Fertilizer Response Research Articles

Fertilizer responsiveness of high-yielding drought-tolerant rice in rainfed lowlands

ABSTRACT Recent advances in rice breeding in tropical Asia led to the release of high-yielding drought-tolerant cultivars. Together with the use of these cultivars, improved nutrient management under drought should further increase rice productivity in rainfed lowland ecosystems. The objectives of this study were to evaluate cultivar differences in the responses of plant growth and grain yield to fertilizer application regimes. We compared 13 drought-tolerant rice cultivars with two irrigated rice cultivars under three nutrient management conditions in irrigated and rainfed lowlands in the Philippines during the wet seasons of 2014 and 2015. Drought stress was mild in both years, with a yield reduction of 11 to 12%, and there was no significant cultivar × nutrient management interaction in yield. The drought-tolerant cultivar NSIC Rc282 proved fertilizer-responsive, and had similar yield to those of the popular high-yielding cultivar NSIC Rc222 under all conditions. An ancillary experiment in 2016 confirmed that NSIC Rc282 was more drought-adapted than NSIC Rc222, with 11% to 37% higher yield under stress. In order to maximize the yield, NSIC Rc282 required N application only when the drought ended, whereas NSIC Rc222 required additional N during the drought. This shows that the details of drought-adaptive nutrient management differ between irrigated and drought-tolerant rice cultivars. We suggest that the introduction of high-yielding drought-tolerant rice cultivars will both improve productivity and increase the nutrient-use efficiency in rainfed environments.

Beyond the Economic Gaze: Childbearing During and After Recessions in the Nordic Countries

During the 2010s, fertility rates fell across the Nordic region. The onset of these declines seems linked to the Great Recession of 2008–2009, but their continuation cannot easily be linked to subsequent economic change. The 1990s, too, brought episodes of economic crises to the Nordic region that were followed by different degrees of fertility decline. In this study, we provide an empirical overview of parity-, age- and education-specific fertility developments in the five Nordic countries in the wake of the economic recessions in 2008 and the early 1990s, respectively. We demonstrate a high degree of heterogeneity in fertility developments across countries after 1990, whereas after 2008, the trends are much more similar across the five countries. Likewise, the educational differences in birth hazards that characterized the developments after 1990 were much smaller in the initial years after 2008–2009. This reversal from heterogeneity to homogeneity in the fertility response to recessions calls for an expansion of theories on the cyclicality of fertility in relation to uncertainty and economic and social change. In our discussion, we consider the role of a set of factors that also incorporates the state, crisis management, and perceptions of economic and welfare uncertainty.

Maize nitrogen uptake and productivity under reduced and conventional tillage

Reduced tillage (RT) systems have been promoted for crop production intensification in low potential areas through enhancement of fertiliser response of degraded soils and drought mitigation. A 3 year study was conducted from 2015/2016 to 2017/2018 growing seasons in sub-humid (650–1000 mm rainfall year−1) Zimbabwe to determine nitrogen (N) uptake and maize yield response to nitrogen fertilisation rate (0, 30, 60, 90 120 150, 180 k gha−1) under RT and conventional tillage (CT). The experimental design was a split plot, with the two tillage systems as main plot and seven N rates as the sub-plot treatments. Four sites were established in smallholder farmer fields with clayey soils (160–400 g clay kg−1; Chromic Luvisols and Rhodic Ferralsols) and sandy soils (40–100 g clay kg−1; Eutric Regosols). Results show that the study sites had rainfall deficits of 4–47% in the first and third growing seasons. Nitrogen uptake rates of 8–60 kg ha−1 resulted in fertiliser N recovery efficiencies of 5–40% which were two fold higher under RT than under CT system. Maize grain yields (0.3–11 t ha−1) were 33% higher under RT than CT and increased 1.88–2.72 fold under N fertilisation compared to the control. The mismatch between top dressed N and peak crop demand require precision fertilisation in the dry seasons. Agroecology based quadratic modelling revealed that maximum maize yields of 2–13 t ha−1 were obtainable at optimum N fertilisation rates that were lower under RT than CT. The study provided a robust starting point in the improvement of nitrogen fertiliser management for maize under reduced tillage and climate variability.

Soil Nitrogen Fertility and Soybean Growth Responses to No-tillage and Manure Compost Application on Paddy-upland Rotation Fields

ABSTRACT With the continuance of soybean (Glycine max (L.) Merr.) cropping on drained paddy soil in Japan, countermeasures against decreasing trend of the available nitrogen (N) are needed. We determined the effect of no-tillage (NT) soybean cropping with manure compost (MC) application on soil N availability and soybean growth under a rice (Oryza sativa L.) -wheat (Triticum aestivum L.) -soybean rotation on a drained paddy field in central Japan. NT significantly increased available N in surface soil after soybean harvest relative to conventional tillage (CT). Application of 2 kg MC m−2 before wheat sowing significantly increased available N just before soybean sowing. Tillage and MC treatments did not affect the ureide-N content in the stem of soybean, which reflects activities of N2 fixation at R6. The effect of NT on nitrate-N in the stem was not clear, but MC application significantly increased the content. NT and MC application significantly increased soybean aboveground biomass at R6, when biomass was maximum. The results indicate that MC application increased the soil N availability, and a higher nitrate uptake increased the aboveground biomass. In NT, however, the relationship between aboveground biomass and N assimilation was not clear. The seed yields were 313–330 g m−2 in 2014 and 213–244 g m−2 in 2015, and the difference among tillage and MC treatments were not statistically significant. Our results indicate that NT soybean cropping with MC application maintained N availability in paddy-upland rotation fields. MC application before wheat sowing is recommended.

Soil quality parameters vis-a-vis growth and yield attributes of sugarcane as influenced by integration of microbial consortium with NPK fertilizers

Intensive agriculture involving high crop intensity, unavailability of organics, and higher use of straight fertilizers causes imbalanced use and deficiencies of several other macro and micronutrients. Nutrients supply through the integration of microbial consortium containing Gluconacetobater diazotrophicus, Trichoderma harzianum, and Pseudomonas fluorescens can reduce the requirements on the one hand and can also increase the response of chemical fertilizers. Thus we had planned the present experiment with the objectives (i) to determine the effect of integrated application of microbial consortium (MC) and NPK fertilizer on soil quality parameters and crop growth and yield attributes and (ii) to assess the effect of integration on agronomic efficiency of N, P and K and find out the possibilities for reduction in applied doses of NPK, if any. Five treatments viz., T1; N0P0K0; T2: N75P13K25; T3: N150P26K50; T4: N75P13K25 + microbial consortium and T5: N150P26K50 + microbial consortium containing new strains of Trichoderma harzianum, Gluconcetobacter diazotrophicus, and Pseudomonas fluorescens (CFU 109–10 per ml liquid culture) were evaluated under four replications in a randomized block design (RBD). Experimental results indicated that integrating microbial consortium and NPK fertilizers' application proved effective in improving soil organic carbon, soil microbial population, microbial biomass carbon, microbial biomass nitrogen, and soil respiration. Integrated use of microbial consortium with NPK also improved the cation exchange capacity of soil and roots. However, the growth and yield attributes, nutrients uptake, sugarcane, and sugar yields also revealed a positive effect of microbial consortium's integrated application with NPK. The integration of MC and NPK also improved the agronomic efficiency of applied nutrients (NPK). Reduction of 50% NPK with these microbial consortia (Trichoderma harzianum, Gluconcetobacter diazotrophicus, and Pseudomonas fluorescens) was found better than the application of full NPK through chemical fertilizers. Thus application of N150P26K50 with microbial consortium can sustain soil fertility besides improving sugarcane and sugar yields in subtropical Indian conditions.

Evaluation of soil-dependent crop yield outcomes in Nepal using ground and satellite-based approaches

Abstract Smallholder farmers face many constraints to achieving food security. Optimal soil management is often limited by a lack of accessible and accurate soil characterization, and an associated lack of soil-specific management practice recommendations. Crop yields depend on both soil quality and soil-mediated fertilizer responses. Existing research on soil-fertilizer interactions is primarily based on farm trials and/or survey data, which are resource intensive and typically restricted to local scales. High-resolution (∼10-meter) remote sensing data and digital soil maps provide a low cost, scalable alternative. Here, we deploy methods based on the Sentinel satellite constellation to estimate soil and fertilizer impacts on irrigated wheat grain yields in Nepal and to inform precision soil and nutrient management recommendations. We first combine field data with Sentinel-1 and Sentinel-2 imagery to delineate wheat cropping areas for 2016–2019 with 92 % accuracy. We then estimate wheat yields at 10-meter resolution using Sentinel-2 and weather covariates based on yield models parameterized from two different methods: 1) APSIM crop model simulations and 2) ground cropcuts from 147 fields. Using a large dataset of soil samples collected by the Nepal Agricultural Research Council, we examine the linear and non-linear effects of soil properties on wheat yields. Finally, the soil maps were combined with a survey of field-level crop management data and our yield estimates to test the interaction of soil quality with fertilizer effectiveness. Our ground-calibrated satellite model predicted yields with good accuracy (R2 = 0.55), while the uncalibrated simulation-based approach had weaker but significant prediction accuracy (R2 = 0.24). We find statistically significant gains in yield of 0.9–2.4 % are possible by increasing soil organic matter and zinc from highly deficient values to optimal values of 2.2 % organic matter (OM) and 0.67 ppm zinc (Zn). Using digital soil maps of Nepal produced by the International Maize and Wheat Improvement Center (CIMMYT), we map croplands deficient in zinc (Zn

Effects of sugar sources on adult longevity, survival and related gene expression in an endoparasitoid, Pteromalus puparum (Hymenoptera: Pteromalidae)

Adult parasitic wasps take sugars to meet their energy needs and display different lifespans and fertility in response to different sugar sources. Pteromalus puparum is an endoparasitoid with a wide range of hosts, including many lepidopteran pests. As a potential natural enemy resource, the availability of sugar sources has profound effects for wasp applications and host populations dynamics. We assessed the effect of feeding sucrose and honey on the lifespan of P. puparum in the range 0-40% (w/v). The results indicated a statistically significant positive effect of sucrose and honey solutions on the lifespan of P. puparum female adults. Correlation analyses confirmed a strong positive correlation between high concentrations of sugar and extended lifespan. The optimum concentration of sucrose solution for wasps was 20%, while 10% for honey. Then, we examined the expression patterns of 15 lifespan-related genes. The results showed that the relative expression levels of 14 genes were significantly correlated with the mean lifespan of sucrose-fed wasps, and six genes correlated with the mean lifespan of honey-fed wasps. In addition, the models for lifespan prediction were constructed. We elaborated the quantitative effects of two sugar sources (sucrose and honey) on P. puparum lifespan, investigated the expression patterns of lifespan-related genes when fed different sugar sources, and developed round lifespan prediction models accordingly. This study provides a novel tool for studying the longevity regulating mechanisms of parasitic wasps, and may be instructive for mass-production of parasitoids as biological control agents. © 2020 Society of Chemical Industry.

Effect of no-tillage and tillage systems on melon (Cucumis melo L.) yield, nutrient uptake and microbial community structures in greenhouse soils

Abstract No-tillage (UT) and tillage (TL) influence melon (Cucumis melo L.) production. However, the mechanism of improving the soil quality under UT in melon production is still unavailable. In this study, we attempted to explore the effects of UT and TL treatments on soil fertility and the microbial abundance and diversity in planting melon under greenhouse condition. Soil properties were determined and the bacterial v4-v5 16S rRNA and the fungal internal transcribed spacer gene were pyrosequenced by extracting greenhouse soil DNA. Results showed that the two treatments had different effects on nutrient uptake in melon plants under facility conditions. Additional nitrogen (N) was absorbed in the leaves and fruit in UT treatment. However, the N content in the UT treatment was kept as similar to that of the TL treatment. The phosphorus (P) contents in melon plant leaves and fruits in the UT treatment were higher than those in the TL treatment. High potassium (K) contents were observed in fruits and melon stem under the UT and TL treatments, respectively. Soil pH, organic matter and the available N influenced the bacterial and fungal distributions. The total N, total P and total K in melon plants were correlated with the bacterial and fungal groups in facility soils. The UT treatment had a substantial effect on the microbial diversity in soils planted with melon. Our study provided insights into the response of soil fertility and microbial structures to UT and TL treatments under greenhouse soils, which may aid in managing greenhouse soil quality.

Assessing and understanding non-responsiveness of maize and soybean to fertilizer applications in African smallholder farms

Use of mineral fertilizers is essential to enhance crop productivity in smallholder farming systems of Sub-Saharan Africa, but various studies have reported ‘non-responsiveness’ where application of inorganic fertilizers does not lead to satisfactory yield gains. This phenomenon is not well defined nor are its extent and causes well understood. In order to close these knowledge gaps, we assessed the effects of commonly recommended nitrogen (N), phosphorus (P) and/or potassium (K) fertilizer inputs on maize grain and soybean production on farmer fields across prevalent land slope and/or soil texture gradients (2 × 2 matrix) in four agroecosystems over two growing seasons. The extent of the problem in the two cropping systems was compared by decomposing frequency distributions into various ranges of fertilizer effect sizes that represent specific degrees of non-responsiveness and responsiveness. Key soil properties and rainfall variables for field trials were also determined to identify the factors that are limiting crop yield increases by mineral fertilizer input.Significant differences were found in mean fertilizer effect on crop productivity and frequency of non-responsiveness among the study areas and growing seasons, with some explicit contrasts between maize and soybean. The application of mineral fertilizers failed to increase maize yields by more than 0.5 t ha−1 in up to 68 % of farmer fields and soybean yields by more than 150 kg ha−1 in up to 65 % of farmer fields for specific study areas and/or growing seasons, while for others crop responses exceeded those levels. Unlike hypothesized, there were no consistent differences in crop fertilizer responses between the soil texture and land slope classes at any of the study sites. The variation in fertilizer effects on maize grain productivity across the study areas and growing seasons was most strongly related to the soil silt and clay content, and exchangeable cation balances of calcium (Ca), magnesium (Mg) and K, whereas fertilizer effects on soybean were most strongly influenced by the evenness in rainfall during growing seasons, and the soil silt content, extractable P, and ratio of total C and total N. Findings from our study emphasize that non-responsiveness by maize and soybean crops in African smallholder agroecosystems is dependent on multiple interacting factors, and requires careful scrutiny to ensure returns on investments.

Beetroot (Beta vulgaris L.) growth and response to N supply – a case study

ABSTRACT There is need for information on the general crop physiology and nitrogen (N) fertiliser responses of beetroot in New Zealand. We investigated the responses to N of beetroot grown in a silt loam near Hastings, Hawke’s Bay. Four fertiliser treatments (0, 160, 320 or 480 kg N ha−1) were applied as urea, split evenly over four application times. The canopy light extinction coefficient averaged 0.64. Radiation use efficiency averaged 1.05 g MJ−1 for the treatments that received N fertiliser. Maximum yield occurred at an N fertiliser rate around 320 kg N ha−1. Published recommendations suggest only 225 kg N ha−1 would have been needed. This underestimation would have led to a yield penalty of only about 6%, but decreased the risk of significant mineral being N left in the soil. We discuss approaches to account for N supply from the soil when forecasting residual mineral N and N leaching risk.

Fertilizer profitability for smallholder maize farmers in Tanzania: A spatially-explicit ex ante analysis.

We present an easily calibrated spatial modeling framework for estimating location-specific fertilizer responses, using smallholder maize farming in Tanzania as a case study. By incorporating spatially varying input and output prices, we predict the expected profitability for a location-specific smallholder farmer. A stochastic rainfall component of the model allows us to quantify the uncertainty around expected economic returns. The resulting mapped estimates of expected profitability and uncertainty are good predictors of actual smallholder fertilizer usage in nationally representative household survey data. The integration of agronomic and economic information in our framework makes it a powerful tool for spatially explicit targeting of agricultural technologies and complementary investments, as well as estimating returns to investments at multiple scales.

Luteal Presence and Ovarian Response at the Beginning of a Timed Artificial Insemination Protocol for Lactating Dairy Cows Affect Fertility: A Meta-Analysis.

Progesterone (P4) concentration during follicular growth has a major impact on fertility response in timed artificial insemination (TAI) protocols. Luteal presence at the beginning of a TAI protocol and ovarian response after the first gonadotropin-releasing hormone (GnRH) injection (G1) affect P4 concentration and subsequently pregnancy per artificial insemination (P/AI). A systematic review of the literature and meta-analytical assessment was performed with the objective of evaluating the magnitude of the effect of luteal presence and ovarian response at the beginning of a TAI protocol on P/AI in lactating dairy cows. We considered only studies using synchronisation protocols consisting of GnRH and prostaglandin F 2α. The time interval between G1 and prostaglandin F 2α (PGF 2α) had to range from 5 to 7 d. The time interval between the PGF 2α injection and G2 had to range from 48 to 72 h. We used 28 controlled experiments from 27 published manuscripts including 16,489 cows with the objective of evaluating the effect size of having a functional corpus luteum (CL) at G1 on P/AI. Information regarding ovulatory response after G1 was available for 5676 cows. In a subset of cows (n = 4291), information was available for luteal presence and ovulatory response at the initiation of the TAI protocol. A functional CL at G1 increased (p < 0.001) the relative risk of conceiving (RR (relative risk) = 1.32; 95% CI = 1.21-1.45) in lactating dairy cows. Ovulation after G1 increased (p < 0.001) the relative risk of conceiving (RR = 1.29; 95% CI = 1.20-1.38) in lactating dairy cows. The effect of ovulatory response on P/AI after G1 was affected by luteal presence at G1. In summary, there was a clear benefit on P/AI for cows starting a TAI protocol with a functional CL (+10.5 percentage units) and cows ovulating at the beginning of a TAI protocol (+11.0 percentage units).

Armed Conflict and the Timing of Childbearing in Azerbaijan

AbstractResearch on fertility changes in former Soviet states of the South Caucasus is scant and has overlooked the role of armed conflicts. This study contributes to filling these gaps by providing the first detailed account of fertility changes in Azerbaijan since independence and by exploring them in relation to the Nagorno‐Karabakh conflict with Armenia. Estimates from retrospective birth history data from the 2006 Demographic and Health Survey show that since 1991 period fertility declined to almost below‐replacement levels, essentially as a result of stopping behavior, and, only recently, slight birth postponement. While the conflict seems to have little influence on aggregate trends, discrete‐time logit models accounting for unobserved heterogeneity reveal a 42–45 percent higher risk of transitioning to the second birth for women who have been exposed to conflict violence—whether in the form of forced migration or because of residence in the conflict‐torn Karabakh region—than for nonexposed women. Never‐migrant women from Karabakh have also significantly higher probability of having a first child. Further positive effects on fertility are observed for women who lost a child during peak conflict years. Risk‐insurance and replacement effects are possible mechanisms explaining such fertility responses.

Forage yield, water use efficiency, and soil fertility response to alfalfa growing age in the semiarid Loess Plateau of China

Water availability is a major constraint for crop production in the Loess Plateau of China; thus, improving water use efficiency (WUE) is a main research target. The impact of alfalfa (Medicago sativa L.) growing age on forage yield, WUE, soil water storage, and soil fertility were examined in a 15-yr study in the western Loess Plateau of China. The results of this study indicate that long-term continuous production of alfalfa aggravated the soil water deficit and reduced soil available phosphorus (AP) and the ratio of soil organic carbon to soil total nitrogen, but increased soil organic carbon, soil total nitrogen, and the ratios of soil organic carbon to soil available phosphorus and soil total nitrogen to soil total phosphorus. After the ninth year of alfalfa production, the greatest soil water storage deficit degree was found in the 0–80 cm soil layer (63 %), followed by the 200–300 (57 %) and 80–200 cm (55 %) soil layers. Forage yield and WUE of alfalfa reached their greatest values following six- to nine-yr-old stands, and then decreased gradually. These results suggest that the yield decline with long-term stands of alfalfa may be related to reductions in soil water storage and AP, and their interaction, and the optimal alfalfa growing age should not extend beyond nine years in semiarid conditions.

Partial substitution of chemical nitrogen with organic nitrogen improves rice yield, soil biochemical indictors and microbial composition in a double rice cropping system in south China

Substitution of chemical fertilizers with organic amendments recycle organic wastes and minimizes adverse environmental effects of mineral-fertilizer overuse. In China, cropping systems which utilize two rice plantings per year are the most important planting pattern for ensuring food security. To date, few studies have comprehensively evaluated the responses of soil fertility and rice performance in double rice cropping systems to the partial substitution of chemical nitrogen (N) with organic N under the same input rates of N, P and K. In addition, the influences of the mineral-to-organic substitution ratio and season on these responses remain poorly understood. Here, a 34-year field fertilizer trial was sampled to determine the impacts of organic substitution regime and growing season on soil biochemical properties and rice yield. Compared with the mineral NPK fertilizer regime, the replacement of 30 %, 50 % and 70 % of total N with organic N increased the yield of early rice by 4.5 %–8.3 %, respectively and that of late rice by 6.7 %–9.6 %. Moreover, the organic substitution regimes significantly improved soil biochemical indicators. The higher organic N substitution percentage resulted in higher values of many soil properties with the exception of TC:TN, fungi:bacteria and G+:G−, which tended to decrease with increasing substitution. Both fertilizer regime and growing season affected soil nutrient contents, enzyme activity and microbial community structure. The relative abundances of identified PLFA biomarkers 16:1ω5c, 16:1ω7c and 18:1ω7c were markedly higher (p ≤ 0.05) in the organic alternative treated soils than the NPK-treated soils in both seasons. Our results suggest that the substitution of 70 % chemical N with organic N is the most effective fertilizer practice for improving soil fertility and rice yield in double rice cropping systems.

Response of soil fertility and Cu and Cd availability to biochar application on paddy soils with different acidification levels

The activation of toxic heavy metals caused by soil acidification has shown detrimental effect on rice safety and quality in paddy soil of southern China. Previous reports have shown that biochar had great potential in controlling heavy metal pollution in soil, but the effect of biochar on soil fertility and heavy metal availability in different soil acidity levels remains unknown. In our study, rice straw (RSBC) and rice husk (RHBC) were selected to produce biochar. An incubation experiment with three biochar application rates, namely 0 (CK), 20 g kg−1 (C1), and 50 g kg−1 (C2) combined with four soil acidification levels, pH value 4.09 (L1), 4.48 (L2), 4.68 (L3), and 5.04 (L4), was conducted in this study. The soil pH, total nitrogen (N), soil organic matter (SOM), available phosphorus (P), available potassium (K), available Cu and Cd concentrations were determined after incubation for 60 days. Results showed that the RSBC is greater in improving the pH and nutrients in acidified soil than RHBC, and the increase depends on biochar dosage. Compared with RHBC, the RSBC showed greater performance in decreasing the availability of Cu and Cd in four soil acidity levels (L1, L2, L3, and L4); the available Cu reduced by 41.32, 25.09, 21.42, and 5.80%, and available Cd by 15.69, 13.73, 17.65, and 17.65%, respectively. In addition, higher soil acidification degree induced smaller increase range of soil pH and available P concentration by biochar. We suggest that biochar can be applied in acidified paddy field to remediate heavy metal pollution in Southern China rice production. At the same time, we need to further ascertain the impact of these two biochars on the bioavailability of heavy metals in different soil acidity levels.

Ovarian Dynamics, Plasma Endocrine Profile and Fertility Response Following Synchronization Protocols in Crossbred Cows with Cystic Ovaries

Background: Cystic ovarian degeneration (COD) with prevalence of 10-13% is a common and economically important condition in dairy cattle affecting fertility. Predisposing factors and aetiology of ovarian cysts are multifaceted. The most widely accepted cause is either absent, insufficient or wrong time occurrence of pre-ovulatory LH-surge. The accuracy of differential diagnosis of cyst per rectum can be increased by simultaneous use of USG and/or plasma progesterone assay and therapeutic success depends on type and duration of cystic condition. The literature on these aspects in crossbred cows is meagre, hence was planned to differentially diagnose the ovarian follicular and luteal cysts based on clinical, sonographic and endocrine findings and to study the estrus response and conception rates following different treatment modalities of COD in crossbred cattle. Methods: This study was conducted on greater than 90 days postpartum HF crossbred cows with cystic ovaries (n=58) confirmed by per rectal palpation and ultrasonography. The animals with follicular cysts were randomly treated with either conventional Ovsynch or Ovsynch + CIDR protocol (n=10 each) and those with luteal cysts with either Double PG injections 11 days apart or modified Ovsynch protocol (n=16 each) with fixed time AI. A group of six cystic cows was kept as untreated control. Blood samples were collected in heparinized vacutainers, together with trans-rectal ultrasonography, on day 0 (just before initiation of treatment), on day of last PGF2á injection, on day of induced estrus/FTAI and on day 12 post-AI for determination of plasma progesterone and estradiol-17â by RIA technique. Results: The mean diameters and wall thickness of ovarian cysts regressed significantly (p less than 0.01) among responded cows of all four protocols. The estrus induction response within 48-96 hrs of last PG injection with Ovsynch, Ovsynch + CIDR, Modified Ovsynch and Double PG protocols was 90.00, 100.00, 87.50 and 81.25 %, respectively. The conception rates at induced estrus with FTAI for these protocols were 50.00, 40.00, 50.00 and 43.75 %, respectively and the corresponding overall conception rates for 3 cycles’ post-treatment were 60.00, 70.00, 68.75 and 56.25 %, respectively, compared to zero result of control group. The mean plasma progesterone concentration varied highly significantly (p less than 0.01) between periods of treatment in all protocols, the values were lower (p less than 0.01) on day 0 and on day of FTAI than on the day of last PG injection and on day 12 post-AI. The values on day 12 post-AI were significantly higher in conceived than non-conceived cows. The trend of estradiol-17â profile on day of last PG injection was reversed than on day 0. The higher levels of estradiol-17â on day of FTAI were associated with regression of cystic structures and development of new dominant follicles with estrogenic activity concomitant to induced estrus and ovulatory LH surge in most of the animals as evident from USG monitoring, behavioural signs and conception rates.

Births and the City: Urban Cycles and Increasing Socio‐Spatial Heterogeneity in a Low‐Fertility Context

AbstractAnalysis of fertility trends along urban gradients contributes to assess socio‐demographic change at larger scales and the new geography of metropolitan growth at smaller scales. At larger scales, urban fertility was systematically lower than rural fertility; at smaller scales, suburbs were found to have higher fertility than central districts and the neighbouring rural areas. However, fertility divides have rarely been re‐contextualised in a long‐term perspective, considering the influence of exogenous factors that change over time with urban cycles. Assuming that spatial fertility variations are contextual to the development stage of a given region, the present study goes beyond the traditional ‘urban‐suburban‐rural’ divide and provides a long‐term vision that integrates small‐scale fertility variations and city life cycles. The study investigates spatial trends in a fertility index along a cycle from urbanisation to re‐urbanisation in a low‐fertility European context (Athens, Greece) using a multi‐scale analysis framework. The empirical findings of this study demonstrate that rural fertility was systematically lower than urban fertility apart from a short time interval (1950s). Fertility in urban locations was the highest during earlier stages of urbanisation. In suburban locations, fertility increased during late suburbanisation, stabilising (or declining slightly) with counter‐urbanisation. Re‐urbanisation was associated with a greater spatial heterogeneity in fertility rates. By documenting a differential response of fertility to urban cycles, our study re‐frames the relationship between natural population dynamics and metropolitan transitions, concluding that regional fertility divides are temporary outcomes of a specific ensemble of socio‐economic forces underlying a given urban model.

Response of soil fertility to 25 years of experimental acidification in a temperate hardwood forest.

The effects of enhanced acid deposition from the atmosphere, and associated elevated inputs of N, are widely evident, especially for forests where excess N has led to a variety of deleterious effects. These include declines in biodiversity, a response that will likely require considerable time for recovery. The purpose of this study was to determine responses of plant nutrient availability in surface mineral soil to 25 yr of experimental acidification and N addition in a central Appalachian hardwood forest ecosystem. We hypothesized that chronic additions of (NH4 )2 SO4 will increase mineral N, decrease soil pH, P, and base cations, increase micronutrients (Mn2+ and Fe2+ ), and increase levels of Al3+ . Results supported these predictions, although Mn2+ did not vary significantly. Earlier work on these plots found no response of any of the extractable nutrients to 3 yr of treatment, yet after 25 yr, our results suggest that impacts are apparent in the top 5cm of the A horizon. We surmise that impacts in these soils may have lagged behind the onset of acidification treatments or that several years of treatment were required to overcome preexisting differences in soil ions. Generally, current findings confirm that (NH4 )2 SO4 treatments have lowered the pH, enhanced levels of exchangeable Al3+ , and increased stream-water exports of NO3 - and base cations-a process that further acidifies soil. The combination of these changes in surface soils, with their high proportion of fine roots, may contribute to the reduced growth and competitiveness of some hardwood species at the acidified site.

Performance of improved short duration finger millet genotypes in red sandy loamy soils of North Coastal Zone of Andhra Pradesh at graded doses of NPK fertilizers

A field experiment was conducted at Agricultural Research Station, Vizianagaram during kharif, 2017 to know the fertilizer responsiveness of improved short duration finger millet genotypes. Experiment was conducted in split plot design with NPK fertilizer levels were assigned to main plots and improved finger millet genotypes were assigned to subplots. Results revealed that among the NPK fertilizer levels, performance of growth as well as yield attributes of finger millet at 100% RDF was on par with 125% RDF, however it was significantly superior over 75% RDF. Similarly yield and economics in 100%RDF was onpar with 125% RDF. Among the finger millet genotypes, highest growth, yield attributes, yield and economics were recorded in VL 386 when compared to other genotypes.