheat (46.4%). Therefore, potato was a noticeable crop, as among the crops, it had the lowest WSA content in the topsoil, while highest in the subsoil. The results shown gave an assumption that the after-effects of some crops (foremost with pea) were noticeable in the soil properties during the following crop. In the topsoil, the differences between crops were significant among crops just for T_W and T_W+M treatments. In T_W, potato was lower than spring barley and winter wheat, but not significantly lower than pea or red clover. In the subsoil, significant differences between crops were observed for T_C and T_W treatments: in T_C, potato was just significantly greater than red clover (but similar to other crops), and in T_W, significantly greater than winter wheat. Furthermore, in the topsoil the soil organic carbon (SOC) content was not significantly affected by crops, and the use of winter cover crops generally increased the SOC content while concurrently decreased the WSA content and the soil maximum water holding capacity. This was probably caused by the additional tillage operations which cancelled out the possible benefits for the soil aggregates. As a consequence of the constantly declining SOC content, caused by the weakened soil aggregates, the plant-available P and K contents, especially in the absence of manure applications, decreased as well, probably due to the combination of fixation and removal of plant biomass. Therefore, it is expected that by continuing this trend, the plant growing conditions decline, which in turn will have a negative effect for the aggregate formation and carbon sequestration, which are essential for plant growth. Full article

The experiments were carried out during 2012–2017. There were 5 crops in rotation: Red clover, winter wheat, pea, potato and barley undersown (us) with red clover. There were 5 cropping systems in the experimental setup: 2 conventional systems with chemical plant protection and mineral fertilizers; 3 organic systems which included winter cover crops and farm manure. The aim of the present research was to study the effect of cultivating barley undersown with red clover and the preceding winter cover crop on the soil microbial hydrolytic activity, the change in the content of soil organic carbon (SOC) and total nitrogen (N_tot) compared to the same parameters from the field that was previously under potato cultivation (forecrop of barley in the rotation). The cultivation of barley with red clover (barley (us)) had a positive impact on the soil micro-organisms activity. In organic systems the soil microbial hydrolytic activity increased on average by 19.0%, compared to the conventional systems. By cultivating barley (us) the soil microbial hydrolytic activity had a significant effect on the SOC content only in organic systems where winter cover crops were used. Organic cultivation systems had positive impact on the soil nitrogen content; N_tot in samples taken before sowing the barley (us) was higher by 17.4% and after the cultivation of barley (us) by 14.4% compared to conventional systems, as an average of experimental years. After cultivation of barley (us) with red clover the soil microbial hydrolytic activity had no effect on the soil N_tot content in either cultivation systems. Full article