Layering Precision Land Leveling and Furrow Irrigated Raised Bed Planting: Productivity and Input Use Efficiency of Irrigated Bread Wheat in Indo-Gangetic Plains

Stagnating yield and declining input use efficiency in irrigated wheat of the Indo-Gangetic Plain (IGP) coupled with diminishing availability of water for agriculture is a major concern of food security in South Asia. The objective of our study was to establish an understanding of how wheat yield and input use efficiency can be improved and how land leveling and crop establishment practices can be modified to be more efficient in water use through layering of precision-conservation crop management techniques. The “precision land leveling with raised bed” planting can be used to improve crop yield, water and nutrient use efficiency over the existing “traditional land leveling with flat” planting practices. We conducted a field experiment during 2002-2004 at Modipuram, India to quantify the benefits of alternate land leveling (precision land leveling) and crop establishment (furrow irrigated raised bed planting) techniques alone or in combination (layering precision-conservation) in terms of crop yield, water savings, and nutrient use efficiency of wheat production in IGP. The wheat yield was about 16.6% higher with nearly 50% less irrigation water with layering precision land leveling and raised bed planting compared to traditional practices (traditional land leveling with flat planting). The agronomic (AE) and uptake efficiency (UE) of N, P and K were significantly improved under precision land leveling with raised bed planting technique compared to other practices.

Variations in Soil Organic Matter Content in Cultivated and Uncultivated Calcareous Soils from the Mediterranean Island of Malta after 15 Years of Cultivation

The soils of Malta are calcareous and generally undeveloped. Organic matter (OM) in these soils is low and farmers are constantly urged to increase it. The objective of this study was to evaluate any temporal variation in soil OM after 15 years of cultivation, and determine whether soil series, soil depth, and cultivation influence variation. OM was determined in the topsoil and subsoil of 7 agricultural and 4 non-agricultural sites. The sites represented 7 different soil series that are present on the island. In sampling periods 1 (t = 0 years) and 2 (t =15 years), the OM content in the collective (all soil series) bulk (topsoil and subsoil) uncultivated soil was 3.9 % and 3.8 % respectively. This was significantly greater than that of the collective bulk cultivated soil (2.4% and 2.3%). The OM in the collective uncultivated topsoil was 5.4% and 5.2% in periods 1 and 2 and was significantly higher than that of the cultivated topsoil (2.5% in both periods). The OM content in the collective uncultivated subsoil was 2.3% and 2.5% in periods 1 and 2 respectively but only that measured in period 2 was significantly higher than that of the cultivated subsoil (2.2% in both periods). On an individual soil series basis, the OM in the uncultivated topsoils was significantly higher than that of their cultivated counterparts. The differences in the subsoils were not significant. Across the uncultivated soil series, OM was significantly higher in the topsoil than in the subsoil but in the cultivated soil series the differences between topsoil and subsoil were not significant. There was no significant difference in OM between the uncultivated soils of different series, but in the cultivated the OM content was higher in soils that were more mature. After 15 years, no significant change in OM occurred in both the collective cultivated and uncultivated bulk soils, the collective topsoil and subsoil, and in most of the individual series. The OM content of each soil series was also similar to what was reported 60 and 50 years earlier by other researchers.

Turbulent Variance Characteristics of Temperature and Humidity over a Non-uniform Land Surface for an Agricultural Ecosystem in China

This paper describes the application of the variance method for flux estimation over a mixed agricultural region in China. Eddy covariance and flux variance measurements were conducted in a near-surface layer over a non-uniform land surface in the central plain of China from 7 June to 20 July 2002. During this period, the mean canopy height was about 0.50 m. The study site consisted of grass （10% of area）, beans （15%）, corn （15%） and rice （60%）. Under unstable conditions, the standard deviations of temperature and water vapor density （normalized by appropriate scaling parameters）, observed by a single instrument, followed the Monin-Obukhov similarity theory. The similarity constants for heat （CT） and water vapor （Cq） were 1.09 and 1.49, respectively. In comparison with direct measurements using eddy covariance techniques, the flux variance method, on average, underestimated sensible heat flux by 21% and latent heat flux by 24%, which may be attributed to the fact that the observed slight deviations （20% or 30% at most） of the similarity ＂constants＂ may be within the expected range of variation of a single instrument from the generally-valid relations.

The Analysis of Dominance Degree of Land Use in Irrigation District——A Case Study of Jinghuiqu Irrigation District in Shaanxi Province

According to the remote sensing interpretation data in study area, statistics and the data concerning agricultural land classification of Shaanxi Province, on the basis of degree of dominance of land use, taking Jinghuiqu Irrigation District as an example, this paper adopts benefit-cost analysis method and the method of degree of dominance of land resources per capita to conduct analysis on degree of dominance of land. The results show that in study area, the ratio of cost and benefit of farmland is 1.5, with relative big value, indicating that farmland is the dominant land resource in Jinghuiqu Irrigation District; the abundance of land resources in study area is 0.73, the combination index of land resources is 2.3, and degree of dominance of land resources per capita is 0.32, indicating that the combination index of land resources in study area is relatively big, while degree of dominance of land resources per capita is relatively small, which shows that in study area, the combination of all kinds of land resources is in a poor state, with poor supporting ability. In view of the status quo that the combination of all kinds of land resources is in a poor state, with poor supporting ability in Jinghuiqu Irrigation District, the corresponding policy suggestions are put forward as follows: first, strictly implement the central policy and protect farmland resources; second, adjust land use structure and strive to promote benefit; third, make rational planning of land resources and take the road of sustainable development; fourth, take the irrigation district as the unit and establish use class and price standard of land in irrigation district.

A Way to Determine the Rationality of Well Irrigation Scheme in Land Consolidation

Through the analysis of investment and benefit in agricultural production,we explore the relationship between the cost of motor-pumped well irrigation and pump head,and provide a simple but effective way to determine whether the well irrigation scheme is economically rational.

Dynamic Variation of Land-use Types of the Constructed Wetland before and after Oil-field Water Irrigation Based on 3S Technology

[Objective] The study aimed at analyzing the dynamic variation of land-use types of the constructed wetland before and after oil-field water irrigation based on 3S technology. [Method] At semi-arid and arid areas in the west of Jilin Province, water resource balance between the amount of oil-field water supply and ecological water requirement in the constructed wetland irrigated by oil-field water during 2001-2010 was investigated firstly. Afterwards, based on 3S technology, the partition and dynamic variation of land-use types of the constructed wetland before and after oil-field water irrigation in 2001, 2006, 2008 and 2010 were analyzed. [Result] The annual ecological water requirement of the constructed wetland from 2003 to 2010 varied from 1.62×106 to 2.24×106 m3, and the annual amount of oil-field water supply in the region changed from 2.12×106 to 2.84×106 m3, which showed that the supply amount of oil-field water could meet the basic ecological water requirement of the constructed wetland. Meanwhile, compared with 2001, the areas of water region and paddy field in 2010 increased by 2.3 and 10.0 times, and the areas of forest and marsh rose by 40.15% and 29.5.0% respectively. [Conclusion] Water shortage and ecological environment problem of arid and semi-arid areas had been improved by oil-field water irrigation.

Modeling crop land soil moisture and impacts of supplimental irrigaiton in a rainfed region of Bangladesh

A robust water balance model has been tested for predicting soil moisture levels and supplemental irrigation requirement of a rainfed region of Bangladesh. The predictions were used for improving the understanding of the impacts of rainwater harvesting on rainfed agriculture. The climate data (i.e., rainfall, temperature, evaporation, and evapotranspiration) were used as inputs for predicting the variations in soil moisture. Soil moisture levels under rainfed and supplementary irrigation conditions were compared. Results showed that rainwater harvesting i.e., rain water storage tanks during rainy seasons can be potentially useful for storing rainwater, which can be utilized for enhancing crop land soil moisture during dry seasons for enhancing crop yield. The study presented here will be useful for improving and disseminating rainwater harvesting approaches for enhancing water availability in rainfed regions.

Combining CLUE-S and SWAT Models to Forecast Land Use Change and Non-point Source Pollution Impact at a Watershed Scale in Liaoning Province, China

Non-point source(NPS) pollution has become a major source of water pollution. A combination of models would provide the necessary direction and approaches designed to control NPS pollution through land use planning. In this study, NPS pollution load was simulated in urban planning, historic trends and ecological protection land use scenarios based on the Conversion of Land Use and its Effect at Small regional extent(CLUE-S) and Soil and Water Assessment Tool(SWAT) models applied to Hunhe-Taizi River Watershed, Liaoning Province, China. Total nitrogen(TN) and total phosphorus(TP) were chosen as NPS pollution indices. The results of models validation showed that CLUE-S and SWAT models were suitable in the study area. NPS pollution mainly came from dry farmland, paddy, rural and urban areas. The spatial distribution of TN and TP exhibited the same trend in 57 sub-catchments. The TN and TP had the highest NPS pollution load in the western and central plains, which concentrated the urban area and farm land. The NPS pollution load would increase in the urban planning and historic trends scenarios, and would be even higher in the urban planning scenario. However, the NPS pollution load decreased in the ecological protection scenario. The differences observed in the three scenarios indicated that land use had a degree of impact on NPS pollution, which showed that scientific and ecologically sound construction could effectively reduce the NPS pollution load in a watershed. This study provides a scientific method for conducting NPS pollution research at the watershed scale, a scientific basis for non-point source pollution control, and a reference for related policy making.

Economic and Land Use Impacts of Improving Water Use Efficiency in Irrigation in South Asia

This paper modifies and uses an advanced computable general equilibrium model coupled with biophysical data on land and water resources by Agro-Ecological Zone (AEZ) at the river basin level to examine the economy-wide consequences of im-provements in water use efficiency (WUE) in irrigation in South Asia. This is the first time the benefits of such improvements have been evaluated in an economy-wide context. It shows that such improvements increase production of food items, enhance food exports, and significantly improve food security in South Asia. Improvement in water use efficiency also leads to lower food prices, provides the opportunity to extend irrigated areas, decreases demand for cropland, and enhances reforestation. Im-provement in water use efficiency in irrigation also generates important net GDP gains across the South Asia region. Investments in improved WUE of up to 40% can be economically justified in Bangladesh, India, and Sri Lanka. However, in Nepal, for an improvement of more than 20% in WUE, the economic gains are smaller than costs from the associated investments. In Pakistan and rest of South Asia, an improvement in WUE of up to 30% appears to be economically profitable.

Non-agricultural Population, Employment and Land:An Econometric Study in an Integrated Framework

This paper explored the relationships among non-agricultural population, employment and land in an integrated framework, taking account of rural-urban land conversion into Carlino-Mills's model on the regional growth. Two-stage-least-squares and ordinary-least-squares were employed. Recent data for district (grade) cities in China (from 1999 to 2005) were used. Our results showed that: first, urban population in-fluenced non-agricultural employment, and vice versa, but the evidence that non-agricultural employment influenced urban population was stronger than the evidence that urban population influenced non-agricultural employment; second, urban popula-tion and nonagricultural employment both influenced rural-urban land conversion, but the evidence that urban population influenced rural urban land conversion was more stronger than the evidence that non-agricultural employment did. We also found that: first, the employment from the secondary industry influenced urban population in a positive way, and vice versa, but the employment from the tertiary industry influenced urban population in a negative way, and vice versa; second, the em-ployment from the secondary industry influenced rural-urban land conversion in a positive way, but the employment from the tertiary industry influenced rural-urban land conversion in a negative way. We can conclude that the key of urbanization is to speed up the process of non-agricultural employment, espe-cially the employment from the tertiary industry, which might promote non-agricultural population, employment and land har-moniously.

Impacts of Agricultural Activities on Land Degradation along the Bomboré River in Burkina Faso

Land along the Bomboré River in the rural commune of Mogtédo in Burkina Faso is experiencing degradation. The explanatory causes of this degradation constitute the subject of this study. To do this, a survey was conducted among agricultural producers deployed along the watercourse. Soil profiles were described and samples were taken to analyze pH, soil organic carbon, soil organic matter, total nitrogen, and texture. The RUSLE model approach based on landstat8 OLI/TIRS and SRTM satellite images dated December 17, 2021 with fairly good radiometric, spatial, and spectral resolution was used to calculate the land loss rate. In terms of results, the potentially irrigable areas that spread out on both sides of the banks of the river cover 209.23 ha with a perimeter of 6.16 km. The number of irrigators is 26 producers and they grow 17.92 ha of vegetables. Soil analyzes indicate the presence of a moderate acid on the vertisol with a pH between 5.57 and 5.86. On the depth 0 - 30 cm of the horizon, the color of the horizons ranges from 5YR4/2 on the talweg and on the right bank to 7.5YR3/2 on the left bank and presents no risk of salinity because the electrical conductivity measured is less than 1dS/cm. The diagnosis of hydromechanical equipment shows that producers use 46 motor pumps for irrigation, of which 15 motor pumps run on gasoline and 31 motor pumps on butane gas with a ratio of 1.7 motor pumps per producer. The number of Polyvinyl Chloride (PVC) pipes used by producers in combination with a motor pump gives an average of 44 per farmer. In terms of mineral fertilization, the gross doses used by producers are 415.53 kg/ha of NPK and 201.55 kg/ha of urea, while the quantities of phytosanitary products are 3.99 l/ha of pesticides and 1.42 l/ha of herbicides. Agricultural activities emit about 222,436.66 kgCO2eq into the atmosphere, whose emissions from motor pumps represent 84.52% of these total emissions. The land loss estimate gives an average rate of 2.30 t/ha/year of land loss. This loss is due to the effects of poor agricultural practices, water erosion, and the drainage channels and gullies created by the anarchic installation of dwellings around the edges of the river. This study calls for more monitoring actions to sustainably safeguard the soil and water resources of this river which contribute to the survival of more than 73,214 inhabitants.

Current Situations and Recommendations for Non-grain Tendency of Farmland in Anhui Province

This paper firstly sorted out current situations of farmland protection and increasingly significant non-grain of farmland in Anhui Province in recent years.Then,it made an in-depth analysis on causes for non-grain problem,and analyzed adverse influence on national grain security.On this basis,it came up with recommendations for alleviating non-grain problem of farmland in Anhui Province:strictly protecting capital farmland,reasonably guiding distribution and scale of grain production;treating non-grain problem of farmland according to specific situations;reforming and improving grain subsidy policy;establishing a new agricultural land circulation mechanism with family farm as subjects,other types as supplements,and access and supervision system as guarantee.

A review of non-agricultural land-use in peri-urbanization area:research progress and perspectives

The peri-urbanization area as a kind of rural-urban interface is changing rapidly, in physical, economic, and social terms. The land use pattern in such area is shifting away from the assumptions of mainstream paradigms to new conceptual landscapes, which leads to a series of problems on economic development and social stabilization. There are many researches on non-agricultural land-use in peri-urbanization area. In this paper both international and domestic research literature is reviewed by dividing six parts. The first part introduces the conception of peri-ur-banization area and its driver factors. Then In the second and the third part, the paper expatiates on the progress in the non-agricultural land-use in peri-urban area on land-use pattern, evolution, characteristics, problems, etc. The forth part focuses on the reasons that cause the land-use problems in the research area, while the fifth part reviews the integrating ways of non-agricultural land-use. Finally, recommendations for further study are draw with specific reference to the current and future position of non-agricultural land-use study in peri-urban area.

MODIS-Derived Nighttime Arctic Land-Surface Temperature Nascent Trends and Non-Stationary Changes

Arctic nighttime land-surface temperatures derived by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors onboard the NASA Terra and Aqua satellites are investigated. We use the local equator crossing times of 22:30 and 01:30, respectively, in the analysis of changes, trends and variations on the Arctic region and within 120° sectors. We show increases in the number of days above 0°C and significant increase trends over their decadal periods of March 2000 through 2010 (MODIS Terra) and July 2002 through 2012 (MODIS Aqua). The MODIS Aqua nighttime Arctic land-surface temperature change, +0.2°C ± 0.2°C with P-value of 0.01 indicates a reduction relative to the MODIS Terra nighttime Arctic land-surface temperature change, +1.8°C ± 0.3°C with P-value of 0.01. This reduction is a decadal non-stationary component of the Arctic land-surface temperature changes. The reduction is greatest, -1.3°C ± 0.2°C with P-value of 0.01 in the Eastern Russia— Western North American sector of the Arctic during the July 2002 through 2012.

Fractal Analysis on the Spatial Structure of Land Use Patterns in a Non-Point Source Polluted Area in Southern China

Based on the TM remote sensing interpretation of land use data of a non-point source polluted area in southern China in 2015, supported by ArcGIS and the fractal theory, this paper established the perimeter-area fractal equation of the spatial structure of land use types, quantitatively calculated the fractal dimension and stability index of various land use types in this non-point source polluted area in 2015, and analyzed the spatial structure characteristics of land use types. The results showed that the fractal dimension values of the different land use types in the research area ranged 1.141–1.657, and the whole fractal dimension of the research area was 1.206. To be specific, the fractal dimension values of unused land, grass land and rural residential land were high, and the fractal dimension values of dry land, paddy filed and waters were low, and the fractal dimension values of urban land, industrial traffic construction land and forest land were moderate. The area of the land use types whose stability index values were 0.2–0.4 accounted for 89.5% of total area, suggesting that the stability of the spatial structure of land use types of Beibei District in 2015 was not high generally. The rural residential land and urban land of the research area should be planned and managed more properly from now on.

非均匀格网下的耕地集中连片等级划分方法

耕地细碎化导致农业生产成本高、效率低,为了提高耕地利用效率,需实现耕地集中式管理。针对均匀网格在对耕地面积进行表达时数据量冗余和格网尺度选择问题,本文提出了根据斑块平均面积和面积表达误差确定格网最适宜起始和终止尺度的方法,构建基于四叉树的非均匀格网,建立了耕地集中连片分析规则、评价指标体系和技术流程,实现非均匀格网下的耕地集中连片等级划分。以江苏省徐州市为试验区开展耕地集中连片分析。结果表明:①与均匀网格相比,非均匀格网减少了43.8%数据冗余,实现了耕地面积最小误差表达,适用性更强。②徐州耕地连片区域占耕地总面积88.6%,其中50%耕地集中连片等级处于中等偏上水平。③连片区域中有21.4%耕地集中连片等级处于中等以下水平,应将其作为提高区域整体连片等级优先优化的耕地。

基于AquaCrop模型的水稻多目标灌溉制度优化研究

【目的】优化现有水稻灌溉制度,节约灌溉用水量,减少稻田氮磷流失量以降低面源污染风险。【方法】构建了基于AquaCrop模型和NSGA-Ⅱ算法的水稻灌溉制度模拟优化模型,利用水稻田间试验数据,开展以产量最大、氮磷流失量最小、灌水次数最少的3种目标组合(产量-氮磷流失量(Y-TNP)、产量-灌水次数(Y-N)、产量-氮磷流失量-灌水次数(Y-TNP-N))下的灌溉制度优化模型研究,提出适应不同生育期降水年型的稳产-控污-提效灌溉制度。【结果】(1)与常规灌溉相比,Y-TNP灌溉制度优化水稻产量下降2.14%,氮磷流失量减少23.09%;Y-N灌溉制度优化水稻产量下降1.76%,灌水次数减少53%;Y-TNP-N灌溉制度优化水稻产量下降2.64%,氮磷流失量减少22.83%,灌水次数减少2次。(2)不同典型年以Y-TNP-N为目标优化的稳产-控污-提效灌溉制度水稻产量介于7.74~7.78 t/hm^(2),同时大幅度减少灌水量进而降低氮磷流失量。【结论】AquaCrop模型可模拟试验区水稻的生长发育过程,本文构建的模拟-优化耦合模型可用于优化不同生育期降水年型下稳产-控污-提效的灌溉制度。

旱区陆面非降水性水分研究进展和展望

随着全球气候变暖,自然生态系统和水资源压力不断增加,加剧了全球水资源的短缺。旱区非降水性水分(Non-precipitation Water,NPW),作为一种重要的水源,对旱区生态系统和陆面水分平衡具有显著影响。本文基于国内外非降水性水分研究现状,总结其在西北旱区的观测方法、变化特征、形成机制及对陆面水分平衡和作物的影响。在结合非降水性水分研究国际趋势的基础上,指出当前研究的不足和问题,以及未来研究的重点方向:揭示陆面非降水性水分的复杂形成机制,加强对不同气候区和下垫面非降水性水分的认知,建立专门的陆面非降水性水分观测系统,发展其在数值模式中的参数化,以及制定陆面非降水性水分开发利用的技术标准。

河套灌区盐渍土壤原核生物群落特征及其潜在功能研究

辨明盐渍土原核生物群落特征及潜在功能对盐渍化程度和土地利用类型的响应,对理解盐渍土壤元素循环与植物互馈效应、构建良性循环农田生态系统具有重要意义。以河套灌区不同盐渍化程度的农田和荒地为研究对象,结合土壤基本理化性质分析与原核生物高通量测序方法,探究盐渍化土壤中原核生物的群落组成特征、环境驱动要素及其潜在功能。结果表明,农田土壤盐渍化程度显著低于荒地,其原核生物多样性更高,尤其是富集了大量农田特有的ASV(扩增子序列变体,amplicon sequence variant);原核生物的群落组成在农田和荒地间差异最大,并主要受到土壤电导率(EC)、pH和有机质(SOM)等环境因子的驱动。基于群落组成和功能预测的差异分析结果表明,盐渍化农田中具有较高丰度的氮循环相关微生物以及潜在的植物促生菌,如亚硝化球菌(Nitrososphaeraceae)、亚硝化单胞菌(Nitrososmonadaceae)、诺卡氏菌(Nocardioidaceae)和鞘氨醇单胞菌(Sphingomonadaceae)等;而盐碱荒地富集了以盐杆菌(Halobacterota)为代表的古菌和具有烃类化合物分解功能的原核生物类群。本研究对于明晰北方灌区盐渍土原核生物群落特征与土壤微环境的互馈关系、揭示土壤养分周转对提升土壤-植物-微生物跨域有益协同具有指导意义。