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Freshwater alternatives to irrigate crops are in dire need of time because of changing climate and scarcity of freshwater. Therefore, seawater can be the best feasible option as it is abundantly available on Earth. Sole application of seawater for agricultural crops is impossible, but the blend with freshwater may not be aggravating the salinization problems in soils. The present investigation was conducted to evaluate the possibility of growing the short period summer vegetables i.e., eggplants, tomato, and pepper with fresh and seawater blends viz. 5%, 10% and 20%, termed as A, B and C treatments, respectively. During the experiment, we considered: (i) crop growth, biomass yield, water consumption, water use efficiency (WUE) and water productivity (WP), (ii) photosynthetic pigments and gas exchange parameters, (iii) concentration of mineral contents and quality traits, (iv) lipid peroxidation, proline contents and ascorbic acid. Tomato productivity was markedly decreased by application of B and C treatments, whereas the growth of eggplant and pepper were not much influenced at the same concentrations. Water consumption dropped, whereas WUE significantly increased in all tested crops upon increasing seawater concentrations. Leaf Na+ concentration and other mineral elements increased. These results assumed that certain concentrations of seawater–freshwater blends revealed that there were no significant effects on the quality characteristics, mineral elements concentration and productivity of eggplant and pepper plants, however, tomato plants indicated sensitivity at the three seawater concentrations (A, B and C SFW treatments). Moreover, low concentrations of salinity stress (5% and 10% SFW) seemed to be necessary to attain better crop nutrition and organoleptic values. Accordingly, the results of present will be helpful to coastline farmers in cultivating vegetables and produce nutritive food for their family.

Background The combination of mulch with N fertilizer application is a common agronomic technique used in the production of rainfed maize (Zea mays L.) to achieve higher yields under conditions of optimum planting density and adequate N supply. However, the combined effects of mulch, planting density, and N fertilizer application rate on plant N uptake and N translocation efficiency are not known. The objective of this study was to quantify the interaction effect of mulch, planting density, and N fertilizer application rate on maize grain yield, N uptake, N translocation, and N translocation efficiency. The experiment was arranged in a randomized complete block design with three factors (2 mulch levels × 2 planting densities × 4 N fertilizer application rates) replicated four times. Results There was a significant interaction among mulch, plant density, and N fertilizer on maize grain yield, kernel number per cob, N uptake, N translocation, and N translocation efficiency. Averaged over the 3 years of the study, total plant N uptake at silking ranged from 79 to 149 kg N ha− 1 with no mulch and from 76 to 178 kg N ha− 1 with mulch. The N uptake at silking in different plant organs ranked as leaf > grain > stem > cob. Averaged across all factors, the highest N translocation was observed in leaves, which was 59.4 and 88.7% higher than observed in stems and ears, respectively. The mean vegetative organ N translocation efficiency averaged over mulch, planting density, and N fertilizer application rate treatments decreased in the order of leaf > stem > cob. Conclusions Mulch, planting density, and N fertilizer application rate not only have significant effects on improving maize grain yield and NUE, but also on N uptake, N translocation, and N translocation efficiency. Our results showed clearly that under high planting density, the combination of mulch and moderate N fertilizer application rate was the optimal strategy for increasing maize grain yield and N use efficiency.

Enhancing agricultural productivity with the minimum possible cost to the environment is crucial for sustainable agriculture development. The effective management of K fertilizer would reduce the pollution risk of fertilizer residue. The data from the 29 experimental sites for rice in Liaoning province were used to determine the effect of different K fertilizer management in increasing yield, K uptake, and potassium fertilizer contribution rates (FCRK) for rice. The relationship among rice yield, biomass accumulation and plant K uptake, and recommended reasonable K fertilizer application rates in different inherent soil productivity levels were evaluated. The four treatments comprised no K fertilizer (K0), K fertilizer application of 60kg ha-1 (K60), 120kg ha-1 (K120), and 180kg ha-1 (K180). The K120 treatment showed a significant yield increase (16.59%) compared to the K0 treatment in this study. The average K uptake of grain in the K60, K120 and K180 treatments was 23.1, 24.8 and 24.9 kg ha-1, which was significantly higher by 12.67%, 20.77%, and 21.48% compared to the K0 treatment. The average K uptake of grain, straw and plant was highest in K180 (134.8 kg ha-1), followed by the K120 and K60. Additionally, the correlation between grain yield, biomass accumulation (y) and plant K uptake (x) showed a significant positive polynomial function. The equation was y = &minus, 0.406x2 + 110.43x + 639.3 and y = &minus, 0.237x2 + 135.3x + 3796.2, respectively. The FCRK followed the sequence as K180 &lt, K60 &lt, K120. Furthermore, the recommended K application rates in the 29 experimental sites were ranged from 92.8 to 134.5 kg ha-1, and the corresponding theoretical yield of recommended K rate were ranged from 7371.5 to 11144.5, and with an average of 9297.5 kg ha-1. Remarkably, the average recommended K rate in the four inherent soil productivity levels was 116.1, 111.2, 112.2 and 111.7 kg ha-1 and the corresponding average theoretical yield was 9966.1 kg ha-1, 10158.8 kg ha-1, 8373.2 kg ha-1 and 8881.9 kg ha-1. The results of this study suggest that different inherent soil productivity levels have different K application rates and yield performance. This result somewhat strengthens the finding of this study that moderate K application is conducive to effectively improving the yield and to the enhancement of agricultural productivity, which is conducive to the sustainable environment.

The balance between fertilizer application and plant nutrient demand is essential for ensuring agricultural production because it is effective to prevent nutrient deficiency and excess, especially for soybean. This study used data from 29 sites of field experiments carried out in the soybean planting area of Liaoning province, China in 2011 to 2013. We (i) study the characteristics of yield, nutrient concentration, and harvest index to (ii) valuate the balanced nutrient uptake at different potential yield levels for soybean. The grain yield ranged from 804 to 4484 kg/ha, and average N, P, and K concentrations in grains were 45.7, 5.0, and 10.1 g/kg, respectively, while those in straw were 14.1, 1.8, and 6.7 g/kg, respectively. Average harvest index values of N, P, and K were 0.69, 0.65, and 0.52 kg/kg, respectively, while approximately 69% N and 65% P of the plant were stored in soybean grain, and 48% K was stored in straw. The two boundary lines of the QUEFTS (quantitative evaluation of the fertility of tropical soils) model were aN = 10.5, dN = 20.6, aP = 65.6, dP = 289.6, aK = 30.4, and dK = 162.7 as model parameters. The QUEFTS model estimated the balanced nutrient uptake with yield targets increased following a linear&ndash, parabolic&ndash, plateau curve. A continual linear increase in grain yield with 65.5 kg N, 7.0 kg P, and 13.9 kg K was required to produce 1000 kg grain, until the yield target reached approximately 60&ndash, 70% of the potential yield, and the corresponding ratio of N, P, and K was 9.35:1:1.8. Results could be used to estimate balanced nutrient uptake to prevent excessive fertilizer being applied and reduce environment risk for ensuring sustainable agricultural development.

Grain quality improvement is a key target for rice breeders, along with yield. It is a multigenic trait that is simultaneously influenced by many factors. Over the past few decades, breeding for semi-dwarf cultivars and hybrids has significantly contributed to the attainment of high yield demands but reduced grain quality, which thus needs the attention of researchers. The availability of rice genome sequences has facilitated gene discovery, targeted mutagenesis, and revealed functional aspects of rice grain quality attributes. Some success has been achieved through the application of molecular markers to understand the genetic mechanisms for better rice grain quality; however, researchers have opted for novel strategies. Genomic alteration employing genome editing technologies (GETs) like clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) for reverse genetics has opened new avenues of research in the life sciences, including for rice grain quality improvement. Currently, CRISPR/Cas9 technology is widely used by researchers for genome editing to achieve the desired biological objectives, because of its simple targeting. Over the past few years many genes that are related to various aspects of rice grain quality have been successfully edited via CRISPR/Cas9 technology. Interestingly, studies on functional genomics at larger scales have become possible because of the availability of GETs. In this review, we discuss the progress made in rice by employing the CRISPR/Cas9 editing system and its eminent applications. We also elaborate possible future avenues of research with this system, and our understanding regarding the biological mechanism of rice grain quality improvement.

The demand for food is expected to significantly increase with continued population growth over the next 50 years, indicating that agricultural efficiency should be simultaneously stabilized and enhanced. Here, we discuss the effects of mulching and nitrogen (N) fertilizer on the soil environment and crop yield to inform food security. The use of mulch in agriculture provides many benefits to the soil by reducing evaporation, improving temperatures, adjusting the microbial biomass, maintaining the soil organic carbon balance, increasing nutrient cycling, promoting soil enzyme activity, enhancing soil aggregate stability and suppressing weed infestation. Nitrogen fertilization can markedly improve soil fertility and crop yield. However, nitrogen use efficiency (NUE) and the environment may be negatively affected by the improper application of N fertilizers. The improvement of NUE has been an important focus in field management for the more sustainable use of valuable N fertilizers. A better understanding of the interaction between N and mulch may improve NUE and crop yields. Inorganic mulches more efficiently alter the soil environment to enhance the NUE and crop yield, while organic mulching materials are more environmentally friendly and inexpensive. The selection of appropriate mulching materials should be combined with effective N management strategies, crop species, crop management practices and climatic conditions. In the future, precise nitrogen fertilizer management on farms and the development of relatively high-NUE and high-yielding crops will be highly feasible.

The WRKY genes are one of the largest families of transcription factors (TFs) and play a crucial role in certain processes in plants including stress signaling, regulation of transcriptional reprogramming associated with stress responses, and other regulatory networks. This study aims to investigate the WRKY gene family in the C3 model plant, Oryza sativa L., using a genome-wide in silico expression analysis. Firstly, 104 WRKY TF family members were identified, and then their molecular properties and expression signatures were analyzed systematically. In silico spatio-temporal and hormonal expression profiling revealed the roles of OsWRKY genes and their dynamism in diverse developmental tissues and hormones, respectively. Comparative mapping between OsWRKY genes and their synteny with C4 panicoid genomes showed the evolutionary insights of the WRKY TF family. Interactions of OsWRKY coding gene sequences represented the complexity of abiotic stress (AbS) and their molecular cross-talks. The expression signature of 26 novel candidate genes in response to stresses exhibited the putative involvement of individual and combined AbS (CAbS) responses. These novel findings unravel the in-depth insights into OsWRKY TF genes and delineate the plant developmental metabolisms and their functional regulations in individual and CAbS conditions.

Weeds pose a great threat to crop production subsequently distressing the equilibrium of agro-ecological systems globally. Instead of relying on chemical weed control, there is a dire need to explore alternative eco-friendly agricultural practices for weed suppression and sustainable wheat production. Mulching being eco-friendly could potentially serve the purpose towards weed suppression organically. To check the usefulness of mulching, two-year studies were conducted under field conditions in Haripur, Pakistan, during 2014 and 2015 to elucidate the response of various mulching materials for weed control in wheat. Six mulch material treatments were used along with Buctril super (used as check) at the rate of 1.235 L ha−1 to control the most problematic weed species of wheat in Pakistan. Experiments were designed under randomized complete block design with four repeats. The analysis of data revealed a significant decrease in weed density, relative weed density, fresh and dry plant biomass at 25, 50 and 75 days after sowing (DAS) where Buctril super at 1.235 L ha−1 and mulch of black plastic were used followed by sugarcane bagasse and dry leaves of mulberry, as compared with control (untreated). Higher density of weed, relative weed density, fresh and dry plant biomass were observed in test weed species of wheat where lentil was applied with wheat and dry leaves of mulberry were incorporated. Net economic benefits in the form of benefit cost ratio (2.55) were higher where grass clippings were applied followed by sugarcane bagasse (2.43), mulberry leaves (2.49), while the lowest net economic benefits (1.72) were obtained when lentil (grown as live mulch crop) with wheat was intercropped. It was concluded from the study that sugarcane bagasse and grass clippings could be a source to control weeds in the wheat with a minimum cost of production at Haripur, Pakistan, and similar agro-climatic environment.

Zinc (Zn) is critical for the activity of many enzymes including involved photosynthetic CO2 fixation and indirectly involved in the production of growth hormones and internode elongation in crop plants. In this regard, a field experiment was conducted to investigate the comparative effectiveness of the Zn blended, Zn coated and bio-activated Zn coated urea on the growth, physiological, yield, and quality of wheat. Three types of urea were prepared including bio-activated Zn coated, Zn coated and Zn blended urea. The bio-activated Zn coated urea was prepared by inoculating the powdered organic material with Zn solubilizing bacterium (Bacillus sp. AZ6) and then this material was mixed with ZnO. This bioactive Zn was coated on urea at the rate to formulate 1.5% bio-activated Zn coated urea. Moreover, Zn blended urea was prepared by mixing powder ZnO with urea while Zn coated urea with 1.5% Zn was prepared by mixing ZnO and urea under proper moisture conditions to ensure proper coating. In results, growth parameters were significantly increased with the application of bio-activated Zn coated urea as compared to other urea formulations and the control. The same treatment caused the maximum increase in quality parameters like oil contents (55%), protein (30%), and N concentration (30%) as compared to the control. In conclusion, the application of 1.5% bio-activated Zn coated urea was highly effective in enhancing the growth, physiological, yield, and quality parameters of wheat.

Potentially toxic element (PTE) pollution is a major abiotic stress, which reduces plant growth and affects food quality by entering the food chain, and ultimately poses hazards to human health. Currently, the use of slag in PTE-contaminated soils has been reported to reduce PTEs and toxicity in plants. This review highlights the role of slag used as a fertilizer for better crop production and sustainable agricultural development. The application of slag increased the growth, yield, and quality of crops under PTE toxicity. The mechanisms followed by slag are the immobilization of PTEs in the soil, enhancement of soil pH, changes in the redox state of PTEs, and positive changes in soil physicochemical and biological properties under PTE toxicity. Nevertheless, these processes are influenced by the plant species, growth conditions, imposition length of stress, and type of slag used. The current review provides an insight into improving plant tolerance to PTE toxicity by slag-based fertilizer application and highlights the theoretical basis for applying slag in PTE-contaminated environments worldwide.

Soil erosion directly leads to the decline of soil fertility, and under hydraulic erosion, the soil nitrogen and phosphorus released by hydrolysis enter the adjacent water body along with surface runoff and soil erosion. This causes potential hazards such as eutrophication and river siltation in the watershed, seriously affecting the safety of the ecological environment. The mechanism of action of the dynamic factors of erosion on nitrogen (N) and phosphorus (P) loss remains unclear. In this study, a series of laboratory experiments were carried out to characterize the N and P loss and its influencing factors under freeze–thaw conditions. Two treatments (i.e., LC: loess control and FT: freeze–thaw treatment) and five soil water contents on a gravimetric basis (SWCs) (i.e., 10%, 15%, 20%, 25% and 30%) were considered. The results showed that the total runoff was higher under 30% SWC and lower under 20% SWC for the LC and FT treatments. The freeze–thaw action caused higher sediment loss under low water content (10% and 15%). The runoff-associated total nitrogen (RTN), runoff-associated total phosphorus (RTP), and sediment-associated total phosphorus (STP) loss rate showed a larger fluctuation for FT than for LC. Freeze-thaw action not only caused the instability of the N and P loss behavior but also caused increased diversity among individual samples. The soil erodibility, runoff energy and runoff power were important dynamic factors associated with erosion, and the freeze–thaw action had a very large impact on these factors. Under freeze–thaw action, the effect of dynamic factors on phosphorus and nitrogen loss was significantly enhanced. For the LC treatments, the SWC could explain 60% of the variation in RTN loss and 63% of the variation in RTP loss; the runoff explained 90% of the variation in STN loss and the runoff time explained 97% of the variation in STP loss. For the FT treatments, the runoff time explained 63% of the variation in STN loss and 53% of the variation in STP loss. The results enable us to understand further the relationship between dynamic factors of rainfall erosion and nitrogen and phosphorus loss under freeze–thaw conditions.

Rational application of water and fertilizer management practices can not only improve mango (Mangifera indica L.) yield and quality but also improve irrigation water-use efficiency (IWUE). However, few studies have addressed the use of water and fertilizer management practices in hot, dry environments with the aim of achieving relatively favorable levels of these parameters concurrently. We used the technique for order preference by similarity to an ideal solution (TOPSIS) method to identify optimal water and fertilizer management practices that resulted in high fruit yields and high IWUE in Southwest China. A randomized block design study with four irrigation levels [full irrigation throughout the growth period (FI), regulated deficit irrigation during flowering (RDIFS), regulated deficit irrigation during fruit expansion (RDIES), and regulated deficit irrigation at maturity (RDIMS)] and three fertilization levels [FH, a water-soluble compound fertilizer (N:P2O5:K2O = 12:8:40) applied at 129.0 kg ha−1; FM, 103.2 kg ha−1; and FL, 77.4 kg ha−1] was implemented in 2018 and 2019 to investigate these relationships. The net photosynthesis rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) of mango under the different water deficit treatments were significantly lower than those under the FI treatment with the same fertilization conditions, but the instantaneous water-use efficiency (WUEi) of the leaves increased. The fresh fruit yield, solids:acid ratio (SOAR), sugar:acid ratio (SUAR), and IWUE under the RDIFS treatment were significantly lower than those under the FI treatment at the same fertilization rates. Averaged over all fertilization rates, the fruit yield under RDIES was 8.6–22.3% lower than that under FI in both years, but the IWUE significantly increased from 3.7% to 18.6%. Compared with the FI treatment, the RDIMS treatment had no significant effect on fruit yield but significantly increased the IWUE (35.5–44.7%), total sugar (TS) content (3.7–8.5%), and carotenoid content (CC) (1.5–13.1%) in both years. At the same irrigation level, the Pn, Gs and Tr increased with an increasing fertilization rate, while the fruit yield, IWUE, TS, and vitamin C (VC) content of fresh fruit first decreased but then increased with increasing fertilization rate. IWUE was more closely related to photosynthesis characteristics at the flowering stage than at the mature stage, but fruit quality was more closely related to photosynthesis characteristics at the mature stage than at the flowering stage. Compared with the FIFH treatment, the RDIMSFM treatment significantly increased the fruit yield by 10.1% and 6.6% in 2018 and 2019, respectively, and increased the IWUE by 28.1% and 35.6%, respectively. On the basis of the TOPSIS method, the multi-target optimum scheduling of mango was achieved under the RDIMSFM treatment. The identified optimum combination of water and fertilizer can provide a scientific basis for irrigation and fertilization optimization and management in the hot, dry environment of Southwest China.

Reasonable water and fertilizer management technology can improve water use efficiency (WUE), fertilizer use efficiency, potato (Solanum tuberosum L.) tuber yield and quality, but there is little research on water and fertilizer management techniques with these parameters simultaneously reaching a relatively better level. We used principal component analysis (PCA) to evaluate and optimize the water and fertilizer management technology with high potato tuber yield, quality, WUE and water and fertilizer use efficiency in Northwest China. To investigate the effects of irrigation amount, dripper discharge rate, and fertilizer application rate on potato tuber yield and quality, irrigation water use efficiency (IWUE), and partial factor productivity (PFP), an orthogonal experiment with three factors and three levels [irrigation amounts: I1, 100 %ETC (ETC is the crop evapotranspiration), I2, 80 % ETC and I3, 60 % ETC; dripper discharge: D1, 1 L h−1, D2, 2 L h−1 and D3, 3 L h−1; fertilizer (N–P2O5–K2O) rates: N240, 240–120–300 kg ha−1, N180, 180–90–225 kg ha−1 and N120, 120–60–150 kg ha−1] was conducted on potatoes in a sandy loam soil in 2017 and 2018. The potato tuber yield, largest tuber weight, commodity tuber weight, dry matter accumulation, and vitamin C content increased with the increase in the fertilizer application rate and the dripper discharge rate. The content of reducing sugar and PFP decreased with increasing fertilizer rate. On average, across all treatments, the potato tuber yield of N240 was 6.7 % and 23.9 % higher than that of N180 and N120, respectively. On average, across all treatments, the starch content of N240 was 23.8 % and 28.9 % higher than that of N180 and N120, respectively. On average, across all treatments, the vitamin C content of N240 was 39.8 % and 60 % higher than that of N180 and N120, respectively; the vitamin C content at 3 L h–1 was 6.2 % and 7.8 % higher than that at 2 L h–1 and 1 L h–1, respectively. On average, across all treatments, the reducing sugar content of N120 was 13.2 % and 29.9 % higher than that of N180 and N240, respectively. On average, across all treatments, the PFP at 80 % ETC was 19.8 % and 20.3 % higher than that of 60 %ETC and 100 %ETC, respectively; the PFP for 2 L h–1 was 11.3 % and 12.3 % higher than that for 1 L h–1 and 3 L h–1, respectively. Interestingly, the T4 treatment (irrigation amount of 80 %ETC, dripper discharge of 3 L h–1, and fertilizer rate of N180) was twice ranked first after combinational evaluations. In conclusion, the proper application of the T4 (I2D3N180) treatment may be a good compromise for growing potatoes in sandy soil with regard to tuber yield and quality, IWUE, and PFP. The present study sheds light on the contributions of these practices, clarifies their impacts, and provides a basis for evaluating and selecting better management practices for growing potatoes.

Knowledge of diffuse horizontal solar radiation (Rd) on horizontal surfaces is a prerequisite for the design and optimization of active and passive solar energy systems such as the solar illumination system within a building, but it is unavailable in many worldwide locations and commonly predicted by readily available climatic variables. However, reliable prediction of Rd is difficult when lack of complete or previous climatic data at the target station. This study evaluated the performance of support vector machine (SVM) and four tree-based soft computing models, i.e. M5 model tree (M5Tree), random forest (RF), extreme gradient boosting (XGBoost) and gradient boosting with categorical features support (CatBoost), for prediction of daily horizontal Rd when using limited local (Scenario 1) and extrinsic (Scenarios 2 and 3) climatic data. Six input combinations of daily global solar radiation (Rs), sunshine hour (n), maximum/minimum temperature (Tmax/Tmin) and relative humidity (RH) during 1996–2015 at 15 weather stations across various climatic rons of China were considered. The results demonstrated that, when lack of Rs, the average root mean square error (RMSE) was considerably increased across China (42.4%) in Scenario 1, especially in the (sub)tropical monsoon ron (68.3%). SVM offered the best combination of prediction accuracy and generalization capability in all scenarios, followed by CatBoost. CatBoost produced the closest daily Rd estimates to SVM and satisfactory generalization capability. In Scenario 2, CatBoost and SVM models developed with climatic data from Beijing gave the overall best daily Rd estimates over the 15 stations, while models developed with data from 14 weather stations in Scenario 3 produced even better and steadier Rd estimates across China compared with those in Scenario 2. The average computational time of SVM (6.6 s) for a single sample was approximately 1.9 times that of CatBoost (3.5 s) in Scenarios 1 and 2, while the corresponding value (842.6 s) was approximately 33.9 times that of CatBoost (24.9 s) in Scenario 3. Comprehensively considering prediction accuracy, generalization capability and computational efficiency, CatBoost is highly recommended to develop general models for daily Rd prediction in various climatic rons of China, particularly when lack of previous local climatic data.

The glomalin-related soil protein (GRSP) is an important fraction of soil organic carbon (SOC) and soil nitrogen (N), and is important for stabilization of SOC and soil aggregates. However, the effects of natural restoration on the concentration and allocation of GRSP differ for different soil aggregate sizes, and how size further affects SOC and soil N restoration, and stabilization of SOC and soil aggregates is not well understood. Here, we present the first characterization of the distribution of GRSP fractions and soil nutrients in soil aggregates following natural restoration by choosing fields of 0, 7, 12, 17, 22, 32 years after cropland abandonment, and a natural grassland as reference. GRSP concentration increased most in microaggregates after 32 years of natural restoration. The processes of rapid accumulation of GRSP (22 to 32 years) occurred simultaneously with the formation of macroaggregates, reduction of microaggregates, and rapid increase of mean weight diameter (22 to 32-years). The soil aggregate stability and contents of GRSP, SOC, labile carbon, total N and phosphorus in each soil aggregate fraction significantly increased in the late stage of natural restoration (22 to 32 years). The most recalcitrant carbon fraction in microaggregates significantly increased between 7 and 32 years (0.887 g kg−1). Our study suggests that abandoning farmland is effective for the restoration of GRSP, soil nutrients and structure and that microaggregates promote the accumulation of recalcitrant carbon and increase the stability of SOC largely through its ability to retain GRSP.

The construction of terraces and vegetation restoration in the hillslope are major soil and water conservation measures on the Chinese Loess Plateau and contributed to the distribution patterns of soil organic carbon (SOC) and soil total nitrogen (STN). Topography influences soil erosion and changes SOC and STN contents. However, little information is available regarding the effects of ecological construction and topography on SOC and STN. A study was undertaken in the Loess Plateau, to evaluate the effects of land use conversion and topographic factors on the topsoil SOC and STN content at three hillslope positions (upper, middle, and foot slopes) under four land uses types: artificial forest, grassland, terraced fields, and sloping cropland. The results showed that land use conversion from sloping cropland to artificial forest and grassland improved the SOC and STN content. Slope position was an important topographic factor governing the SOC and STN distribution at the slope scale in artificial forest, grassland, and sloping cropland, with the foot slope having the highest SOC and STN content, followed by the upper slope, while the middle slope had the lowest values. SOC and STN showed positive correlation with Caesium-137 (137Cs) content. Land use types, slope position, and soil erosion had significant relationships with SON and STN. The results suggested that vegetation restoration of sloping cropland will contribute to soil carbon (C) and nitrogen (N) sequestration in the loess hilly region. The quantitative estimation of land use change and topography effects on SOC and STN could improve the accuracy of SOC and STN predictions in the region with a complex topography.

Nitrogen (N) fertilizer is known to improve the quality and biomass of vegetables, but it is unclear how to manage the large amount of NO3-N that accumulates in the soil after vegetable harvest. In this study, we examined the influence of irrigation level and irrigation frequency on the growth and soil residual NO3-N of the catch crop mini Chinese cabbage (Brassica pekinensis) in a greenhouse. Using conventional border irrigation with adequate water supply as a control (CK), three irrigation levels (WH: 160% crop evapotranspiration (ETc), WM: 120% ETc and WL: 80% ETc) and three irrigation frequencies (intervals of F2: 2 days, F4: 4 days, and F8: 8 days) were assessed in 2014, 2015 and 2016 in northwest China. The results showed that the weight of the leaves and leaf stalks was the primary determinant of yield, and that these are the primary N-containing vegetative organs of the plants. At the same irrigation level, the total N content of the plants increased in the order F8 &lt, F2 &lt, F4. The trend in the total N content in the mini Chinese cabbage plants among different treatments was synchronized with the yield. The highest total N content in the plants was observed in the WMF4 treatment during all three years. The three-year averages of mini Chinese cabbage aboveground biomass, yield and water use efficiency (WUE) in the WMF4 treatment were 60%, 64.5% and 119.2% higher respectively than in the CK treatment. The residual NO3-N content in the soil in the WMF4 treatment was only 1.3% higher than that in the CK treatment. The total N uptake in the WMF4 treatment was 79.2% higher than that in the CK treatment, and the N loss in the WMF4 treatment was 46.3% lower than that in the CK treatment. Under these experimental conditions, the WMF4 treatment can be recommended as an appropriate irrigation regime for mini Chinese cabbage under fallow greenhouse management in northwest China.

The demand for increased grain production to support population and consumption growth has led to increased interest in field management approaches that incorporate plastic mulching and fertilization management. The purpose of this study was to investigate the effects of plastic mulching and basal nitrogen (N)-fertilizer application depth on N balance estimations, N use efficiency (NUE) and maize yield. The experiment was conducted in 2014 and 2015 with six treatments: no N fertilizer and no mulching (CK), traditional broadcast N fertilizer with mulching (T0), basal N-fertilizer application at a depth of 6 cm with no mulching (T1), basal N-fertilizer application at a depth of 6 cm with plastic mulching (T2), basal N-fertilizer application at a depth of 12 cm with no mulching (T3) and basal N-fertilizer application at a depth of 12 cm with plastic mulching (T4). Mulching and basal N-fertilizer application depth each had significant effects on grain yield, but there were no significant interactions between them. The highest grain yield was observed in the T2 treatment and was 89.1% and 99.8% higher than the grain yield in the CK treatment in 2014 and 2015, respectively. The N uptake in T2 was 21.3% and 25.3% higher than that in the T0 treatment in 2014 and 2015, respectively. Relative to the value in the T0 treatment, the mean N loss over the two years was reduced by 34.6% in T2 and by 39.8% in T4. The basal N-fertilizer application depth of 12 cm yielded an obvious increase in NUE, but a high N residual remained below 50 cm after harvest, indicating the higher potential for N losses. In addition, the field application of this type of fertilizer management would require more labour in the absence of the implementation of mechanization. Based on the results, basal N-fertilizer application a depth of 6 cm without plastic mulching is recommended because it significantly increased grain yield and NUE, reduced N loss and requires no investment in plastic film, which are conducive to food security and environmental conservation.

Nitrogen (N) fertilization potentially affects the amount of N uptake and N translocation (NT) within plants, but the synergetic effects of plastic mulching and N application rates on the grain yield (GY), N uptake and NT of maize have not been studied. A fertilization experiment with six N application rates (0, 80, 160, 240, 350 and 450 kg ha−1) with or without mulch was conducted in 2015 and 2016 in the Loess Plateau of China. There were significant interactions between mulch and the N fertilizer rate on the GY. Under mulch treatments, the highest GY was observed at 450 kg ha−1, which was 53.9%, 36.4%, 20.2%, 1.6% and 0.3% higher than those obtained with N application rates of 0, 80, 160, 240 and 350 kg ha−1, respectively, in 2015. The ranking of NT to grain N accumulation was leaves > sheaths and stems > ear axis > bracts. The NT efficiency (NTE) levels averaged over the different N fertilization rates under the no-mulch treatment were 5.6% and 12.9% higher than those under the plastic mulch treatment in 2015 and 2016, respectively. We conclude that an N fertilizer application rate of 240 kg ha−1 with mulch can achieve a relatively higher NTE, GY, WUE and NUE.

Irrigation and fertilization are key practices for improving the fruit quality and yield of vegetables grown in greenhouses. We carried out an experiment in a solar greenhouse spanning three consecutive growing seasons to evaluate the effects of irrigation and fertilization on the fruit yield and quality, water use efficiency (WUE) and fertilizer partial factor productivity (PFP) of tomatoes. Interactions between irrigation and fertilization treatments and individual factors of irrigation and fertilization significantly (p ET 0 ) and high fertilizer level (F1: 240N−120P2O5−150K2O kg ha−1) was twice ranked first after a combinational evaluation. In conclusion, the proper application of drip fertigation (W2F1) may be a good compromise for solar greenhouse-grown tomatoes with regard to fruit yield and quality, WUE, and PFP. The present study sheds light on the contributions of these practices, clarifies their impacts, and provides a basis for evaluating and selecting better management practices for growing greenhouse vegetables.

The purpose of this study was to investigate the effect of irrigation and nitrogen fertilization on maize growth and yield components. Three irrigation treatments were included, 100, 150, and 200 mm, and three nitrogen levels were applied as follows: high nitrogen was 240 kg ha−1, medium nitrogen was 180 kg ha−1, and low nitrogen was 120 kg ha−1. The results indicated that the interaction of nitrogen and irrigation has no significant effects on maize height, but the signal factor has a significant effect on plant height in the whole growth period. The changing trend of crop growth rate in the whole growth period was increasing first and then falling, and the CK treatment was always lower than other treatments. The maize growth rate was related to the nitrogen fertilizer level, and the positive relationship between nitrogen fertilizer level and growth rate. In single factor of fertilization, there was a negative correlation between units increased in yield and unit nitrogen. The interaction of nitrogen and irrigation has significant effects on biomass yield. The greatest yield-increasing potential was obtained in MF treatment. At the same irrigation level, the grain yield increased and had a most significant correlation relation with the harvest index. The population physiological indices of maize were increased with irrigation amount and fertilizer level, except the harvest index, and the incentive of population physiological indices in irrigation was higher than nitrogen fertilization. Therefore, MFHW treatment may be considered the most efficient for maize production in the rain-fed area of the Loess Plateau, China.

Differences in crop yield between different fields in the same region have existed for a long time. Methods for improving the productivity of low-yield fields are a hot topic in large-scale agriculture. This experiment was carried out in potato planting farmland and at a potato experimental station in the Loess Plateau in China to study the effects of soil moisture and soil nutrients on potato yield potential and yield gap. The relationships between potato yield and soil nutrient factors were analyzed using the grey correlation method. The grey correlation method is a new technique for performing prediction, relational analysis and decision-making in many areas. The results indicate that (1) the high-yield group at the potato experimental station (HE) was 72,678 kg/ha, the mean-yield group at the potato experimental station (ME) was 36,083 kg/ha, the high-yield group in the potato planting farmland (HF) was 34,259 kg/ha, and the mean-yield group in the potato planting farmland (MF) was 19,386 kg/ha. (2) The yield gap (YG1) between HF and MF was 14,873 kg/ha, the yield gap (YG2) between ME and the MF was 16,697 kg/ha, the yield gap (YG3) between HE and the MF was 53291 kg/ha. (3) The effects of soil moisture and nutrients on potato yield were ranked from large to small: soil available potassium content &gt, soil nitrate nitrogen content &gt, soil organic matter content &gt, soil water content &gt, soil available phosphorus content. The results of correlation analysis and grey correlation analysis showed that the available potassium had the strongest correlation with potato tuber yield. (4) The content of nitrate nitrogen was significantly correlated with the content of available potassium and available phosphorus, while the water content was significantly correlated with the content of organic matter. According to the influence of soil moisture and nutrients on the potato tuber yield, it is suggested that integrated water and fertilizer cultivation measures be implemented, and the input of potash fertilizer and nitrogen fertilizer be increased.

Mulching and nitrogen are critical drivers of crop production for smallholders of the Loess Plateau in China. The purpose of this study was to investigate the effect of mulching and nitrogen fertilizer on the soil water content, soil nitrate-N content and vertical distribution in maize root-zone. The experiment was conducted over two consecutive years and used randomly assigned field plots with three replicates. The six treatments consisted of no fertilizer without plastic film (CK), plastic film mulching with no basal fertilizer and no top dressing (MN0), basal fertilizer with no top dressing and no mulching (BN1), plastic film mulching and basal fertilizer with no top dressing (MN1), basal fertilizer and top dressing with no mulching (BN2) and plastic film mulching with basal fertilizer and top dressing (MN2). In the top soil layers, the soil water content was a little high in the plastic film mulching than that without mulching. The mean soil water content from 0 to 40 cm without mulching were 3.35% lower than those measured in the corresponding mulching treatments in 31 days after sowing in 2012. The mulching treatment increased the soil nitrate-N content was observed in the 0–40-cm soil layers. The results indicate that high contents of soil nitrate-N were mainly distributed at 0–20-cm at 31 days after sowing in 2012, and the soil nitrate-N concentration in the MN2 treatment was 1.58 times higher than that did not receive fertilizer. The MN2 treatment greatly increased the soil nitrate-N content in the upper layer of soil (0–40-cm), and the mean soil nitrate-N content was increased nearly 50 mg kg−1 at 105 days after sowing compared with CK treatment in 2012. The soil nitrate-N leaching amount in MN1 treatment was 28.61% and 39.14% lower than BN1 treatment, and the mulch effect attained to 42.55% and 65.27% in MN2 lower than BN2 in both years. The yield increased with an increase in the basal fertilizer, top dressing and plastic film mulching, and the grain yield increase ranged from 31.41% to 83.61% in two consecutive years. The MN1 and MN2 treatment is recommended because it increased the grain yield and improved the fertilizer use efficiency, compared with the no-mulching treatment.

Soil water and nutrients are key factors for plant growth and development as they are involved in many processes in plants. The purpose of this study was to investigate the effect of water deficit in different growth stages on maize growth and water use efficiency. Randomized block design with three replications and the treatments consisted of three levels of irrigation and three levels of N fertilizer were used. Three irrigation levels were W1 (water deficit at seedling stage), W2 (water deficit at jointing stage), W3 (water deficit at filling stage) and nitrogen (N) fertilizer levels were F1 (0.1 g pure N kg -1 soil), F2 (0.2 g pure N kg -1 soil) and F3 (0.3 g pure N kg -1 soil). The control treatment was composed of full irrigation and without N fertilizer application (CK). The results indicated that the interactions between irrigation and N fertilizer were important for shoot dry matter and root dry matter. The ranking of N fertilizer treatments, from high to low accumulations of root and stem-leaf dry matter averages, was F1>F3>F2. The falling of accumulation of nitrate in plants was mainly attributed to the proper enhancing ammonium reduced the adsorptive capacity of nitrate. Water deficit at different growth stages were significantly increase the total N content of stem-leaf. In conclusion, the maize can repair itself so they stop growing when water deficit at seedling stage, but do not die. They simply resume growth later when the water supply is plenty.

Soil desiccation is one of the key factors to influence the sustainable development of crop production on the Loess Plateau of China. Depletion of soil water during growth period and its recovery in the fallow period is influenced by the amount of rainfall, its distribution, the type of crop and its rotation sequence. This study analyzed depletion and restoration of soil water for different cropping systems, based on a series of long-term experimental data at Changwu Agriculture Station from 1985 to 2001. Results of this study indicated that: (1) temporary soil desiccation took place in 1–3 m soil for MM, PWM and MW cropping system. (2) Permanent soil desiccation took place in 1–5 m and 1–10 m soil for APW and AF cropping system respectively. (3) When a rotation system was built to recover soil desiccation, broomcorn millet and potato can be considered first pea and spring maize also can be considered in rainy years or normal years. During fallow period, mulch or canopy can relief the soil desiccation in winter wheat land.