DM distribution in shoots and roots of vegetative plants depending on various environmental conditions and experimental interventions is discussed. Because of the difficulties in maintaining conditions at a sufficiently constant level for some time, functional equilibria are not likely to exist during prolonged periods of time. From the responses occurring after transferring plants including perennial ryegrass and maize from one condition to another or after disturbance of existing relationships, it is demonstrated once more that nutritional control, i.e. functional control, of distribution is still the most reasonable interpretation of the observed reaction patterns. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Scientists, environmentalists, and farmers are currently in pursuit of sustainable agricultural practices that can effectively ensure global food security while simultaneously mitigating environmental degradation. A field experiment was conducted to elucidate the impact of low-cost capacitance soil moisture-based sensors on lettuce (Lactuca sativa L.) irrigation water conservation, agro-physiological aspects, and nutritional characteristics. The experiment also involved the use of five different types of soil mulching films: white geotextile (WGup), green geotextile (GGup), black plastic (BPup), white geotextile for both above and below ground (WGup-down), green geotextile for both above and below ground (GGup-down), in addition to un-mulched soil (control). The findings demonstrated that the application of WGup, BPup, WGup&down, and GGup&down resulted in a significant improvement in irrigation water conservation, with WGup exhibiting the highest savings at 41.86%, while the control group exhibited the least amount of water savings at 19.87%. Moreover, the highest productivity levels were observed in plants mulched with GGup&down, reaching 47,944.68 kg ha−1, whereas the lowest productivity was recorded in plants mulched with green geotextile GGup at 22,377.89 kg ha−1. In terms of irrigation water productivity (IWP), the order of effectiveness was BPup > GGup-down > WGup > WGup-down > GGup > Control, with BPup achieving the highest IWP at 60.19 kg m−3 and the control treatment reporting the lowest at 27.80 kg m−3. The percentage of the irrigation water applied for crop evapotranspiration (Irc) showed that the control treatment saved the least amount of irrigation water, saving only 19.87%, while the best treatment was WGup, achieved the highest percentage of irrigation water savings at 41.86%. Additionally, mulched plants exhibited higher levels of nutrients (N, P, Ca, Mg, Fe, Mn, and Zn), ascorbic acid (AsA), and total phenol content (TPC), while showing lower nitrate content in the leaves compared to non-mulched plants. Overall, the utilization of soil moisture-based capacitance sensors and biodegradable mulching films has proven to be highly effective and low cost by 16.633 US$ year−1 to enhance irrigation water productivity, growth performance, nutritional quality, and overall productivity of lettuce crops, thereby contributing to the sustainability of lettuce production in arid regions.

The deficit irrigation offers water savings potential that is becoming popular in arid and semi-arid regions reducing freshwater use over time. A two-year factorial experiment was conducted to evaluate growth, yield and water productivity of tomato under water deficit irrigation of the drip and furrow method. The experiment was carried out in a split-plot design with drip irrigation and furrow irrigation as main plot treatments, and soil moisture regimes (0, -10, -20, -30 kPa) as subplots. Data were collected on growth parameters, physiological traits, yield and water productivity of tomato. The results showed that physiological traits, yield, and water productivity were significantly influenced by irrigation system and soil moisture regime. The drip irrigation system with -10 kPa soil moisture regime reduced total water input by 22.6% and 19.8% and gave 28% and 22% higher fruit yields in 2020 and 2021, respectively, compared with furrow irrigation system. Plant growth was higher and flowering occurred earlier (3 days) with drip irrigation system than with furrow irrigation. When the soil water content was -10 kPa, drip irrigation performed significantly better than for other soil moisture regimes by improving physiological and phenological attributes, and thereby, advancing tomato growth and fruit yield. Thus, a drip irrigation system with soil moisture regime -10 kPa could reduce total water input through precise irrigation, maximizing tomato yield and water productivity.

When optimizing irrigation methods, much consideration is given to crop growth indicators while less attention has been paid to soil’s gaseous carbon (C) and nitrogen (N) emission indicators. Therefore, adopting an irrigation practice that can reduce emissions while maintaining crop yield and quality is of great interest. Thus, open-field experiments were conducted from September 2020 to January 2022 using a single-factor randomized block design with three replications. The lettuce plants (“Feiqiao Lettuce No.1”) were grown using four different irrigation methods established by setting the lower limit of drip irrigation to 75%, 65%, and 55% of soil water content at field capacity corresponding to DR1, DR2, and DR3, respectively. Furrow irrigation (FI) was used as a control. Crop growth indicators and soil gas emissions were observed. Results showed that the mean lettuce yield under DR1 (64,500 kg/ha) was the highest, and it was lower under DR3 and FI. The lettuces under DR3 showed greater concentrations of crude fiber, vitamin C, and soluble sugar, and a greater nitrate concentration. Compared with FI, the DR treatments were more conducive to improving the comprehensive quality of lettuce, including the measured appearance and nutritional quality. Among all the irrigation methods, FI had the maximum cracking rate of lettuce, reaching 25.3%, 24.6%, and 22.7%, respectively, for the three continuous seasons. The stem cracking rates under DR2 were the lowest—only 10.1%, 14.4%, and 8.2%, respectively, which were decreased to nearly half compared with FI. The entropy model detected that the weight coefficient evaluation value of DR2 was the greatest, reaching 0.93, indicating that the DR2 method has the optimal benefits under comprehensive consideration of water saving, yield increase, quality improvement, and emission reduction.

设施栽培氮肥投入大、残留高，过量氮肥残留导致土壤环境恶化，然而，残留氮也是重要的土壤氮素资源。为研究不同水分调控方案对土壤残留氮分布和再利用的影响，采用¹⁵N同位素标记技术，种植2茬青梗菜，首茬青梗菜设N1、N2、N3共3种施氮水平，分别为150、225、300 kg/hm²的¹⁵NH₂CO₂ ¹⁵NH₂），二茬青梗菜设W1、W2、W3共3种水分下限方案（占田间持水量的百分数），分别为60%、70%和80%，观测不同处理下残留氮的分布、再利用和平衡规律。研究结果表明：N1-N3处理共有72.3、123.6和195.3 kg/hm²的氮肥残留于0~60 cm土体中，主要以矿质态存在。在N1、N2和N3共3种残留氮场景下，均以W2处理根系鲜重最大，分别达到0.182、0.188和0.195 g/株。不同处理以W2N1处理青梗菜残留氮利用效率最高，达到5.4%。在相同土壤氮残留量条件下，W2处理残留氮利用效率显著（p＜0.05）高于W1和W3。前茬施氮量越高，残留氮肥在后茬栽培过程中的损失风险越大；控水下限越高，残留氮更易向40 cm以下土层迁移，总损失量也越大，与W1相比，W3处理残留氮损失量增加了29.9%~66.7%（2.29~6.97 kg/hm²）。推荐70%控水下限作为提升残留氮利用效率的最优水分调控方案。