A field experiment was conducted in 2011 and 2012 to study the effect of fertigation on yield, fruit quality and nutrient uptake of ‘Nabbut-Ahmar’ date palm cultivar grown in sandy loam soil. Three fertigation treatments were compared with traditional application. In traditional treatment (CT), the recommended dose [2300 g nitrogen (N), 1200 g phosphorus (P) and 1400 g/ tree] was applied as a soil broadcast in three equal doses. The fertigation treatments, (T2), (T3) and (T4), represent all nitrogen, phosphorus and potassium (NPK) amounts of CT, 2/3 CT and 1/3 CT, respectively that were injected in twelve equal doses. The results showed that compared to CT, the fertigation treatments increased yield/palm by 41%, 31% and 18% for T3, T2 and T4, respectively. Beside the increase in yield, 33% and 66% of the applied fertilizers were saved by T3 and T4, respectively, compared with CT. Feritgation treatments had no negative impact on the overall fruit quality characteristics and even increased total soluble solids (TSS), soluble tannins and total phenols concentrations compared to the conventional fertilization. Availability of NPK increased by fertigation but without further increase in leaves and fruit. In conclusion applying 2/3 of the recommended dose of NPK fertilizers under dry land condition through fertigation maximize yield, quality and fertilizer use efficiency.

Screening of drought tolerant genotypes for arid land cultivation is the best approach to avoid yield losses as breeding and selection are time taking techniques. A current experiment was planned to evaluate late sown wheat cultivars potential for drought tolerance and adaptability in Jeddah region, KSA. Four wheat cultivars (YocoroRojo [YR], Faisalabad-2008, F-10 and L-7096) were tested against drought stress applied as (75% and 50%) of total crop water requirement. A 100% water requirement was also applied as a control. Data regarding crop growth stages, growth, grain yield, and yield contributors were tested using MSTAT-C. Drought stress significantly decreased all growth and yield traits except harvest index, and the effect of water stress was the most severe where 50% of the total water requirement was applied. Both studied crop growth stages (days to complete tillering and days to complete 50% heading) were also affected to applied water stress and effect was a more pronounced for days to complete 50% heading. Studied cultivars responded variably for different growth and yield traits. Cultivar YR took minimum days to complete tillering and heading while L-7096 presented the highest plant height and dry biomass accumulation. Faisalabad-2008 reported maximum values for grain yield and yield contributors except spike length that was maximum in YR. Based on the field evaluation, it is concluded that Faisalabad-2008 produced significant results for growth and yield traits among studied cultivars and can be successfully grown in arid land conditions under limited water supplies.

Understanding the critical period of weed competition is indispensable in the development of an effective weed management program in field crops. Current experiment was planned to evaluate the critical growth period of Setaria and level of yield losses associated with delay in weeding in rain-fed drip irrigated wheat production system of Saudi Arabia. Field experiment was conducted to evaluate the effect of weeding interval (07-21, 14-28, 21-35, 28-42 and 35-49 days after sowing) and drought stress (75% and 50% of field capacity) on Setaria growth, wheat yield and water use efficiency. Season long weedy check and wellwatered (100% FC) plots were also maintained for comparison. Weeding interval and drought stress significantly (p ≤ 0.05) affected the growth and yield of Setaria and wheat. Drought stress from 75% to 50% FC resulted in reductions of 29-40% in Setaria height, 14-27% in Setaria density and 11-26% in Setaria dry biomass. All weeding intervals except 35-49 DAS significantly suppressed Setaria growth as compared with control. Delay in weeding increased weed-crop competition interval and reduced wheat yield and yield contributors. Therefore, the lowest yield of 1836 kg ha-1 was attained for weeding interval of 35-49 DAS at 50% FC. Water use efficiency and harvest index increased with decreasing FC levels but reduced with delay in weeding. Correlation analysis predicted negative association of Setaria density with wheat yield and yield contributors and the highest negative association was for harvest index (-0.913) and water use efficiency (-0.614). Early management of Setaria is imperative for successful wheat production otherwise yield losses are beyond economical limits.

tA field experiment was conducted during 2013 and 2014 seasons to compare fertigation and conventionalsoil broadcast fertilization on growth, yield, fruit quality and nutrient uptake of tissue culture-regenerated‘Barhee’ date palm grown in sandy loam calcareous soil in a newly established orchard. In the conventionaltreatment (CT), the recommended dose (450 g N, 225 g P and 225 K g/tree) was applied as a soil broad-cast in three equal doses. In the fertigation treatments, the NPK fertilizers were injected with irrigationwater in 12 equal doses, (T2), (T3) and (T4), represent all NPK amounts of CT, 2/3 CT and 1/3 CT, respec-tively. The highest fertilization regime either applied as soil broadcast or as fertigation produced thehighest total yield per palm compared with other fertigation treatments. However, fruit physical qualityparameters were higher at T3 and T4 than other treatments. On the other hand, fruit biochemical qualitycharacteristics showed unspecific trend. Palm growth parameters, chlorophyll a, b, and total chlorophyllsconcentration as well as chlorophyll a/b ratio were not affected by the fertilization treatments. The CT andthe fertigation treatments T2 and T3 increased nitrogen availability without, however, a further increasein leaves, except for T2. At the end of the sixth growing season (third flowering season from transplan-ting), all the cultivated ‘Barhee’ palms were rapidly and strongly growing without any losses in all thetreatments. However, some flowering abnormalities were observed such as multiple carpels formation, arelatively low fruit set percentage and albinism that were lower in 2014 than 2013 season. In conclusion,fertilization is critical to increase yield of young tissue culture-regenerated palms which might have arelatively high nutrient demand.

Field experiment was conducted to optimize forage production and water use efficiency (WUE) under dry land condition at the Agriculture Research Station of King Abdulaziz University located at Hada Al-Sham, Jeddah. Aim of the research was to produce the optimum forage production with the least amount of irrigation water in alfalfa and blue panic forage crops. To fulfill the above mentioned objective three irrigation systems (sprinkler, drip and sub-surface drip) were investigated using three water regimes namely: 100% water requirement (WR), 75%WR and 50 % WR. Under these treatments alfalfa and blue panic crops were investigated. Results revealed that, total water supply was increased along the growing season to reach its maximum in June, then decreased. Sub-surface drip produced the highest forage yield under fully water requirement (100% WR). Surface drip increased yield production under stress treatments (75% WR and 50% WR) while sprinkler system produced the least forage yield. Under fully and stress treatments, blue panic produced higher forage yield than alfalfa. WUE was the best under subsurface drip followed by surface drip while the least was recorded in sprinkler irrigation.

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A field experiment was conducted in the Agricultural Research Station of King Abdulaziz University located in Hada Al-Sham, 110 kilometers south-east of Jeddah, KSA to identify the effect of irrigating with magnetic saline waters , water salinity level and sulfur amendment addition to the soil at rates of 0, 5 and 10 tons per hectare on the crop production and water use efficiency of eggplant. Five irrigation water salinity level namely: 2000, 4000, 6000, 8000 and 10000 mg/l were used to irrigate the eggplant before and after passing through a magnetic field. Results indicated that, magnetic water increased crop yield and water use efficiency under saline irrigation water compared with non-magnetic water. The yield and the water use efficiency were 18.99 and 15.63 t/ha and (2.01 and 1.84 kg/m3 for magnetic water compared to 11.41 and 9.39 t/ha and 1.21 and 1.10 kg/m3 for non-magnetic water during the both growing seasons respectively. For sulfur addition, the yield and the water use efficiency increases were 19.11 and 15.73 t/ha and (2.02 and 1.85 kg/m3 ) for the 10 t/ha sulfur, followed by 14.74 and 12.13 t/ha and 1.56 and 1.41 kg/m3 for the 5 t/ha sulfur compared to 11.74 and 9.66 t/ha and 1.24 and 1.13 kg/m3 for 0 t/ha sulfur addition during both growing seasons respectively. Therefore, it is recommended to use magnetic water and sulfur amendment addition with a rate of 10 tons per hectare when using saline irrigation water to improve crop production and water use efficiency.

Effect of biochar, derived from unfertilized dates, on the immobilization of Cd and Ni, in a sandy loam alkaline soil, was investigated. The biochar was applied to the soil columns at the rate of 0.5, 1, and 2 % (w/w) artificially polluted with 10 mg kg−1 Cd and 100 mg kg−1 Ni. After 1 month incubation of soilbiochar mixture under ambient conditions, the soil bulk density was reduced by 0.19 g cm−3 as compared with no biochar additionwith increase in soil pH. A reduction of 53%in the NH4NO3-extractable soilNi was recorded as compared with the corresponding control without biochar addition. After incubation, the water-soluble Ni and NH4NO3-extractable soil Cd and Ni contents were significantly lower in all the biochar treatments than the control. A reduction of 53 % in the NH4NO3- extractable soil Ni was recorded as compared with the corresponding control. The biochar content separated from the incubated soil showed low concentrations of NH4NO3-extractable Cd and Ni. The total Ni and Cd contents recovered from biochar samples after incubation were 35.2 and 3.7 mg kg−1, respectively. Their contents in soil were substantially reduced by the incorporation of biochar amendment (114 to 57.2 mg kg−1 Ni, 9 to 5.6 kg−1 Cd) as compared with the no-biochar control. Therefore, addition of the biochar improved the soil physical properties and succeeded in immobilizing the studied metals.

This study investigate calcareous saline sodic soil was conducted during winter and spring (2012 pozzolan placements (PP) cm, and control (no pozzolan)) squash yield and the contents of soil nitrogen (N), phosphorus (P), potassium (K), pH, electric conductivity (EC), and organic matter (OM). experiment was statistically analyzed mean separation using least significant difference ( PP in the soil surface gave the best soil reclamation. significantly decreased soil respectively. Moreover, the to 53.91 ppm, 0.79 to 0.93%, and 0.3401 to 0.3684% significantly affected in increasing squash yield 1 in spring season.

A field experiment was conducted to study the effect of water regime (W), row spacing (RS) and plant density (D) on growth and productivity of tomato cv. ’Pito Pride’ at the Agriculture Experimental Station of King Abdulaziz University. Two water regimes, W1 (70% of water requirement) and W2 (full water requirement) were studied. Under each water regime three row spacings (RS1, RS2, RS3) and two plant densities D1 (single plant per dripper) and D2 (two plants per dripper) were investigated. Results revealed that W1 reduced number of days to flowering and fruit setting, plant height, plant fresh weight and total yield, while it increased water productivity (WP). Decreasing RS increased water supply and total yield but decreased growth characteristics. D2 increased total yield by 122–168% and WP by 131–180% compared to D1. Interaction between the three variables investigated was significant for all assessed characteristics except fruit yield per plant, total fruit yield and WP. These characteristics were affected by the interaction between RS and D. The highest total yield and WP were obtained from the RS2-D2 treatment. This treatment increased total yield per ha by 11–331%andWP by 12–300% compared with the maximum and minimum yield of other investigated treatments of both seasons. Copyright © 2014 John Wiley & Sons, Ltd.