Growing Media Affects Biomass-Water Use Efficiency Trade-Off in Sub-Surface Irrigated Pak Choi ( Brassica rapa L. subsp. chinensis )

EFFECT OF NPK LEVELS ON GROWTH AND BULB QUALITY OF SOME GEOPHYTES IN SUBSTRATE CULTURE

Lettuce (Lactuca sativa L.) is a vegetable whose commercial value is quite good and the demand for lettuce has increased, including from hydroponic results. The use of rockwool planting media in hydroponics is often not available when needed and is expensive. Therefore it is necessary to study of using local planting media, such as: coconut fiber and rice husk charcoal as a replacement of rockwool planting media and whether the increased concentration of nutrients given to the planting media affects the rate of plant growth and yield of lettuce. The purpose of this research to study are interaction between planting media and nutrient concentrations (AB Mix) on the growth and development rate of plants, as well as the yield of lettuce hydroponically with the NFT system. The research was arranged in factorial with two factors using a Split Plot Design. The the main plot is AB Mix nutritional concentration (K) consisting of 3 levels (600 ppm, 900 ppm and 1200 ppm), while the subplot is a planting media (M) consisting of 3 treatment, namely: Rockwool, Coconut Fiber, and Rice Husk Charcoal. The results showed that the combination treatment of rice husk charcoal planting media and AB Mix concentration of 1200 ppm (M3K3) produced the best growth and increased the fresh weight of lettuce plants by 447,54% compared to the combination treatment of rockwool media and AB mix concentration of 600 ppm (M1K1). Rice Husk Charcoal planting media increases the growth rate of plant length and leaf area respectively by 26% and 81,54% compared to rockwool planting media. AB Mix concentration of 1200 ppm gives the best response and increases the growth rate of plant length and lettuce leaf area respectively by 367,5% and 165% compared to the concentration of 600 ppm.

Crop water requirement is an important factor to increase water use efficiency and avoid crop failure in dryland. A way to increase water use efficiency is by determining an irrigation interval scenario and utilizing a planting hole system. Research on the analysis of water requirement in the planting hole system with an irrigation interval for maize is still limited. Therefore, this study aims to analyze the level of water requirement for maize in dryland. This research was conducted in Camplong Village, Kupang District, East Nusa Tenggara (NTT) from January-May 2020. The design used was a split-plot of various treatments. There were three different techniques of applying fertilizer as the main plot, and two treatments of pruning maize leaves as sub-plots. The different treatments of fertilizer application includes: 1) mixing manure with rice husk charcoal (Ls+As), 2) separating manure from rice husk charcoal (Ls/As), 3) no addition of manure or rice husk charcoal into the planting hole (control). The sub-plots were divided into 2 treatments namely with leaf pruning (P) and without leaf pruning (TP). The water requirement was analyzed based on the FAO 56 approach with the production calculation in weight unit of tiles (ubinan). The results showed that 75% water efficiency was achieved or there was a water saving of 3,119 m3/ha/planting season when compared to conventional techniques. The highest maize productivity (7 tons/ha) was attained in treatment of mixing manure with rice husk charcoal with leaf pruning. The result indicated that this water savings may be used to expand the planting area to 3 ha.

White bok choy is a vegetable from the Brassicaceae family that holds high economic value and is highly sought after by consumers. However, its cultivation is often constrained by the selection of appropriate growing media, especially in limited urban spaces. This study aimed to determine the effect of different growing media compositions on the growth and yield of white bok choy plants. The research was conducted from January to February 2025 in the backyard area of a house located in Ciputat District, South Tangerang City. A Randomized Complete Block Design (RCBD) was used with six treatment levels: soil (control); organic growing media; soil + rice husk charcoal (1:1); soil + organic growing media (1:1); organic growing media + rice husk charcoal (1:1); and soil + rice husk charcoal + organic growing media (1:1:1), each replicated four times. The results showed that the composition of the growing medium had no significant effect on any of the observed variables. Soil alone as the growing medium produced comparable results to other growing media and can be recommended as an efficient growing medium for white bok choy cultivation.

Seedling growth and water use of six North American oak species were studied in a series of four experiments to determine inter- and intraspecies water use characteristics. Xeric-site adapted species (chestnut oak, Q. prinus [L.] and black oak, Q. velutina [Lamb.]) had slower growth (height and dry weight accumulation and lower shoot:root ratios) than mesic-site adapted species (bur oak, Quercus macrocarpus [Michx.]; pin oak, Q. palustris [Muenchh.], northern red oak, Q. rubra [L]; and Shumard oak, Q. shumardii [Buckl.]). Principal component analysis (a statistical technique used to identify correlated variables) using 11 variables found that seedling water use loaded positively with seedling growth factors (taller seedlings tended to have higher dry weights and greater leaf and root areas and used more water than shorter seedlings, which tended to have lower dry weights, smaller leaf, and root areas) in the first principal component. However, in the third experiment, seedling growth factors loaded negatively with seedling water use for Q. prinus. Tall Q. prinus seedlings tended to use less water than short seedlings. However, other measures of water use (g water cm −1height and cm −2leaf and root area) loaded negatively on the first principal component. Correlations between seedling heights and seedling waters use were significant and positive, but great within-species and within half-sib family differences in height-adjusted water use (g water cm −1height) were found. By plotting height-adjusted water use against seedling height, efficient and inefficient water use seedlings could be identified. Inefficient water use seedlings were shorter and had higher water use cm −1height than efficient water use seedlings. Inefficient water use seedlings were described as having a xeric-water use habit, whereas tall seedlings had a mesic-water use habit. Potentially, height-adjusted water use could be used as a method for selecting individual oak seedlings better adapted to stressful urban planting sites.

Introduction. Physical-hydraulic characterization of substrates is critical for designing irrigation strategies aimed at enhancing water and nutrient use efficiency and improving crop performance in greenhouse systems. Objective. To evaluate the effect of three levels of water depletion on the physical-hydraulic and physicochemical properties of the substrate, as well as on growth, yield, and water use efficiency of sweet pepper and tomato crops grown in coconut fiber (coir) under greenhouse conditions. Materials and methods. The study was conducted from August 2020 to January 2021 in a multi tunnel greenhouse at the Fabio Baudrit Moreno Agricultural Experiment Station, Alajuela, Costa Rica. Three substrate water depletion levels (Ag11, Ag22 y Ag32) were evaluated in a completely randomized design with three replicates. The response variables included volumetric water content (θ), unsaturated hydraulic conductivity (K(θ)), pH, electrical conductivity (EC), irrigation volume and frequency, leaf area, dry matter, marketable yield, and water use efficiency (WUE). Data was analyzed using the R statistical environment. Results. The Ag11 treatment, characterized by more frequent irrigations with lower volumes, maintained adequate moisture, stable EC, and higher K(θ), which promoted greater vegetative and reproductive growth, as well as high water use efficiency (WUE). The Ag22 treatment achieved yields and WUE values equivalent to those of Ag11, with lower irrigation frequency but higher volume irrigations, without increasing EC to critical levels. The Ag32 treatment significantly reduced growth, yield, and WUE, without raising EC to critical levels, showing a similar irrigation frequency to Ag22 but with a higher applied volume. Conclusion. The Ag11 treatment represented an equilibrium among aeration, water retention, and hydraulic and electrical conductivities, as evidenced by stable yields and efficient water use.

Abstract. Purba JH, Suarmika IGM, Prabawa PS. 2026. Optimizing banana corm-based local microorganisms for reduced NPK fertilization in pak choi (Brassica rapa). Asian J Agric 10 (1): g100145. https://doi.org/10.13057/asianjagric/g100145. This study evaluated the effectiveness of banana corm-based local microorganisms (MOL) in reducing inorganic NPK fertilizer, particularly nitrogen, phosphorus, and potassium, inputs while maintaining pak choi (Brassica rapa) productivity, as measured by fresh and oven-dry biomass. This study quantitatively evaluates MOL × NPK interactions and identifies the agronomic optimum MOL dose using regression analysis, a topic that has rarely been addressed in previous MOL studies. The experiment was conducted from December 2023 to February 2024 in a lowland tropical agroecosystem in Bali, Indonesia, using a factorial Randomized Complete Block Design with two factors: three MOL doses (0, 30, and 60 mL polybag-¹) and four NPK levels (100%, 75%, 50%, and 25% of the recommended dose). Growth and yield parameters included plant height, leaf number, leaf area, and fresh and oven-dry biomass of shoots, roots, and total plants. Analysis of variance showed that MOL application significantly affected leaf area, root biomass, and total biomass (p < 0.05), whereas NPK level alone was not significant. However, a significant MOL × NPK interaction was observed for root and total biomass (p < 0.05). The 30 mL MOL treatment combined with 50-75% NPK produced the highest biomass, indicating a synergistic effect and allowing up to a 50% reduction in inorganic NPK fertilizer without loss of productivity. Quadratic regression analysis identified an agronomic optimum MOL dose of approximately 33 mL polybag-¹ under reduced NPK conditions (R² = 0.82). This study provides quantitative evidence that integrating MOL with reduced NPK fertilization improves nutrient-use efficiency in pak choi cultivation. However, the results are based on a short-term pot experiment, and field-scale validation is required. The integration of locally available organic microbial inputs offers a promising approach to support more sustainable and cost-effective vegetable production systems.

Ecosystem water use efficiency (WUE) and carbon use efficiency (CUE) are critical indicators for understanding the coupling of water and carbon cycles, particularly sensitive to moisture conditions in drylands. However, the multifaceted responses of WUE and CUE to atmospheric, vegetation, and soil moisture factors remain unclear in drylands. In this study, we examined the spatial and temporal dynamics of WUE and CUE in the northern drylands of China during 2003–2018, and employed spatial random forest model to explore the nonlinear responses of WUE and CUE to vapor pressure deficit (VPD), vegetation optical depth (VOD), and soil moisture in vegetation greening and browning areas. Regionally, WUE significantly increased (0.01 gC kg −1 H 2 O yr −1 ), while CUE slightly declined. Vegetation greening areas showed rising WUE and declining CUE, whereas browning areas exhibited the opposite trends. The VPD was the most important factor explaining WUE variability, while the trends of VOD and VPD were almost equally important in explaining CUE variability across the drylands. In significant greening areas, higher VPD (>5), sufficient soil moisture, and moderate VOD (0.3–0.4) promoted increases in WUE but intensified declines in CUE. Conversely, in significant browning areas (less than 3% of study area), WUE displayed a complex nonlinear response to different moisture conditions, and higher VPD and a stronger soil wetting trend enhanced CUE, although higher VOD moderated this effect. These findings revealed the divergent nonlinear characteristics of WUE and CUE to moisture variability under different vegetation dynamics, offering insights into water‐carbon coupling processes and supporting dryland ecosystem management.

The search for techniques that allow a more efficient use of water is a global task, since this resource is increasingly scarce and its quality is constantly deteriorating. The objective of this study was to determine the effect of applying coconut fiber CF on physical-hydric parameters of the soil and its water use efficiency (WUE). The effects of coconut fiber (CF) were assessed on water consumption, water use efficiency and aerial and root biomass of Italian ryegrass (Lolium multiflorum L.). In addition, it was also evaluated whether CF causes toxic effects on lettuce seeds (Lactuca sativa L.). Treatments were established according to the proportion of CF and soil in g g-1 soil CF: T1 = 1:80, T2 = 1:40 and T3 = 1:20, and a control treatment (T0 = no substrate). Additionally, 3 charges of water (100, 75, 50 % of field capacity) were established. Results showed that the best treatment for water consumption was T3-50 (377.8 ml), for WUE the best treatment was T3-100 (8.52 kg DM m-3), for aerial biomass it was T3-100 (4.59 g MS) and in the case of root biomass the best treatment was T3-100 (1.92 g MS). It was concluded that the addition of coconut fiber substrate to the mix improves the physical and hydrological characteristics of degraded soil. There were no toxic effects on lettuce among the applied rates of CF. The germination index (IG) ranged from 124.82 to 156.03 % and the best treatments were T3 and T2.

This study examined the interaction between a reflective particle film and water use efficiency (WUE) response of irrigated and non-irrigated apple trees ( Malus × domestica ) over a wide range of environmental conditions. The objectives were to measure isotopic discrimination (Δ 13 C and δ 18 O), specific gas exchange, and WUE response of ‘Empire’ apple treated with a reflective particle film (PF), with and without supplemental irrigation, compared with an untreated control, with and without supplemental irrigation, over a range of leaf area indices (LAI), seasonal evapotranspiration (ETo), and vapor pressure deficits (VPD) to determine the mechanisms of action affecting WUE in apple. Short-term whole canopy gas exchange studies and isotope discrimination analysis were used to test the hypothesis that WUE was modified by the use of a PF. In whole canopy gas exchange studies, carbon assimilation (A) and transpiration tended to increase, and WUE and canopy conductance tended to decrease, with VPD within each LAI class from 2 to 6. For VPD > 1 kPa, the PF irrigated treatment consistently had the greatest WUE and other treatments were intermediate for LAI of 2 to 4. The PF irrigated and non-irrigated treatments had greater WUE than the control irrigated and non-irrigated treatments for VPD ≤ 2 kPa and there were no treatment effects for VPD > 2 kPa in the LAI range of 4 to 6. The PF non-irrigated was equivalent to the control non-irrigated treatment at VPD of 1 to 3 kPa, but was significantly lower at VPD of 3 to 4 kPa. PF irrigated and non-irrigated treatments had the greatest carbon isotope discrimination (Δ 13 C), the control non-irrigated treatment had the lowest Δ 13 C, and the control-irrigated treatment was intermediate. Oxygen isotope enrichment (δ 18 O) was positively correlated with the mean growing season VPD and mean growing season evapotranspiration. Δ 13 C was significantly and positively correlated with δ 18 O. Seasonal WUE was negatively correlated with Δ 13 C and there was an interaction with LAI. The seasonal water use of apple is better evaluated with stable isotope discrimination integrating seasonal variation rather that the use of whole canopy gas exchange measurements that measure WUE for brief periods of time. Δ 13 C was an accurate measurement of apple WUE and indicated that the PF irrigated treatment had the greatest Δ 13 C and so the lowest WUE compared with the control non-irrigated treatment at LAI from 4 to 6. The reduced WUE of the PF irrigated treatment compared with the control non-irrigated treatment is likely due to increased g S from lower canopy temperature and increased canopy photosynthetically active radiation diffusion that drove increased A. δ 18 O was an indicator of seasonal water use over six growing seasons due to its high correlation with ETo. In ‘Empire’ apple, A can be increased with PF and irrigation treatments, but at the cost of decreased WUE.

Ecosystem water use efficiency (WUE) plays an important role in maintaining the carbon assimilation–water transpiration balance in ecosystems. However, spatiotemporal changes in WUE in the subtropical region of China (STC) and the impact of driving forces remain unclear. In this study, we analyzed the spatiotemporal variation in WUE in the STC and used ridge regression combined with path analysis to identify direct and indirect effects of climate change, vegetation growth, and elevated atmospheric CO2 concentration (Ca) on the interannual trend in WUE. We then quantified the actual and relative contributions of these drivers to WUE change based on the sensitivity of these variables on WUE and the trends of the variables themselves. Results reveal a mean WUE of 1.57 g C/m2/mm in the STC. The annual WUE series showed a descending trend with a decline rate of 0.0006 g C/m2/mm/year. The annual average temperature (MAT) and leaf area index (LAI) had strong positive direct effects on the WUE, while the vapor pressure deficit (VPD) had a strong negative direct effect. Opposite direct and indirect effects offset each other, but overall there was a total positive effect of Ca and VPD on WUE. In terms of actual contribution, LAI, Ca, and VPD were the main driving factors; LAI caused WUE to increase by 0.0026 g C/m2/mm/year, while Ca and VPD caused WUE to decrease by 0.0021 and 0.0012 g C/m2/mm/year, respectively. In terms of relative contribution, LAI dominated the WUE trend, although Ca and VPD were also important factors. Other drivers contributed less to the WUE trend. The results of this study have implications for ecological management and restoration under environmental climate change conditions in subtropical regions worldwide.

Microgreens are new foods with bioactive compounds that are beneficial for human health. Microgreens Brassica rapa L. are small-scale, naturally occurring vegetable crops that possess a high antioxidant value and natural nutrient density.The profile of bioactive compounds is influenced by variations in growing media on microgreens Brassica rapa L. including rice husk charcoal, cocopeat, and top soil.The purpose of this study was to analyze the increase in flavonoid, chlorophyll and carotenoid compounds in several variations of growing media: This research was conducted using a Non-Factorial Randomized Group Design (RAK) with three treatment levels, namely top soil, top soil + rice husk charcoal, top soil + cocopeat with five replications. Parameters measured were flavonoid compounds, chlorophyll a b, and carotenoids. Results: the analysis showed that the best planting media were rice husk charcoal, cocopeat, and top soil, respectively had a significant effect on the increase in Chlorophyll (42.12 mg L-1) and Carotenoids (10.63 µmol/L) Flavonoids (19.19 µmol g-1). Conclusion: The best recommended planting medium is rice husk charcoal which shows a significant effect on increasing Chlorophyll (42.12 mg L-1) Carotenoids (10.63 µmol/L) and cocopeat which shows a significant effect on increasing flavonoid content (19.19 µmol g-1).

Soil water content and vapor pressure deficit affect ecosystem water use efficiency through different pathways

Three diploid (Triticum boeoticum, AA; Aegilops speltoides, BB and Ae. tauschii, DD), two tetraploid (T. dicoccoides, AABB and T. dicoccon, AABB) and one hexaploid (T. vulgare, AABBDD) varieties of wheat, which are very important in the evolution of wheat were chosen in this study. A pot experiment was carried out on the wheat under different water and nutrient conditions (i) to understand the differences in biomass, yield, water use efficiency (WUE), and nutrient (N, P and K) use efficiency (uptake and utilization efficiency) among ploidies in the evolution of wheat; (ii) to clarify the effect of water and nutrient conditions on water and nutrient use efficiency; and (iii) to assess the relationship of water and nutrient use efficiency in the evolution of wheat. Our results showed that from diploid to tetraploid then to hexaploid during the evolution of wheat, both root biomass and above‐ground biomass increased initially and then decreased. Water consumption for transpiration decreased remarkably, correlating with the decline of the growth period, while grain yield, harvest index, WUE, N, P and K uptake efficiency, and N, P and K utilization efficiency increased significantly. Grain yield, harvest index and WUE decreased in the same order: T. vulgare > T. dicoccon > T. dicoccoides > Ae. tauschii > Ae. speltoides > T. boeoticum. Water stress significantly decreased root biomass, above‐ground biomass, yield, and water consumption for transpiration by 47–52%, but remarkably increased WUE. Increasing the nutrient supply increased wheat above‐ground biomass, grain yield, harvest index, water consumption for transpiration and WUE under different water levels, but reduced root biomass under drought conditions. Generally, water stress and low nutrient supply resulted in the lower nutrient uptake efficiency of wheat. However, water and nutrient application had no significant effects on nutrient utilization efficiency, suggesting that wheat nutrient utilization efficiency is mainly controlled by genotypes. Compared to the other two diploid wheats, Ae. squarrosa (DD) had significant higher WUE and nutrient utilization efficiency, indicating that the D genome may carry genes controlling high efficient utilization of water and nutrient. Significant relationships were found between WUE and N, P and K utilization efficiency.(Handling editor: Jin‐Zhong Cui)

Efficient use of limited irrigation water is essential for sustaining crop productivity in water-scarce regions of Ethiopia. Onion (Allium cepa L.), a high-value horticultural crop, is widely cultivated under small-scale irrigation systems, yet its production is often constrained by inefficient water management. This study evaluated the effects of three furrow irrigation methods — Alternative Furrow Irrigation (AFI), Fixed Furrow Irrigation (FFI), and Conventional Furrow Irrigation (CFI) — combined with three irrigation levels (50%, 70%, and 100% ETc) on the growth, yield, and water use efficiency of onion in the Jimma Zone of southwestern Oromia. A randomized complete block design with three replications was used over two cropping seasons. The results demonstrated that irrigation method and irrigation level had significant impacts on key agronomic traits, bulb yield components, and water use efficiencies. The highest marketable bulb yields were obtained from CFI100% ETc (9.3 t/ha) and CFI70% ETc, followed closely by AFI100% ETc (8.7 t/ha), which produced statistically comparable yields while using 50% less irrigation water. Deficit irrigation under AFI showed remarkable water-saving benefits without substantial yield penalties. AFI50% ETc and AFI70% ETc produced moderate yields but achieved the highest irrigation water use efficiency (IWUE) and crop water use efficiency (CWUE), reaching 74.37 kg/mm and 55.73 kg/m<sup>3</sup>, respectively. In contrast, FFI50% ETc produced the lowest yield performance due to prolonged water stress in non-irrigated furrows. Overall, AFI100% ETc provided the best balance between high yield and efficient water use, demonstrating its suitability for water-limited environments. The findings suggest that AFI, particularly at full irrigation, can serve as a sustainable alternative to conventional furrow irrigation, helping farmers optimize water productivity without compromising crop output. The study recommends wider adoption of AFI100% ETc in regions facing irrigation water shortages.