Sprinkler Irrigation Methods Research Articles

Current Status of Microsprinkler Irrigation in the United States

Microsprinkler irrigation is often the preferred method of irrigation for tree and vine crops since it provides a greater degree of freeze protection than drip irrigation and provides water and energy savings over sprinkler and flood irrigation methods. With chemigation, microirrigation also provides an economical method of applying fertilizer and other agricultural chemicals on a timely basis. However, microsprinkler systems generally require more maintenance than drip or overhead systems, and they require a higher level of management expertise than sprinkler or flood irrigation methods. This article discusses the current status of design, operation, and maintenance of microsprinkler systems and the benefits and limitations of these systems for several agricultural crops. Types and characteristics of available microsprinklers are discussed in relation to appropriate application considering crops, soils, and management philosophy. Topics include uniformity, clogging, insect problems, wetting patterns, emitter maintenance, chemigation, system evaluation, management for both young and mature trees, crop response, and freeze protection.

An empirical method to measure the relative efficiency of irrigation methods in agricultural industry

b Member of Research and Education of Ministry of Agricultural , Tehran, Iran A R T I C L E I N F O A B S T R A C T One of the most important issues affecting future world is managing the existing water resources. There is no doubt that global warming has created significant troubles on people's lives and it has caused shortage of water in the world. Therefore, we need to manage the water resources by allocating appropriate methods. In this paper, we use data envelopment analysis to measure the relative efficiency of fourteen different irrigation methods. The proposed model of this paper uses four inputs including cost, risk, maintenance and expertise and two outputs including flexibility and durability of irrigation methods. The preliminary results indicate that two surface irrigation methods, two sprinkler irrigation methods and one subsurface irrigation method are considered efficient. Other irrigation methods are only as much as 50 to 94 percent efficient compared with these five irrigation methods.

Effects of Urban Wastewater on Accumulation of Heavy Metals in Soil and Corn (Zea mays L.) with Sprinkler Irrigation Method

Effects of Urban Wastewater on Accumulation of Heavy Metals in Soil and Corn (Zea mays L.) with Sprinkler Irrigation Method

Farklı Sulama Yöntemlerinin Topraktan Karbondioksit (CO2) Çıkışı Üzerine Etkisi

Global warming and greenhouse gas emission are one of the important researches in recent years. There are a wide range of greenhouse gas resources and one of them is agricultural activities. During agricultural activities CO 2 emission from soil occurs. Water requirement in plant production is met by using various irrigation methods. The most widely used methods are drip irrigation, sprinkler irrigation and surface irrigation. Drip irrigation in recent years has been preferred due to its less water use. This study was carried out to determine soil CO 2 emission in apple orchard of Jersey Mac apple cultivars grafted on M9 which was irrigated by drip irrigation, sprinkler irrigation and surface irrigation methods. In the study, soil CO 2 flux was measured after irrigation. CO 2 flux of drip, sprinkler and surface irrigation was 0.065, 0.071 and 0.084 g.CO 2 .m -2 .h -1 , respectively Evaporation from the soil was 8.06, 8.85 and 8.95 g.H 2 O.m -2 .h -1 for drip, sprinkler and surface irrigation, respectively. Even though there were no significant differences among irrigation methods in terms of CO 2 flux and evaporation value (P>0.05), these results indicated that CO 2 emission and evaporation values in drip irrigation method tended to decrease.

FEEECT OF DIFFERENT IRRIGATION METHODS IN SOME MORPHOLOGICAL AND PHYSICAL PROPERTIES OF AN GYPSIFEROUS SOIL AT AL-THIRTHAR AREA

This study was conducted at fields of Al-Majd agricultural company which located between falluga and thirthar at al saqlawia / Al-Anbar government, to study the effect of using different irrigation methods (flood - drip - sprinkler) irrigation to using its gypsiferous soils with irrigation water class C3S1, to know the effect of this irrigation methods in some soil morphological and physical properties . After semi detail survey, four positions were pointed that were different in agricultural using nature for three years as following:P1 virgin soil (B), P2 land which used for cereals with flood irrigation method (FW3), P3 land which used for cereals with sprinkler irrigation method (SW3) and P4 land which used for vegetable with drip irrigation method (DV3).These four pedons were described morphologically then soil samples were taken from each horizon to analysis some physical properties. The results showed that following: 1. The thickness of surface horizons for cultivated site increased in comparison with uncultivated soil from 18cm to 25 cm. 2. The soil structure grade was weak in all pedon’s , especially at soil which was under the flood irrigation 3. There is no significant effect for irrigation method on particle density at all horizons, this property data was showed decreasing in its value with increasing soil content of gypsum, but the bulk density was effected by irrigation practice significantly, it was increased 5.4%, 10.0% and 13.9%as mean for treatments DV3, SW3 and FW3 respectively. 4. There is significant effect for irrigation method on studied soil water properties (field capacity, wilting point and available water).Using of drip irrigation method was showed higher increasing in these properties in comparison with other irrigation methods. 5. Soil penetration resistance was decreased 3.9% in farming lands without significant different in comparison with virgin land, and lower value was pointed at Ap horizon for DV3 treatment reached 2.6 kg.cm-2 while the same horizon for SW3 treatment was showed the higher value 3.1 kg.cm-2.

Nitrogen Availability for Sugarbeet affected by Tillage System and Sprinkler Irrigation Method

Many shank‐type strip tillage (ST) implements band fertilizer below the seed without incorporating crop residue into the soil, potentially affecting N availability. Sprinkler irrigation method may also affect N availability due to its influence on water and NO3–N movement in soil. A field study was conducted at Sidney, MT, to determine if sugarbeet (Beta vulgaris L.) petiole NO3–N concentration and soil available (i.e., mineral) N distribution differ under (i) conventional tillage (CT) and ST systems and (ii) mid‐elevation spray application (MESA) and low energy precision application (LEPA) irrigation methods. Mid‐season petiole NO3–N concentration was lower with ST than with CT in 1 of 3 yr. In‐season mineral N concentration in the top 45 cm of soil was lower with ST than with CT. Postharvest mineral N was 10% lower with ST than with CT. There were few measurable effects of irrigation method except that in‐season mineral N in the top 45 cm of soil was 10% greater with LEPA than with MESA. Root yield and sugar production were reported to be similar with the two tillage systems. It was concluded that differences in petiole NO3–N concentration and soil mineral N content were not sufficient to justify altering N application rate based on the tillage systems or irrigation methods evaluated. However, there were indications that NO3–N leaching may be reduced by combining LEPA, with which irrigation water is applied between alternating crop rows, with strip tillage, where N is banded beneath the crop row.

Comparison of different irrigation methods based on the parametric evaluation approach in Dosalegh plain: Iran

Declining water resources and limited clean water reservoirs call for more efficient water use for food production in the future. The objective of this research was to compare different irrigation methods based on a parametric evaluation system in an area of 60,000 ha in the Dosalegh plain of the Khuzestan province, in the southwest of Iran. After the soil properties were analyzed and evaluated, suitability maps were generated for surface, sprinkler and drip irrigation methods, using Remote Sensing (RS) techniques and Geographic Information System (GIS). The results demonstrated that by applying sprinkler and drip irrigation instead of surface irrigation method, the land suitability of 23,790 and 33,261 ha (39.89%) in the Dosalegh plain will improve, respectively. The comparison of the different types of irrigation techniques revealed that the drip and sprinkler irrigations methods were more effective and efficient than that of surface irrigation for improved land productivity. However, the main limiting factor in using either surface or/and sprinkler irrigation methods in this area were soil texture , salinity , and slope, and the main limiting factor in using drip irrigation methods were the calcium carbonate content, soil texture and salinity.

Leaching with Subsurface Drip Irrigation under Saline, Shallow Groundwater Conditions

One option for coping with the high soil salinity levels caused by saline, shallow groundwater conditions along the west side of the San Joaquin Valley is to convert from sprinkler or surface irrigation methods to drip irrigation. Experiments in commercial fields revealed that subsurface drip irrigation of processing tomato (Lycopersicon esculentum Mill. var. esculentum) is highly profitable under these conditions compared with other irrigation methods. The experiments also showed that little or no field‐wide leaching occurred, based on the conventional or water balance approach to estimating the leaching fraction (LF), yet soil salinity measurements showed considerable leaching around the drip lines. Actual LFs could not be calculated because LF, soil salinity, soil water content, and root density all varied with distance and depth around the drip lines. Therefore, we conducted a numerical modeling study using the HYDRUS‐2D computer simulation model to evaluate leaching with drip irrigation under saline, shallow groundwater conditions for different amounts of applied water, water table depths, and irrigation water salinity, described by the electrical conductivity of the irrigation water (ECiw). Results showed that LF values ranged from 7.7 to 30.9% as applied water amounts increased from 60 to 115% of the potential evapotranspiration (ETpot) for the ECiw = 0.3 dS m−1 irrigation water, even though the water balance method showed no leaching for applied water amounts equal to or smaller than ETpot The spatially varying soil wetting patterns that occur under drip irrigation caused the localized leaching, which was concentrated near the drip line.

Farklı Sulama Yöntemlerinin Topraktaki Amonyum ve Nitrat Azotu Kapsamlarına Etkisi

Bu çalıĢmayla, farklı sulama yöntemlerinin, topraktaki amonyum ve nitrat azotunun etkili kök bölgesindeki(0-80 cm) ııhareketine ve yıkanmasına etkisi araĢtırılmıĢtır. Deneme tesadüf parselleri tarla denemesi Ģeklinde kurulmuĢ olup, mısır bitkisi yetiĢtirilmiĢ ve ekimle birlikte amonyum nitrat gübresi tek seferde uygulanmıĢtır. Bitki geliĢim periyodu sürecinde etkili kök bölgesi derinliklerinden (20cm lik aralıklarda) alınan örneklerde amonyum ve nitrat azotları belirlenerek taĢınma , nitrifikasyon ve kayıplar araĢtırılmıĢtır. Damla, karık ve yağmurlama sulama yöntemlerinin kök bölgesindeki amonyum–nitrat hareketlerine etkisi birbirinden farklı bulunmamıĢtır. Farklı çıkmamasının nedeni her üç yöntemde de verilen su miktarlarının birbirine yakın değerlerde olması olabilir. Denememizde ilk sulamalarla azot kaybının fazla miktarda gerçekleĢtiği görülmüĢtür. Kaybın önlenmesi amacıyla azotlu gübrelemenin mümkün olduğunca parçalara ayrılarak ve bitki azot alımının en fazla olduğu dönemlerde yapılması önerilmiĢtir.

Determining the Uniformity Coefficient and Water Distribution Characteristics of Some Sprinklers

The basic aim of the sprinkler irrigation method, as in other irrigation methods, is to apply irrigation water as uniformly as possible to the root zone. The uniform distribution of the applied water in sprinkler irrigation depends on factors such as sprinkler type, number and size of nozzles, arrangement of sprinklers, working pressure and the speed and direction of the wind. Sprinkler and lateral spacing should be determined by also taking the speed and direction of the wind into consideration. The aim of this study was to determine the application limits and the curves of water distribution under different working pressures, spatial arrangement and nozzle diameters under field conditions of some irrigation sprinklers which are widely used in Turkey. The objective was to determine the most appropriate system arrangement by using a computer program called CATCH3D. Five sprinklers were tested in the experimental area of Ondokuz Mayis University Campus and their water distribution characteristics identified. The most suitable operating parameters for Bereket 3: 12 x 18 m, Bereket 2: 12 x 18 m, Egeyildiz 6 x 18m, Goktepe 6 x 12 m and for Atesler sprinkler 12 x 18 m arrangement type were determined.

Bodur Kiraz Bahçelerinde Dam la ve Mikro Yağmurlama Sulama Yöntemlerinin Yatırım ve İşletme Masraflan Yonunden Karşılaştırılması

Bu çalışmada, Tekirdağ Bağcılık Araştırma Enstitüsü arazisinde seçilen 27.3 da büyüklüğündeki birkiraz bahçesinde, damla ve mikro yağmurlama sulama yöntemlerinin sulama suyu ihtiyacı, ilk tesis masrafı, yıllıkişletme masrafı, enerji masrafı ve toplam masraflar açısından karşılaştırılması amaçlanmıştır. Bu amaçla, alanıtoprak özellikleri saptanmış, kirazın su tüketimi ve sulama suyu ihtiyacı hesaplanmış, sulama sistemleriplanlanmış, sistem debileri belirlenmiş, sistem unsurları boyutlandırılmış ve 2006 yılı fiyatlarına göre proje keşifözetleri hazırlanmıştır. Ekonomik analiz yapılarak, her sistem için, tesis masrafı, yatırım masrafı, yıllık sabitmasraf, enerji masrafı, bakım-onarım masrafı, sulama işçiliği masrafı ve yıllık toplam masraf değerleribelirlenmiştir. Sonuçta, mevsimlik toplam sulama suyu ihtiyacı, damla sulama yönteminde 397 mm, mikroyağmurlama sulama yönteminde ise 482 mm bulunmuştur. Sistem debisi damla sulama yönteminde 3.56 L/s,mikro yağmurlama sulama yönteminde ise 5.12 L/s olmuştur. Yıllık toplam yatırım masrafı ve yıllık toplammasraflar, damla sulama yönteminde mikro yağmurlama sulama yöntemine göre sırasıyla % 17 ve % 13 dahafazla bulunmuştur. Bu değerlere göre, kiraz sulamasında düşük dinamik yüksekliğe sahip kuyulardanyararlanılması durumunda, su kaynağı yeterli ise mikro yağmurlama sulama, aksi takdirde, damla sulamayönteminin seçilmesi önerilmiştir

Water Management of Irrigated-Drained Fields in the Jordan Valley South of Lake Kinneret

The Jordan Valley is one of the primary regions for growing winter crops of fruit and vegetables in Israel and Jordan. Control of water management in these fields is obtained by solid-set irrigation systems and subsurface drainage. Detailed field observations were conducted at a location near the Jordan River, south of Lake Kinneret. Water table heights were measured by approximately 100 piezometers. An exiting wide spacing s160 md subsurface drainage system was monitored and the total drainage discharge from this regional drainage system to Lake Kinneret was measured. Rainfall, irrigation, and evapotranspiration rates were measured and overall hydrological balance was conducted. The old irrigation method in the region was border irrigation with very high leaching fraction and poor irrigation efficiency. During the 1970s the irrigation method was changed to computer operated drip irrigation. The leaching fraction was reduced and irrigation efficiency increased. Reduction of the total drainage discharge to Lake Kinneret by a factor of about 10 was observed. Water table rise under hand moving sprinkler and soil-set drip irrigation methods were measured and compared for assessment of salinization of the root zone by upward movement of groundwater. The result indicates the strong effect of irrigation time interval on the extent of these rises. The effect of irrigation mode on the extent of water table rises was measured at the field by comparing that under hand moving sprinkler irrigation to that under water solid set drip method. This effect depends, among other variables, on the irrigation time interval, a fact which complicates prediction of water table rise under different irrigation practices. These field results support previous theoretical analysis by the writers and highlighted the interrelationship between irrigation practice and drainage design. The effect of water table drawdown towards the Jordan River was monitored and found to be about 4.6%. The strong influence of the Jordan River on water table height at the drained field is magnified by the existence of sandy layers in the soil profile. This observed gradient may be used for the estimation of lateral seepage flow from the irrigated agricultural field towards the adjacent Jordan River. This study provides a useful source of data for future studies in similar situations.

Trickle and sprinkler irrigation of potato ( Solanum tuberosum L.) in the Middle Anatolian Region in Turkey

The potato ( Solanum tuberosum L.) is widely planted in the Middle Anatolian Region, especially in the Nigde-Nevsehir district where 25% of the total potato growing area is located and produces 44% of the total yield. In recent years, the farmers in the Nigde-Nevsehir district have been applying high amounts of nitrogen (N) fertilizers (sometimes more than 900 kg N ha −1) and frequent irrigation at high rates in order to get a much higher yield. This situation results in increased irrigation and fertilization costs as well as polluted ground water resources and soil. Thus, it is critical to know the water and nitrogen requirements of the crop, as well as how to improve irrigation efficiency. Field experiments were conducted in the Nigde-Nevsehir (arid) region on a Fluvents ( Entisols) soil to determine water and nitrogen requirements of potato crops under sprinkler and trickle irrigation methods. Irrigation treatments were based on Class A pan evaporation and nitrogen levels were formed with different nitrogen concentrations. The highest yield, averaging 47,505 kg ha −1, was measured in sprinkler-irrigated plots at the 60 g m −3 nitrogen concentration level in the irrigation treatment with limited irrigation (480 mm). Statistically higher tuber yields were obtained at the 45 and 60 g m −3 nitrogen concentration levels in irrigation treatments with full and limited irrigation. Maximum yields were obtained with about 17% less water in the sprinkler method as compared to the trickle method (not statistically significant). On the loam and sandy loam soils, tuber yields were reduced by deficit irrigation corresponding to 70% and 74% of evapotranspiration in sprinkler and trickle irrigations, respectively. Water use of the potato crop ranged from 490 to 760 mm for sprinkler-irrigated plots and 565–830 mm for trickle-irrigated treatments. The highest water use efficiency (WUE) levels of 7.37 and 4.79 kg m −3 were obtained in sprinkle and trickle irrigated plots, respectively. There were inverse effects of irrigation and nitrogen levels on the WUE of the potato crops. Significant linear relationships were found between tuber yield and water use for both irrigation methods. Yield response factors were calculated at 1.05 for sprinkler methods and 0.68 for trickle methods. There were statistically significant linear and polynomial relationships between tuber yield and nitrogen amounts used in trickle and sprinkler-irrigated treatments, respectively. In sprinkler-irrigated treatments, the maximum tuber yield was obtained with 199 kg N ha −1. The tuber cumulative nitrogen use efficiency (NUE cu) and incremental nitrogen use efficiency (NUE in) were affected quite differently by water, nitrogen levels and years. NUE cu varied from 16 to 472 g kg −1 and NUE in varied from 75 to 1035 g kg −1 depending on the irrigation method. In both years, the NH 4-N concentrations were lower than NO 3-N, and thus the removed nitrogen and nitrogen losses were found to be 19–87 kg ha −1 for sprinkler methods and 25–89 kg ha −1 for trickle methods. Nitrogen losses in sprinkler methods reached 76%, which were higher than losses in trickle methods.

Analysis of irrigation systems and irrigation strategies for durum wheat in Tunisia

To help identify an irrigation system and irrigation strategy to improve durum wheat production in the context of water scarcity of Tunisia, the PILOTE (operative water balance and yield estimation) model and the RAIEOPT (furrow irrigation) model are coupled. The first step was to choose the most efficient surface irrigation system (SIS) with its irrigation strategy. On the basis of field experiment data, an economic-optimization model allows the identification of the best SIS with its irrigation strategy for conditions of water scarcity in Tunisia. The furrow system with an inter-furrow spacing of 1.5 m and a strategy which consists on irrigating when the soil water reserve is 80% depleted are selected by the optimization model. Using “deficit irrigation” principles which establish a ratio between the amount of water applied to a given crop and a economically acceptable target yield value, irrigation strategies for sprinkler and the selected SIS are identified. RAIEOPT–PILOTE coupling is used to perform this analysis for SIS. The results of the simulations, based on climatic data spanning the last 20 years, raise questions about the suitability of sprinkler irrigation method for clay soil conditions in Tunisia. This paper also aims to contribute to future economic studies that will take into account social constraints. This study should allow managers to choose between sprinkler irrigation methods and SIS modernization.

Irrigation scheduling of confectionery groundnut (Arachis hypogeaea L.) in Senegal using a simple water balance model

The sustainability of the groundnut production in North of Senegal hydro-agricultural systems depends on the development of irrigation methods which guarantee yield, quality and meet best water management practices. To achieve this goal, a water balance model taking into account plant development and soil water status was developed. The proposed model expresses evapotranspiration as a function of the observed leaf area index (LAI) and simulated soil water status. Compared to classical tools, mostly based on crop coefficients, the conceptual advantage of the developed model is to take into account not only the impact of water availability on leaf development of the crop but also their incidence on transpiration. Irrigation scheduling consists of determining net irrigation levels by adjusting the fraction of transpirable soil water (FTSW). The model was first calibrated and validated using experiments carried out in 1994, 1996 and 2000, on two groundnut varieties, Fleur 11 and GH 119-20, at the experimental station of Bambey in Senegal, using sprinkler irrigation methods. The model was then applied in 2000 during the dry season to the Senegal river valley under drip irrigation conditions so as to schedule irrigation according to diverse situations of water resource availability. Evidence was made of the model capacity to devise a sustainable irrigation method which guarantees yield, quality and appropriate water management practices.

Irrigation scheduling of confectionery groundnut ( Arachis hypogeaea L.) in Senegal using a simple water balance model

The sustainability of the groundnut production in North of Senegal hydro-agricultural systems depends on the development of irrigation methods which guarantee yield, quality and meet best water management practices. To achieve this goal, a water balance model taking into account plant development and soil water status was developed. The proposed model expresses evapotranspiration as a function of the observed leaf area index (LAI) and simulated soil water status. Compared to classical tools, mostly based on crop coefficients, the conceptual advantage of the developed model is to take into account not only the impact of water availability on leaf development of the crop but also their incidence on transpiration. Irrigation scheduling consists of determining net irrigation levels by adjusting the fraction of transpirable soil water (FTSW). The model was first calibrated and validated using experiments carried out in 1994, 1996 and 2000, on two groundnut varieties, Fleur 11 and GH 119-20, at the experimental station of Bambey in Senegal, using sprinkler irrigation methods. The model was then applied in 2000 during the dry season to the Senegal river valley under drip irrigation conditions so as to schedule irrigation according to diverse situations of water resource availability. Evidence was made of the model capacity to devise a sustainable irrigation method which guarantees yield, quality and appropriate water management practices.

Hydrologic Impacts due to Changes in Conveyance and Conversion from Flood to Sprinkler Irrigation Practices

Improvements in irrigation efficiency are well documented when changing from flood to sprinkler irrigation methods; however, other impacts to the watershed associated with this change are not well known. The resulting impacts to a river basin hydrology when irrigation and conveyance methods are changed are the focus of this study. In an attempt to improve water application and conveyance efficiencies in the Salt River Basin of western Wyoming, irrigation practices were changed from flood irrigation to sprinkler irrigation beginning in the late 1960s, with completion by the mid-1970s. Based upon a water balance, flow in the Salt River increased an average of 65.62 MCM/year. Return flow timing was also impacted by the conversion to sprinkler irrigation. Flows increased 34% in May and 50% in June, while decreasing 15 and 14% in August and September. These changes may have coincided with decreases in groundwater storage. However, analysis of changes in groundwater levels with time was inconclusive. Surface wa...

Comparative research on water and energy-saving irrigation systems in the GAP and Aegean regions of Turkey

This research was carried out to determine the effects of furrow, sprinkler, drip, mobile nozzle, mobile drip and LEPA (Low Energy Precision Application) irrigation methods on the yields and Water Use Efficiency of cotton in the South Eastern Anatolian Project (GAP) Area and in the Aegean Region. According to the results obtained, the highest yield was produced from the drip irrigation method. The drip, sprinkler and mobile nozzle forms of irrigation require 31, 28 and 26% less irrigation water respectively than furrow irrigation when related to the optimum yields and the feasible irrigation water quantities in the GAP Area. The drip irrigation method has utilised the irrigation water more efficiently than the other methods. LEPA and mobile drip did not show any significant difference in the effective use of irrigation water compared to furrow irrigation. Similar results were obtained in the Aegean Region of Turkey.

Comparative research on water and energy-saving irrigation systems in the GAP and Aegean regions of Turkey

This research was carried out to determine the effects of furrow, sprinkler, drip, mobile nozzle, mobile drip and LEPA (Low Energy Precision Application) irrigation methods on the yields and Water Use Efficiency of cotton in the South Eastern Anatolian Project (GAP) Area and in the Aegean Region. According to the results obtained, the highest yield was produced from the drip irrigation method. The drip, sprinkler and mobile nozzle forms of irrigation require 31, 28 and 26% less irrigation water respectively than furrow irrigation when related to the optimum yields and the feasible irrigation water quantities in the GAP Area. The drip irrigation method has utilised the irrigation water more efficiently than the other methods. LEPA and mobile drip did not show any significant difference in the effective use of irrigation water compared to furrow irrigation. Similar results were obtained in the Aegean Region of Turkey.

Ogallala aquifer depletion: economic impact on the Texas high plains

The impacts of the depletion of the Ogallala aquifer on the economy of the Southern High Plains of Texas were estimated by predicting future cropping patterns over a 30-year time horizon as the saturated thickness of the aquifer declines. Increased adoption of sprinkler irrigation methods, increased cotton acreage, and a shift to dryland production were the main responses found to declining water availability in the region. As the Ogallala aquifer is depleted, the region could experience a downturn in agricultural production with possible negative impacts on the regional economy assuming no other offsetting exogenous shocks to the economy.