Dryland irrigation increases accumulation rates of pedogenic carbonate and releases soil abiotic CO2

Agricultural fields in drylands are challenged globally by limited freshwater resources for irrigation and also by elevated soil salinity and sodicity. It is well known that pedogenic carbonate is less soluble than evaporate salts and commonly forms in natural drylands. However, few studies have evaluated how irrigation loads dissolved calcium and bicarbonate to agricultural fields, accelerating formation rates of secondary calcite and simultaneously releasing abiotic CO2 to the atmosphere. This study reports one of the first geochemical and isotopic studies of such “anthropogenic” pedogenic carbonates and CO2 from irrigated drylands of southwestern United States. A pecan orchard and an alfalfa field, where flood-irrigation using the Rio Grande river is a common practice, were compared to a nearby natural dryland site. Strontium and carbon isotope ratios show that bulk pedogenic carbonates in irrigated soils at the pecan orchard primarily formed due to flood-irrigation, and that approximately 20–50% of soil CO2 in these irrigated soils is calcite-derived abiotic CO2 instead of soil-respired or atmospheric origins. Multiple variables that control the salt buildup in this region are identified and impact the crop production and soil sustainability regionally and globally. Irrigation intensity and water chemistry (irrigation water quantity and quality) dictate salt loading, and soil texture governs water infiltration and salt leaching. In the study area, agricultural soils have accumulated up to 10 wt% of calcite after just about 100 years of cultivation. These rates will likely increase in the future due to the combined effects of climate variability (reduced rainfall and more intense evaporation), use of more brackish groundwater for irrigation, and reduced porosity in soils. The enhanced accumulation rates of pedogenic carbonate are accompanied by release of large amounts of abiotic CO2 from irrigated drylands to atmosphere. Extensive field studies and modelling approaches are needed to further quantify these effluxes at local, regional and global scales.

Analysis of cropping intensity and irrigation intensity in North Twenty Four Parganas district, West Bengal, India

An attempt has been made in this paper to analyse the spatio-temporal variations of cropping intensity and irrigation intensity, and their relationship, in North Twenty Four Parganas district in West Bengal, India from 1996/97 to 2015/16. The relationship between cropping intensity and irrigation intensity has been assessed using partial correlation, residual mapping and hierarchical cluster analysis. One-way ANOVA has been conducted for testing the equality of cluster means. Temporal analysis from 1996/97 to 2015/16 has shown a low positive correlation between cropping intensity and irrigation intensity for the entire district. Analysis at Agricultural Block level has revealed that cropping intensity decreased in many cases even after an increase in irrigation intensity. In general, cropping intensity has increased with the increase in irrigation intensity in the Coastal Saline Region and the Ichhamati Basin, whereas cropping intensity has increased even after a decrease in irrigation intensity in the Gangetic Plains Region in the district.

The result of the influence of center pivot irrigation machine operations on rain (irrigation) intensity

The water consumption through the nozzle or water pressure through the nozzle at the given water thickness (У,min) the two technological parameters, the pressure of the nozzle (X1, PSI) and the rotational speed of the nozzle (X2, m/min) are used to determine the state of the impact at 8 mm nozzle. The experiment was determined under laboratory conditions on a Low Energy Nozzle (LEN). The experiment was conducted in the ‘’ Irrigation machinery and equipment design’’ laboratory of the School of Engineering and Technology of the MULS using the ‘’Low pressure nozzle distribution radius and rain intensity measuring equipment’’. The maximum intensity of water supplied by the nozzle is 1.727 mm / min or the maximum pressure is 30 PSI and the minimum flow rate is 0.313 mm / min. The pressure regulator at 20 min was at a value of 20 PSI, and the transition speed was at a maximum of 3 m / min. Бороожуулах эрчимд машины ажиллах горим нөлөөлөх байдлыг тодорхойлсон дүн Бороожуулах хошуугаар өгч байгаа усны зарцуулгын хэмжээ буюу өгсөн усны зузаанд (Y, мм) хошуугаар гарах усны даралт , машины тойрох хурд гэсэн технологийн хоёр параметр дангаараа болон хавсран үзүүлэх нөлөөллийн төлвийг тодорхойлох туршилтыг 8 мм голчтой бороожуулах хошуун дээр лабораторийн нөхцөлд тодорхойлов. ХААИС-ийн ИТС-ийн “ Усалгааны машин, тоног төхөөрөмжийн хийц “лабораторт 2019 онд “Бороожуулах хошууны борооны эрчим, усны жигд тархалт тодорхойлох төхөөрөмж”- ийг ашиглан туршилтыг хийж гүйцэтгэв. Нам даралтат бороожуулах хошууны борооны эрчмийг тодорхойлж, үр дүнг математик статистикийн аргаар боловсруулахад бороожуулах хошуугаар өгч буй усны хамгийн их хэмжээ 1.727 мм/мин нь даралт хамгийн их 30 PSI, шилжих хурд хамгийн бага 1м/мин үед байгаа бол хамгийн бага хэмжээ 0.313 мм/мин нь даралт тохируулагч 20 PSI утга дээр, шилжих хурд хамгийн их буюу 3 м/мин байв. Түлхүүр үг: Даралт тохируулагч, бороожуулах хошууны жигд тархалт, нам даралтат бороожуулах хошуу

The impact of soil development, rainfall intensity and vegetation complexity on subsurface flow paths along a glacial chronosequence of 10 millennia

Hydrologic processes play an important role in the hydro-pedo-geomorphological feedback cycle of landscape evolution. Soil properties and subsurface flow paths change over time, but due to lack of observations important hydrologic processes such as water flow paths are often not properly considered in soil and landscape evolution studies. We investigated the evolution of subsurface flow paths during landscape development in the calcareous glacier forefield at the Griessfirn in the Swiss Alps. While the main focus was on flow path evolution and the formation of preferential flow paths with soil development, we also looked at the impact of irrigation intensity and vegetation complexity (in what way does the vegetation complexity defined by degree of vegetation cover and functional diversity at each age class relate to subsurface structures and flow path initialization?). We chose four glacial moraines of different ages (110, 160, 4 900, and 13 500 years) and conducted dye tracer experiments with Brilliant Blue (4 g l−1) on three plots at each moraine. The three plots at each age class differed by their degree of vegetation complexity (low, medium, and high) and each was further divided into three equal subplots where dyed water was applied with three different irrigation intensities (20, 40, and 60 mm h−1) and an irrigation amount of 40 mm. Dye pattern characteristics in form of volume density and surface area density were derived by digital image analysis and compared via statistical analysis.Volume density was used to classify the observed dye patterns into specific flow type categories. The effect of soil formation and thus changing soil characteristics on flow types were investigated by the analysis of structural and textural parameters in form of grain size distribution, porosity, bulk density, and loss on ignition. A change in flow types with increasing moraine age was observed from a rather homogeneous matrix flow to heterogeneous matrix and finger flow. Along the soil chronosequence, a reduction in particle sizes and an ongoing vegetation development resulted in an accumulation of organic matter in the topsoil and an increase in water storage capacity (decrease in bulk density and increase in porosity). Differences in irrigation intensity only had an effect on flow types at the oldest moraine, where the frequency of finger flow decreased with increasing irrigation intensity. A relation between vegetation complexity and flow types was only observed at the older moraines, which had a dense vegetation cover. With increasing vegetation complexity the proportion of preferential flow paths in form of finger flow also increased.

Effects of mulching with crushed wheat straw padding and plastic film on sunflower emergence, yield, and yield components under different irrigation intensity in the northwest arid regions, China

Crops in the northwest arid region of China frequently suffer from low emergence and poor yield due to high water deficit. Mulching is an important approach to reduce irrigation amount while increasing productivity but faces challenge of ecological adaptability in this region. A field experiment was carried out in the three growing seasons from 2011 to 2013 to study effects of mulching with crushed wheat straw padding and plastic film on sunflower seed emergence and yields under different irrigation intensities. A two factor (mulching, irrigation intensity) completely randomized block design was applied, resulting in a total of 12 treatments repeated three times. Mulching treatments includes: zero mulch (N), straw mulching at the beginning of trial (S), plastic film mulching when sowing (F), a commonly used mulching by local farmers, and double mulching with plastic film on the crushed wheat straw layer (SF). Irrigation intensity includes: High (H=900 m3 ha-1), Medium (M=750m3 ha-1), Low (L=600m3 ha-1). Results showed that all mulching treatments promoted early emergence of seedlings compared with N, with SF and F performing the better than the rest. SF was the best-performing mulching approach in this study, and had significantly improved sunflower yield and yield components compared with other treatments. In SF, medium irrigation level had significantly increased sunflower 100-seed weight. Therefore, SF with medium irrigation level showed the most positive effect on sunflower production and in now the recommended agronomic solution for sunflower production in the northwest arid regions and potentially, other irrigated areas with similar ecological conditions.

Factors Affecting Farm Income of Different Farming System in Madhya Pradesh

The present study was conducted in Umaria and Anuppur districts of Madhya Pradesh with the specific objective viz. to examine the factors influencing farm income of the respondents. The study confined to two locations of AICRP on IFS, JNKVV, Jabalpur. Total 240 respondents, consisted of 120 beneficiaries under IFS and 120 non-beneficiaries with similar socio economic, were involved in this work. The log linear form of Cobb-Douglas production function was applied to determine the effects of socio-economic variables on farm income. Apart from this, some descriptive statistical analyses were carried out to examine the socio-economic characteristics of the households. The estimated results of the regression models revealed that land holding, irrigation intensity, cost of farm inputs and employment generation had a significant positive effect on farm income among beneficiary’s respondents. On the other hand, age, education, cost of farm inputs and employment generation had a significant positive effect on farm income among non-beneficiary’s respondents. The results of the present study help in increasing the farm income by the enhancement of the factors which found significant during the study period and the policy makers can also plan accordingly for the betterment of both the respondents.

Evaluating the Feasibility of Water Sharing as a Drought Risk Management Tool for Irrigated Agriculture

Droughts can exert significant pressure on regional water resources resulting in abstraction constraints for irrigated agriculture with consequences for productivity and revenue. While water trading can support more efficient water allocation, high transactional costs and delays in approvals often restrict its wider uptake among users. Collaborative water sharing is an alternative approach to formal water trading that has received much less regulatory and industry attention. This study assessed how the potential benefits of water sharing to reduce water resources risks in agriculture are affected by both drought severity and the spatial scale of water-sharing agreements. The research focused on an intensively farmed lowland catchment in Eastern England, a known hot-spot for irrigation intensity and recurrent abstraction pressures. The benefits of water sharing were modelled at four spatial scales: (i) individual licence (with no water sharing), (ii) tributary water sharing among small farmer groups (iii) sub-catchment and (iv) catchment scale. The benefits of water sharing were evaluated based on the modelled reductions in the probability of an irrigation deficit occurring (reducing drought risks) and reduced licensed ‘headroom’ (spare capacity redeployed for more equitable allocation). The potential benefits of water sharing were found to increase with scale, but its impact was limited at high levels of drought severity due to regulatory drought management controls. The broader implications for water sharing to mitigate drought impacts, the barriers to wider uptake and the environmental consequences are discussed.

Norway Spruce Seedlings from an Eastern Baltic Provenance Show Tolerance to Simulated Drought

In Northern Europe, an increase in heterogeneity of summer precipitation regime will subject forests to water deficit and drought. This is particularly topical for Norway spruce (Picea abies Karst.), which is a drought sensitive, yet economically important species. Nevertheless, local populations still might be highly plastic and tolerant, supporting their commercial application. Accordingly, the tolerance of Norway spruce seedlings from an Eastern Baltic provenance (western part of Latvia) to artificial drought according to soil type was assessed in a shelter experiment. To simulate drought, seedlings were subjected to reduced amounts (0%, 25%, 50%, 75%, and 100%) of naturally occurring precipitation (irrigation intensity). Three soil types (oligotrophic mineral, mesotrophic mineral, and peat) were tested. Seedling height, chlorophyll a concentration, and fluorescence parameters were measured. Both growth and photochemical reactions were affected by the irrigation intensity, the effect of which experienced an interacted with soil type, implying complex controls of drought sensitivity. Seedlings were more sensitive to irrigation intensity on mesotrophic mineral soil, as suggested by growth and photosynthetic activity. However, the responses were nonlinear, as the highest performance (growth and fluorescence parameters) of seedlings occurred in response to intermediate drought. On peat soil, which had the highest water-bearing capacity, an inverse response to irrigation intensity was observed. In general, fluorescence parameters were more sensitive and showed more immediate reaction to soil water deficit than concentration of chlorophyll on mesotrophic mineral and peat soils, while the latter was a better indicator of seedling performance on oligotrophic soil. This indicated considerable plastic acclimation and hence tolerance of seedlings from the local Norway spruce population to drought, though drought sensitivity is age-dependent.

Socio-economic impacts of the adoption of MIS (Micro-irrigation system) among small and marginal farmers of Coimbatore district, India

Considerable attention has been given to micro-irrigation technologies by policymakers to help farmers in overcoming water scarcity problems. In this paper, the potential impacts of MIS on farmers’ livelihood and economic viability of using drip in banana cultivation were analyzed using discounted cash flow techniques. The study focused on small and marginal farmers of Coimbatore district of Tamil Nadu as they were provided with 100% subsidy. Adoption of MIS increased the total cropped area (6.54%), extended area under irrigation (6.55%), increased cropping intensity (69.19%) and irrigation intensity (70.95%). Investment on drip irrigation system by farmers were found financially feasible (NPV Rs.43,851.16, BCR 1.42 and IRR 30.88%). The study also brought out the constraints faced by farmers in the adoption of MIS such as lack of technical support, the inefficiency of the system with poor quality water and damage caused by animals. The research work would be helpful in understanding the advantages of using MIS by small and marginal farmers and problems encountered by them in adoption even though the investment was economically viable.