Yu.N. Nikolskii  I.P. Aidarov  C. Landeros‐Sanchez  V.V. Pchyolkin 《Irrigation and Drainage》2019,68(5):993-1001

Irrigation increases agricultural productivity and inevitably affects soil properties. When irrigation water is of a good quality and does not cause soil salinity or sodicity or contamination, and when there is no soil erosion, a gradual increase in soil fertility under irrigation conditions is, as a rule, expected. However, studies in various countries present examples of a gradual decline in soil fertility under long‐term freshwater irrigation due to leaching of organic matter and exchangeable cations. It is known that ploughing and agricultural activities modify natural soil formation processes and soil fertility. Irrigation enhances soil formation processes but also causes soil leaching. This paper presents data on the impact of long‐term freshwater irrigation on soil fertility for different climatic zones of Mexico, assessed by comparing some agrochemical properties of irrigated and non‐irrigated soils. This comparison shows that irrigation generally has a positive effect on soil fertility in arid conditions and a negative effect in semi‐arid, semi‐humid and humid tropical zones. Therefore, when planning and applying irrigation to crops, it is necessary to take into account not only crop water requirements, but also the need to preserve and improve soil fertility. © 2019 John Wiley & Sons, Ltd.  相似文献   

    

M. A. Mojid  A. B. M. Z. Hossain  G. C. L. Wyseure 《Communications in Soil Science and Plant Analysis》2019,50(10):1199-1213

Reliable transport parameters of agrochemicals and soluble pollutants are crucial for modeling and management of soil and groundwater quality. This study investigated impacts of municipal wastewater on the transport parameters of five heavy metal/metalloid compounds (NaAsO₂, Cd(NO₃)₂, Pb(NO₃)₂, Ni(NO₃)₂ & ZnCl₂), two pesticides (cartap & carbendazim) and an inert salt (CaCl₂) in four agricultural soils of Bangladesh. Solute-breakthrough concentrations were measured in repacked soil columns with time-domain reflectometry (TDR) both before and after wastewater treatment. Transport velocity (V), dispersion coefficient (D), dispersivity (λ) and retardation factor (R) of the solutes, and pertinent soil properties were determined. Wastewater reduced bulk density (γ) of the soils (from 1.32–1.37 g/cm³ to 1.26–1.35 g/cm³) by increasing organic carbon (OC) (from 0.37%–0.84% to 0.40–0.93%), increased pore-size distribution index (n) (by 0.02 unit) and reduced soil pH (from 6.32–7.45 to 5.92–6.46). D and λ decreased while V and R increased after wastewater treatment; D decreased and R increased linearly with decreasing bulk density. The correlations of V, D, and R with n improved significantly (p < 0.05) after wastewater treatment. The correlation between λ and OC improved markedly for Ca, Pb, Ni, and cartap. The observed indicative results have practical implications in developing pedo-transfer functions for solute-transport parameters using basic soil properties, which are subject to progressive modification due to agrochemicals application and wastewater irrigation.  相似文献   

    

Pradipta Majhi  K. K. Rout  Gangadhar Nanda  Muneshwar Singh 《Communications in Soil Science and Plant Analysis》2019,50(11):1330-1343

Productivity and sustainability of rice-rice cropping system depend upon the soil quality which is primarily governed by application of fertilizers and manures. However, such information is limited and hence, the present investigation was carried out in a 9-year-old long-term fertilizer experiment at Bhubaneswar, India. There were seven treatments (control, application of 100% NPK, 150% NPK, 100% NPK + Zn, 100% NPK + FYM, 100% NPK + Zn + B, and 100% NPK + Zn + S) laid out in randomized block design with four replications. Indicators of soil quality (physical, chemical, and biological) were diagnosed from 30 numbers of soil properties measured on the post-wet season soil and soil quality was assessed taking productivity and sustainability of dry season rice as goal functions. Results revealed that the highest productivity and sustainability of dry season rice was found with application of 100% NPK + FYM. This treatment, in general, showed better physical, chemical, and biological properties than rest of the treatments. The highest soil quality index (SQI) was recorded in 100% NPK + FYM (0.941) treatment followed by 150% NPK (0.826) with CEC diagnosed as the only key indicator for rice productivity. For yield sustainability in dry season, reserve K and total N were important contributing 89% and 11%, respectively to the SQI. Therefore, these soil properties could be used to monitor soil quality in wet season. Application of FYM along with 100% NPK could sustain the productivity of dry season rice by improving soil properties under subtropical rice-rice system.  相似文献   

    

Xu‐Chao Zhu  Rui‐Xue Cao  Ming‐An Shao 《Land Degradation u0026amp; Development》2019,30(3):278-289

Soil‐water content (SWC) is a key factor in restoring degraded vegetation in alpine meadow ecosystems, but it has rarely been spatially simulated on a hectometer scale. We simulated SWC for typical dry and wet days in an alpine meadow using multivariate linear regression and autoregressive state‐space equations based on SWC and other soil, terrain, and vegetation parameters to evaluate the efficiency of these two methods in dry and wet soil‐moisture conditions. SWC measured on a typical dry day (SWC‐D) and a wet day (SWC‐W) increased and decreased with depth, respectively, and SWC‐D was similar to SWC‐W at a depth of 50 cm. Both SWC‐D and SWC‐W were significantly correlated with soil bulk density (BD), capillary porosity, silt content (Silt), gravel and stone content (GSC), pH, and organic carbon density (OCD), and both SWC‐D and SWC‐W were significantly auto‐correlated and cross‐correlated with BD, Silt, GSC, pH, and OCD at more than one lag distance. Multivariate linear regression using three variables in both dry and wet conditions had the highest accuracy, and the accuracy was generally higher for dry conditions than it was for wet conditions. The bivariate state‐space model was the most accurate for both dry and wet soil conditions, but the expression variables were totally different, with pH and OCD for dry day and BD and Silt for wet day. The conditions of soil moisture should thus be considered when choosing variables with which to simulate SWC, instead of only considering the relationships between SWC and other variables.  相似文献   

    

Bingqian Su  Zhouping Shangguan 《Land Degradation u0026amp; Development》2019,30(3):290-299

Afforestation brings lots of water‐related benefits, including reducing soil erosion and improving water conservation, simultaneously; it is considered to be a land use activity, which threatens water resources security. Characterizing the response of soil moisture to revegetation is important for the sustainability of water and plants on the Loess Plateau of China. In this study, we conducted a meta‐analysis of 1,262 observations from 66 published studies to evaluate the effect of land use on the soil moisture of forest, shrubland, and grassland regions at a depth of 5 m in different ecological zones of the Loess Plateau. The results indicated that (a) Soil moisture content (SMC) decreased after land use conversion in all three ecological zones and was inconsistent among different soil layers. (b) Except for other grassland species, changes in the response size for soil moisture were not significant among any tree species, including Pinus tabuliformis, Robinia pseudoacacia, other forest species, Caragana korshinskii, other shrubland species, and Medicago sativa. (c) Soil moisture changes varied with different restoration types and ages. (d) The change in response to precipitation was not significant, whereas the change in response to temperature was significant. In addition, the responses of the initial soil moisture levels exhibited a negative correlation with revegetation. These results indicate that it is vital for scientific afforestation in the Loess Plateau to complement local climate conditions and soil properties.  相似文献   

    

Niels H. Batjes 《Land Degradation u0026amp; Development》2019,30(1):25-32

Reported potentials for sequestration of carbon in soils of agricultural lands are overly optimistic because they assume that all degraded cropland and grassland can be subjected to best management practices. Two approaches for estimating this potential are presented. Method 1 (M1) considers literature‐derived best estimates for annual soil organic carbon (SOC) gains (Mg C ha⁻¹) by bioclimatic zone; Method 2 (M2) assumes an annual C increase of 3 to 5 promille with respect to present SOC mass (similar to the French ‘4 pour mille’ initiative). Four management scenarios are considered, capturing the varying level of plausibility of meeting the full technological potential. According to M1, achievable gains range from 0.05–0.12 Pg C yr⁻¹ to 0.14–0.37 Pg C yr⁻¹, with a technological potential of 0.32–0.86 Pg C yr⁻¹. For M2, these are 0.07–0.12 Pg C yr⁻¹, 0.21–0.35 Pg C yr⁻¹, and 0.60–1.01 Pg C yr⁻¹. Consideration of the technological potential only and use of a proportional annual increase in SOC (M2), rather than using best estimates for soil carbon gains by bioclimatic zone (M1), will provide too ‘bright a picture’ in the context of rehabilitating degraded lands and mitigating/adapting to climate change. Further, M2 assumes that possible C gains will be greatest where present SOC stocks are highest, which is counter‐intuitive. Although all measures aimed at increasing SOC content should be encouraged due to the creation of win‐win situations, it is important to create a realistic picture of the amount of SOC gains that are feasible based on bioclimatic and management implementation constraints.  相似文献   

    

Jessica Sosa‐Quintero  Hctor Godínez‐Alvarez 《Land Degradation u0026amp; Development》2019,30(5):494-503

The impacts of human activities on temperate and subtropical deserts have been evaluated worldwide. However, data about tropical deserts are scarce. In this study, we evaluated the impacts of rainfed agriculture and firewood extraction on vegetation and soil of abandoned croplands (mesquite cropland and goldeneye cropland) and mesquite shrublands (open‐canopy mesquite and closed‐canopy mesquite) in a tropical Mexican desert. We interviewed peasants to understand their management practices and evaluated vegetation traits and soil properties of sites. We also examined the impacts of land management on vegetation and soil with structural equation modeling. Rainfed agriculture consisted of cultivating crops, fertilizing with manure, and introducing goats to croplands after harvest. Goldeneye cropland had higher canopy cover, vegetation structure, and litter cover than mesquite cropland. However, soil in both croplands was highly compacted with low infiltration rate, organic matter, and nutrient content. Firewood extraction only consisted of removing mesquite branches. Open‐canopy mesquite had lower canopy and litter cover and higher biological soil crust cover than closed‐canopy mesquite. The soil in both shrublands was less compacted with relatively high infiltration rate, organic matter, and nutrient content. Rainfed agriculture decreased soil nutrient content due to removal of native vegetation, plowing, and goat introduction to croplands. In contrast, firewood extraction maintained a relatively high soil nutrient content because branch removal enables the establishment of biological soil crusts, which increased the infiltration rate and nutrient availability. Thus, firewood extraction has a lower impact on the structure and function of fluvial terraces than rainfed agriculture in this tropical desert.  相似文献   

    

Emily Schmidt  Fanaye Tadesse 《Land Degradation u0026amp; Development》2019,30(7):777-787

Agricultural productivity in the highlands of Ethiopia is threatened by severe land degradation, resulting in significant reductions in agricultural GDP. In order to mitigate ongoing erosion and soil nutrient loss, the government of Ethiopia initiated a Sustainable Land Management Program (SLMP) targeting 177 micro‐watersheds in six regions of the Country. This study evaluates the impact of SLMP on the value of agricultural production across diverse agro‐ecological zones by using a panel survey from 2010 to 2014. Results suggest the need for long‐term engagement in SLM activities regardless of underlying biophysical endowments and environmental characteristics. The analysis finds that the SLMP is not associated with significant increases in household‐level agricultural value of production after 4 years of program participation regardless of agro‐ecological zone or landscape type. However, SLM investments and agricultural value of production increased significantly in both treatment and nontreatment areas between 2010 and 2014. Although data suggest positive trends in agricultural productivity and SLM activities during program years, past soil and water conservation programs in Ethiopia have failed to maintain momentum in rural communities after programs ceased funding. Given the results presented in this paper, SLM programs should place emphasis on SLM infrastructure maintenance over the medium to long term in order to reap sustainable effects of SLM on agricultural productivity in critical watersheds.  相似文献   

    

Zhigang Li  Rebecca L. Schneider  Stephen J. Morreale  Yingzhong Xie  Jian Li  Changxiao Li  Xilu Ni 《Land Degradation u0026amp; Development》2019,30(11):1313-1324

Solutions are urgently needed to address the continued degradation of agricultural soils worldwide, which has severely impacted the ability to grow crops and has led to increased irrigation demand from already rapidly depleting freshwater resources. This project evaluated a unique, previously untested, type of soil organic amendment, that is, coarse wood chips, for capturing and storing scarce precipitation and improving desertified, sandy soils. A field plot experiment was conducted in Ningxia, China, from 2011 through 2016, comparing unamended sandy soils with three coarse woody amendments, including (a) surface‐applied mulch, (b) wood chips incorporated into the top 20 cm of soil, and 3) incorporated wood chips combined with a branch lattice shelter over the soil surface—all treatments replicated under both irrigated and nonirrigated conditions. Precipitation patterns and soil moisture content were compared between 2012 and 2015, and related soil physical and chemical properties were monitored continuously, as well as alfalfa yields in 2015 and 2016. Results indicated that amended soils maintained significantly higher soil water contents between rain events, decreased the number of days below the permanent wilting point, and improved soil properties and alfalfa growth. The combination treatment of wood chips and a branch shelter performed the best among treatments, exhibiting increases in average water storage 50% or more above controls. Unlike highly degradable soil amendments, the slow decomposition of the coarse wood chips resulted in continuous benefits for all 5 years. This use of coarse wood chips represents a timely new addition to the toolbox of soil amendments, providing a mechanism for immediate, long‐lasting restoration of the world's degraded and desertified soils that will foster global food and water security.  相似文献   

    

Tian Cai  Charles Steinfield  Hastings Chiwasa  Tadala Ganunga 《Land Degradation u0026amp; Development》2019,30(11):1336-1344

Soil and land degradation is a common issue in Sub‐Saharan Africa leading to poor yield and threatening food security, yet soil conservation technologies remain underutilized. To build on prior work that primarily emphasizes demographic differences in adoption, this study contributes by identifying underlying social and cultural factors that influence farmers' perceptions about and willingness to adopt soil conservation management practices in a rural region of Malawi. Key informant interviews were first conducted to identify constraints slowing composting adoption, which were then used to structure the creation of participatory videos—videos created with the active participation of local farmers that demonstrated compost manure practices and benefits. Farmers from the same communities subsequently participated in focus group discussions before and after the moderated screening and discussion of these videos in order to obtain a more in‐depth understanding of the constraints and possible ways to overcome them. Among the identified constraints to the use of composting were inefficient government programs such as the Farm Input Subsidy Program that contributed to a belief that only subsidized chemical fertilizers provided positive returns on investment, a lack of support from extension services that diminished compost use, social norms around gender that hindered women farmers from attempting to use composting, and livelihood strategy changes that led to labour shortages. Findings from the focus groups showed that the participatory video method encouraged adoption by helping farmers, and especially women, to reconsider composting, test it, and reflect upon social and cultural constraints impeding adoption. Over half of the farmers in the study tested composting for the first time after discussing the videos and changed their perception of both the value of composting and their own ability to use these types of soil conservation practices.  相似文献