Subsoil improvement for sustainable intensification : impact of loosening with straw incorporation or liming on subsoil properties, crop performance and water quality

Subsoil has a high capacity for nutrient and water retention, but arable subsoil is often nutrient poor, carbon-deficient and compacted, affecting both root growth and yield. In field and lysimeter experiments, this thesis investigated the effects of subsoil loosening and loosening with cereal straw incorporation (24-60 Mg ha-1) (loosening + straw) on crop yield, soil properties (bulk density, penetration resistance, moisture characteristics) and leaching. A rectangular metal tube welded behind each tine of a deep loosener was used to inject straw as a slurry in the field, while subsoil was loosened and mixed manually with milled straw in lysimeter studies. In laboratory experiments, subsoil was limed with different amounts of CaCO3 and CaO to increase soil pH from 7.0 to 7.5, 8.0 and 8.4 and incubated for 22 months to examine changes in soil structural stability and dissolved reactive phosphorus. Field subsoil loosening + straw significantly increased soil organic carbon, total nitrogen and water holding capacity. It also decreased bulk density, from around 1.5 Mg m-3 in the control to about 1.0 Mg m-3. The effects of loosening + straw persisted for at least three years, but loosening alone had weak and short-lived effects. Loosening + straw significantly increased grain yield in the first cropping season (6% higher than the control), but not in the following two years. Nitrogen balance calculations of lysimeters showed that short-term nitrogen losses were lowest in the subsoil loosening + straw treatment and that nitrogen leaching was reduced by about 62%. In incubations, subsoil liming decreased clay dispersion. Wet aggregate stability and concentration of dissolved reactive phosphorus increased and peaked around pH 7.8 and 7.5, respectively. Combining loosening with straw incorporation into subsoil appeared to improve soil properties and water quality, but not crop yield on the experimental soil. On other soil types, this practice may have more beneficial effects

Evaluation of process based model 3-PG for simulation of net primary production of Picea abies in northern and southern regions of Sweden under climate change

The results of this evaluation reveal good performance of 3-PG and seems reasonable to use it for simulation of net primary production in Sweden. Subsequently,the NPP of Picea abies was simulated using 3-PG for 110 years in northern and southern Sweden under climate change. RCA3 generated climate data on two emission scenarios (A2 and B2) was used in the simulations as driving variables. The initial stand data and site factors were taken from well known sites in northern and southern Sweden to determine fertility rating input factor of 3-PG and to use for input data for Heureka StandWise and 3-PG for simulation and valida-tion. The outcome from the simulation of 2071-2100 in A2 and B2 scenario were summa-rized for 2071-75, 2076-80, 2081-85, 2086-90, 2091-95 & 2096-2100 and compared against their corresponding reference years (1961-1990). The average relative increment of NPP af-ter 110 years was 89,7% and 60,5 % for A2 and B2 in northern and 88,6% & 60,3% for A2 & B2 of southern Sweden respectively. Higher relative increase of temperature in autumn, spring & winter in northern Sweden led to higher relative increase of NPP in northern than Southern Sweden in both scenarios. Sensitivity testing of the model based on predicted NPP was carried out independently for temperature, rainfall and fertility rating. The result point-ed-out that NPP from 3-PG was more sensitive for fertility rating than for temperature and rainfall. Rainfall was almost indifferent for the test. Sensitivity of the factors considered in the exercise was found to be site dependent. Total biomass outputs from 3-PG and Heureka StandWise simulations were compared for validation. There was no significance difference between total biomass from the two models. Modeling efficiency was 78,5 % for northern and 89 % for southern Sweden. The average model bias explained the error with 8,6% and -3,2%; the mean absolute difference outcome was about 8,6% and 7% and the root mean square error was13% and 9,5% in northern & southern regions respectively. Overall, the results from this work suggest that there were possibilities to use 3-PG for predicting NPP in Sweden with due considerations of thinning operation, determination of fertility rating and Leaf area index outcomes

Effects of loosening combined with straw incorporation into the upper subsoil on soil properties and crop yield in a three-year field experiment

Subsoil management needs to be integrated into the current tillage regimes in order to access additional resources of water and nutrients and sustain crop production. However, arable subsoil is often deficient in nutrients and carbon, and it is compacted, affecting root growth and yield. In this study, crop yield and soil responses to loosening of the upper subsoil, without and with straw injection below the plough layer (25-34 cm), were studied during three crop cycles (2016-2018) in a field experiment near Uppsala, Sweden. Responses to straw injection after loosening were studied after single and triple consecutive applications of 24-30 Mg ha-1 during 2015-2017 to spring-sown barley and oats. Subsoil loosening combined with one-time or repeated straw addition (LS treatments) significantly reduced soil bulk density (BD) and increased porosity, soil organic carbon (SOC) and total nitrogen (N) compared with loosening (L) alone (one-time or repeated annually) and the control. In treatment L, the soil re-compacted over time to a similar level as in the control. Field inspections indicated higher abundance of earthworms and biopores in and close to straw incorporation strips. Aggregates readily crumbled/fragmented by hand and casts (fine crumbs) were frequently observed in earthworm burrows. The treatment LS improved soil properties (SOC and porosity) and water holding capacity, but had no significant influence on crop yield compared with the control. Crop yield in all treatments was 6.5-6.8 Mg ha-1 in 2017 and 3.8-4.0 Mg ha-1 in 2018, and differences were non-significant. Absence of yield effect due to treatments could be possibly due to other confounding factors buffering expression of treatment effects on yield. Lower relative chlorophyll content in leaves in the loosening with straw treatment during early growth stages, did not affect final crop yield. Subsoil loosening performed three times gave no further improvement in soil properties and grain yield compared with one-time loosening. There was no difference in yield between repeated subsoil loosening + straw and one-time treatment. It will be interesting to study the long-term effects of deep straw injection and evaluate its impact under other soil and weather conditions

Lysimeter deep N fertilizer placement reduced leaching and improved N use efficiency

Deep fertilization has been tested widely for nitrogen (N) use efficiency but there is little evidence of its impact on N leaching and the interplay between climate factors and crop N use. In this study, we tested the effect of three fertilizer N placements on leaching, crop growth, and greenhouse gas (GHG) emissions in a lysimeter experiment over three consecutive years with spring-sown cereals (S1, S2, and S3). Leaching was additionally monitored in an 11-month fallow period (F1) preceding S1 and a 15-month fallow period (F2) following S3. In addition to a control with no N fertilizer (Control), 100 kg N ha(-1) year(-1) of ammonium nitrate was placed at 0.2 m (Deep), 0.07 m (Shallow), or halved between 0.07 m and 0.2 m (Mixed). Deep reduced leachate amount in each cropping period, with significant reductions (p < 0.05) in the drought year (S2) and cumulatively for S1-S3. Overall, Deep reduced leaching by 22, 25 and 34% compared to Shallow, Mixed and Control, respectively. Deep and Mixed reduced N leaching across S1-S3 compared with Shallow, but Deep further reduced N loads by 15% compared to Mixed and was significantly lowest (p < 0.05) among the fertilized treatments in S1 and S2. In S3, Deep increased grain yields by 28 and 22% compared to Shallow and Mixed, respectively, while nearly doubling the agronomic efficiency of N (AE(N)) and the recovery efficiency of N (REN). Deep N placement is a promising mitigation practice that should be further investigated

Measuring progress and projecting attainment on the basis of past trends of the health-related Sustainable Development Goals in 188 countries: an analysis from the Global Burden of Disease Study 2016

The UN’s Sustainable Development Goals (SDGs) are grounded in the global ambition of “leaving no one behind”. Understanding today’s gains and gaps for the health-related SDGs is essential for decision makers as they aim to improve the health of populations. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016), we measured 37 of the 50 health-related SDG indicators over the period 1990–2016 for 188 countries, and then on the basis of these past trends, we projected indicators to 2030

Liming with CaCO3 or CaO affects aggregate stability and dissolved reactive phosphorus in a heavy clay subsoil

A 22-month incubation experiment was conducted to study the effect of lime on clay dispersion, wet aggregate stability (WAS) and dissolved reactive phosphorus (DRP), using a heavy clay subsoil with an initial pH of 7.0 and 7.3 g kg(-1) of soil organic carbon. Lime was applied to achieve soil pH values of 7.5, 8 and 8.4. Clay dispersion decreased linearly with increased pH (corresponding to an increase in lime amount) for both lime types (R-2 = 0.44 for CaO; R-2 = 0.53 for CaCO3, P < 0.05), with a decrease of 2-16 % (CaO) and 3-17 % (CaCO3) compared with the control.Both WAS and DRP followed piece-wise linear functions, with an increase and peak around pH 7.5-7.8, and a decline at higher pH (WAS: R-2 = 0.73 for CaO, R-2 = 0.68 for CaCO3, P < 0.001; DRP: R-2 = 0.84 for CaCO3, R-2 = 0.33 for CaO, P < 0.001). Wet aggregate stability increased on average by 13 % and 11 % at the lowest and intermediate levels, respectively, compared with the control. At the highest lime application rate, WAS was 6 % (CaO) and 8 % (CaCO3) lower than in the control. These differences were probably caused by changes in electrical charge and in concentrations of soluble calcium and dissolved organic carbon (DOC) as the pH increased. More studies are needed to understand the processes in detail and to draw conclusions that are more robust

Impact of loosening and straw addition to the subsoil on crop performance and nitrogen leaching: A lysimeter study

Poor subsoil properties are difficult to ameliorate and detrimental to soil fertility and crop yield. The effects of loosening (L) and loosening + straw (LS) similar to 60 Mg ha(-1) into the subsoil (25-40 cm depth) on crop yield, water flow, and the nitrogen (N) balance components under bare soil conditions and a barley (Hordeum vulgare L.) crop were investigated in an about 21-mo lysimeter study and compared with a control treatment. Undisturbed soil columns (n = 12) were excavated from an agricultural field in May 2016, installed at a lysimeter station, and exposed to outdoor climatic conditions in Uppsala, Sweden, in August 2016. Spring barley ('Makof') was grown between June and September 2017. Total N leaching loads over the 21 mo were high (74-193 kg ha(-1)). The LS treatment reduced the N load by 49% (P = .01) and 62% (P = .001) compared with the L and control treatments, respectively. Loosening reduced N load by 25% (P .05), respectively. These results suggest that LS can reduce N leaching. The overall effects of LS on crop performance and N removal and leaching should be further scrutinized in long-term field studies

Measuring progress and projecting attainment on the basis of past trends of the health-related Sustainable Development Goals in 188 countries : an analysis from the Global Burden of Disease Study 2016

Background The UN's Sustainable Development Goals (SDGs) are grounded in the global ambition of "leaving no one behind". Understanding today's gains and gaps for the health-related SDGs is essential for decision makers as they aim to improve the health of populations. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016), we measured 37 of the 50 health-related SDG indicators over the period 1990-2016 for 188 countries, and then on the basis of these past trends, we projected indicators to 2030. Methods We used standardised GBD 2016 methods to measure 37 health-related indicators from 1990 to 2016, an increase of four indicators since GBD 2015. We substantially revised the universal health coverage (UHC) measure, which focuses on coverage of essential health services, to also represent personal health-care access and quality for several non-communicable diseases. We transformed each indicator on a scale of 0-100, with 0 as the 2.5th percentile estimated between 1990 and 2030, and 100 as the 97.5th percentile during that time. An index representing all 37 health-related SDG indicators was constructed by taking the geometric mean of scaled indicators by target. On the basis of past trends, we produced projections of indicator values, using a weighted average of the indicator and country-specific annualised rates of change from 1990 to 2016 with weights for each annual rate of change based on out-of-sample validity. 24 of the currently measured health-related SDG indicators have defined SDG targets, against which we assessed attainment. Findings Globally, the median health-related SDG index was 56.7 (IQR 31.9-66.8) in 2016 and country-level performance markedly varied, with Singapore (86.8, 95% uncertainty interval 84.6-88.9), Iceland (86.0, 84.1-87.6), and Sweden (85.6, 81.8-87.8) having the highest levels in 2016 and Afghanistan (10.9, 9.6-11.9), the Central African Republic (11.0, 8.8-13.8), and Somalia (11.3, 9.5-13.1) recording the lowest. Between 2000 and 2016, notable improvements in the UHC index were achieved by several countries, including Cambodia, Rwanda, Equatorial Guinea, Laos, Turkey, and China; however, a number of countries, such as Lesotho and the Central African Republic, but also high-income countries, such as the USA, showed minimal gains. Based on projections of past trends, the median number of SDG targets attained in 2030 was five (IQR 2-8) of the 24 defined targets currently measured. Globally, projected target attainment considerably varied by SDG indicator, ranging from more than 60% of countries projected to reach targets for under-5 mortality, neonatal mortality, maternal mortality ratio, and malaria, to less than 5% of countries projected to achieve targets linked to 11 indicator targets, including those for childhood overweight, tuberculosis, and road injury mortality. For several of the health-related SDGs, meeting defined targets hinges upon substantially faster progress than what most countries have achieved in the past. Interpretation GBD 2016 provides an updated and expanded evidence base on where the world currently stands in terms of the health-related SDGs. Our improved measure of UHC offers a basis to monitor the expansion of health services necessary to meet the SDGs. Based on past rates of progress, many places are facing challenges in meeting defined health-related SDG targets, particularly among countries that are the worst off. In view of the early stages of SDG implementation, however, opportunity remains to take actions to accelerate progress, as shown by the catalytic effects of adopting the Millennium Development Goals after 2000. With the SDGs' broader, bolder development agenda, multisectoral commitments and investments are vital to make the health-related SDGs within reach of all populations. Copyright The Authors. Published by Elsevier Ltd. This is an Open Access article published under the CC BY 4.0 license.Peer reviewe