Production In Semi-arid Areas Research Articles

Integrated effects of furrow irrigation systems and irrigation regimes on water productivity of onion (Allium cepa L.) crop in a semi-arid area

Dwindling water resources with inept field water management impends sustainable agricultural production in semi-arid areas of Ethiopia. Thus, the adaption and adoption of improved irrigation water running lines are indispensable and imperative to recuperate water productivity in areas where water resources are inadequate. The ground experiments were pointed to elucidate the weight of conventional, alternate, and fixed furrow irrigation systems under irrigation levels of 100 %, 70 %, and 40 % of crop evapotranspiration (ETc) on onion growth, yield, water productivity, and economic return in Alage, Central, Ethiopia. The field trials were conducted at nine treatments arranged in a randomized complete block design with three replications and water was managed at fixed intervals with variable depth approach. The result illustrated that furrow systems in conjunction with irrigation levels had a weighty pertain (P < 0.05) on onion growth, yield, water productivity, and economic return. The highest yield of 30.75 ton ha−1 was achieved at conventional furrow irrigation with 100%ETc dictated to zero water saving subsequently, the crop and irrigation water productivity dropped with the values of 6.86 and 5.61 kg m−3 respectively. The diminished yield of 6.39 ton ha−1 obtained at fixed furrow irrigation with 40%ETc conquered the saved water output lastly, the crop and irrigation water productivities demoted with values of 6.87 and 5.70 kg m−3 respectively. Nevertheless, 24.93ton ha−1 of ideal yield was obtained under alternative furrow irrigation with 100%ETc and the 50 % hoarded water was higher than the yield decline. Consequently, the crop and irrigation water productivities rose with values of 10.96 and 9.09 kg m−3 respectively. Eventually, the saved water opened for 0.03ha extra irrigable area that will onward to the highest total expected yield of 37.40 ton ha−1 as compared with all other treatments. Under conventional furrow irrigation with 100%ETc, the obtained yield dominated the wastewater accordingly, the highest net return of 668484ETB ha−1 and benefit-cost ratio of 3.63 was achieved. Besides, the unbearable yield penalty under fixed furrow with 40 % headed to negative net return and lowest befit cost ratio as related with other treatments. However, further economic results confirmed that the 50 % saved water under alternative furrow with 100 % can recompense for the net return reduction that will make this trial combination preferable as compared with other treatments. Other results also recommended that, under water-limiting and inefficient field water governing conditions, alternative furrow irrigation with 100%ETc can be the ideal blend to enhance water productivity in semi-arid regions of Ethiopia and elsewhere that share similar agroclimatic conditions.

Trichoderma Rhizosphere Soil Improvement: Regulation of Nitrogen Fertilizer in Saline–Alkali Soil in Semi-Arid Region and Its Effect on the Microbial Community Structure of Maize Roots

In order to reduce the actual impact of a saline–alkali environment on maize production in semi-arid areas, it is particularly important to use the combined fertilization strategy of Trichoderma microbial fertilizer and nitrogen fertilizer. The purpose of this study was to investigate the effects of different concentrations of nitrogen fertilizer combined with Trichoderma on improving the structural characteristics and ecological functions of maize rhizosphere microbial community in semi-arid saline–alkali soil. Through the microbiome analysis of maize rhizosphere soil samples with 60 kg N·ha−1 (N1) and 300 kg N·ha−1 (N2) nitrogen fertilizer combined with Trichoderma (T1) and without Trichoderma (T0), we found that the combination of Trichoderma and different concentrations of nitrogen fertilizer significantly affected the structure of bacterial and fungal communities. The results of this study showed that the combination of Trichoderma and low-concentration nitrogen fertilizer (N1T1) could improve soil nutritional status and enhance its productivity potential, revealing the relationship between beneficial and harmful fungal genera, microbial diversity and abundance, and crop biomass, which is of great significance for improving agricultural production efficiency and sustainable development.

Two Genotypes of Tomato Cultivated in Gobi Agriculture System Show a Varying Response to Deficit Drip Irrigation under Semi-Arid Conditions

Water-saving irrigation is of extraordinary importance for tomato production in semi-arid areas of northwest China. For this purpose, we conducted a two-season trial in a solar greenhouse of two tomato genotypes named ‘181’ and ‘Mao Fen 802’ and cultivated with substrate, under four irrigation regimes, i.e., well-watered (WW), low (LWD, 80% WW), moderate (MWD, 60% WW) and high (HWD, 40% WW) water deficit. The substrate water content of WW treatment was 75%θf to 90%θf (where θf is the field capacity). The study results showed that the single fruit weight and yield of tomato were significantly declined with an increasing water deficit degree. Compared to WW treatment, the fruit weight and yield were decreased about 34.45% and 20.35% for ‘181’ and ‘Mao Fen 802’ under HWD treatment, respectively. Conversely, water deficit treatment led to an obvious promotion of WUE and showed an upward trend as the water deficit level increased. In addition, compared to WW treatment, the water deficit significantly decreased the total flavonoids of the ‘181’ tomato by 24.4–93.1%, whereas there was no significant impact on that of ‘Mao Fen 802’. Nonetheless, different individual polyphenols were increased by suitable deficit irrigation for two tomato cultivars. Gallic acid, 3,4-dihydroxybenzoic acid, and naringin of ‘181’tomato were increased by 128.4–195.2%, 8.6–43.7%, and 31–73-fold, respectively, under water deficit compared to WW treatment. Further, under water deficit treatment, p-coumaric acid, benzoic acid, and 3,4-dihydroxybenzoic acid of ‘Mao Fen 802’ were increased by 36.2–49.2%, 59.1–189.7%, and 36.3–106.4% compared to WW treatment. As the main carotenoid component, the lycopene content of tomato fruit exhibited a significant rise of 7.84–20.02% and 20.55–32.13% for ‘181’ and ‘Mao Fen 802’ under three degrees of water deficit compared to WW treatment. Linear regression showed a significantly positive relationship between irrigation amounts and yield, and total polyphenols, whereas there was a significantly negative relationship between irrigation amounts and WUE, and total carotenoids. Based on correlation and PCA, WW and LWD, and MWD and HWD, were gathered together for ‘181’, while LWD, MWD, and HWD, were gathered, and only WW scattered for ‘Mao Fen 802’, along the PC1 direction. It was proposed that ‘Mao Fen 802’ was more sensitive to water deficit than the ‘181’ tomato. In conclusion, water deficit is conductive to water-saving cultivation of the greenhouse tomato and the tomato genotypes, and water deficit level is a key factor necessary for consideration.

Reducing fertilization with high planting density increases maize yield stability and nitrogen use efficiency in semi-arid areas

High-density planting is a vital cultivation measure to improve crop yield. In the semi-arid region, insufficient precipitation and high variability are the primary factors that restrict agricultural development. Matching planting density and fertilizer application with precipitation is a promising technical strategy to ensure yield stability and enhance nitrogen (N) use efficiency (NUE). To achieve this objective, we conducted a continuous field experiment in the Loess Plateau region of Northwest China between 2015 and 2020. Under conventional (CF) and reduced fertilization (RF, 20 % CF) conditions, we investigated the response characteristics of dry matter accumulation, yield, yield components, NUE, N surplus, and net income of maize as the density increased from 5.25 (D1) to 6.75 (D2), 8.25 (D3), and 9.75 (D4) × 104 plants ha−1. The results indicated that reduced fertilizer application led to a decrease in grain yield by 6.2–8.7 %, whereas increasing the density by at least 1.50 × 104 plants ha−1 (D2) could compensate for the yield reduction caused by reduced fertilization (N 55 + P2O5 27 kg ha−1) in normal and wet years. The compensatory effect initially increased and then decreased as the density increased, with the highest yield observed at planting density D3. By increasing the rapid growth rate of maize (6.3–17.1 %) and extending the rapid growth duration (0.9–2.5 days) through high planting density, reduced fertilization combined with high-density planting (RF·D3) significantly increased the cumulative yield, yield stability, net income, and NUE was by 9.4 %, 18.9 %, 10.6 %, and 37.0 %, respectively, over six years, compared with CF·D1 treatment. Additionally, the N surplus was reduced by 44.6 %. In conclusion, using reduced fertilization with high planting density measures can achieve yield stability and sustainable maize production in semi-arid areas.

Evaluating effects of selected water conservation techniques and manure on sorghum yields and rainwater use efficiency in dry region of Zimbabwe

Sorghum production in semi-arid areas of Zimbabwe is constrained by low and erratic rainfall, low fertility and soil moisture stress. Sorghum grain yields ranges from 0.2 to 0.4 t ha−1 in sandy-to-sandy loam soils respectively. The objective of the study was to assess cattle manure and rainwater harvesting techniques in improving sorghum grain yield in a semi-arid region of Zimbabwe. The experiment used a randomised complete block design with rainwater harvesting technique as a main treatment factor at three levels. Sub-plot factor was cattle manure at five levels (0, 2.5, 5, 10 and 15 t ha−1) and two sorghum varieties (Macia and SV1) as sub-sub plot factor. Sorghum grain yields were improved significantly (p < 0.05) for both varieties using tied contours. Increasing application rates of cattle manure, showed significant increase (p < 0.05) in sorghum grain yield over the control (0 t ha−1). Tied contour had higher grain yield (1.15 t ha−1) with the use of Macia variety. Stover yield was highly influenced by rainwater harvesting method of tied contour (p < 0.05) compared with infiltration pit and standard contour. Increase in application levels of cattle manure show significant (p < 0.05) increase in stover yields. Tied contour had the highest (3.11 kg ha−1 mm−1) rainwater use efficiency which show significant differences (p < 0.05) from infiltration pits and standard contour. Interaction of tied contour and different rates of cattle manure showed significant increments in rainwater use efficiency with increases in manure application rates. Tied contours, 15 t ha−1 cattle manure and Macia variety are potential strategy to achieve climate smart agriculture and improve food security in semi-arid areas. Sorghum production in marginalised areas can be productive with adoption of tested techniques.

Effects of banqueting on water infiltration and physico-chemical properties of soil in semi-arid lands

Banqueting is a simple and cheap soil conservation practice in natural rangelands under dry climates. Little research exists about its impacts compared to other land uses, where agriculture and land abandonment may be important reasons for degradation. This study has evaluated water infiltration and key physico-chemical properties of soil in natural rangelands with banquets in West Azerbaijan (North-Western Iran) compared to: (i) undisturbed sites (assumed as reference condition) and (ii) cultivated or abandoned dry farmlands. Under these soil conditions, the texture, bulk density, porosity, water content, pH, electrical conductivity, organic carbon and carbonate contents of soil (using common physical-chemical methods) as well as the hydraulic conductivity (using a single-cylinder infiltrometer) were measured in the topsoil (0–20 cm). This data was further processed by applying the Principal Component Analysis and the Agglomerative Hierarchical Cluster Analysis. In areas with banquets, soil hydraulic conductivity was higher by 84% compared to dry farmlands (abandoned or not), where water infiltration was noticeably reduced (−44%) compared to the reference soil condition. Moreover, a noticeable increase in organic carbon content (+80%) and a lower salinity (−36%) of soil compared to cultivated areas was measured. These effects are important to enhance soil fertility on one side, and resistance to erosion on the other side. Therefore, in the experimental areas, banqueting may counteract the degradation of soil due to the agricultural activity as well as its abandonment, and restore the properties of the undisturbed soils that are typical of natural rangelands. The results of this study may be of help for landscape managers and agronomists for the pressing needs for soil conservation and productivity in semi-arid areas that are prone to degradation and abandonment.

The effect of phosphorus utilization efficiency on durum wheat cultivars under semi-arid environmental conditions

Faced with the high cost of phosphate fertilisers in several African countries, including Algeria, and in order to better select varieties according to their fertiliser use efficiency, this study was proposed. The goal of the study was to determine how “variety” impacts durum wheat's capacity to utilize phosphorus effectively and to try to pinpoint the agro-morphological factors that contribute to this efficiency so that they can be taken into consideration when choosing which varieties to sow in semi-arid environments. The experimental setup consisted of a split plot with two investigated factors and three repetitions, with the main plot receiving the phosphate treatment while the sub plot receives the variety. The trial set up consisted of 11 durum wheat varieties, which were cultivated over two years successively. The PUE of the fertiliser, provided in 46% triple superphosphate (TSP) granules, and agro-morphological parameters like aerial biomass, plant height, grain yield and yield components were determined. The findings demonstrated that triple superphosphate, a type of phosphorus fertilizer, increases grain yield by between 40 and 60% for all varieties examined as compared to the phosphorus-free control at the average dose employed in this field trial, or 20 kg P2O5.ha-1. This increase in yield is due to an increase: from 20 to 22% in the number of ears per m², 41.5% in the number of grains per ear, and 9% in the average weight of the grain. The PUE is strongly correlated to the yield components (Number of ears per square meter- NEM, Number of grains per ear- NGE, thousand grain weight- TGW and Yield) but also to the height at heading (r=0.86) and dry matter (r=0.85). Phosphorus use efficiency is also strongly correlated to flag leaf length and width as well as leaf area. Also, that genotypes with higher weight of thousand grains (WTG) showed better use of available phosphorus. The principal component analysis (PCA) confirms that the efficiency of phosphorus use by the varieties tested explains a large portion of the variation noted in these varieties. This genetic variation in PUE was associated with plant height and phosphorus content of the sown grains. These results could be of a significant impact in improving rainfed durum wheat productivity in semi-arid areas and preserving the environment as well. Key words: Durum wheat, Phosphorus use efficiency, Plant’s height, Genetic variation, Fertilizers’ reduction

Prospects and Challenges of the Chololo Pits Technology In Enhancing Crop Production in Semi-Arid Areas Of Central Tanzania

This article explores the prospects and challenges affecting farmers practising the use of chololo pits[1] due to the semi-arid nature of Dodoma. It investigates the prospects and challenges of chololo pits technology in enhancing crop production in the semi-arid Chamwino District. Data was collected through documentary review, household interviews, focus group discussions, key informant interviews and field observation. Findings indicate that improvement of the soil water holding capacity (77.7%, n=337), economic use of fertilizers (74.4%, n=337) and increases in cereal yields (70.6%, n=337) were the major prospects for enhancing crop production. Labour intensity (43%, n=337), required skills (29%, n=337) and difficulty to maintain (13.5%, n=337) were the major challenges of chololo pits in enhancing crop production in the study area. Other minor prospects were reducing soil erosion, concentrating nutrients and protecting seeds and humus from being washed away, while shortage of fertilizer and waterlogging were the minor challenges of chololo pits. The study recommends that the government, in collaboration with NGOs and CBOs, should use more efficient tools to supplement the use of the hand-hoe (agriculture research institutions, COSTECH and SIDO should take lead on this). Also, further research should be conducted, and climate smart agriculture (CSA) and scaling up the chololo pits technology should be advocated.

Enhancing carbon sequestration and greenhouse gas mitigation in semiarid farmland: The promising role of biochar application with biodegradable film mulching

Long-term mulching has improved crop yields and farmland productivity in semiarid areas but also increased greenhouse gas (GHG) emissions and depleted soil fertility. Biochar application has emerged as a promising solution for addressing this issue. In this study, we investigated the effects of four biochar application rates (no biochar (N)=0 t ha–1, low (L)=3 t ha–1, medium (M)=6 t ha–1, and high (H)=9 t ha–1) under film mulching and no mulching over three growing seasons. We assessed the impact on greenhouse gas emissions, soil organic carbon sequestration (SOCS), and maize yield to evaluate the productivity and sustainability of farmland ecosystems. Our results demonstrated that mulching increased maize yield (18.68–41.80%), total fixed C in straw (23.64%), grain (28.87%), and root (46.31%) biomass, and GHG emissions (CO2, 10.78%; N2O, 3.41%), while decreasing SOCS (6.57%) and greenhouse gas intensity (GHGI; 13.61%). Under mulching, biochar application significantly increased maize yield (10.20%), total fixed C in straw (17.97%), grain (17.69%), root (16.75%) biomass, and SOCS (4.78%). Moreover, it decreased GHG emissions (CO2, 3.09%; N2O, 6.36%) and GHGI (12.28%). These effects correlated with the biochar addition rate, with the optimal rate being 9.0 t ha–1. In conclusion, biochar application reduced CO2 and N2O emissions, enhanced CH4 absorption, and improved maize yield under film mulching. It also improved the soil carbon fixation capacity while mitigating the warming potential, making it a promising sustainable management method for mulched farmland in semiarid areas.

Drought limits vegetation carbon sequestration by affecting photosynthetic capacity of semi-arid ecosystems on the Loess Plateau

Drought is the driver for ecosystem production in semi-arid areas. However, the response mechanism of ecosystem productivity to drought remains largely unknown. In particular, it is still unclear whether drought limits the production via photosynthetic capacity or phenological process. Herein, we assess the effects of maximum seasonal photosynthesis, growing season length, and climate on the annual gross primary productivity (GPP) in vegetation areas of the Loess Plateau using multi-source remote sensing and climate data from 2001 to 2021. We found that maximum seasonal photosynthesis rather than growing season length dominates annual GPP, with above 90 % of the study area showing significant and positive correlation. GPP and maximum seasonal photosynthesis were positively correlated with self-calibrating Palmer Drought Severity Index (scPDSI), standardized precipitation and evapotranspiration index (SPEI) in >95 % of the study area. Structural equation model demonstrated that both drought indices contributed to the annual GPP by promoting the maximum seasonal photosynthesis. Total annual precipitation had a positive and significant effect on two drought indices, whereas the effects of temperature and radiation were not significant. Evidence from wood formation data also confirmed that low precipitation inhibited long-term carbon sequestration by decreasing the maximum growth rate in forests. Our findings suggest that drought limits ecosystem carbon sequestration by inhibiting vegetation photosynthetic capacity rather than phenology, providing a support for assessing the future dynamics of the terrestrial carbon cycle and guiding landscape management in semi-arid ecosystems.

Integrated application of fertilization and reduced irrigation improved maize (Zea mays L.) yield, crop water productivity and nitrogen use efficiency in a semi-arid region

Water scarcity as well as soil degradation and environmental problems potentially caused by excessive application of chemical fertilizers are major challenges to agricultural production in semi-arid areas. It is crucial to explore a suitable and eco-friendly strategy to achieve sustainable production of maize with high crop water productivity and nitrogen use efficiency. Here, a two-year field experiment with three irrigation levels of W1 (220 mm), W2 (140 mm) and W3 (60 mm), and five fertilization types of no fertilizer (CK), chemical fertilizer (CF), bio-fertilizer combined with CF (CFB), organic fertilizer combined with 70% CF (CFO) and bio-fertilizer combined with CFO (CFOB) was conducted to investigate the effect on dry matter, N uptake and remobilization, grain yield, crop water productivity, nitrogen use efficiency and economic benefits of maize in 2021 and 2022. The results showed that the W2 and W3 decreased in the leaf area index, photosynthetic rate, dry matter accumulation, the maximum dry matter accumulation rate and actual crop evapotranspiration. Under W1 condition, the CFB improved the growth of maize, increased the dry matter and nitrogen accumulation and yield, with 8.1% and 7.4% higher than CF in 2021 and 2022, respectively. Under deficit irrigation (W2 and W3), CFOB significantly increased the leaf area index, photosynthetic rate, dry matter accumulation at later growth stage, in addition, CFOB increased the post-silking N uptake and the percentage in total N content, finally improved the grain yield with 23.8% and 22.8% under W2, 22.5% and 25.7% under W3 higher than that of the CF in 2021 and 2022, respectively. Irrigation and fertilizer showed a coupling effect on grain yield, crop water productivity, agronomy efficiency and nitrogen use efficiency. Overall, the CFOB under moderate deficit (W2) exhibited the highest water productivity, nitrogen use efficiency and economic benefits, as well as maintained the high yield, could be a promising approach to sustainable development of local maize.

Feed potential of small cereal grains in poultry production in semi-arid areas: A review

Feed potential of small cereal grains in poultry production in semi-arid areas: A review

Determinants of the Adoption of Charco Dam Rainwater Harvesting Technology by Pastoralists in Semi-Arid Areas of Monduli District in Tanzania

The use of water harvesting ponds in Tanzania known as charco dams in watering livestock have been developed to enhance livestock production in semi-arid areas. However, the adoption of charco dam has been very low. This paper examined the determinants of the adoption of charco dam by pastoralists in semi-arid areas of Monduli District in Tanzania. The study used a cross-sectional research design where data were collected at a single point in time. Quantitative data were collected by using pre-tested structured questionnaire from 367 respondents who were randomly selected from seven villages, namely Moita Kipok, Moita Kilorit, Kilimatinde, Moita Bwawani, Makuyuni, Mbuyuni and Naiti in Monduli District. The collected data was entered into SPSS.20 for analysis. Data was analysed using frequency, percentages, and a binary logistic regression model. The study results show that the intervening factors (perceived advantages and disadvantages of charco dam) have a slightly high influence on the adoption of charco dam with predictive power R2 ranging from 29.5 to 44.5 per cent as compared to independent variables with predictive power R2 ranging from 27 to 37 per cent at a 5 per cent level of significance. Furthermore, the study results indicate that the independent variables namely socio-economic factors specifically age (p=0.000), household size (p=0.002), off-farm income (p=0.025), livestock keeping experience (0.001), herd size (0.002) and institutional factors including access to extension services (p=0.030) and subsidies (p=0.005) have an influence on the adoption of charco dam. This study recommends policymakers to devote more weight to perceived advantages and disadvantages of charco dam technology while constructing charco dam rainwater harvesting projects in order to influence pastoralists to accept the technology and increase water access for livestock in semi-arid areas.

Long-term anthropogenic field management enhanced wheat productivity and resource utilization in the Loess Plateau region of China

Low precipitation and poor soil quality are the main factors that limit wheat production in the Loess Plateau region of China. Straw incorporation and/or adding organic fertilizer can enhance wheat productivity by improving the soil water content (SWC) and soil fertility, but systematic long-term research has not yet been conducted. Thus, we conducted a 12-year continuous in-situ experiment in the Loess Plateau by testing four treatments: (1) CK: no fertilization and wheat straw removal; (2) FM: straw removal and application of inorganic fertilizer; (3) SI: straw incorporation and application of inorganic fertilizer; (4) SIOM: straw incorporation and application of inorganic fertilizer, with organic fertilizer added to replace 10% of the inorganic fertilizer. Under CK, the soil chemical properties and enzyme activities tended to decrease over the years. The soil fertility was significantly higher under FM than CK, and higher under SI and SIOM than FM (P < 0.05). SIOM significantly improved the soil nutrients and wheat productivity than other treatments (P < 0.05). Compared with FM, the soil bulk density in the 0–20 cm soil layer under SIOM decreased by 4.5%, while SOC, TN, TP, AN, and Olsen-P increased by 4.5%, 6.1%, 4.9%, and 12.3%, respectively. The DOC, DON, MBC, and MBN contents increased by 18.5%, 26.4%, 15.8%, and 16.2%, respectively. The activities of urease, sucrase, and catalase increased by 12.8%, 13.6%, and 22.8%, and the N uptake, nitrogen use efficiency (NUE), water use efficiency (WUE), water productivity, and wheat yield increased by 17.8%, 43.7%, 38.6%, 33.5%, and 22.4%. SIOM obtained the highest NUE, WUE, yield, and economic benefits of 37.83%, 14.34 kg ha–1 mm–1, 4579.16 kg ha–1, and 7990.39 Yuan ha–1, respectively. Linear mixed effects modeling showed that the year and treatment significantly affected the soil fertility and wheat productivity (P < 0.05). Random forest and structural equation modeling showed that the soil and fertilizer management strategies increased wheat productivity (R2 = 0.50) by improving the soil fertility. Therefore, straw incorporation and applying inorganic/organic fertilizers are effective management strategies for improving soil fertility and wheat productivity in semi-arid areas of Loess Plateau regions.

Optimizing soil and fertilizer management strategy to facilitate sustainable development of wheat production in a semi-arid area: A 12-year in-situ study on the Loess Plateau

ContextThe low precipitation and low soil fertility in the Loess Plateau region of China limit the sustainable development of farmland. No-tillage, straw mulching, or planting green manure can improve soil water storage or soil quality. However, further research is needed to optimize these soil and fertilizer management strategies to maximize yield and effectively utilize resources. ObjectiveThe present study aimed to determine the optimal soil and fertilizer management strategies to maximize wheat growth and water/nitrogen utilization efficiency, while minimizing nitrogen fertilizer input. MethodsFive different soil and fertilizer treatments were tested on the Loess Plateau between 2009 and 2021, including traditional tillage followed by bare soil (CK), no-till with straw mulching (NTSM), no-till with straw mulching followed by leguminous green manure (OPT), and reductions in N fertilizer inputs of 10% (OPT10) and 20% (OPT20) under OPT. ResultsThe average results from 12 years of research revealed that the soil water content (SWC) and NO3–-N content in the 0–20 cm soil depth under OPT were higher by 4.3% and 13.4% compared to CK (P < 0.01), and the length and surface area of the wheat roots were higher by 20.9% and 11.0% (P < 0.01), respectively. Optimized soil and fertilizer management delayed leaf senescence and enhanced the antioxidant and photosynthetic capacities of the wheat crop. Compared with CK, the net photosynthetic rate and superoxide dismutase activity were 38.6% and 11.6% higher under OPT, respectively, and no significant differences were observed between OPT and OPT10. Optimized soil and fertilizer management promoted wheat yield formation, water and fertilizer use efficiency, and OPT obtained the highest yield (4497.3 kg ha−1), N uptake (138.7 kg ha−1), and water use efficiency (WUE, 13.3 kg ha−1). Compared with CK, OPT increased the wheat yield, N uptake, WUE, and WP by 21.5%, 16.7%, 16.6%, and 12.6%, respectively, and there were no significant differences between OPT10 and OPT. ConclusionsOptimizing the soil and fertilizer management strategies increased the soil water and NO3–-N contents, delayed leaf senescence, enhanced the leaf antioxidant and photosynthetic capacities, promoted wheat yield formation and efficient resource utilization. A 10% reduction in N fertilizer input based on no-till, straw mulching and green manure planting during the fallow period is an efficient soil and fertilizer management strategy for ensuring sustainable wheat production in semi-arid areas of the Loess Plateau. ImplicationsOur findings provide a reference for wheat production in semi-arid regions similar to the Loess Plateau throughout the world.

Factoring labour when comparing in situ rainwater harvesting technologies for semi-arid areas of central Tanzania

ABSTRACT Erratic rainfall, high evapotranspiration rates and droughts are major factors limiting crop production in semi-arid areas. Tied ridges that have crossed ties within the furrow are among the physical soil and water conservation measures. During the 2018/19 and 2019/20 seasons, we examined the efficacy of repaired tied ridges for maize crop (Zea mays) and sorghum (Sorghum bicolor) in Kongwa district of Tanzania as an alternate labour saving strategy for managing climate risks associated with variable rainfall. Treatments consisted of three tillage methods: conventional tillage (CT) which involved the preparation of a flat seedbed using handhoe, annually constructed tied ridges (ATR) and tied ridges that had been constructed during the previous season and had been repaired (residual tied ridges–RTR). Data were collected on labour requirements and crop performance. RTR increased economic returns by 29% and 80% over ATR and CT, respectively. Maize grain yield shows a trend of RTR >ATR>CT with values ranging from 2465 kg ha−1 to 4185 kg ha−1 (P < 0.01). While tillage and/or variety did not influence sorghum grain yield significantly (P > 0.05). The use of RTR is recommended because of low labour requirements and greater economic benefits than CT and ATR under maize cropping systems.

Impact of maize straw biochar and tied‐ridge‐furrow rainwater harvesting on soil erosion and soil quality in a semiarid region

AbstractIn dryland areas, integrating biochar soil amendment with in situ rainwater harvesting systems may decrease soil erosion, improve soil quality, and increase crop productivity and yield. This study was conducted to investigate the effect of maize straw biochar amendment and ridge‐furrow rainwater harvesting systems on run‐off, sediment yield and the physico‐chemical properties of a Calcic Cambisol soil in semiarid areas. The experiment was conducted on alfalfa (Medicago sativa) production land at the Anjiagou Catchment experimental station in Gansu province, China. The experimental layout was a split‐plot design with three replications. Biochar was applied at a rate of 0 and 30 t ha−1, respectively. The tillage treatments were flat planting, open‐ridging, and tied‐ridging (TR). Overall, the integration of maize straw biochar with TR decreased soil bulk density at 0–40 cm depth. Biochar application reduced run‐off by 37.8% and soil loss by 55.5% during alfalfa‐growing seasons compared to the control. In general, biochar addition increased soil total potassium, but the same effect was not observed for soil pH, total nitrogen, total phosphorus, and available phosphorus. These findings demonstrate the potential of integrating maize straw biochar and tillage systems to reduce soil erosion and improve soil quality for rainfed crop production in semiarid areas. Further studies on the effect of biochar‐tillage system interaction are warranted to improve soil conditions for plant growth and increase crop yield in dryland areas.

Plow layer management during the fallow season can enhance the wheat productivity and resource utilization in a semi-arid region

The soil quality is poor in the arid areas of Northwest China and planting green manure can improve the soil quality but it also increases the soil water consumption. Straw mulching in the wheat (Triticum aestivum L.) fallow season can improve the soil water content. It is unclear whether green manure can be planted in addition to straw mulching to improve the soil water content and quality. Therefore, a field experiment was conducted in the semi-arid area of the Loess Plateau in China from 2009 to 2017 with the following treatments; (1) traditional bare land in fallow season after plowing (CK), (2) no-tillage with straw mulching (NTSM), (3) and no-tillage with straw mulching and planting soybean as green manure (NTSGM). We determined the effects of these three treatments on the soil water, nutrients, and wheat productivity. Compared with CK, the average soil water contents in 0–100 cm soil depth increased by 11.1% and 3.6% under NTSM and NTSGM, respectively, during the soybean full bloom stage, and by 13.06% and 6.6% before wheat sowing. Compared with CK, the decomposition of green manure increased the NO3–-N contents in the 0–100 cm soil depth by 6.6% and 5.3% under NTSGM before wheat sowing and after harvesting, respectively, and NTSM and NTSGM significantly improved the soil nutrients, microbial biomass contents, and enzyme activities. The superior soil quality and water content under NTSM and NTSGM increased the fertilizer uptake and partial factor productivity. Compared with CK, the average precipitation storage efficiency, water use efficiency during the whole year, biomass, and wheat yield were 32.6%, 23.2%, 16.2%, and 21.6% higher under NTSGM, respectively. Therefore, NTSGM is an effective method for improving the soil water storage and NO3–-N contents before sowing wheat, as well as the water use efficiency, soil quality, utilization of nutrients, and wheat productivity in semi-arid areas of the Loess Plateau.

Participatory inventory and nutritional evaluation of local forage resources for smallholder free-range beef production in semi-arid areas of South Africa

Feed scarcity is a major challenge facing free-range beef farming in semi-arid areas. Specifically, low quality and quantity of forage in rangelands and higher feeding costs are the main constraints limiting smallholder free-range beef farmers’ participation in mainstream beef markets. Using farmers’ participatory approaches, this study identified major locally available forage resources (LAFRs) and evaluated their nutritional value. A total of 40 free-ranging commercially orientated smallholder beef farmers were interviewed using semi-structured questionnaires and tasked to identify LAFRs in the Cradock and Middelburg areas of the Eastern Cape, South Africa. Chemical analysis was conducted for the most cited forages such as African sheepbush (Pentzia incana), sweet thorn (Vachellia karroo) leaves and pods, reed (Phragmites australis), lucerne (Medicago sativa) hay, natural pasture grasses (NPGs) and barbary fig, or prickly pear cactus, (Opuntia ficus-indica) cladodes collected from twelve participants’ farms. Feed shortage was ranked by more than 53% respondents as the main constraint to smallholder beef production. Regardless of the farming area, crude protein content of V. karroo leaves and pods averaging 18.8 and 19.5%, respectively, was higher than other LAFRs. However, V. karoo pods had relatively low ash content than other forages in both farming areas. Opuntia ficus-indica attained high in vitro neutral detergent fibre digestibility at 12, 24 and 48 hr incubation periods, due to low neutral detergent fibre, acid detergent fibre and acid detergent lignin. Integration of participatory inventory and chemical analysis proved to be reliable in identifying LAFRs, with V. karroo leaves and O. ficus-indica cladodes being the main potential forage resources for inclusion in beef cattle diets. Further research is recommended to substantiate their supplementary nutritive value and level of inclusion in beef cattle finishing diets.

Effects of Irrigation Methods and Scheduling on Water and Onion Productivity in Semi-Arid Areas of Ethiopia

Highlights Irrigation experiments on onion productivity were conducted at two sites for two consecutive years in Ethiopia. Factors from irrigation interval and irrigation method analyzed independently and factorially. Basin irrigation and fixed irrigation produced higher bulb yields and water productivity. Farmers’ income can be enhanced using improved irrigation practices for increased onion productivity. Abstract. How to meet the crop water demand and improve crop productivity is a particular concern for small-scale farmers, where the availability of water resources is limited. This study evaluated three different irrigation methods (furrow, basin and border) and two types of irrigation scheduling (CROPWAT schedule and farmers’ practices) with three replications for two consecutive years (2016-2017) at two sites using onion crops. The results showed that the CROPWAT schedule, basin irrigation method, and their interactions showed better performances and produced higher yield and water productivity. An average of 26 and 27 metric tons/hectare of onion were obtained under the basin irrigation method and basin irrigation with CROPWAT schedule combined, respectively. The water productivity (WP) and irrigation water productivity (IWP) also showed higher results under the basin irrigation method compared to other treatment combinations. The basin irrigation method produced higher marketable onion bulbs with firm medium bulb sizes that are essential for onion producers to earn maximum profit. The findings of this study also indicate that focusing on enhanced irrigation scheduling techniques and irrigation methods is paramount for better onion productivity in irrigation water-limited areas. Keywords: Irrigation interval, Irrigation methods, Irrigation practices, Onion productivity, Water management.