Influence of Soil and Fertilizer Nutrients on Sustainability of Rainfed Finger Millet Yield and Soil Fertility in Semi-arid Alfisols

Productivity of rainfed finger millet in semiarid tropical Alfisols is predominantly constrained by erratic rainfall, limited soil moisture, low soil fertility, and less fertilizer use by the poor farmers. In order to identify the efficient nutrient use treatment for ensuring higher yield, higher sustainability, and improved soil fertility, long term field experiments were conducted during 1984 to 2008 in a permanent site under rainfed semi-arid tropical Alfisol at Bangalore in Southern India. The experiment had two blocks—Farm Yard Manure (FYM) and Maize Residue (MR) with 5 fertilizer treatments, namely: control, FYM at 10 t ha^?1, FYM at 10 t ha^?1 + 50% NPK [nitrogen (N), phosphorus (P), potassium (K)], FYM at 10 t ha^?1 + 100% NPK (50 kg N + 50 kg P + 25 kg K ha^?1) and 100% NPK in FYM block; and control, MR at 5 t ha^?1, MR at 5 t ha^?1 + 50% NPK, MR at 5 t ha^?1 + 100% NPK and 100% NPK in MR block. The treatments differed significantly from each other at p < 0.01 level of probability in influencing finger millet grain yield, soil N, P, and K in different years. Application of FYM at 10 t ha^?1 + 100% NPK gave a significantly higher yield ranging from 1821 to 4552 kg ha^?1 with a mean of 3167 kg ha^?1 and variation of 22.7%, while application of maize residue at 5 t ha^?1 + 100% NPK gave a yield of 593 to 4591 kg ha^?1 with a mean of 2518 kg ha^?1 and variation of 39.3% over years. In FYM block, FYM at 10 t ha^?1 + 100% NPK gave a significantly higher organic carbon (0.45%), available N (204 kg ha^?1), available P (68.6 kg ha^?1), and available K (107 kg ha^?1) over years. In maize residue block, application of MR at 5 t ha^?1 + 100% NPK gave a significantly higher organic carbon (0.39%), available soil N (190 kg ha^?1), available soil P (47.5 kg ha^?1), and available soil K (86 kg ha^?1). The regression model (1) of yield as a function of seasonal rainfall, organic carbon, and soil P and K nutrients gave a predictability in the range of 0.19 under FYM at 10 t ha^?1 to 0.51 under 100% NPK in FYM block compared to 0.30 under 100% NPK to 0.67 under MR at 5 t ha^?1 application in MR block. The regression model (2) of yield as a function of seasonal rainfall, soil N, P, and K nutrients gave a predictability in the range of 0.11 under FYM at 10 t ha^?1 to 0.52 under 100% NPK in FYM block compared to 0.18 under MR at 5 t ha^?1 + 50% NPK to 0.60 under MR at 5 t ha^?1 application in MR block. An assessment of yield sustainability under different crop seasonal rainfall situations indicated that FYM at 10 t ha^?1 + 100% NPK was efficient in FYM block with a maximum Sustainability Yield Index (SYI) of 41.4% in <500 mm, 64.7% in 500–750 mm, 60.2% in 750–1000 mm and 60.4% in 1000–1250 mm rainfall, while MR at 5 t ha^?1 + 100% NPK was efficient with SYI of 29.6% in <500 mm, 50.2% in 500–750 mm, 40.6% in 750–1000 mm, and 39.7% in 1000–1250 mm rainfall in semi-arid Alfisols. Thus, the results obtained from these long term studies incurring huge expenditure provide very good conjunctive nutrient use options with good conformity for different rainfall situations of rainfed semiarid tropical Alfisol soils for ensuring higher finger millet yield, maintaining higher SYI, and maintaining improved soil fertility.     

Productivity,Nutrient Balance,Soil Quality,and Sustainability of Rice (Oryza sativa L.) under Organic and Conventional Production Systems

A field experiment was conducted for 5 years (2004–2005 to 2009–2010) covering 10 crop seasons [five wet (WS; Kharif) and five dry (DS; Rabi)] at the Directorate of Rice Research farm, Hyderabad, India, to compare the influence of organic and conventional farming systems on productivity of fine grain rice varieties, cumulative partial nutrient balance, and soil health/quality in terms of nutrient availability, physical and biological properties, and sustainability index. Two main plot treatments were with and without plant protection measures, and four subplot treatments were (1) control (CON), (2) inorganic fertilizers (CF), (3) organics (OF), and (4) inorganics + organics (integrated nutrient management, INM). During wet season, grain yields with CF and INM were near stable (5.0 to 5.5 t ha^?1) and superior to organics by 15–20% during the first 2 years, which improved with OF (4.8 to 5.4 t ha^?1) in the later years to comparable levels with CF and INM. However, during DS, CF and INM were superior to OF for 4 consecutive years and OF recorded yields on par with CF and INM in the fifth year. The partial nutrient balance over 10 crop seasons for N and P was positive and greater with OF and INM over CF and for K it was positive with OF alone and negative with CF and INM. There were increases in SOC and available N, P, and K by 50–58%, 3–10%, 10–30%, and 8–25% respectively, with OF, over CF at the end of 5 years. The sustainability index (SI) of the soil system was maximum with organics (1.63) and CF recorded 1.33, which was just above the minimum sustainability index of 1.30 after 5 years. Thus, organic farming needs more than 2 years to stabilize rice productivity and bring about perceptible improvement in soil quality and sustainability in irrigated rice.     

The implications of controlling grazed sward height for the operation and productivity of upland sheep systems in the UK. 5. The effect of stocking rate and reduced levels of nitrogen fertilizer

The implications for UK upland sheep systems of reducing nitrogen fertilizer application to perennial ryegrass/white clover swards were studied over 3 years. Sward height (3·5–5·5 cm) was controlled for ewes with lambs until weaning using surplus pasture areas for silage; thereafter, ewes and weaned lambs were grazed on separate areas, and sward height was controlled by adjusting the size of the areas grazed and using surplus pasture areas for silage if necessary. Combinations from three stocking rates [10, 6 and 4 ewes ha⁻¹ on the total area (grazed and ensiled)] and four nitrogen fertilizer levels (150, 100, 50 and 0 kg ha⁻¹) provided six treatments that were replicated three times. Average white clover content was negatively correlated with level of nitrogen fertilizer. The proportion of white clover in the swards increased over the duration of the experiment. Control of sward height and the contribution from white clover resulted in similar levels of lamb liveweight gain on all treatments. All treatments provided adequate winter fodder as silage. It is concluded that the application of nitrogen fertilizer can be reduced or removed from upland sheep pastures without compromising individual animal performance provided that white clover content and sward height are maintained. Resting pastures from grazing by changing ensiled and grazed areas from year to year sustained white clover content over a 3-year period.     

基于改进生态足迹模型的县域生态可持续评价

针对传统生态足迹模型（EFM,eco-footprint model）中存在诸多不足,提出了改进生态足迹模型（IEFM,improve eco-footprint model）的计算方法。从陕西省长武县实际资源消耗量与产量出发,对长武县2007年生态可持续性进行了计算和分析,并与EFM计算结果进行了比较。结果表明：1）长武县2007年人均生态足迹为0.29 hm2/人,人均生态承载力是1.23 hm2/人,人均生态盈余为0.94 hm2/人;2）长武县生态适度人口为7.208×105人,实际人口与生态适度人口的比例是0.24;生态利用效率为1.54 万元/hm2;3）长武县耕地、能源地的人均足迹占人均生态足迹的72%,林地和畜牧用地的人均足迹占人均生态足迹27%,人均建成地、水域、电力用地、垃圾排放用地的生态足迹仅占人均生态足迹的1.2%;4）长武县的人均足迹、人均承载力IEFM的计算值分别是EFM计算值的0.515倍和5.467倍;IEFM与EFM的生态赤字/盈余情况相反。长武县自然生态系统的压力处于生态承载力范围之内,生态系统处于可持续发展状态。     

贵州岩溶土壤形成及其可持续利用

通过对影响和促进贵州岩溶土壤形成的主要因素分析,探讨了形成岩溶土壤的地质基础、地形地貌、大气环境、生物条件等的特殊性,指出贵州岩溶土壤应该归属于一种不可更新的资源范畴,而这一资源目前正面临极度破坏--石漠化.然而,贵州岩溶土壤资源的可持续利用关系到贵州经济的正常发展,因此,岩溶土壤的保护已经到了刻不容缓的时期,而加强民众的环境教育,促进岩溶区生态发展建设,减轻岩溶土壤负担,加大岩溶土壤及其环境的科学研究力度,针对不同的岩溶土壤进行科学合理有效的利用和治理,才能扫除贵州经济发展道路上的障碍.     

Long-term productivity growth and sustainability of Greek irrigated agriculture

The present study examines the long-term productivity growth and sustainability of Greek irrigated agriculture. A log linear trend model was used to measure long-term productivity growth, and the total factor productivity (TFP) approach measures the sustainability of the irrigated production system. A time series database of inputs and outputs data were used for the production period of 1961?–?2001 (41 years) which revealed that there is an increasing trend in the irrigated area of the country. The annual growth rate of the irrigated area is 2.6% during this time period. The long-term trends in yields of crops grown in irrigated agriculture are positive. Fertilizer use rate per ha sharply increases during this period. The productivity of irrigated Greek agriculture also increases over the time period as a result of the introduction of High Yielding Variety (HYV), seed, fertilizer and water technology. The measurement of TFP indices indicates that the long-term trend in productivity growth of irrigated Greek agricultural system is positive. The result implies that the irrigated Greek agricultural production system has long-term sustainability. The result also indicates that fertilizer, fixed capital, rainfall and temperature are positively contributing to the mean production of Greek irrigated agriculture. On the other hand, pesticide, labour and fixed capital reduces variability of irrigated agriculture. To this end, long-term agricultural sustainability depends on patterns of input use.     

Soil fertility in three cropping systems after conversion from conventional to organic farming

Abstract

Temporal changes in the scores of selected soil fertility indices were studied over six years in three different cases of organic crop rotation located in southern, eastern and central Norway. The cropping history and the initial scores of fertility indices prior to conversion to organic cropping differed between the sites. Crop yields, regarded as an overall, integrating fertility indicator, were in all rotations highly variable with few consistent temporal trends following the first year after conversion. On the site in eastern Norway, where conversion followed several years of all-arable crop rotations, earthworm number and biomass and soil physical properties improved, whereas the system was apparently degrading with regard to P and K trade balances and contents in soil. On the other two sites, the picture was less clear. On the southern site, which had a relatively fertile soil before conversion, the contents of soil organic matter and K decreased during the six-year period, but the scores of other fertility indices showed no trends. On the site in central Norway, there were positive trends for earthworm-related indices such as worm biomass and tubular biopores, and negative trends for soil porosity. The results, especially those from the eastern site, illustrate the general difficulty in drawing conclusions about overall fertility or sustainability when partial indicators show divergent trends. Consequently, the study gave no unambiguous support to the initial working hypothesis that organic farming increases inherent overall soil fertility, but rather showed that the effect varied among indicators and depended on status of the cases at conversion. It is concluded that indicators are probably better used as tools to learn about and improve system components than as absolute measures of sustainability.     

Effect of Water pH on Yield and Nutritional Status of Greenhouse Cucumber Grown in Recirculating Hydroponics

ABSTRACT

Cucumbers are produced in integrated hydroponic and aquaculture systems (aquaponics). Aquaponics balances pH for plants, fish, and nitrifying bacteria. Nitrification prevents buildup of toxic waste ammonia by conversion to nitrate (NO₃ ^?)- nitrogen (N). The pH for hydroponic cucumbers (5.5–6.0) and nitrification (7.5–9.0) requires reconciliation to improve systems integration. Cucumbers were grown at pH of 5.0, 6.0, 7.0, and 8.0 with additional foliar sprays at pH 7.0 and 8.0. Plant shoot dry weight, length, N, and phosphorus (P) content at 14 DAT were similar from pH 5.0 to 7.0, but reduced at pH 8.0. Nutrient solution and shoot dry matter Mn and Fe decreased as pH increased. Foliar sprays had no effect on cucumber fruit yield. Early yield was higher at pH 5.0 compared to pH 8.0 but total yield was unaffected by pH. Cucumbers in recirculating culture may be maintained at pH levels more optimum for nitrification (7.5–8.0) except during production for early season markets.     

A bibliometric analysis of carbon exchange in global drylands

Drylands refer to regions with an aridity index lower than 0.65, and billions of people depend on services provided by the critically important ecosystems in these areas. How ecosystem carbon exchange in global drylands (CED) occurs and how climate change affects CED are critical to the global carbon cycle. Here, we performed a comprehensive bibliometric study on the fields of annual publications, marked journals, marked institutions, marked countries, popular keywords, and their temporal evolution to understand the temporal trends of CED research over the past 30 a (1991-2020). We found that the annual scientific publications on CED research increased significantly at an average growth rate of 7.93%. Agricultural Water Management ranked first among all journals and had the most citations. The ten most productive institutions were centered on drylands in America, China, and Australia that had the largest number and most citations of publications on CED research. "Climate change" and climate-related (such as "drought", "precipitation", "temperature", and "rainfall") research were found to be the most popular study areas. Keywords were classified into five clusters, indicating the five main research focuses on CED studies: hydrological cycle, effects of climate change, carbon and water balance, productivity, and carbon-nitrogen-phosphorous coupling cycles. The temporal evolution of keywords further showed that the areas of focus on CED studies were transformed from classical pedology and agricultural research to applied ecology and then to global change ecological research over the past 30 a. In future CED studies, basic themes (such as "water", "yield", and "salinity") and motor themes (such as "climate change", "sustainability", and "remote sensing") will be the focus of research on CED. In particular, multiple integrated methods to understand climate change and ecosystem sustainability are potential new research trends and hotspots.     

PORK PRODUCTION SYSTEMS IN CHINA: A REVIEW OF THEIR DEVELOPMENT,CHALLENGES AND PROSPECTS IN GREEN PRODUCTION

•Large-scale industrial pork production enterprises are preferred in China in the future.•Challenges to green pork production include emissions, feed shortage and residues.•Potential solutions to green production include precise feeding and manure recycling.This paper reviews the changes in pork production in China, the largest pork producing and consuming nation in the world. The pork sector in China has changed dramatically since the 1990s, with large-scale intensive pork production systems replacing the former, exclusively family-based pork production systems. Modern breeding, feeding, vaccinating, and management technologies are widely used now. However, smallholders still account for a large proportion of the total production. The intensification and specialization of the pork sector is expected to continue in the future, but there is increasing awareness and pressure to develop more environmentally-sustainable production systems. The relative shortage of domestically produced feed, the low utilization efficiency of feed ingredients, the large emissions of nitrogen and phosphorus to the environment, the high use of antibiotics, and the presence of residual metals in manures are very large challenges for the pork sector nowadays. To solve these problems, techniques including new feed resource utilization, precise feeding, low-protein diets, alternatives to antibiotics and increased manure recycling are all important topics and research directions today. With new techniques and management approaches, it is possible to build more sustainable pork production systems in China.