INNOVATIVE REMOTE SENSING TECHNIQUES TO INCREASE NITROGEN USE EFFICIENCY OF CORN

Nitrogen (N) fertilizer recommendations made without adequate knowledge of the N supply capability of a soil can lead to inefficient use of N. Proper crediting of N from manure and legumes as well as mineralization of N from organic matter is difficult. Remote sensing techniques that use the crop to indicate its N status show considerable promise for improving N management. Objectives of this paper were twofold: 1) to compare the N Reflectance Index (NRI) calculated from ground-based radiometer measurements acquired over irrigated corn (Zea mays L.) at a nadir view (0 °) and an oblique view (75 °) with measured plant N and 2) to evaluate the NRI obtained from both view angles for correcting in-season N deficiencies in a commercial corn field. The NRI calculated from canopy reflectance was not representative of plant N at the sixth leaf growth stage (V6) for either view angle because of the soil background influence on canopy reflectance. However, the oblique view NRI was a good predictor of plant N at V9 and V12 as was the nadir view NRI at V12. The nadir view NRI was not as sensitive as the oblique view NRI at the V9 growth stage because soil was still visible through the canopy. Consequently, the nadir view NRI provides a conservative estimate of plant N prior to complete canopy cover. Use of the nadir view NRI to detect in-season corn N deficiencies for the 1999 growing season reduced N application during the growing season by 39.2 kg N ha-1 without reducing grain yield. If the oblique view NRI would have been used to assess the plant N status, the first fertigation would not have been recommended which would have saved additional N

Tuzlu suların sulamada kullanımı: değişimli su uygulama modelleri

TEZ1178Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 1992.Kaynakça (s. 84-94) var.v, 96 s. ; 30 cm.

Determination of evapotranspiration for cotton by using micrometeorologicel and water budget methods under Çukurova conditions

Bu çalışma 1998-1999 yıllarında, Çukurova Üniversitesi, Ziraat Fakültesi Tarımsal Yapılar ve Sulama Bölümü deneme alanında yürütülmüştür. Araştırmada, tam ve eksik sulama koşullarında, mikrometeorolojik ve su bütçesi yöntemleri kullanılarak pamuk bitkisinin gerçek su tüketimleri ölçülmüştür. Elde edilen sonuçlara göre, tam sulama koşulunda toplam 438 mm (5 sulama), eksik sulama koşulunda 199 mm (1 sulama) sulama suyu uygulanmıştır. Pamuğun mevsimlik su tüketiminin ise tam sulama koşulunda, enerji dengesi ve su bütçesi yöntemleriyle sırasıyla, 496 ile 629 mm, eksik sulama koşulunda, 404 ile 394 mm olduğu anlaşılmıştır. Çalışmanın fam ve eksik sulama koşullarına ilişkin verim değerleri ise sırasıyla, 2040 ile 3300 kg/ha olarak elde edilmiştir,This study was conducted at the experimental field of the Department of Agricultural Structures and Irrigation, Faculty of Agriculture, University of Çukurova in 1998 and 1999. The actual evapotranspiration of cotton plant was measured by using the Mierometeorological and water budget methods under fall and limited irrigation conditions. According to the results, in the full irrigation condition the total irrigation water applied with 5 irrigation practices was 438 mm, whereas in the limited irrigation condition it was 399 mm (1 irrigation). The evapotranspirations of cotton under full irrigation condition were 496 and 629 mm for the energy balance and water budget methods, respectively. Corresponding values under limited irrigation conditions were 404 and 394 mm. The yield was 2040 and 3300 kg/ha under full and limited irrigation conditions, respectively

Şanlıurfa Harran Ovası’nda pamuk üretimi ve su artırımı için farklı karık işletim teknikleri

Abstract: In this study, the water saving and conservation potential of various furrow irrigation management techniques for irrigated cotton were compared. Conventional every-furrow irrigation with open-end furrows (EFO) and blockedend furrows (EFB), and alternate every-other-furrow management with open-end furrows (AFO) and blocked-end furrows (AFB), were considered. Considerable seasonal water savings were obtained with AFO and AFB fl ows, on average from 717 mm to 906 mm, respectively, when compared to EFO. Alternate furrows showed the ability to reduce tailwater runoff considerably. When compared with EFO, water use was reduced by 9063 m3 ha–1 (60%) using AFB and 7167 m3 ha–1 (48%) using AFO, with decreases in yield of 765 kg ha–1 (27%) and 492 kg ha–1 (17%), respectively. Similarly, average water use effi ciencies were 0.36 kg m–3 for AFB and 0.31 kg m–3 for AFO, compared to 0.20 kg m–3 for EFO. Results showed the possibility of applying alternate-fl ow furrow management techniques for water conservation in cotton irrigation. Additionally, the alternate furrow method could also be considered as a defi cit irrigation approach in the Harran Plain.Özet: Bu çalışmada, pamuk tarımında, su artırımı ve korunumu ile ilişkili olarak, farklı karık işletim biçimleri karşılaştırılmıştır. Geleneksel sürekli karıklarlarla ardışık karıklar, serbest drenajlı (SKSD, AKSD) ve gölendirmeli (SKG, AKG) olarak, ele alınmıştır. Sürekli karık yöntemine göre, ardışık karıklardan ortalama 717-906 mm mevsimlik su artırımı sağlanmıştır. Ardışık karık sulama tekniklerinin, yüzey akış kayıplarını önemli ölçüde azalttığı saptanmıştır. Ucu açık karıkla (serbest drenajlı) karşılaştırıldığında, su kullanımı, sırasıyla, AKG tekniğinde 9063 m3 ha–1 (% 60), AKSD’de ise 7167 m3 ha–1 (% 48); verim, anılan tekniklerde sırasıyla, 765 kg ha–1 (% 27) ve 492 kg ha–1 (% 17) azalmıştır. Aynı şekilde, su kullanım randımanı, AKG’de 0.36 kg m–3 ve AKSD’de 0.31 kg m–3, SKSD’de ise 0.20 kg m–3 olarak elde edilmiştir. Sonuçlar, pamuk sulamasında su artırımı için ardışık karık yönteminin kullanılabileceğini göstermiştir. Ayrıca, ardışık karık yönteminin Harran Ovası’nda bir kısıntılı sulama yaklaşımı olarak kabul edilebileceği anlaşılmıştır

Mikrometeorolojik ve su bütçesi yöntemleriyle belirlenen pamuk su tüketimlerinin karşılaştırılması

This study aimed at comparing actual water consumption of cotton obtained by the water balance method under full and limited irrigation conditions, with that estimated by a micrometeorological method (energy balance), which is being widely used nowadays. Results indicated that in the first year the total irrigation water applied was 438 mm, whereas in the second year it was 199 mm. Deep percolation losses were were 6 and 0 mm, respectively, in the first and second year of the experiment. The evapotranspirations of cotton under full irrigation condition were 496 and 629 mm for the energy balance and water budget methods, respectively. Corresponding values under limited irrigation conditions were 404 and 394 mm. Strong relationships ($R^{2}$= 0.99) were found between the evapotranspirations estimated by water balance and micrometeorological methods. Consequently, as compared to the water balance approach, the energy balance method under full irrigation conditions produced lower evapotranspiration (ET). This could be a result of the field measurements of deep percolation included in ET calculation by water balance.This study aimed at comparing actual water consumption of cotton obtained by the water balance method under full and limited irrigation conditions, with that estimated by a micrometeorological method (energy balance), which is being widely used nowadays. Results indicated that in the first year the total irrigation water applied was 438 mm, whereas in the second year it was 199 mm. Deep percolation losses were were 6 and 0 mm, respectively, in the first and second year of the experiment. The evapotranspirations of cotton under full irrigation condition were 496 and 629 mm for the energy balance and water budget methods, respectively. Corresponding values under limited irrigation conditions were 404 and 394 mm. Strong relationships ($R^{2}$= 0.99) were found between the evapotranspirations estimated by water balance and micrometeorological methods. Consequently, as compared to the water balance approach, the energy balance method under full irrigation conditions produced lower evapotranspiration (ET). This could be a result of the field measurements of deep percolation included in ET calculation by water balance

Distribution of Water Loss via Evapotranspiration in a Pistachio Tree Orchard under Drip Irrigation and Non-Irrigation Conditions

WOS: 000351184700008The present study aimed to measure the distribution of water loss via evapotranspiration (ET) in a pistachio tree orchard under drip irrigation and non-irrigation conditions at the experimental orchard of the Pistachio Research Institute, Gaziantep, Turkey. The experimental design consisted of a 10 x 10 m(2) grid system constructed of PVC pipes spaced 2 in apart (horizontally and vertically) that was placed around each tree for the drip irrigation condition (water applied every 7 days) and the non-irrigated condition. Moisture content was measured using the neutron scattering method for both treatments. Water loss via ET was estimated based on the soil water balance method, which included measurement of soil moisture, precipitation, and irrigation. Total water loss via ET under drip irrigation conditions was 518 mm vs 220 mm under non-irrigated conditions. Water loss via ET for the total soil profile and individual layers under non-irrigated conditions was higher at the four outer corners of each 10 x 10 m(2) grid than under irrigated conditions. Moreover, water loss via ET was the highest at the grid system pipes closest to the two laterals under irrigation conditions. In addition, the total percentage of water loss via ET was the highest at the 60-80-cm and 20-40-cm soil layers under drip irrigation and non-irrigation conditions, respectively, and the total percentage of water loss via ET was the lowest at the 40-60-cm and 0-20-cm soil layers under drip irrigation and non-irrigation conditions, respectively. Lastly, it could be considered that root density increased as water loss via ET increased.TUBITAK (Turkish Scientific and Technological Research Council)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK)The authors thank TUBITAK (Turkish Scientific and Technological Research Council) for financial support of this study. Furthermore, the authors thank Dr. E. Uz of the University of Uludag, Bursa, Turkey, and Dr. T. SHAPLAND of the University of California, Davis, USA, for their help in preparing this manuscript

Different furrow management techniques for cotton production and water conservation in Harran Plain, Sanliurfa

WOS: 000300600400008In this study, the water saving and conservation potential of various furrow irrigation management techniques for irrigated cotton were compared. Conventional every-furrow irrigation with open-end furrows (EFO) and blocked-end furrows (EFB), and alternate every-other-furrow management with open-end furrows (AFO) and blocked-end furrows (AFB), were considered. Considerable seasonal water savings were obtained with AFO and AFB flows, on average from 717 mm to 906 mm, respectively, when compared to EFO. Alternate furrows showed the ability to reduce tailwater runoff considerably. When compared with EFO, water use was reduced by 9063 m(3) ha(-1) (60%) using AFB and 7167 m(3) ha(-1) (48%) using AFO, with decreases in yield of 765 kg ha(-1) (27%) and 492 kg ha(-1) (17%), respectively. Similarly, average water use efficiencies were 0.36 kg m(-3) for AFB and 0.31 kg m(-3) for AFO, compared to 0.20 kg m(-3) for EFO. Results showed the possibility of applying alternate-flow furrow management techniques for water conservation in cotton irrigation. Additionally, the alternate furrow method could also be considered as a deficit irrigation approach in the Harran Plain.Southeast Anatolia Project Authority in AnkaraTurkiye Cumhuriyeti Kalkinma BakanligiThe authors are grateful to the Southeast Anatolia Project Authority in Ankara for financial support of this project

Line Source Sprinkler Irrigation Systems for Plant Production Functions Studies

Sulamaya ayrılan su miktarı, kentsel kullanım ve çevre kirliliği nedeniyle giderek azalmaktadır. O nedenle sulama sistemlerinin kısıntılı su koşullarına göre planlanması ve işletilmesi önem kazanmaktadır. Böyle bir uygulama için öncelikle verim ile sulama arasındaki ilişkileri ortaya koyan kapsamlı çalışmalara gerek vardır. Anılan çalışmalar çok sayıda yöntemle ele alınabilmektedir. Bunlar içerisinde çizgi kaynaklı yağmurlama sistemi son yıllarda üzerinde en fazla durulan yöntemlerden birisi, belki de en önemlisidir. Değinilen yöntemde, parsel ortasına yerleştirilmiş tekil bir yağmurlama laterali kullanılır. Lateraller üzerinde belli aralıklarla konumlandırılmış yağmurlama başlıkları bulunur. Sistemde, lateral boyunca eş su dağılımı sağlanmasına karşın, hattan uzaklaştıkça uygulanan su miktarının yaklaşık doğrusal olarak azalması prensibinden yararlanılmaktadır. Bu çalışmada, sözü edilen sistemin planlanma ve değerlendirmesine ilişkin ilkeler verilmiş; ayrıca sınırlılıkları ve üstünlükleri gösterilmiştir