Drip Irrigation Conditions Research Articles

Effects of Straw Biochar on Soil Microbial Metabolism and Bacterial Community Composition in Drip-irrigated Cotton Field

A five year field experiment was conducted to evaluate the effect of continually returning cotton straw or biochar on microbial metabolic function and bacterial community composition of soil in a cotton field under drip irrigation conditions. The experiment involved three treatments:control (single application of chemical fertilizer, CK), cotton straw (returning of cotton straw plus chemical fertilizer application, ST), and biochar (returning of cotton straw biochar plus chemical fertilizer application, BC). The returning of cotton straw and biochar both significantly increased soil organic matter, total nitrogen, and available nutrients, but the effect of returning biochar was more significant. The carbon source metabolic activities of the soil in the ST treatment was the highest, followed by the BC treatment, which was significantly higher than of that in the CK treatment. The returning of cotton straw promoted the metabolism of carbohydrate and amine carbon sources, while biochar significantly increased the metabolism of polymer carbon sources. Compared with the CK treatment, the ST treatment significantly increased the phylum of Proteobacteria, Actinobacteria, Bacteroides, and the family of Xanthomonadaceae, Acidobacteriaceae, Microbacteriaceae, and Cytophagaceae. The BC treatment significantly increased the phylum of Acidobacteria, Gemmatimonadetes, Nitrospirae, and the family of Blastocatellaceae (subgroup 4), Gemmatimonadaceae, and Nitrosomonadaceae. The correlation analysis showed that there were significant positive correlations between the relative abundances of Xanthomonadaceae and Acidobacteriaceae and the carbon source metabolic activities of carbohydrates, amino acids, carboxylic acids, and amines. The relative abundances of Microbacteriaceae and Cytophagaceae were positively correlated with carbohydrates and amines. There was a significant positive correlation between the relative abundance of Blastocatellaceae (subgroup 4), Gemmatimonadaceae, Nitrosomonadaceae and the carbon metabolism of polymers. These results suggest that the continual returning of biochar increased soil nutrients, change bacterial community composition, and promoted the metabolic activity of polymer carbon sources in the drip-irrigated cotton field.

Seed productivity of carrot (Daucas carota L.) grown by stacking on the conditions of drip irrigation in the south of Ukraine

Seed productivity of carrot (Daucas carota L.) grown by stacking on the conditions of drip irrigation in the south of Ukraine

Вплив способів зрошення на продуктивність кукурудзи

Modern methods of irrigation are considered as a key factor in the intensification of technologies for growing of grain corn. The productivity of the crop as a result of the optimization of water and nutrient regimes increases from 100 to 380% in comparison with non-irrigated conditions. The aim of the research was to study the effect of sprinkling, drip irrigation and subsurface drip irrigation on growth processes, the structure of the crop formation and the yield of grain corn. Field experimental studies were conducted on the lands of Kamyans'ko-Dnieprovs'ka research station IWPLM of NAAS during 2018-2020The obtained results confirm that the method of irrigation significantly affects the formation of basic biometric parameters, yield structure and productivity. It is established that the maximum parameters of growth processes (plant height, leaf surface area, as well as photosynthetic potential and net photosynthesis productivity) of corn are provided by drip irrigation. Significantly lower and similar values were determined for the conditions of subsurface drip irrigation and sprinkling, and the lowest parameters of corn productivity were obtained under natural moisture conditions. The highest yield of corn grain was obtained under drip irrigation – 20,69 t on ha, while under subsurface laying of irrigation pipelines it was significantly lower – 16,44 t on ha. In the variant with sprinkling, the decrease in grain yield by 0,62 t on ha compared to subsurface drip irrigation was within the least significant difference of the experiment (LSDА0,5 = 1,93). On the variant of conditional control (without irrigation), on average, for three years, a low yield level was obtained - only 3,85 t on ha, which confirms the significant risks and inexpediency of this crop in the Steppe conditions without irrigation. The results also confirm the existence of a close correlation between corn yield and leaf surface area of plants. The obtained dependence is described by a linear equation of the form y = 0,6227x – 14,133, and the coefficient of determination is R2 = 0,98.

Effects of straw returning combined with nitrogen fertilizer on spring maize yield and soil physicochemical properties under drip irrigation condition in Yellow River pumping irrigation area, Ningxia, China

Soil compaction and nutrient deficiency are common problems in Ningxia Yellow River pumping irrigation area, which adversely affect crop yield. A two-year (2017-2018) field experiment of straw returning combined with nitrogen fertilizer were designed. Four nitrogen application levels (pure N with 0, 150, 300 and 450 kg·hm-2) were set under the condition of full smashing of maize straw (12000 kg·hm-2) returning, with the conventional nitrogen application (pure N with 225 kg·hm-2) without straw returning as the control (CK) to investigate the effects of straw returning combined with different amounts of nitrogen fertilizer on soil physical and chemical properties and maize yield under drip irrigation condition. The results showed that, compared with no-straw returning treatment, the treatments of straw returning combined nitrogen fertilizer with 300 and 450 kg·hm-2 reduced soil bulk density (0-20 cm) by 3.3% and 5.4%, but increased soil porosity by 3.7% and 7.1%, respectively. Straw returning combined with nitrogen with 300 kg·hm-2 and 450 kg·hm-2 was the best treatment which increased soil organic matter content, available K, P, alkaline N and total N in 0-40 cm soil layer. Compared with the non-returning treatment, straw returning combined with nitrogen fertilizer 300 kg·hm-2 significantly increased soil water storage by 13.6% and 22.1%, increased maize yield by 31.1% and 46.0 % in 2017 and 2018, respectively. The analysis of yield components showed that the high maize yield was achieved mainly by increasing grain number and the100-grain weight. Curve fitting showed that the optimum amount of nitrogen fertilizer was 260 kg·hm-2. Our results provide important basis for soil fertility improvement and sustainable production.

Simulation of Water and Salt Transport in Soil under Pipe Drainage and Drip Irrigation Conditions in Xinjiang

With the popularization and development of drip irrigation under film, the problem of secondary soil salinization in Xinjiang is becoming more and more serious. To explore water and salt transport in drip irrigation under mulch and drainpipe drainage, drainage tests of drainage ditches in saline-alkali soil in the Xinjiang 112 group were used to monitor soil salinity changes by controlling field irrigation. Then, a HYDRUS (PC-Progress, Prague, Czech Republic) numerical model was used to simulate and analyze the changes in salinity during cotton growth and the autumn salt return stage in saline-alkali soil under drainage conditions. The agreement between the simulated and measured values was high, and the model parameters were reliable. During the growth period of cotton, the salinity continued to decrease, and the salt began to return after the harvest. Compared with before planting, in the 0–80 cm soil layer, the average desalinization rate reached 43.52% under the mulching films, and the average desalinization rate reached 13.83% under and between the mulching films. After the cotton was harvested, salt returned to the upper layer of soil. However, it still showed a decrease compared with the level before sowing. The average salt content of 0–80 cm soil decreased by 5.14%, and the average salt content of 0–200 cm decreased by 2.60%. This shows that the total salt content in soil will continue to decrease after long-term use of drip irrigation and underground pipe drainage.

Effects of Irrigation on the Selective Transport of Na+ and K+ in Corn

Due to its special climate and geological reasons, Tianjin Binhai area has formed a large area of saline-alkali land. It is of great significance to explore the distribution of salt ions in crops under drip irrigation conditions. In this paper, maize was used as the research object, and different irrigation amount treatment was set up to study the distribution of Na+ and K+ in corn under drip irrigation conditions, and the transport selectivity of corn to Na+ and K+ was analyzed. The results show that the Na+ absorbed by corn is mainly distributed in roots and K+ is mainly distributed in stems and leaves; the transport selectivity coefficient decreases with the increase of irrigation amount, and the increase of Na+/K+ value is the improvement of salt tolerance of corn when irrigation amount is small. Corn can inhibit the transport of Na+ to the ground by enhancing the transport of K+ and reduce the damage to corn.

A novel compost alleviate drought stress for sugar beet production grown in Cd-contaminated saline soil

Supplying novel compost [70:30 w/w sugarcane bagasse and animal blood used as composting raw materials] under deficit drip irrigation conditions could be a practical solution to avoid the detrimental effects of irrigation shortage on sugar beet grown in cadmium (Cd)-contaminated salty soil. In this regard, two experiments were conducted in open field during 2016/17 and 2017/18 at El Fayoum region, Egypt. Three novel compost (NC) rates (0, 10 and 20 t ha−1) were supplied as a soil amendment combined with three irrigation levels [100, 80 and 60% of crop evapotranspiration (ETc)]. The NC improved soil properties and reduced leaves and roots Cd uptake. Sugar beet yield, quality, and irrigation use efficiency (IUE) were positively affected by irrigation regime and by NC rates. Leaf area, dry matter, relative water content (RWC%), chlorophyll fluorescence, chlorophyll content (SPAD), harvest index (HI) and membrane stability index (MSI%), were also positively affected by irrigation quantity and by NC rates. The highest yields [root yield (97.2, t ha−1), biomass yield (32.3, t ha−1) and white sugar (15.2 t ha−1) were recorded under fully irrigated and 20 t ha−1 of NC. Novel compost of 20 t ha−1and 10 t ha−1 significantly (p ≤ 0.05), in particular, increased root yield by 53.49 and 15.93% compared to control. The results revealed that the detrimental impacts of drought stress can be greatly reduced by using NC as a soil amendment for sugar beet production. The results also revealed Combining deficit irrigation and NC maximized crop water productivity.

Assessment of AquaCrop model in simulating maize canopy cover, soil-water, evapotranspiration, yield, and water productivity for different planting dates and densities under irrigated and rainfed conditions

A well-tested crop model can be an important tool in assessment of different crop management scenarios to improve crop yield and water productivity. In this study, the FAO AquaCrop model was evaluated for predicting maize (Zea mays L.) canopy cover (CC), available soil-water (ASW), grain yield, crop evapotranspiration (ETc), and water use efficiency (WUE) when grown at three different planting dates and densities under rainfed and subsurface drip-irrigated conditions in Nebraska, USA. The model adequately simulated CC in 2011 with root mean squared error (RMSE) and model efficiency (EF) in the range of 5.3 to 12.7% and 0.42 to 0.94, respectively; while in drier 2012, CC was substantially under-predicted with higher RMSE of 24.4%. ASW was consistently underestimated in both years with negative EF value for most treatments in 2011, while in 2012, this trend was more pronounced in irrigated treatments, especially during mid-season. ETc estimates were marginal with prediction error of up to 15% in 2011 and 18% in 2012, and overall RMSE of 35 mm for both years. Simulated grain yield was acceptable in 2011 with deviations from measured data up to 8% while in 2012, the deviations were much higher up to 40% for rainfed treatments with overestimations in both years. The errors in ETc and yield simulations are considered high, especially when considering the model application in water-limiting or/and rainfed conditions, and low-yielding areas in which these errors can be a substantial portion of the total yields produced and in seasonal total ETc from production fields and can cause challenges for growers and decision-makers. The overestimation of yield and underestimation of ETc resulted in overestimation of WUE, producing inconsistent estimates in both years. Detailed analyses of model performance and potential reasons for the discrepancies and areas that require improvements in the model are presented.

Effects of organic wastes on structural characterizations of fulvic acid in semiarid soil under plastic mulched drip irrigation

Poor soil has restricted the crop production in semiarid soil. Fulvic acid (FA) is considered to play an significant role in soil fertility. The amount and structure of FA after application of different organic wastes (OWs) was assessed in this work. Six treatments were involved in this experiment: chemical fertilizer combined with chicken manure (CM), sheep manure (SM), maize straw (MS), fodder grass (FG), and tree leaves (TL), while chemical fertilizer only was used as control (CK). The soil FA content (P < 0.05) after the application of TL was the highest than other OWs. The E4/E6 ratios, ΔlogK values, aliphatic C/aromatic C ratios of soil FA after the application of TL were the lowest than other OWs, whereas the C/H ratio was the highest. The specific fluorescence intensities (SFI) of peak A (Ex/Em 260–265/415-430 nm) and peak B (Ex/Em 310–315/415-430 nm) from EEM fluorescence spectrum of FA were the lowest after the application of TL. In conclusion, the application of TL was the most effective for improving FA accumulation, and making FA complex and stability. Thus, TL is the recommended OW for use in semiarid soil under plastic mulched drip irrigation conditions.

EFFECTS OF DIFFERENT WATER CONDITIONS ON RICE GROWTH AT THE SEEDLING STAGE

ABSTRACT Water scarcity has led to the adoption of water-saving irrigation technology around the world. Drip-irrigation has been used for rice (Oryza sativa L.) cultivation in Xinjiang, China. Researchers reported 12.0 t/ha yield; however, drip-irrigated rice produces around 6-8 t/ha in practice, and it is clear that water deficiency explains this gap. Therefore, the objective of this experiment was to compare the growth, photosynthetic characteristics, and antioxidant activity of rice grown in nutrient solutions with water potentials of 0.00, -0.02, -0.05, and -0.09 MPa [0, 2.5, 5.0, and 7.5% polyethylene glycol (PEG), respectively], to determine the optimal water conditions for drip-irrigated rice. There was no significant difference between the 0, 2.5, and 5.0% PEG treatments for relative growth rate and relative water content after 10 and 20 days. However, 2.5 and 5.0% PEG treatments substantially affected the photosynthetic capacity and antioxidant enzyme activity after 10 and 20 days. Treatment with 7.5% PEG inhibited shoot growth. There was a significant reduction in antioxidant enzyme activity. Water-saving rice cultivation, such as drip-irrigated rice, suffered mild drought stress at -0.02 to -0.05 Mpa, but this did not inhibit growth. The amount of irrigation should be increased to obtain higher rice yields under drip-irrigation conditions.

Response of different cotton cultivars to water stress on water-yield relations under drip irrigation conditions in Aydın Plain

Bu çalışma, kısıntılı sulamanın Carisma (V1), Candia (V2) ve Gloria (V3)pamuk çeşitlerinde su-verim ilişkileri üzerine etkilerini belirlemek amacıyla 2018 yılında, Aydın Ovası koşullarında yürütülmüş olan denemede üç tekerrürlü iki faktörlü tesadüf blokları deneme deseni kullanılmıştır. Denemede 8 gün aralığında A Sınıfı Buharlaşma Kabı’ndan oluşan toplam buharlaşmanın %100, %67, %33 ve %0’ı damla sulama yöntemiyle uygulanmıştır. Uygulanan sulamalar pamuk kütlü verimini önemli düzeyde etkilemiştir Çeşitlere göre pamukta mevsimlik bitki su tüketimi 206-826 mm arasında değişmiştir. Ortalama pamuk kütlü verimi ise 187-630 kg da-1 arasında bulunmuştur. Ortalama pamuk kütlü verimi su kısıntısı uygulanmayan S1 (Carisma-V1) konusundan 630 kg da-1 olarak sağlanmıştır. Kütlü verimi açısından Carisma (V1) çeşidi Candia (V2) ve Gloria (V3)çeşidinden daha yüksek verim vermiştir. Ortalama su kullanım randımanı (WUE) değerleri 0.735-1.134 kg m-3 arasında değişmiştir. Verim tepki etmeni (ky) sırasıyla 0.75 (Carisma-V1) ve 0.80 (Candia-V2) ve 0.78 (Gloria-V3) olarak belirlenmiştir. Sonuç olarak, su kaynağının sınırlı olmadığı koşullarda Carisma (V1) çeşidinde sulama suyunun tam uygulandığı S1 konusunun en iyi sulama konusu olduğu söylenebilir. Su kaynaklarının yetersiz olduğu şartlarda ise %67 düzeyinde su uygulanan S2 konusunun (Carisma-V1), verim ve WUE açısından uygun olacağı sonucuna varılabilir.

Substantiation in Selection of Precursors to Rice in Drip Irrigation Conditions on Light Chestnut Soils of the Volga Upland

Study results of the All-Russia Research Institute of Irrigated Agriculture obtained in 2014–2016 in conditions of the southern slope of the Volga Upland are presented. The possibility of rice cultivation with innovative water-saving technology on general-purpose irrigation systems, including a different set of agricultural crops as precursors in other crop rotations, has been determined. To assess the preferences of different rice precursors, we selected soybean, a legume culture, potato, a row crop, and a narrow-crop rice. Studies have shown that, despite small time differences, rice crops after all precursors completed the vegetation period and formed a yield close to the planned one without negative impact on soil, phytosanitary condition, and growth and development of rice. All this makes it possible to recommend them to be used as rice precursors in rice crop rotations on general-purpose irrigation systems with periodic irrigation in the following order: soybean → potatoes → rice.

Sap flow of a wild cherry tree plantation growing under Mediterranean conditions: Assessing the role of environmental conditions on canopy conductance and the effect of branch pruning on water productivity

In recent decades, wild cherry has been one of the species most widely used for reforestation in Europe. Studies aiming to select and improve trees to give them the best growth rates and wood properties have increased in response to growers’ demands. However, information relating to key physiological processes such as transpiration or stomatal conductance and to the effect of the common practice of pruning on plant–water relations is scarce. The main objective of this study was to assess the effects of environmental conditions on canopy conductance dynamics. Its secondary objective was to examine the short- and medium-term effects of branch pruning on tree transpiration, growth and derived water productivity. To this end, we measured sap flow in an experimental plantation where trees were subjected to drip irrigation and rain-fed conditions and where variables characterizing climate, soil and tree growth were also monitored. The results demonstrated that the Jarvis–Stewart approach was appropriate for studying the responses of canopy conductance to environmental factors. As well as the role of vapour pressure deficit and net radiation in controlling the daily variations of canopy conductance, the single effects of decreasing soil water content (optimum relative extractable water, REW, higher than 0.4) and increasing air temperature (optimum of 21 °C), as summer conditions approached, were correctly incorporated into the modelling exercise. Soil water content exerted the greatest control on canopy conductance for trees growing under rain-fed conditions, while air temperature did for irrigated trees. Pruning significantly reduced transpiration to about 35% when pre- and post-sub-periods were compared, but also affected annual water productivity regardless of the irrigation treatment. To assess the long-term effects of pruning on water productivity, measurements in both pruned and unpruned trees would be desirable.

Effects of poly-γ-glutamic acid on water use efficiency, cotton yield, and fiber quality in the sandy soil of southern Xinjiang, China

Poly-γ-glutamic acid (γ-PGA) is a promising, environmentally friendly, non-toxic, biodegradable, and super water-absorbable polymer. Using γ-PGA in agriculture is of great significance to promote crop growth, save irrigation water, and cope with water scarcity problems. The objectives of this study were to investigate the effects of application of different γ-PGA amounts on soil water storage, cotton growth, water use efficiency (WUE), cotton yield, and fiber quality under plastic mulched drip irrigation conditions. A 2-year potted experiment in a cotton field were conducted in the sandy soil of southern Xinjiang, China. Five different amounts of γ-PGA consisted of 0 kg ha−1 (P0), 20 kg ha−1 (P20), 40 kg ha−1 (P40), 80 kg ha−1 (P80), and 160 kg ha−1 (P160) were applied to these potted plots. All treatments were arranged in a randomized block designed with three replicates. The result showed that using γ-PGA significantly increased soil water storage and soil profile water content in the 0–40 cm soil layers compared to P0. γ-PGA significantly increased cotton stem diameter, boll numbers per plant, plant height, and leaf area index compared to the P0. Furthermore, cotton yield was significantly increased as well as WUE and fiber length; however, no influence was found on the fiber quality of cotton. Quadratic relationships were found between the different amount of γ-PGA applied and WUE and between the different applied amounts of γ-PGA and seed cotton yield. High WUE (7.48–8.19 kg ha−1 mm−1) and cotton yield (4376–4682.5 kg ha−1) were obtained under the P80 treatment. The study suggested that γ-PGA improved soil water-holding capacity, promoted cotton growth, and enhanced WUE and cotton yield. Therefore, these results recommend using γ-PGA at a dose of 80 kg ha−1 for dealing with drought conditions in the sandy soil of southern Xinjiang, China.

Local moisture zones profile of subdrip soil space

The defining indicator of drip irrigation quality is soil moistening area (zone) formed in the sub-drip soil space; its shape and parameters should correspond to the biological needs of cultivated plants. The task of determining the boundary moisture contours profile and the inner contour distribution of isopleths with a certain level of soil moisture still remains unresolved due to the multifactorial influence of the environment and drip irrigation conditions on the formation of geometric parameters and humidity characteristics of the moistened subdrip space. The systematically accumulated base of experimental material for the study of single soil moisture contours and inner contour distribution of moisture isopleths allows to obtain an equation describing the bounding lines outline, and the affinity of the location of soil moisture isopleths allowing to construct the profile of "isopleth" dissimilar moisture contours located within the area of soil space moistening .The obtained experimental equation describing the outline of wetting zones of subdrip soil space allows not only to predict and determine the profile of drip moisture contours, their geometric parameters and moisture characteristics, but also to control their formation in accordance with the biological features and needs of agricultural crops cultivated under drip irrigation with corresponding increase of their productivity. &nbsp; &nbsp

Effects of Biochar Application and Irrigation Methods on Soil Temperature in Farmland

Soil temperature plays a vital role in determining crop yield. Excessive irrigation may result in low soil temperature and a waste of water resources. In this paper, field experiments were carried out to evaluate the influence of irrigation methods and biochar application on soil temperature. The experiment included six treatments: (a) YB: biochar application in border irrigation with Yellow River water; (b) GB: biochar application in border irrigation with groundwater; (c) DB: biochar application in drip irrigation with groundwater; (d) Y(CK): border irrigation with Yellow River water; (e) G(CK): border irrigation with groundwater; (f) D(CK): drip irrigation with groundwater. The results are as follows: coupling drip irrigation and biochar, soil temperature increased by 1.20–3.87%. In the biochar application in border irrigation with Yellow River water and groundwater, soil temperature increased by 0.80–2.40% and 1.01–5.15%, respectively. Biochar is a medium for reducing the heat exchange of soil and atmosphere, as it hinders bi-directional heat movement. This mechanism was especially apparent at a 0–10 cm soil depth in the treatments of border irrigation using Yellow River water and groundwater. Biochar may help stabilize the fluctuation of soil temperature and improve the soil accumulated temperature. The effect of drip irrigation at 5–10 cm depth, border irrigation using the groundwater and the Yellow River water was great on soil temperatures above the 10 cm level but less on deep soil temperatures. After applying biochar to soil, the soil temperature was more sensitive to external temperature changes, such as air temperature and water temperature. Therefore, in the Hetao irrigation area, applying a proper amount of biochar to farmland soil was shown to improve the water and heat environment and improve the effectiveness of traditional border irrigation in synchronizing water and heat, especially under the drip irrigation condition. The results here suggest that using biochar under drip irrigation can promote growth and increase yield.

Combining Electrical Resistivity Tomography and Satellite Images for Improving Evapotranspiration Estimates of Citrus Orchards

An adjusted satellite-based model was proposed with the aim of improving spatially distributed evapotranspiration (ET) estimates under plant water stress conditions. Remote sensing data and near surface geophysics information, using electrical resistivity tomography (ERT), were used in a revised version of the original dual crop coefficient (Kc) FAO-56 approach. Sentinel 2-A imagery were used to compute vegetation indices (VIs) required for spatially estimating ET. The potentiality of the ERT technique was exploited for tracking the soil wetting distribution patterns during and after irrigation phases. The ERT-derived information helped to accurately estimate the wet exposed fraction (few) and therefore the water evaporated from the soil surface into the dual Kc FAO-56 approach. Results, validated by site-specific ET measurements (ETEC) obtained using the eddy covariance (EC) technique, showed that ERT-adjusted ET estimates (ETERT) were considerably reduced (15%) when compared with the original dual Kc FAO-56 approach (ETFAO), soil evaporation overestimation being the main reason for these discrepancies. Nevertheless, ETFAO and ETERT showed overestimations of 64% and 40% compared to ETEC. This is because both approaches determine ET under standard conditions without water limitation, whereas EC is able to determine ET even under soil water deficit conditions. From the comparison between ETEC and ETERT, the water stress coefficient was experimentally derived, reaching a mean value for the irrigation season of 0.74. The obtained results highlight how new technologies for soil water status monitoring can be incorporated for improving ET estimations, particularly under drip irrigation conditions.

Using irrigation intervals to optimize water-use efficiency and maize yield in Xinjiang, northwest China

Worldwide, scarce water resources and substantial food demands require efficient water use and high yield. This study investigated whether irrigation frequency can be used to adjust soil moisture to increase grain yield and water use efficiency (WUE) of high-yield maize under conditions of mulching and drip irrigation. A field experiment was conducted using three irrigation intervals in 2016: 6, 9, and 12 days (labeled D6, D9, and D12) and five irrigation intervals in 2017: 3, 6, 9, 12, and 15 days (D3, D6, D9, D12, and D15). In Xinjiang, an optimal irrigation quota is 540 mm for high-yield maize. The D3, D6, D9, D12, and D15 irrigation intervals gave grain yields of 19.7, 19.1–21.0, 18.8–20.0, 18.2–19.2, and 17.2 Mg ha−1 and a WUE of 2.48, 2.53–2.80, 2.47–2.63, 2.34–2.45, and 2.08 kg m−3, respectively. Treatment D6 led to the highest soil water storage, but evapotranspiration and soil-water evaporation were lower than other treatments. These results show that irrigation interval D6 can help maintain a favorable soil-moisture environment in the upper-60-cm soil layer, reduce soil-water evaporation and evapotranspiration, and produce the highest yield and WUE. In this arid region and in other regions with similar soil and climate conditions, a similar irrigation interval would thus be beneficial for adjusting soil moisture to increase maize yield and WUE under conditions of mulching and drip irrigation.

Leaf area index of sweet corn (Zea mays ssp. saccharata L.) crops depending on cultivation technology in the drip-irrigated conditions of the south of Ukraine

The paper presents the results of the study dedicated to the investigation of sweet corn leaf apparatus growth and development in dependence to the crop cultivation technology elements, viz. depth of plowing, mineral fertilizers application doses, plants density, in the drip-irrigated conditions of the South of Ukraine. The field trials were carried out during three years (2014-2016) by using the split-plot design method in four replications with accordance to the modern requirements of the experimental work in agronomy. The results of the study showed the significant effect of all the studied agro technological treatments on the crop leaf apparatus. The highest Leaf Area Index (LAI) that averaged to 3.72 was obtained under moldboard plowing at the depth of 20-22 cm, fertilization with N120P120, and plants density of 80000 ha-1. The total amplitude of fluctuation of LAI averaged to 2.42. Increased plowing depth improved LAI of sweet corn only under the non-fertilized conditions, however, increased fertilizers doses and thickening of the crops positively affected the studied bio-metric index.

Monitoring of soil moisture and irrigation forecast under the condition of drip irrigation in greenhouse

The accurate prediction of the soil moisture in greenhouse can improve the accuracy of irrigation forecast, thus saving water and increasing production. In this paper, the monitoring data were obtained from the greenhouse in Agricultural Demonstration Park of Northland Spring, Wuqing District, Tianjin. The soil moisture was predicted based on the GM (1,1) model, and the effect of water-saving and increased production was tested with the results of the economic irrigation research in the same area. The results show that the GM (1,1) model has a higher accuracy of soil moisture prediction. The correlation coefficient (R2) of the predicted value and the measured value is higher than 0.9; the small error probability P is 1; the mean relative prediction errors are all less than 0.1. Therefore, the GM (1,1) model can be used to predict soil moisture content.