Shortage of fresh water and drought stress are important factors limiting crop productivity in semi-arid and arid regions. Irrigation management needs to be optimised to improve irrigation water-use efficiency (IWUE), and thus, agricultural sustainability in these climates. A field experiment was conducted at two semi-arid locations in Iran to evaluate the impact of irrigation regime (applied after crop evapotranspiration of 70 mm (I70), 100 mm (I100) or 130 mm (I130)) and irrigation method (applied to every furrow (EFI) or variable alternate furrow (AFI)) on yield and IWUE of maize (Zea mays L.). Yield response to irrigation rate was quadratic. Kernel yield was 8476 kg ha–1 under I70, and this reduced by 12.3% under I100 and 27.7% under I130. Yield reduction due to water stress was attributed to decline in both kernel number and kernel weight. Implementation of AFI resulted in a significant saving in irrigation water. At I70, 31% less water was used with AFI than with EFI. Irrigation water saving was even greater under I100 and I130 when AFI was implemented. Regardless of irrigation regime, IWUE under AFI was always greater than under EFI (1.32 vs 1.03 kg m–3 for grain and 3.30 vs 2.47 kg m–3 for biomass production). In addition, plants were shorter with a longer root system under AFI, and the role of carbohydrate remobilisation in kernel filling was greater under AFI consistently among irrigation regimes. The results indicated good potential of AFI for development of water-saving strategies for maize production in semi-arid climates.

BACKGROUND: The production of sufficient animal feed in arid and semi-arid regions plays a significant role in food security in these areas. The present study was conducted based on the hypothesis that intercropping of sorghum and amaranth, comprising relatively drought tolerant forages, will enhance the yield and quality of the feed under limited irrigation water availability. RESULTS: Implementation of fixed alternate furrow irrigation (FFI) and alternate furrow irrigation (AFI) resulted in a saving of 22.5% and 19.7% of irrigation water, respectively. However, the water saving declined both yield and quality of forage. In conventional furrow irrigation (CFI), the highest dry matter (DM) yield was 15.5 Mg ha −1 , obtained from S 50 -A 50 treatment. In FFI and AFI, sole sorghum produced the highest DM. However, their maximum yields (11.2 and 12.6 Mg ha -1 , respectively) were not significantly different from yields in S 75 -A 25 intercropping ratios. Irrigation water use efficiency (IWUE) was similar in CFI and AFI and considerably higher than FFI. Sorghum monoculture and the S 75 -A 25 intercropping had the highest IWUE (3.4 and 3.3 kg m −3 ), whereas IWUE of the sole amaranth was 1.7 kg m −3 . The partial land equivalent ratio and monetary advantage index of amaranth and sorghum indicated that sorghum would benefit from intercropping as long as its ratio in the intercropping is more than 25%. CONCLUSION: When sufficient irrigation is available, intercropping of sorghum and amaranth can considerably improve yield and quality of emergency feed. However, the benefits from intercropping faded under the two partial root-zone irrigation methods used in the present study.

The experiment was conducted in spring 2014 to evaluate the effect of defoliation on the quantitative and qualitative characteristics of sugar beet in Motahari research station located in the Kamal Shahr region in Karaj, Iran. The study was conducted in split plot factorial with completely randomized block design with four replications. The main factors included two planting dates viz 23 April, 2014 (suitable planting time) and 18 May, 2014 (Late planting) and the sub-factors included five levels of defoliation including stage of early cotyledon growth to two true leaves (2 leaves), the stage of plant deployment (about 12 leaves), mid-growth (about 32 leaves) and late season of growth (about 54 leaves) and another sub-factors included five levels of defoliation intensity of leaves included 25%, 50%, 75% and 100% of defoliation and non-defoliation stage (control) as randomized and factorial were considered. Result of study revealed that different planting dates have significant effect on the sugar percentage of root. In addition, the treatment of defoliation stage could have a significant effect on root yield and white sugar yield (p>0.01).The treatment of defoliation intensity had a significant effect on all three traits (p>0.01). In general, increase in the defoliation intensity negatively affects the root yield and significantly reduced the white sugar yield (compared to control). Among the various stages of defoliation, middle stages of the defoliation have least effect on the evaluated traits which indicated more sensitivity of this treatment during the growing season of plant.

BACKGROUND Strategies to enhance the efficient use of irrigation water require a major shift in irrigation and cropping systems. It was hypothesized that (i) replacing water‐demanding crops such as corn silage with more drought‐tolerant forages species, (ii) adoption of intercropping instead of monoculture, and (iii) use of alternative irrigation methods, may alleviate the water shortage in semi‐arid regions, while producing high‐quality forage. RESULTS Adoption of drip irrigation (DRIP) and alternate furrow irrigation (AFI) reduced water consumption by 43% and 20%, respectively. Additionally, DRIP produced 11% more biomass than the conventional furrow irrigation. The intercropped ratio of 50% sorghum and 50% amaranth under DRIP maximized forage production and improved irrigation water‐use efficiency (IWUE). Principal component analysis indicated that the DRIP increased the dry matter yield and IWUE, whereas the AFI improved the forage quality. The intercropped ratio of 75% sorghum and 25% amaranth demonstrated the highest yield stability and was considered superior cropping system regardless of the irrigation strategies. CONCLUSIONS DRIP and AFI strategies were effective in reducing water consumption, with DRIP being the most water‐efficient method. Intercropping sorghum and amaranth at a ratio of 50:50 under DRIP resulted in the highest forage yield and IWUE. While sole amaranth had the highest forage quality, intercropping sorghum and amaranth increased dry matter production with better forage quality than sorghum monoculture. Overall, the combination of DRIP and intercropping sorghum and amaranth at a ratio of 50:50 considered as a suitable strategy for improving forage yield and quality, as well as IWUE. © 2023 Society of Chemical Industry.

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