Search

There is an increased need of identifying reduced tillage method that improves soil organic matter and soil fertility and at the same time best crop performance in organic farming. This study assessed the effects of organically managed reduced tillage and conventional tillage on dynamic soil properties and winter triticale performance. Organic farm that has been treated with three different tillage systems for six consecutive years was used in this study at Drovendaal organic facility of Wageningen University and Research. The tillage systems included two reduced tillage NIT at 10 cm and ECO up to 20 cm deep and CON at a depth of 30 cm. The parameters evaluated are soil physico-chemical properties, leaf area index (LAI), plant dry matter, ear number per area, plant height and chlorophyll content (SPAD) at ear formation stage . Use of NIT led to higher SOM and N-NO3 of 13.03 mg kg-1 at 0-10 cm soil depth. Also, shallow soil depths had lower bulk density and penetration resistance compared to deeper depths but NIT had higher penetration resistance in all soil depths compared to ECO and CON. Based on crop performance, ECO and CON revealed a better crop performance than NIT. Therefore, ECO having intermediate potentials in soil properties and crop performance could be the right tillage system for organic crop production compared to NIT and CON. Moreover, ECO will be a suitable tillage system that improves soil fertility, mitigates greenhouse gases and at the same time influence high crop performance.

Purpose: Complex rice systems (CRSs) are polycultures of plants and animals that enhance ecological processes contributing to sustainable and profitable farming systems. However, the contextual management complexity can hamper adoption, despite the large long-term benefits that CRSs offer. This paper aimed to provide a method that encourages active farmer involvement and integrates farmer’s feedback to deliver timely adaptations to CRS management. Design/methodology/approach: FFSs that are commonly used in guiding rural development processes involve a long process of preparation, weekly meetings and dissemination of new technologies with a greater knowledge flows from researchers or institutions to farmers than contrariwise. We have simplified FFS components and modified its curriculum focusing on extracting and integrating farmers’ feedback into adaptation measures. Surveys were conducted and their results were validated through focus group discussions, which provided an adequate database to simplify the steps in the FFS approach. Findings: Only four meetings for agroecosystems analysis that emphasised an analytical and reflective learning cycle generated suitable adaptation measures selected from farmers’ feedback. Repetition of the shortened FFS over several rice cropping cycles proved more effective than the frequent meetings within one cropping cycle. Practical implications: The modified FFS could be considered as a promising approach to training farmers, whilst simultaneously identifying and discovering adaptations of agricultural innovations and monitoring the evolution of complex polycultures like CRSs, under diverse conditions. Theoretical implications: The modified FFS provides participants additional time to reflect on the training topics, resulting in a significant improvement in their knowledge and the performance of the CRS. Originality/value: The modified FFS approach is focused on reflexive learning cycles and adaptation of innovations. Therefore, it is highly suitable for management of complex polycultures such as CRSs.

Recent research has revealed that complex rice systems (CRSs), in which several plant and animal species, including azolla, fish, ducks and border plants have been integrated, can produce high and stable rice yields over time. However, the mechanisms that support these benefits have not been examined in detail. On-farm experiments were conducted in Indonesia during five rice cropping cycles. We compared three monoculture rice systems receiving chemical or organic inputs, and four organic polyculture rice systems that varied in level of complexity. To investigate the agro-ecological mechanisms of weed and pest suppression and nutrient cycling that determine rice productivity and stability, the dynamics of weeds, pests, nutrients and rice yields were monitored and related to rice system complexity. The observations revealed that increasing the level of complexity resulted in lower levels of weed and pest infestation. Analysis of duck behaviour and their gizzard composition showed that ducks foraged intensively on weeds, insects, and snails. Furthermore, nutrient cycling was accelerated by ducks via feeding and excretion as well as by their movement in the field. This could explain why rice yields increased along the gradient of complexity, and overall were higher and less variable in the most complex systems in comparison to the rice monocultures. In complex rice systems, increasing the number of species that are compatible to the rice ecosystems and could play a role in generating ecosystem services of weed and pest suppression as well as nutrient recycling, can lead to higher and less variable rice yields.

We studied the influence of lava meal, zeolite and top layer of sandy soil as bedding additives on gaseous C and N losses from a sloping-floor barn of naturally ventilated animal housing. We selected four barn units where eight young bulls’ group was reared in each barn. Chopped straw of wheat and barley applied daily at the rate of 5 kg per livestock unit (LU) in bedding areas where one LU consisted of 500 kg body mass of live bulls. Zeolite, lava meal and sandy soil (18% clay + silt) applied in barn at the rate of 10, 20 and 30% of straw dose, respectively. Static flux chamber was used to measure gases emissions from the barn unit and mass balance calculation was used to calculate straw manure total N (TN) losses during housing phase. On an average, all bedding additives decreased 85% of the NH3 emission compared to control; however, they did not influence CH4 emission. Zeolite decreased CO2 (35%) and N2O (37%) emission rates. Subsequently, lava meal, sandy soil and zeolite decreased 23, 37, and 50% of TN losses from barn manure, respectively. Overall, measured N emissions through NH3-N and N2O-N from the barns was 11% of calculated TN losses while remainder 89% was most probably attributed to di-nitrogen (N2), a harmless gas. Hence, in straw-based cattle housings, zeolite could be a promising additive for reduction of CO2, N2O and NH3 emissions and sandy soil can be considered as cheap and readily available resource for reducing NH3 emission.

Elevating soil organic matter (SOM) levels through changes in grassland management may contribute to lower greenhouse gas concentrations in the atmosphere and mitigate climate change. SOM dynamics of grassland soils may be affected by grazing systems and plant species composition. We analyzed the effects of simulated grazing systems (continuous (CG), rotational (RG), and lenient strip grazing (LG)) and species composition (monocultures of perennial ryegrass fertilized (LP+) and unfertilized (LP&minus, )), tall fescue (fertilized, FA+), and a mixture of these two species with white clover (fertilized, LFT+)) on root biomass and SOM dynamics in field experiments on loamy and sandy soils in the Netherlands. Dried cattle manure was added to all fertilized treatments. We hypothesized that SOM accumulation would be highest under CG and LG, and FA+ and LFT+ as a consequence of greater belowground biomass production. SOM was monitored after conversion from arable land for a period of two years (loamy and sandy soil) and five years (sandy soil). We found that management practices to increase SOM storage were strongly influenced by sampling depth and length of the grassland period. SOM increased significantly in nearly all fertilized treatments in the 0&ndash, 60 cm layer. No differences between species compositions were found. However, when only the 30&ndash, 60 cm soil layer was considered, significantly higher SOM increases were found under FA+, which is consistent with its greater root biomass than the other species. SOM increases tended to be higher under LG than RG. The results of this study suggest that it seems possible to comply with the 4-thousandth initiative during a period of five years with fertilized perennial ryegrass or tall fescue in monoculture after conversion from arable land. It remains to be investigated to which extent this sequestration of carbon can be maintained after converting grassland back to arable land.

Extreme weather events and pest outbreaks decrease rice yields and increase their variability, presenting challenges for the agricultural agenda to increase rice productivity and yield stability in Asia. The integration of azolla, fish and ducks has been shown to create robust systems that maintain high yields under heavy rainfall, but no clear evidence exists that rice yields in these systems are stable across locations and throughout time under divergent weather conditions. We show that the introduction of additional elements into the rice cropping system enhanced the adaptive capacity to extreme weather events across four locations and three cropping cycles. The complex system showed both static and dynamic stability, and had the highest reliability index, thereby outperforming the conventional and organic monoculture systems. The complex rice system design provides a promising example for resilience towards the impacts of climate change on rice production and for safeguarding food security in Asia and beyond.

The Loss-on-Ignition (LOI) method is widely employed for measuring the organic matter (OM) content of soil samples. There is a risk of carbonate losses when calcareous soil samples are analyzed through LOI, but this has never been investigated in detail. Moreover, a worldwide standard protocol for determining the carbonate content of soils is not available. The aims of this study were (i) to evaluate two commonly employed carbonate analysis procedures using calcareous and non-calcareous soil samples: the gravimetric method with (GMF) and without (GM) the addition of the antioxidant iron(II) chloride (FeCl2) and the acetic acid dissolution procedure (AAD); (ii) to evaluate the effect of ignition temperature on losses of pure calcite, calcite-quartz and calcareous soil samples. We found that the average apparent carbonate content of the non-calcareous soils was greatest for the GMF method followed by the AAD procedure. The GM method showed the smallest apparent carbonate contents. For the calcite-quartz sand mixture, ignition losses started at 600°C and increased with temperature in a sigmoidal way. LOI values stabilized at 750°C when 80% of the carbon dioxide was released. We recommend the GM procedure for carbonate analysis because the apparent carbonate contents of the non-calcareous soil samples were smallest. Furthermore, we recommend an LOI temperature of 550°C because at this ignition temperature 99.8% of the total calcite fraction remains in the soil samples.

Water hyacinth poses serious socio-economic and environmental problems in Ethiopia. To integrate fungal pathogens into water hyacinth management, a survey was conducted in the Rift Valley of Ethiopia. Based on morphological characterization and DNA sequencing, 25 fungal species were identified that belong to nine genera. Alternaria tenuissima, A. alternata, Aspergillus niger, Phoma sp., Curvularia trifolii, Mucor fragilis, M. racemosus, A. fumigatus, Fusarium oxysporum, and F. equiseti were the most common fungi detected. However, their occurrence was influenced by water wave action, temperature, season, and altitude. Among the fungal pathogens, A. alternata, A. tenuissima, F. oxysporum, F. equiseti, and Neofisicoccum parvum were highly pathogenic to water hyacinth. Alternaria alternata and A. tenuissima did not cause disease symptoms on ecologically important plant species (e.g. Noug, Tef, and Coffee). Application of the fungal pathogens on water hyacinth plants also showed 11%–67%, 22%–72%, 15%–55%, and 12%–50% reduction in fresh weight, dry weight, plant height, and root length of water hyacinth, respectively. This study suggests that fungal species have the potential to control water hyacinth biologically and provides baseline data for biological control efforts in the future.

Recently, we reported for the first time that home field advantage (HFA) of litter decomposition also exists in agricultural production systems, in addition to earlier reports from natural ecosystems. Here, we provide evidence that adaptation of the soil decomposer community to differences in the chemical composition of solid cattle manure (SCM) explains the HFA. Two dairy farms were selected which differed in type of home-produced SCM (high-quality stacked or low-quality composted SCM) and soil type (sand or peat). Manure was exchanged between these two farms. Also, manure was incubated in fields of two neighbouring non-SCM farms. Using litterbags with three different mesh-sizes (125 μm, 1.5 mm, and 4 mm), we investigated the contribution of microbiota, mesofauna and macrofauna, to SCM dry matter (DM) and nitrogen (N) disappearance after 60, 120 and 240 days of litterbag placement. Home field advantage was estimated after accounting for effects related to structural differences in manure quality (quality index) and grassland soil biota communities (ability index). We found HFA in meso- (14–34%) and macro-mesh (19–31%) size litterbags. In micro-mesh litterbags, the HFA for dry matter and nitrogen disappearance was significant only after 120 days (18 and 26%, respectively). With time, trends of initial increase and then decrease in HFA of both aforementioned parameters were observed, but these were not significant. The quality index indicated that the composted manure had a lower dry matter and nitrogen disappearance rate compared to the stacked manure, irrespective of the location of incubation. The difference between the two manure types for N disappearance had vanished at day 240. Also, the chemical composition of the manure that remained in the litterbags changed over time. After 120 days, the C:N ratio of SCM at home was significantly higher compared to the translocated SCM (P

European canker (EC), caused by Neonectria ditissima, is an important disease in apple-producing regions in New Zealand. In order to improve plant protection, Geographic Information Systems (GIS) can be used to map plant disease location and severity in agricultural settings. Data were compiled from apple growers in Tasman, New Zealand, to investigate EC distribution over 4 years, for the period 2015–2018. ArcGIS software, including the Spatial Analyst, Interpolation and Geospatial statistics toolboxes, was used to map EC incidence at the spatial scale of orchard blocks, which allowed the identification of disease hot-spots. A clustered spatial pattern of disease was detected every year and areas with higher risk of EC were identified within the region. The spatial patterns detected were related to disease pressure over time for different apple cultivars. The use of GIS provides a platform for analysing and visually communicating disease patterns over time. Investigating disease spatial pattern allows the inference of spatial processes and further hypothesis generation to understand the pathogen.

Infestation by coffee white stem borer, Xylotrechus quadripes Chevrolat (Coleoptera: Cerambycidae) is becoming severe in parts of Asia and Africa. In recent years, the pest has also been found in North and South America. This study in Gulmi District, Nepal, aimed to determine the severity of infestation by coffee white stem borer in relation to soil and plant nutrient content and associated quality aspects. Eighty plantations of coffee, Coffea arabica L., were inspected, 68 coffee growers were interviewed, and 120 soil and plant samples were analyzed. During the interviews, 72% respondents claimed coffee white stem borer was a major hurdle to production of coffee. Depending on the amount of damage, annual yield loss in infested plantations was as much as 60%. Based on principal component analysis (PCA), plants growing with more soil nitrogen, pH, and organic matter were healthier than plants with less. Results suggested that soil attributes are crucial for management of coffee white stem borer.

SummaryThe objectives of the present study were to quantify the effects of contrasting methods for storing solid cattle manure on: (i) total carbon (C) and nitrogen (N) balances during storage, and (ii) crop apparent N recovery (ANR) following manure application to arable land, with maize as a test crop. Portions of 10 t of fresh solid cattle manure were stored for 5 months during 2009/10 in three replicates as: (i) stockpiled heaps, (ii) roofed heaps, (iii) covered heaps and (iv) turned heaps at Wageningen University, the Netherlands. Surface emissions of ammonia (NH3), nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) were measured regularly using a static flux chamber connected to a photo-acoustic gas monitor. Total C and N losses during storage were determined through the mass balance method. After storage, the manures were surface-applied and incorporated into a sandy soil, and maize ANR was measured as a proportion of both N applied to the field (ANRF) and N collected from the barn (ANRB).During the storage period, the average losses of initial total N (Ntotal) were 6% from the covered, 12% from the roofed, 21% from the stockpiled and 33% from the turned heaps. Of the total N losses, 2–9% was lost as NH3-N, 1–4% as N2O-N and 16–32% through leaching. However, the greatest part of the total N loss from the four storage methods was unaccounted for and constituted in all probability of harmless dinitrogen gas. Of the initial C content,c. 13, 14, 17 and 22% was lost from the covered, stockpiled, roofed and turned heaps, respectively. Maize ANRFwas highest from covered (39% of the applied N) followed by roofed (31%), stockpiled (29%) and turned manure (20%). The respective values in case of maize ANRBwere 37, 27, 23 and 13%. It is concluded that from a viewpoint of on-farm N recycling the storage of solid cattle manure under an impermeable plastic cover is much better than traditional stockpiling or turning heaps in the open air.

For an integrated evaluation of the effect of nutritional strategies on the utilization and losses of N at dairy farms, reliable estimates of excreta production and composition are indispensable. An extant, dynamic, mechanistic model of rumen functioning was extended with static equations that describe intestinal digestion to simulate the composition of dairy cow feces and urine as a function of diet composition. The extended model predicts organic matter (OM), carbon (C), and nitrogen (N) output of both feces and urine, classified in different components. Total N excretion was partitioned in three fractions based on the C:N ratio of individual components representing their availability of N following manure application to crops, viz. NM (immediately available), NE (easily decomposable), and NR (resistant). Forty nutritional strategies for stall-fed dairy cows, covering diets with a wide range in protein content and OM digestibility, were evaluated. The simulated ranges in fecal and urinary composition were largely in line with values reported in literature. Diet intake and composition had a substantial effect on simulated total N excretion and excreta composition, mainly because of differences in the level of NM excretion and the C:N ratio of the NR fraction. Furthermore, it was shown that the type of OM excreted varies considerably between different diets. A simplified simulation of degradation processes during the first 4 months of excreta storage produced average values and ranges of slurry characteristics that were in line with values reported in literature. The simulated variation in slurry characteristics suggested a strong variability in ammonia N losses from the slurry pit and a moderate variability in plant availability of slurry N. Further efforts are required to integrate effects of manure storage conditions on the storage processes. In conclusion, the model can be a tool to predict fecal and urinary composition of cattle, and ultimately to improve the utilization of N from field applied manure as well as to evaluate the effects of different nutritional strategies on the whole-farm N balance.

The aim of this study was to assess the short-term effects of tillage practice (reduced tillage – RT; standard tillage – ST) and fertilisation regime (solid cattle manure – SCM; lucerne pellets – LP; grass/clover silage – GCS) on soil quality indicators in an organic potato (Solanum tuberosum L.) production system. Use of RT enhanced the biomass and number of earthworms compared with ST. Concentrations of soil mineral N ((Formula presented.) and (Formula presented.)) showed similar decreasing patterns over time across both tillage systems during the potato production period. However, soil mineral N was overall higher in the 0–15 cm soil layer for RT and in the 15–30 cm layer for ST. Soil bulk density was higher for RT than ST at 1, 4 and 7 weeks after planting, while a linear reverse correlation was found between soil bulk density and tuber yield. Although both soil temperature and soil moisture content were not found to be greatly affected by tillage practice, net soil N mineralisation was estimated to be 65 kg N ha−1 greater under ST than RT for the potato production period. The application of LP and GCS resulted in higher mid- and end-season soil mineral N concentrations and crop N accumulation at harvest compared to SCM. During initial adaptation to reduced tillage practices in organic potato systems, farmers need to carefully weigh potential conflicts between initial yield reductions and soil conservation goals.

This study examined the influences of three potential additives, i.e., lava meal, sandy soil top-layer and zeolite (used in animal bedding) amended solid cattle manures on (i) ammonia (NH3), dinitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) emissions and (ii) maize crop or grassland apparent N recovery (ANR). Diffusion samplers were installed at 20 cm height on grassland surface to measure the concentrations of NH3 from the manures. A photoacoustic gas monitor was used to quantitate the fluxes of N2O, CH4 and CO2 after manures’ incorporation into the maize-field. Herbage ANR was calculated from dry matter yield and N uptake of three successive harvests, while maize crop ANR was determined at cusp of juvenile stage, outset of grain filling as well as physiological maturity stages. Use of additives decreased the NH3 emission rates by about two-third from the manures applied on grassland surface than control untreated-manure. Total herbage ANR was more than doubled in treated manures and was 25% from manure amended with farm soil, 26% and 28% from zeolite and lava meal, respectively compared to 11% from control manure. In maize experiment, mean N2O and CO2 emission rates were the highest from the latter treatment but these rates were not differed from zero control in case of manures amended with farm soil or zeolite. However, mean CH4 emissions was not differed among all treatments during the whole measuring period. The highest maize crop ANR was obtained at the beginning of grain filling stage (11–40%), however ample lower crop recoveries (8–14%) were achieved at the final physiological maturity stage. This phenomenon was occurred due to leaf senescence N losses from maize crop during the period of grains filling. The lowest losses were observed from control manure at this stage. Hence, all additives decreased the N losses from animal manure and enhanced crop N uptake thus improved the agro-environmental worth of animal manure.

Loss on ignition (LOI) is one of the most widely used methods for measuring organic matter content in soils but does not have a universal standard protocol. A large number of factors may influence its accuracy, such as furnace type, sample mass, duration and temperature of ignition and clay content of samples. We conducted a series of experiments to quantify these effects, which enabled us to derive (i) guidelines for ignition conditions (sample mass, duration and temperature), (ii) temperature-specific soil organic matter (SOM) to soil organic carbon (SOC) conversion factors and (iii) clay content-dependent correction factors for structural water loss (SWL). Bulk samples of a sandy soil (4% clay) and a silt loam soil (25% clay) were used to evaluate the effects of ignition conditions. Samples with a range of clay contents (0-50%) were used to quantify conversion and correction factors. Two furnaces, one without and one with pre-heated air, did not show significant differences in terms of within-batch LOI variability. In both furnaces less combustion occurred close to the door, which necessitated tray turning at half-time as this reduced the standard deviation per batch significantly. Variation in mass loss declined exponentially with sample mass (range, 0.15-20g). The LOI increased with duration at lower temperatures (≤550°C) for the sandy soil. At greater temperatures (600 and 650°C), no effect of duration was found. For the silt loam soil, LOI values increased with duration for each temperature, which was attributed to SWL. The SOM to SOC conversion factor decreased strongly with temperature at an ignition duration of 3hours from 0.70 (350°C) to 0.57 (500°C) and stabilized around 0.55 between 550 and 650°C, indicating that at temperatures ≥550°C all SOM had been removed. The clay correction factor for SWL increased from 0.01 to 0.09 as the temperature of ignition increased from 350 to 650°C. To minimize within-batch LOI variation we recommend a standard ignition duration of 3hours, tray turning at half-time, a sample mass ≥20g and temperatures equal to or greater than 550°C. To avoid over-estimates of SOM through structural water loss, the presented SWL correction procedure should always be applied.

Aims: The main aim of the study was to assess the effects of organic manure on nitrogen mineralization, uptake, use and recovery of cauliflower. Methodology: Nitrogen is one of the major yield limiting nutrients in cauliflower production. However, organic manure is applied to supplement soil nitrogen supply to maximize dry-matter yield. A field experiment was conducted at the Droevendaal Certified Organic Research and Demonstration Site of Wageningen University, Netherlands during 2012. The experiment was laid out in a randomized complete block design with four replications. The treatments comprised of four rates (0, 75, 150 and 225kgN.ha-1) each of lucerne pellets (LUP) and dry grass clover (DGC) organic manures. Results: Results showed that LUP amended plots exhibited highest initial N-mineralization compared to DGC and control plots. Nitrogen uptake in plant organs increased with increasing organic manure application. Nitrogen accumulation was highest in cauliflower leaf (38.28mg.kg-1), followed by the head (16.96mg.kg-1) and lowest in the stem (3.01mg.kg-1). Conclusion: Results suggest that timely and adequate nitrogen release from organic manures is important for the success of conservation and sustainable farming systems. Findings in this study could be utilized in improving efficiency of N use in crop management rotation systems.

Land use change and intensification in agricultural landscapes of the Andean highlands have resulted in widespread soil degradation and a loss in soil-based ecosystem services and biodiversity. This trend threatens the sustainability of farming communities in the Andes, with important implications for food security and biodiversity conservation throughout the region. Based on these challenges, we sought to understand the impact of current and future land use practices on soil fertility and biodiversity, so as to inform landscape planning and management decisions for sustainable agroecosystem management. We worked with local communities to identify and map dominant land uses in an agricultural landscape surrounding Quilcas, Peru. These land uses existed within two elevations zones (low-medium, 3200-3800 m, and high elevation, 3800-4300 m). They included three types of low-medium elevation forests (eucalyptus, alder, and mixed/native species), five pasture management types (permanent pasture, temporal pasture [in fallow stage], degraded pasture, high-altitude permanent pasture, and high-altitude temporal pasture [in fallow stage]) and six cropping systems (forage crops, maize/beans, and potato under four types of management). Soil fertility was evaluated in surface soils (0-20 cm) with soil physicochemical parameters (e.g., pH, soil organic matter, available nutrients, texture), while soil biological properties were assessed using the abundance and diversity of soil macrofauna and ground cover vegetation. Our results indicated clear impacts of land use on soil fertility and biological communities. Altitude demonstrated the strongest effect on soil physicochemical properties, but management systems within the low-mid elevation zone also showed important differences in soil biological communities. In general, the less-disturbed forest and pasture systems supported more diverse soil communities than the more intensively managed croplands. Degraded soils demonstrated the lowest overall soil fertility and abundance of soil macrofauna, but this may be reversible via the planting of alder forests. Our findings also indicated significant covariation between soil physicochemical parameters, soil macrofauna, and ground vegetation. This suggests that management for any one of these soil properties may yield unintended cascading effects throughout the soil subsystem. In summary, our findings suggest that shifts in land use across the landscape are likely to have important impacts on soil functioning and biodiversity.

Coffee white stem borer, Xylotrechus quadripes Chevrolat (Coleoptera: Cerambycidae) is a major coffee pest in parts of Asia and Africa. In recent years, the pest has also been found in American countries. This study in Gulmi District, Nepal, aimed to determine the infestation by coffee white stem borer in relation to coffee plantations in shade or sun. Eighty plantations of coffee were inspected and 68 coffee growers were interviewed. Of 68, 52 (76%) respondents reported high to very high infestation by pests in sun coffee, while 50 (74%) claimed low to very low infestation in shade coffee. There was a significant (χ2 = 5.8, p < 0.05) association between coffee plantations (shade and sun) and infestation by coffee white stem borer. Pest prevalence was significantly (χ2 = 75, p < 0.05) greater for sun (60%) compared to shade (40%) coffee plants. The total number of infested plants showed significant negative correlation (r =-0.54, n = 68, p < 0.05) with the number of permanent shading trees in plantations. Results suggested that developing a stand of permanent shading trees could be a potential strategy for management of coffee white stem borer.

Aims: The main aim of the study wasto assess the influence of organic fertilizers on selected soil bio -physical properties and dry matter partitioning in cauliflow er. Methodology: A field experiment was conducted at Wageningen University Experimental Site, Netherlands during 2012 cropping season. The experiment was laid in a Randomized Complete Block Design (RCBD) with four replications. The treatments included N-source (dried grass clover (DGC) and lucerne pellets (LUP)) and N application rate (0, 75, 150 and 225 kg N.ha -1

We studied two different grassland fertiliser management regimes on sand and peat soils: above-ground application of a combination of organic N-rich slurry manure and solid cattle manure (SCM) vs. slit-injected, mineral N-rich slurry manure, whether or not supplemented with chemical fertiliser (non-SCM). Measurements of field N mineralisation as estimated from herbage N uptake in unfertilised plots were compared with (i) potential N mineralisation as determined from a standard laboratory soil incubation, (ii) the contribution of groups of soil organisms to N mineralisation based on production-ecological model calculations, and (iii) N mineralisation calculated according to the Dutch fertilisation recommendation for grasslands. Density and biomass of soil biota (bacteria, fungi, enchytraeids, microarthropods and earthworms) as well as net plant N-uptake were higher in the SCM input grasslands compared to the non-SCM input grasslands. The currently used method in Dutch fertilisation recommendations underestimated actual soil N supply capacity by, on average, 102 kg N ha-1 (202 vs. 304 kg ha-1 = 34%). The summed production-ecological model estimate for N mineralisation by bacteria, fungi, protozoa, and enchytraeids was 87–120% of the measured potential soil N mineralisation. Adding the modelled N mineralisation by earthworms to potential soil N mineralisation explained 98–107% of the measured herbage N uptake from soil. For all grasslands and soil biota groups together, the model estimated 105% of the measured net herbage N uptake from soil. Soil biota production-ecological modelling is a powerful tool to understand and predict N uptake in grassland, reflecting the effects of previous manure management and soil type. The results show that combining production ecological modelling to predict N supply with existing soil N tests using aerobic incubation methods, can add to a scientifically based improvement of the N fertilisation recommendations for production grasslands.

This paper describes the year-over-year improvement of the nitrogen (N) efficiency in a prototype mixed farm system through the implementation of a coherent set of ecotechnological adjustments. This farm, the former APMinderhoudhoeve, was located on a marine clay loam soil in Oostelijk Flevoland, the Netherlands, reclaimed from the sea in the late 1950s. The designed farm structure was representative for the Dutch soil-bound agriculture in the late 1990s in terms of food crops’ choice and average level of milk production per ha of farmland. Key management strategies were the inclusion of grass-clover leys in the 7-year crop rotation, restricted grazing of the dairy herd and protein-poor and fibre-rich cattle diets including cereal straw. The farm components animal-manure-soil-crop were analysed in-depth in order to evaluate N flows and soil organic matter (SOM) dynamics at the farm system level, covering a period of six years. In its final experimental state, farm N use efficiency, expressed as the proportion of purchased crop fertilizers and cattle feed that was sold as exported products (crops, milk and cattle), was as high as 73%, Besides, total environmental losses were as low as 42kg N ha−1 yr−1. A scenario analysis revealed that these losses could be further minimized to 30kg N ha−1 yr−1 in the stabilization phase, of which one-third as leached nitrate and a somewhat higher fraction as volatilized ammonia. The remaining losses represented mainly denitrified harmless N2 from the stored animal slurry and farmyard manure. Soil N accumulated at an average rate of 89kg N ha−1 yr−1, whereas SOM showed a positive trend but with fluctuations from year to year which were negatively related to the annual rainfall amount. Despite the lowered protein content in the cow diets, average annual milk production increased from 8100 tot 8700kg cow−1. This could be mainly ascribed to a lower cow replacement rate due to less animal health problems, leading to an increased average lactation number of the dairy herd. Overall, the obtained environmental side effects on the prototype farm in its final experimental state were already below the targets set by the European Union with respect to the Nitrate Directive for the year 2020. It is concluded that when the best ecotechnological means are combined in a balanced mixed farm system a multiple win situation is attained in terms of food production capacity, cattle health and environmental quality.

This study investigated the effect of using a trailing-shoe system to apply cattle slurry, under different conditions of grass height (low [LG]: freshly cut sward [4–5 cm height] vs. high [HG]: application delayed by 7–19 d and applied to taller grass sward [4–11 cm] height) and month of application (June vs. April), on the nitrogen fertilizer replacement value (NFRV) and apparent N recovery (ANRS) of cattle slurry applied to grassland. NFRV was calculated using two methods: (i) NFRVN based on the apparent recovery of slurry-N relative to that of mineral-N fertilizer; and (ii) NFRVDM based on DM yield. The effect of applying slurry into HG swards, relative to LG swards, decreased the DM yield by 0·47 t ha-1 (P = 0·001), N uptake by 5 kg ha-1 (P = 0·05), ANRS by 0·05 kg kg-1 (P = 0·036), NFRVN by 0·05 kg kg-1 (P = 0·090) and NFRVDM by 0·11 kg kg-1 (P

Based on evidence from forest ecosystems that litter decomposition is highest in its home habitat, the so-called home field advantage (HFA), we tested whether HFA also occurs in production grasslands, to which solid cattle manure (SCM) was applied. Two dairy farms were selected which differed in type of home-produced SCM (stacked or composted) and soil type (sand or peat). Disappearance patterns of manure dry matter (DM) and nitrogen (N) were monitored from litterbags (4 mm mesh size) during the grass growing season. At the same time, apparent herbage N recovery (ANR) of SCM, applied at two rates (200 and 400 kg N ha-1 yr-1), was measured. On average, manure DM and N disappearances on the home farms were 20 and 14% greater, respectively, than on away farms. Differences in ANR were also very pronounced (on average 14 and 53% higher at home than away for the two respective application rates). The two SCM types were also studied on two neighbouring dairy farms (one on sand and one on peat soil) where no SCM had been applied for many years. Here, manure DM and N disappearances from the litterbags were much lower (P

This study aimed to quantify the effects of contrasting composted methods of solid cattle manure (SCM) ondry matter (DM) yield and crop apparent N recovery (ANR)following manure application to maize land. Fresh SCM was stored as stockpiled, roofed, covered and composted heaps. After storage, the manures were incorporated in a sandy soil, and maize ANR both as a proportion of field applied N (ANR F) and collected N from the barn (ANR B),and DM yield was established at three successive growth stages: end of juvenile phase, start of grain filling, and physiological maturity. During the storage period, on average 6% of the initial Ntotal was lost from covered, whereas this fraction was 12, 21 and 33% from roofed, stockpiled, and composted heaps, respectively. DM yield of maize increased with the application of all the manure types as compared to the unfertilized control, at the end of Juvenile (2.2 vs. 3.1-3.4 Mg ha-1), grain filling (11.2 vs. 13.6-16.4 Mg ha-1) and physiological maturity stages (13.9 vs. 15.3-15.9 Mg ha-1). At a given growth stage, the greatest value was obtained from covered than roofed, stockpiled and composted manures.Maize ANR F was the highest at start of grain filling (20, 29, 31, and 39% of the applied N for composted, stockpiled, roofed and covered treatments, respectively) but lower values were obtained at physiological maturity (12-21%). The respective values in case of maize ANR B were 13, 23, 27 and 37% of total N taken from barn at the start of grain filling while it was also lower (8-20%) at physiological maturity. It is concluded thatstorage of SCM under an impermeable plastic cover reduce N losses, increased DM yield and ANR thereby improves on-farm N cycling as compared to traditional stockpiling or composting.

Aims The importance of quantifying carbon stocks in terrestrial ecosystems is crucial for determining climate change dynamics. However, the present regional assessments of carbon stocks in tropical grasslands are extrapolated to unsampled areas with a high degree of uncertainty and without considering the carbon and nitrogen composition of vegetation and soil along altitudinal ranges. This study aims to assess carbon and nitrogen concentrations in soil and vegetation, aboveground carbon stocks distribution and soil organic carbon stocks along an altitudinal range in the páramo region in the Ecuadorian Andes. Methods The vegetation inventory was conducted using 15×15 m sampling plots distributed in three altitudinal ranges. Based on the patterns exhibited by the dominant vegetation growth forms, biomass and soil were sampled to quantify the corresponding carbon and nitrogen concentrations. Subsequently, the aboveground live biomass along the páramo altitudinal range was estimated using allometric equations. Finally, soil and vegetation carbon stocks were estimated for the entire basin. Important Findings Altitudinal analysis supported a potential distribution of carbon and nitrogen concentrations in soil, litter and live tissues, where higher concentrations were found in the low altitudinal range mainly for tussocks and acaulescent rosettes. Cellulose in litter showed higher concentrations at low altitudinal ranges for acaulescent rosettes and cushions only. For the same growth forms, lignin patterns in litter were higher in high altitudinal ranges. Soil texture provided complementary information: high percentage of silt was highly correlated to high soil nitrogen and carbon concentration. Tussocks were found to be responsive to altitude with their, highest aboveground carbon stocks occurring at the low altitudinal range, but cushions and acaulescent rosettes responded differently. The established relationships among soil, vegetation and altitude shown in this study must be taken into account to estimate both aboveground and soil organic carbon stocks in páramo regions - such estimates will be considerably inaccurate if these relationships are ignored.

The majority of Dutch farmers perceive that mouldboard ploughing prior to potato planting is necessary, despite its negative impacts on inherent soil fertility and soil structure. An innovative agronomic practice in Dutch organic agriculture is the use of cut-and-carry fertilizers with which above-ground biomass of crops with high nitrogen content (e.g. grass/clover) is harvested and transferred to other fields as plant-based fertilizers. The objective of this study was to investigate the interactive effects of two tillage systems (reduced tillage (RT), standard tillage (ST)) and three organic fertilizer amendments (solid cattle manure (SCM), lucerne pellets (LP), grass/clover silage (GCS)) on crop performance and nitrogen utilization of organic potato. Use of RT decreased tuber yield by 13.4 % compared to ST due to lower average tuber size which was related to higher soil bulk density and increased vulnerability to drought stress during tuber bulking. On the other hand, use of RT positively affected nitrogen utilization and tuber quality in terms of specific gravity, dry matter and starch contents. However, the price premium associated with enhanced tuber quality may not offset the observed yield gap between RT and ST. Plant-based fertilizers enhanced nitrogen utilization in terms of apparent nitrogen recovery compared to animal-based. Although use of LP resulted in the highest yield for both tillage systems, its high price may be cost-inhibitive. An integrated approach taking into account N release patterns, environmental conditions, final yields, and production costs is needed in order to optimize resource use efficiency and overall profitability for farmers., Organic Agriculture, 6 (2), ISSN:1879-4238, ISSN:1879-4246

Attempts to increase food crop yields by intensifying agricultural systems using high inputs of nonrenewable resources and chemicals frequently lead to de-gradation of natural resources, whereas most technological innovations are not accessible for smallholders that represent the majority of farmers world wide. Alternatively, cocultures consisting of assemblages of plant and animal species can support ecological processes of nutrient cycling and pest control, which may lead to increasing yields and declining susceptibility to extreme weather conditions with increasing complexity of the systems. Here we show that enhancing the complexity of a rice production system by adding combinations of compost, azolla, ducks, and fish resulted in strongly increased grain yields and revenues in a season with extremely adverse weather conditions on East Java, Indonesia. We found that azolla, duck, and fish increased plant nutrient content, tillering and leaf area expansion, and strongly reduced the density of six different pests. In the most complex system comprising all components the highest grain yield was obtained. The net revenues of this system from sales of rice grain, fish, and ducks, after correction for extra costs, were 114% higher than rice cultivation with only compost as fertilizer. These results provide more insight in the agro-ecological processes and demonstrate how complex agricultural systems can contribute to food security in a changing climate. If smallholders can be trained to manage these systems and are supported for initial investments by credits, their livelihoods can be improved while producing in an ecologically benign way.

Background: The use of antibiotics in the livestock sector is increasing to such an extent that it threatensnegativeconsequences for human health, animalhealthand theenvironment. Homeopathy might be an alternative to antibiotics. It has therefore been tested in a randomised placebo-controlled trial to prevent Escherichia coli diarrhoea in neonatal piglets. Method: On a commercial pig farm 52 sows of different parities, in their last month of gestation, were treated twice a week with either the homeopathic agent Coli 30K or placebo. The 525 piglets born from these sows were scored for occurrence and duration of diarrhoea. Results: Piglets of the homeopathic treated group had significantly lessE. coli diarrhoea than piglets in the placebo group (P< .0001). Especially piglets from first parity sows gave a good response to treatment with Coli 30K. The diarrhoea seemed to be less severe in the homeopathically treated litters, there was less transmission and duration appeared shorter. Homeopathy (2010) 99, 57–62.

Attainment of acceptable levels of land and labor productivity and low external input use is not a mutually exclusive proposition. This study examines characteristics of a range of current specialized dairy farming systems (DFS) and mixed (crop-livestock) farming systems (MFS) in Cuba to determine their efficiency in the process of food and feed production. The central question was whether the favorable results of MFS realized in a small-scale experimental system were also attainable in larger, commercial farms. To this end, we collected data on 93 farms from around the country for a period of 1 year. The farms were classified according to four predictor variables: farm type, years since conversion from DFS to MFS, proportion of land allocated to crops in rotation and farm size. Farms were compared based on 12 pre-selected Agro-Ecological Indicators (AEIs) by using analysis of variance and Tukey's HSD tests. The 12 AEIs were also subjected to a principal components analysis and related to the four predictor variables by reduced-rank regression, also known as redundancy analysis. Three farm types were distinguished: mixed farming experimental (MFe), mixed farming commercial (MFc) and specialized dairy farming (DFS). Total energy output per unit of farm area was on average four to six times higher on the mixed farms than on the specialized dairy farms, while protein output three to four times higher. Milk yield per unit of forage area was highest on MFe (2.4 Mg ha-1 yr-1), followed by MFc (1.7), while it was much lower (0.7) on DFS. The redundancy analysis revealed that MFe did only slightly better than MFc and was most opposite to DFS in terms of AEIs. In conclusion, the previous experimental findings were confirmed nationwide, thus demonstrating the benefits of MFS for agro-ecological performance in Cuba.

From the 1960s onwards, a ‘High External Input’ dairy production model was applied widely in Cuba. Overall milk production of the national herd increased considerably, but the system was inefficient from both a financial and energetic point of view. In the early 1990s, after the abrupt end of inflow of capital and other resources from Eastern Europe, the dairy sector collapsed. In the short term, the modern infrastructure of milk production deteriorated and the sector experienced profound vulnerability. However, in the longer term, this situation stimulated a search for more sustainable approaches, such as low external input Mixed Farming Systems (MFS). The current study aimed to evaluate two small scale prototype farms to assess the implications of converting ‘Low External Input’ Dairy Farming Systems into MFS. Fifteen agro-ecological and financial indicators were selected and monitored over a 6-year period. Two configurations of MFS, i.e. the proportion of the farm area occupied by arable crops, were tested: 25 and 50%. Productivity, energy efficiency and cost-effectiveness all improved following conversion. Total energy input was low for both farms and decreased over time, whereas energy efficiency was high and increased over time. Human labour input was high directly following conversion, but decreased by one-third over the 6-year period. This study demonstrates, at an experimental scale, the potential of MFS to achieve ecological, productivity and financial advantages for dairy production in Cuba.

peer-reviewed The high degradability of grass protein is an important factor in the low nitrogen (N) utilization of grazing bovines in intensive European grassland systems. We tested the hypothesis that protein degradability as measured by the Cornell Net Carbohydrate and Protein System (CNCPS) protein fractionation scheme, can be manipulated by herbage management tools, with the aim to reduce N loss to the environment. A field experiment comprising the factorial combinations of three fertilizer N application rates (0, 90 and 390 kg N ha−1 year−1), three regrowth periods (2–3, 4–5, and 6–7 weeks), two perennial ryegrass (Lolium perenne L.) cultivars [Aberdart (high sugar content) and Respect (low sugar content)] and two cutting heights (approximately 8 and 12 cm) was conducted at Teagasc, Johnstown Castle Research Centre, Wexford, Ireland. The plots were sampled during four seasons [September/October 2002 (late season), April 2003 (early season), May/June 2003 (mid season) and September 2003 (late season)] and protein fractions were determined in both sheath and lamina material. The protein was highly soluble and on average 19% and 28% of total N was in the form of non-protein N, 16% and 19% in the form of buffer-soluble protein, 52% and 40% in the form of buffer-insoluble protein, and 12% and 13% in the form of potentially available cell wall N for lamina and sheath material, respectively. In both materials only 0.9% of total N was present as unavailable cell wall N. In general the herbage management tools investigated did not have much effect on protein fractionation. The effects of regrowth period, cultivar and cutting height were small and inconsistent. High N application rates significantly increased protein degradability, especially during late season. This is relevant, as it has been shown that enhanced protein degradation increases the potential N loss through urine excretion at a time when urine-N excreted onto pasture is prone to leaching. However, the effect was most evident for sheath material, which forms only a small proportion of the animals' intake. It was concluded that there appears to be little scope for manipulating the herbage-N fractionation through herbage management. The consequences for modelling herbage quality could be positive as there does not seem to be a need to model the individual N fractions; in most cases the N fractions can be expressed as a fixed proportion of total N instead.

Farming systems in the Costa Chica region in Mexico face limitations linked to low yields and soil fertility degradation. Several alternative maize-based cropping systems have been proposed to improve current limitations. These field-level options need to be evaluated at farm level in order to assess their feasibility, taking into account input requirements, contributions to self-sufficiency in food and long-term soil fertility, and the availability of labor. In this study, we defined four scenarios to explore consequences of changes in current farming systems for eight typical farms in the region; the first two scenarios comprised redressing current imbalances in crop nutrition and organic matter (OM) supply, respectively, and the last two scenarios explored high fertilizer input and animal husbandry. Farms responded in different ways to the various options depending on available land, current soil quality, current cropping systems and presence of livestock. Improvements in crop nutrition based on mineral fertilizers increased family income but only had substantial effects on soil OM (SOM) balances when fertilizer rates were double the amount currently subsidized. Addition of organic fertilizers resulted in positive effects on SOM balance, but with often strong trade-offs with family income due to costs of acquisition, transport and application. Animals played an important role in increasing SOM balances, but had relatively little effect on improving family income. The results demonstrated that improvements in family income and SOM balance at farm scale were feasible but that without more fundamental system changes trade-offs between short-term yield increases and longer-term soil fertility increases should be expected. The results highlight the need for policies that take into account farm-specific differences in crop and livestock intensification opportunities.

Neochetina weevils have potential as biocontrol agents for water hyacinth, an aquatic weed which seriously affects irrigation water supply in sugarcane, vegetables and other horticultural crop production in the Rift Valley of Ethiopia. A study was conducted on (i) the adaptability and duration of developmental stages of Neochetina weevils and (ii) the damage they cause to water hyacinth in the Rift Valley of Ethiopia. The Rift Valley weather conditions appeared to be suitable for the two weevil species studied, enabling them to produce four generations per year. The egg hatching period of Neochetina bruchi ranged from 4 to 10 days, while Neochetina eichhorniae took 8–12 days. Larvae of N. bruchi took a comparatively shorter period (32–38 days) than N. eichhorniae (52–60 days) to complete their development. N. bruchi laid a maximum of 10.4 eggs female−1 day−1, whereas N. eichhorniae laid 8.2 eggs female−1 day−1. The intrinsic rate of increase of N. bruchi was found to be 0.06 with a generation time of 74.8 days and a population doubling period of 14.3 days. The intrinsic rate of increase of N. eichhorniae was 0.046 accompanied by a generation time of 94.8 days and a doubling period of 18.7 days. Feeding by adult weevils and tunnelling by larvae significantly impacted the vigour and reproduction of water hyacinth plants. N. bruchi and N. eichhorniae affected plants had about 72% (76%) and 66% (58%) reduction in fresh (and dry) weight, respectively. Thus, based on their damage potential and difference in rate of population growth, it is concluded that N. bruchi could be considered as a promising candidate for biological control of water hyacinth under Ethiopian conditions.

The implementation of the statutory Mineral Accounting System (MINAS) in the Netherlands in the period 1998–2003 required large reductions in nutrient inputs of dairy farms. Patterns in farm management adjustments throughout 6 years and their effectiveness in terms of nitrogen use efficiency (NUE) and economic performance were evaluated for 45 commercial farms participating in a regional nutrient management project. Six groups of farms were identified that differed in initial NUE and the change therein. Three groups of farms that were able to rapidly reduce fertilizer N input and establish a consistent farm management strategy were most successful in improving NUE. These farms had a higher gross margin per 100 kg milk than farms without a consistent strategy. The three effective strategies were primarily characterized by (i) continuous, gradual adjustment of the integrated farm management combined with a slight reduction in milk production per ha (re-balancing) versus increasing productivity per animal, thereby reducing maintenance N requirements, while (ii) maintaining or (iii) increasing the production intensity per ha. It was concluded that different approaches to improve NUE can be successful, also in economic terms, although a direct relationship between NUE and gross margin was not observed. The probably implicit choice for adoption of a strategy may be governed by farm endowment and the farmer's skills and objectives.

An object-oriented simulation model was developed to integrate detailed analyses of perennial ryegrass (Lolium perenne) plant part dimensions, and their mass, cell wall content (CWC) and cell wall digestibility (CWD). The model was validated against data from two field experiments, carried out in The Netherlands (52degreesN) and Norway (67degreesN). In the experiments, the effects of temperature x daylength interactions on development, growth and digestibility were determined. Three cultivars differing in heading date were used, and undisturbed growth and regrowth after early (only in The Netherlands) and late cutting were studied. The sensitivity of the model was tested for changes in parameters determining morphological development. A grass plant was modelled as an aggregation of shoot objects. A shoot is an aggregation of phytomers, plus an inflorescence in the reproductive development stage. A phytomer consists of a leaf blade, a leaf sheath, a stem internode and a root. Each phytomer has an axillary bud, which can develop into a new shoot. Morphological development, organic matter (OM) growth and composition were simulated well by the model. Only for regrowing crops in The Netherlands CWC was lower and CWD was higher in the simulations than observed in the field, whereas the differences increased when stem development was more advanced at the moment of cutting. This was attributed to residual stems in the stubble after cutting due to difficulties with machine cutting of lodged crops on the experimental plots. The model can be considered as sufficiently accurate to simulate OM yield and composition of grass cultivars differing in heading date and growing under strongly contrasting temperature and daylength conditions. When the leaf appearance rate, width or length of the leaf blade were increased in the sensitivity analysis, OM yield enhanced, but composition and digestibility of the reproductive grass crops were not systematically affected. (C) 2004 Elsevier B.V. All rights reserved.

To assess cattle slurry manure quality in relation to feeding strategy, a field experiment and a bio-assay were carried out with slurries from four dairy farming systems that used diets differing in protein content and digestibility. Several quality aspects were evaluated. In the field experiment the effects of slurry manure type on herbage rejection by grazing heifers and herbage yield on undisturbed plots under cages were studied for a grass monoculture and a grass/clover mixture. The bio-assay, consisting of a cress (Lepidium sativum L.) seed germination test, was used to study differences in phytotoxicity between the slurry types. After five weeks of undisturbed growth at equal amounts of applied inorganic nitrogen (N), the herbage yields differed statistically for the different slurries. This was probably due to immobilization of N in the case of the two slurries from farming systems in which straw was fed and used as bedding material. Herbage rejection by grazing animals was significantly shown for all slurry types and was significantly and positively correlated with the NH3/NH4+-N content of the slurry. The slurries showed large differences in phytotoxicity to seeds and seedlings in the bio-assay. Ammonia and electric conductivity appeared to be the most important slurry parameters with inhibiting effects. The slurries with a high C/N ratio showed lowest phytotoxicity. Phytotoxicity in the cress seed germination test did not account for reduced herbage yields in the field experiment. On the contrary, when the slurries were ranked according to their phytotoxicity the order was the same as the ranking on the basis of undisturbed herbage yield. It was concluded that there is a need for other laboratory tests that show greater resemblance with what is observed in the field to assess slurry quality.

The analysis of the intrinsic properties and processes of ecosystems, which regulate the production stability of mixed grasslands, has been complicated by the environmental noise caused by stochastic weather fluctuations. A mathematical framework is presented to deduct the actual, the extrinsic and the intrinsic stability of grassland ecosystems, as defined in the companion paper, from their yield patterns and the environmental patterns during a long time-course. Intrinsically stable grassland ecosystems remain stable when subjected to structured environmental fluctuations, yet are destabilised by stochastic environmental fluctuations. Contrastingly, intrinsically oscillating grassland ecosystems are on average somewhat stabilised by stochastic environmental fluctuations in temperate climates. Structured environmental fluctuations may fully stabilise these systems in continental climates. However, in these climates these ecosystems are destabilised by stochastic environmental fluctuations. As in some cases the actual stability of yields may be higher in intrinsically oscillating systems than in intrinsically stable systems, the stability of yields observed in short-term experiments is a poor reflection of the intrinsic ecosystem properties. Subsequently, this mathematical framework is applied to a number of experimental ecosystems in the Park Grass Experiment (UK) and at the Ossekampen (The Netherlands), which were subjected to various fertiliser and lime applications, and to a regime of either cutting or grazing, respectively. In the Park Grass Experiment, the yields of all plots studied appeared to be extrinsically unstable, with only small differences between fertiliser treatments. However, plots receiving lime showed a higher extrinsic stability than unlined plots. The extrinsic stability of the plot receiving farmyard manure (FYM) was lower than that of the plot receiving an equivalent of mineral nitrogen. Also at the Ossekampen, only small differences arose between the extrinsic stability of plots receiving various fertiliser treatments. Instead, the grassland management of the plots had an overriding effect on these stability levels. Whereas the extrinsic stability of all cut plots was low, all grazed plots were nearly entirely stable. It is argued that the nitrogen dynamics in grassland ecosystems have only a small impact on their extrinsic stability levels, in spite of the predictions by simulation models. Instead, pH-related soil processes and the grassland management play an overriding role in the maintenance of the production stability of mixed grassland. It is conceivable that a large number of other processes, which regulate ecosystem stability, could be identified in other plots and experiments, using the same mathematical framework.

Long term use of inorganic fertilisers and reduced organic matter inputs have contributed to acidification of agricultural soils. This strongly affects the soil dwelling fauna and nutrient mineralisation. Organic fertilisers such as solid cattle manure (SCM) resurge as an option to overcome this acidification problem and to provide the required blend of essential macro- and micronutrients for plant growth. We assessed the effects of earthworm density (400 or 700 m-2) at two levels of soil pH (ambient and increased), with or without application of solid cattle manure (SCM), on herbage nitrogen (N) uptake, and CO2 and N2O emissions over a period of 134 days using undisturbed soil cores from an acid peat grassland in a mesocosm experiment. Liming proved to be beneficial for earthworm performance and grassland productivity. A higher soil pH and earthworm density resulted in a higher soil biological activity measured as soil respiration. The combined application of lime and earthworms increased herbage apparent N recovery from SCM by 83% compared to SCM only. In the manured treatments, herbage N uptake was positively correlated with earthworm density (R2 = 0.92). N2O emissions increased by 37% when SCM was applied compared to the unfertilised control. Following SCM application, the cumulative increase in herbage N uptake was almost ten times greater than the measured total N2O losses. No relationship was observed between earthworm density and level of N2O emission. N mineralisation and herbage N uptake from SCM in acidic peat grasslands were greatly stimulated by the combined increase in soil pH and earthworm density. This stimulated the activity of soil biota, resulting in an increased herbage N recovery from the applied SCM.

With the Dry Weight Rank (DWR) method of 't Mannetje and Haydock [see Journal of British Grassland Society (1963) 18, 268-275] for botanical analysis in pastures, the dry weight proportions of species are estimated from their first, second and third ranks in dry weight in single quadrats. The yield correction of Haydock and Shaw [see Australian Journal of Experimental Agriculture and Animal Husbandry (1975) 15, 663-670] is used additionally to solve the problem of the respective under- and overestimates of the dry weight proportions of high and low yielding species when these grow in patches. In this paper the DWR method is evaluated by means of computer simulation. Main element of the simulation model is a computer sampling program with which a fictitious vegetation can be sampled with a circular quadrat. The output shows that the DWR method works well using relatively small sampling quadrats with, on average, only a few plants per quadrat, irrespective of the horizontal vegetation structure. In vegetations where species grow patchwise, satisfactory results are also obtained using large quadrats with much more plants (i.e. tens) per quadrat. The reason is that in these cases also minor species can compete successfully for first, second and third ranks. However, it appeared that only a certain degree of patchiness is necessary, and with the usually applied quadrat sizes up to 25 dmsuperscript 2, probably in most vegetations this condition is fulfilled. Care should be taken in applying the DWR method for estimating species composition in recently sown grasslands where species usually occur more or less at random. In those cases, in principle a very small sampling quadrat (smaller than 1 dmsuperscript 2) could be used. However, this has practical limitations since the quadrat size should not be too small for realistic yield estimations, needed for the Haydock & Shaw yield correction. The simulations revealed that one condition (i.e., that the sampling quadrat should be at least as large that it usually contains three or more species) is not necessary because of the almost always perfect functioning of the correction for missing ranks. Generally speaking, a sampling quadrat should be chosen not larger than is strictly necessary from the viewpoint of horizontal vegetation structure and from the viewpoint of realistic yield estimations. Multipliers calculated from simulation data could satisfactorily mimic the original multipliers of DWR given by 't Mannetje & Haydock. It is postulated that the DWR method is well suited for studying vegetation changes in old, floristically diverse grasslands with dominant species often in moderate dry weight proportions and species usually growing in patches.

Background and aim - Typical values of plant available nitrogen (N) from animal manures are provided in fertilizer recommendation schemes. However, only a few attempts have been made thus far to study the variation in these values among contrasting soil types. The objective of this study was to examine the interactions between animal manure and soil types on N mineralization and total plant N recovery (shoots¿+¿roots) during one growing season. Methods - A pot experiment was conducted in a greenhouse during a growth period of 180 days. Experimental treatments included solid cattle manure (SCM), cattle slurry (CS) and poultry manure (PM), all applied to sandy, clay and peat soils sown with perennial ryegrass. Total N application rate was 120 kg ha-1. Results - There were clear interactions (P¿¿sandy¿>¿clay. In case of the peat soil, net mineralization of the applied organic N was on average 90 % from PM, 39 % from SCM and 26 % from CS. However, in the clay soil a positive net N mineralization occurred only from PM (42 %). Besides, significant proportions of the applied mineral N from SCM (17 %) and CS (35 %) were immobilized in this soil type. Consequently, apparent total plant N recovery was highest in the peat soil with values of 80, 57 and 50 % from PM, CS and SCM, respectively. In contrast, these values were only 57, 28 and 15 % for the clay soil. Conclusions - It is concluded that wide variations do exist in the extent of net N mineralization and plant N recovery from a given animal manure type when applied to diverging soil types. This indicates the need for more soil-specific manure fertilizer recommendations.

Maize yields in continuous maize production systems of smallholders in the Costa Chica, a region in Southwest Mexico, are low despite consistent inputs of fertilizers and herbicides. This study was aimed at investigating the prospects of intercropping maize (Zea mays L.) and maize-roselle (Hibiscus sabdariffa L.) mixtures with the legumes canavalia (Canavalia brasiliensis Mart. ex Benth) and mucuna (Mucuna pruriens var. utilis) for improving nutrient uptake and weed suppression. Farmer-managed experiments were established in two communities in the region during 2006 and 2007 using randomized split-plot designs. Maize monocrops and maize-roselle intercrops grown with different sources of nutrients were intercropped with both legume species, sown 4–6 weeks after maize. Neither the legumes decreased yields of maize nor roselle, whereas they caused a reduction of the weed biomass by 24–55%. Total aboveground biomass returned to the soil increased up to 36% and total N, P, and K uptake was increased on average by 52%, 24%, and 30%, respectively. Legumes acted not only as a N-fixing crop, but also as a “catch” crop, preventing N and K leaching. With its prostrate growth habit and adaptation to poor soil conditions, canavalia demonstrated agronomic advantages in comparison to mucuna.

Many measures have been proposed to mitigate gaseous emissions and other nutrient losses from agroecosystems, which can have large detrimental effects for the quality of soils, water and air, and contribute to eutrophication and global warming. Due to complexities in farm management, biological interactions and emission measurements, most experiments focus on analysis of short-term effects of isolated mitigation practices. Here we present a model that allows simulating long-term effects at the whole-farm level of combined measures related to grassland management, animal housing and manure handling after excretion, during storage and after field application. The model describes the dynamics of pools of organic carbon and nitrogen (N), and of inorganic N, as affected by farm management in grassland-based dairy systems. We assessed the long-term effects of delayed grass mowing, housing type (cubicle and sloping floor barns, resulting in production of slurry and solid cattle manure, respectively), manure additives, contrasting manure storage methods and irrigation after application of covered manure. Simulations demonstrated that individually applied practices often result in compensatory loss pathways. For instance, methods to reduce ammonia emissions during storage like roofing or covering of manure led to larger losses through ammonia volatilization, nitrate leaching or denitrification after application, unless extra measures like irrigation were used. A strategy of combined management practices of delayed mowing and fertilization with solid cattle manure that is treated with zeolite, stored under an impermeable sheet and irrigated after application was effective to increase soil carbon stocks, increase feed self-sufficiency and reduce losses by ammonia volatilization and soil N losses. Although long-term datasets (>25 years) of farm nutrient dynamics and loss flows are not available to validate the model, the model is firmly based on knowledge of processes and measured effects of individual practices, and allows the integrated exploration of effective emission mitigation strategies.

Recently developed time-related gas production techniques to quantify the kinetics of ruminant feed fermentation have a high resolution. Consequently, fermentation processes with clearly contrasting gas production kinetics can be identified. Parameterization of the separate processes is possible with a suitable multiphasic model and modelling method. A flexible, empirical, multiphasic model was proposed for parameterization of gas production profiles. This equation was fitted, using a two-step method, to four gas production profiles and the maximum fractional rate of substrate digestion (RM) was calculated for each phase. In the first step, the number of phases and starting values for parameters of the multiphasic model were derived from a combination of either (1) the measured cumulative gas production profile and its first (rate of gas production) and second (change in rate of gas production) derivative or (2) a fitted monophasic curve and the residuals between this curve and the observations. In the second step, the starting values were used to fit di- or triphasic models. Using Approach 1 was complicated by frequent fluctuations in the gas production rate. However, the combined graph of the fitted monophasic curve and residuals (Approach 2) gave good results for every profile. The multiphasic model fitted the profiles well. The robustness of the model declined when the number of phases was increased, underlining the importance of accurate estimations of starting values. It is argued that the model parameters and the calculated RM are useful for feed quality evaluation. The results show that mathematical description of gas production profiles requires a two-step approach and a multiphasic model.

A 2-year study was carried out to examine the effects of solid cattle manure storage method on (1) total carbon (C) and nitrogen (N) losses, (2) first-year and residual manure dry matter (DM) and N disappearance after litterbag placement on grassland, and (3) apparent herbage N recovery (ANR) after a single surface application to a sandy grassland field. About twelve tonnes of fresh (FRE) manure taken from a litter barn were stored per treatment as stockpiled (STO), composted (COM) and covered (COV) heaps for 130 days, and total C and N losses were estimated. Thereafter, patterns of DM and N disappearance from FRE, COM and COV manures were monitored using litterbags with three mesh sizes (45 μm, 1 mm and 4 mm). Herbage ANR from these manures was measured at application rates of 200, 400 and 600 kg N ha−1. During the storage period, only about 10 % of the initial Ntotal was lost from the COV heap, whereas these losses were 31 % from the STO heap and 46 % from the COM heap. The respective Ctotal losses were 17, 59 and 67 %. After field placement, overall manure DM and N disappearance rates from all mesh sizes of the litterbags were in the order: COV > FRE > COM (P

Building on previous research at the experimental and national scales, this study was carried out at the local scale over a four-year period on three farms of reference: one specialized dairy farm ‘Vaquería 10’ (33.7 ha) and two mixed farms, ‘Remedio’ (9.4 ha) and ‘La Sarita’ (47 ha). All three farms are located in the San Antonio de Los Baños municipality, Havana, Cuba. This study illustrates the application of the Ecological Framework for the Assessment of Sustainability (ECOFAS). This methodology consists of a cyclical structure of six steps, aimed at guiding the process of implementing innovative mixed (crop–livestock) farming strategies. Local stakeholders (farmers, researchers, extension officers and representatives of the ministry of agriculture in the municipality) identified alternative strategies for agriculture in the region, based on the critical technological, environmental and socio-economic factors constraining the current performance of farming systems. The results show that implementation of ‘best practice’ mixed farming systems management strategies in the region potentially can lead to a strong positive impact on land productivity, food self-sufficiency as well as improve socio-economic performance.

Considerable losses of nitrogen (N) may occur during and after surface-application of solid cattle manure to grassland. These losses are due mainly to the emission of ammonia (NH3) and represent a threat to the environment. Consequently, N fertilizer value of the manure is reduced. Therefore, adjusted manure application strategies were evaluated in three field experiments focusing on NH3 emission and herbage N recovery. Fresh, composted and anaerobically stored solid cattle manures were surface-applied to grassland at a rate of 400 kg N ha-1 with or without irrigation and/or lava meal addition. NH3 emissions were estimated by means of diffusion samplers installed 20 cm above the soil surface for a period of 3–4 days. Irrigation (5 mm) immediately after applying fresh manure reduced (P

Attempts to increase food crop yields by intensifying agricultural systems using high inputs of nonrenewable resources and chemicals frequently lead to de-gradation of natural resources, whereas most technological innovations are not accessible for smallholders that represent the majority of farmers world wide. Alternatively, cocultures consisting of assemblages of plant and animal species can support ecological processes of nutrient cycling and pest control, which may lead to increasing yields and declining susceptibility to extreme weather conditions with increasing complexity of the systems. Here we show that enhancing the complexity of a rice production system by adding combinations of compost, azolla, ducks, and fish resulted in strongly increased grain yields and revenues in a season with extremely adverse weather conditions on East Java, Indonesia. We found that azolla, duck, and fish increased plant nutrient content, tillering and leaf area expansion, and strongly reduced the density of six different pests. In the most complex system comprising all components the highest grain yield was obtained. The net revenues of this system from sales of rice grain, fish, and ducks, after correction for extra costs, were 114% higher than rice cultivation with only compost as fertilizer. These results provide more insight in the agro-ecological processes and demonstrate how complex agricultural systems can contribute to food security in a changing climate. If smallholders can be trained to manage these systems and are supported for initial investments by credits, their livelihoods can be improved while producing in an ecologically benign way.