Dryland Farming Areas Research Articles

Climate and Soil Geochemistry Influence the Soil Organic Carbon Content in Drylands of the Songliao Plain, Northeast China

AbstractThe understanding of the spatial distribution of soil organic carbon (SOC) and its influencing factors is crucial for comprehending the global carbon cycle. However, the impact of soil geochemical and climatic conditions on SOC remains limited, particularly in dryland farming areas. In this study, we aimed to enhance the understanding of the factors influencing the distribution of SOC in the drylands of the Songliao Plain, Northeast China. A dataset comprising 35,188 measured soil samples was used to map the SOC distribution in the region. Multiple linear regression (MLR) and random forest models (RFM) were employed to assess the importance of driving indicators for SOC. We also carried out partial correlation and path analyses to further investigate the relationship between climate and geochemistry. The SOC content in dryland soils of the Songliao Plain ranged from 0.05% to 11.63%, with a mean value of 1.47% ± 0.90%. There was a notable increasing trend in SOC content from the southwest to the northeast regions. The results of MLR and RFM revealed that temperature was the most critical factor, demonstrating a significant negative correlation with SOC content. Additionally, iron oxide was the most important soil geochemical indicator affecting SOC variability. Our research further suggested that climate may exert an indirect influence on SOC concentrations through its effect on geochemical properties of soil. These insights highlight the importance of considering both the direct and indirect impact of climate in predicting the SOC under future climate change.

The water–energy–food–ecosystem nexus in North Africa dryland farming: a multi-criteria analysis of climate-resilient innovations in Morocco

Smallholder farmers, who mostly engage in low-value agriculture in the drylands of Northern Africa, were the first to have felt the effects of climate change, with threats to their livelihoods and food security. The increasing costs of agricultural production, poor water and energy infrastructure, loss of agricultural land due to urban expansion, fragmented resource management, and unsustainable management practices all contribute to this vulnerability to climate change. This highlights the urgent need for innovative practices in farming systems. Within the framework of the water–energy–food–ecosystem nexus, this paper explores innovative practices in dryland farming systems, by assessing their impact on water, energy, food, and ecosystem through stakeholder perception. In this work, we aim to present a systems approach for assessing the resilience of the water–energy–food–ecosystem nexus in arid and semiarid regions. By using a multi-criteria analysis (MCA) approach, the study—which focuses on the Fès–Meknès region in Morocco—involves local actors to help researchers identify the key variables in order to assist farmers in their adaptation to climate change. The findings revealed different priorities between farmers and other stakeholders regarding the adoption of agricultural innovations. Farmers prioritize innovations that guarantee higher profitability and more market opportunities, such as integrating olive trees with cereal crops, by highlighting the importance of sustainable income sources. Meanwhile, stakeholders, such as researchers, engineers, government officials, and agribusiness entrepreneurs, prioritize innovations that emphasize high water use efficiency, which is crucial for the resilience of dryland farming areas: for instance, rainwater harvesting or the use of drought-resistant crop varieties that directly address the need for water conservation. But in doing so they are overlooking broader aspects within the water–energy–food–ecosystem nexus.

Optimizing Ridge–Furrow Rainwater-Harvesting Strategies for Potato Cultivation in the Drylands of Northwestern China: A Regional Approach

The arid and semi-arid region of Northwest China plays a significant role in potato production, yet yields are often hampered by drought due to limited precipitation and irrigation water. The ridge–furrow rainwater-harvesting technology is an efficient and widely used technique to relieve drought impact and improve crop yield by changing the micro-topography to harvest rainwater to meet the water demand of crops. An analysis of precipitation, water demand, and runoff data spanning 30 years guided the selection of suitable rainwater-harvesting methods tailored to meteorological conditions. The results showed that potato water demand exceeded precipitation in the region. The mulching approach performed best in the western arid region with the most significant increase in yield and water use efficiency (WUE) and was suitable for the western semi-arid region and the agro-pastoral ecotone. In the potato dryland farming areas, the water deficit increased from southeast to northwest. Specifically, northern Gansu, northern Ningxia, and midwestern Inner Mongolia experienced a water deficit of over 200 mm, and rainwater harvesting combined with irrigation was recommended. Conversely, regarding deficits below 200 mm in southern Gansu, Ningxia, and central Inner Mongolia, a 1:1 or 2:1 pattern of ridges could be applied, and mulching was needed only in the necessary areas. For the southern Qinghai, Shaanxi, and eastern Inner Mongolia regions, ridge–furrow rainwater harvesting could be replaced by flat potato cropping. In summary, rainwater harvesting addresses water deficits, aiding climate adaptation in Northwest China’s arid and semi-arid regions. The implementation of mulching and ridge–furrow technology must be location-specific.

Impact of long-term tillage on the soil organic carbon storage and its composition in black soil.

Soil organic carbon (SOC) is essential for maintaining soil fertility and promoting sustainable agricultu-ral development. We investigated the impact of long-term tillage practices on soil organic carbon storage (SOCS) and its components in dryland farming areas of the black soil region, based on a 39-year tillage practice experiment. We compared the effects of different tillage practices (conventional rotary and ridge tillage, CT; no-tillage, NT; subsoiling tillage, ST; moldboard plowing, MP) on SOCS, active organic carbon components, and microbial necromass carbon (MNC) content in the 0-40 cm soil layer. The results showed that, compared to CT, NT significantly increased the contents of SOCS, SOC, dissolved organic carbon (DOC), microbial biomass carbon (MBC), easily oxidizable organic carbon (EOC), and MNC in the 0-20 cm soil layer. Both ST and MP significantly improved the contents of SOCS, SOC, and EOC in 0-20 and 20-40 cm soil layers compared to CT and increased MBC content in the 20-40 cm soil layer. Additionally, MP treatment significantly improved the contents of DOC, particulate organic carbon, and MNC in the 20-40 cm soil layer compared to other treatments. ST and MP significantly reduced the contribution rate of MNC to SOC in both soil layers compared to CT and NT treatments. Results of structural equation modeling showed that enhancing the mean weight diameter of soil aggregates, field capacity, and total phosphorus content, along with increasing the activities of β-glucosidase, amylase, and lignin peroxidase, could promote MNC accumulation. MP treatment facilitated the uniform distribution of SOC, active organic carbon, and MNC in the 0-40 cm soil layer, which was more conducive to the fixation of SOC in farmland in the black soil region.

Soil Amendment Combining Bentonite and Maize Straw Improves Soil Quality Cropped to Oat in a Semi-Arid Region

Soil amendments have been proposed as an effective way to enhance soil carbon stocks on degraded soils, particularly in dryland farming areas. Soil organic carbon (SOC) plays an important role in improving soil quality, and soil aggregates are known to be crucial in sequestering and protecting SOC. However, how aggregation and protection of SOC by aggregates respond to a single application of bentonite combined with maize straw remains unknown, especially in the sandy soil of a semi-arid region. A three-year field experiment with four treatments [no amendment (CK), maize straw amendment addition only (T1, 6 Mg ha−1), bentonite amendment addition only (T2, 18 Mg ha−1), and maize straw combined with bentonite amendment (T3, 6 Mg ha−1 maize straw plus 18 Mg ha−1 bentonite)] was conducted in the Loess Plateau of China to assess the effects of bentonite and maize straw on aggregation and SOC. The results indicated that soil bulk density decreased by 2.72–5.42%, and soil porosity increased by 3.38–8.77% with three years of T3 application, especially in the 20–40 cm layer, compared with CK. T3 increased the amount of C input, SOC stock, and SOC stock sequestration rate by 1.04 Mg ha−1 y−1, 0.84–1.08 Mg ha−1, and 0.49 Mg ha−1 y−1, respectively, and it increased the mass proportions and aggregate-associated C stock of >0.25 mm aggregates by 1.15–2.51- and 1.59–2.96-fold compared with CK. Correlation analysis showed a positive correlation of total SOC stock with the C concentration of >2 mm, 0.25–2 mm, and 0.053–0.25 mm aggregates. Aggregates of various sizes in sandy soils have the potential for greater SOC stock. Our findings suggest that the application of maize straw (6 Mg ha−1) combined with bentonite (18 Mg ha−1) would be an effective management strategy to enhance the bulk soil C pools by improving the soil structure and thereby improving soil fertility.

Integrated transcriptomic and metabolomic analyses reveals the molecular bases of alfalfa regrowth processes of new shoots after cutting under different water and nitrogen availability

Alfalfa regrowth is a complex process that is frequently constrained by deficits in water and N fertilisers after cutting. However, the transcriptomic regulatory networks and primary metabolic changes during regrowth are largely unknown. The alfalfa regrowth biomass responses to water deficiency and water deficiency supplied with N fertilisers and corresponding transcriptional and primary metabolic changes in new leaves and roots were systematically explored at 9 and 14 d after cutting. Water deficiency significantly decreased the alfalfa regrowth biomass. Integrated transcriptomic and metabolomic analysis demonstrated that osmoprotection related genes, sucrose and starch metabolic pathways, hormone biosynthesis and signalling pathways, and key transcription factors in new leaves and roots are responsible for alfalfa regrowth under water deficiency. Furthermore, alfalfa regrowth biomass was significantly improved in the presence of N fertilisers under water deficiency through multigene network coordination and metabolic pathway rearrangement. Interestingly, differentially expressed genes expression occurred predominantly in roots at 9 d after cutting, while it mainly occurred in the new leaves at 14 d after cutting. This study revealed the complex molecular mechanisms of alfalfa regrowth and provided theoretical support for optimal irrigation and N fertiliser strategies that will achieve maximum biomass of alfalfa in dryland farming areas.

Influence of the Role of Agriculture Extension Worker (AEW) Against Farming Group Dynamics In the Dry Land Agricultural Area, West Lombok Regency

The dynamism of farmer groups is influenced by internal factors, namely the farmer group itself, and external factors, namely the role of the Agriculture Extension Worker (AEW). This research was carried out in West Lombok Regency with the criteria of selecting 2 sub-districts in West Lombok Regency which had a larger dry land area compared to other sub-districts, namely Sekotong District and Lembar District; from each sub-district 3, villages were selected with the criteria of having the largest number of farmers, determining selected farmer groups based on criteria. Farmer groups have been registered in the Decree of the Head of the West Lombok Regency Agricultural Service and have been recorded in the agricultural extension system (simluhtan). This research aimed to analyze the role of AEW, the dynamics of farmer groups, and the influence of the role of Agriculture Extension Worker (AEW) on the dynamics of farmer groups in dryland farming areas in West Lombok Regency. The analytical method used was descriptive analysis with a Likert scale by giving a score of 1-5 for each criterion for each indicator. The research results showed that the respondents' assessment of the role of field agricultural instructors as facilitators, educators, motivators, and organizers was in a good category. Farming group dynamics seen from the aspects of group goals, group structure, task functions, group coaching and development, group cohesiveness, group atmosphere, and group effectiveness was in the quite good category, and the relationship/correlation between the role of AEW and the dynamics of farmer groups was very strong.

Interspecific competition and productivity in a dryland silage maize/alfalfa intercropping system

AbstractCereal–legume intercropping has the potential to reduce the use of nitrogen (N) fertilizer and increase forage yield and quality, however, how to optimize system design to fully realize interspecific complementary and enhance crop production in an annual and perennial crops intercropping was not well understood. This study was conducted to evaluate the interspecific interaction and yield performance of silage maize (Zea mays L.) and alfalfa (Medicago sativa L.) intercropping in response to N management and row arrangement under the rain‐fed conditions on the Chinese Loess Plateau. Five planting arrangements, namely, sole maize, sole alfalfa, and maize and alfalfa intercropping in rows of 1:2 (I12), 2:2 (I22), and 2:4 (I24), were compared over a period of 4 years (2018–2021). Two N‐levels (150 and 90 kg N ha−1) were applied to maize in each planting arrangement. Our results show that maize was the dominant species in 2018. In the next 3 years (2019–2021), maize was outcompeted by alfalfa during the first and second cuts of alfalfa, and complete recovery growth of maize was recorded at the third cut. The interspecific competition of I24 was less severe, resulting in a higher yield than I12 and I22. Although the reduction of N application reduced the biomass and crude protein (CP) yield, it weakened the interspecific competition and substantially increased the land equivalent ratio (LER). I24 under low N yielded more than sole cropping, with the LER based on biomass and CP yield of 1.01–1.12 and 1.08–1.18, respectively. In addition, I24 had the highest net revenue of 24,251 ¥ ha−1 on average. Therefore, maize/alfalfa intercrop with a higher alfalfa proportion and a wide strip arrangement (I24) in combination with low N application could alleviate interspecific competition and improve forage production, which is suggested for our study region and similar dryland farming areas worldwide. Maize/alfalfa intercropping provides a basis for grain and livestock mixed farming and helps to improve food supply and resilience of the farming system.

Diffusion and transformation of methane within the soil profile and surface uptake in dryland spring maize fields under different fertilizer application depths

It is important to assess the potential uptake of methane (CH4) in dryland farming and its contribution to global warming mitigation by elucidating the migration characteristics of CH4 in the soil profile. Therefore, before planting spring maize in the Loess Plateau region of China in 2019–2020, we applied fertilizer at soil depths of 5, 15, 25, and 35 cm (D5, D15, D25, and D35, respectively). The uptake of CH4 and diffusion flux were determined simultaneously in the soil surface and profile. We found that the dryland soil was a sink for CH4 and the cumulative CH4 uptake amount by soil without fertilization during the maize growth stage was 1.54 kg ha–1. Fertilization inhibited the uptake of CH4 by the soil, but deep fertilization promoted its uptake. The cumulative surface CH4 uptake amounts under D15, D25, and D35 were significantly higher than that under D5, i.e., by 42.4%, 105.6%, and 169.1%, respectively. The CH4 concentration and diffusion flux decreased as the soil depth increased, and CH4 diffused downward in the soil profile. The CH4 consumption rate was greater than the production rate in the 0–20 cm soil layer, whereas the opposite was found in the 20–30 cm layer. The surface CH4 uptake flux was significantly positively correlated with the diffusion flux in the 0–30 cm soil layer. Inorganic nitrogen (N) inhibited the diffusion of CH4 from the surface through the soil profile and its diffusion within the profile. The highest maize yield and biomass were obtained under D25. Therefore, increasing the fertilization depth can promote the uptake of CH4 by the soil in maize fields to alleviate climate change, and a fertilization depth of 25 cm is suitable for balancing the requirements for environmental protection and agricultural production. Our findings provide important insights into the production, consumption, diffusion, and uptake of CH4 in dryland farming areas.

Present status and future directions for management of root lesion nematode (Pratylenchus thornei) in chickpea

Chickpea is a popular legume crop in Asia and Africa's semi-arid regions. Crop production gains, on the other hand, have been modest, owing to biotic and abiotic stressors. Among the different biotic stresses, nematodes portray serious threat to chickpea production and colossal losses have been reported due to stress-free infection by other pathogens on infection with root lesion nematode (RLN). The worldwide distribution of two major species of RLN namely P. thornei and P. neglectus made them a focus research area especially on management aspect. In dryland farming areas of southeastern Australia, the P. thornei alone can cause yield losses of up to 40% in cereals and legumes. Despite the fact that chickpea breeders have been working persistently to generate superior chickpea varieties with increased resilience or tolerance to biotic and abiotic challenges, contemporary biotechnology technologies can help to speed up this process. To incorporate these tools and/or accelerate breeding programmes, identification of RLN resistant source with its genetic factor is first step in developing improved cultivars. However, study of resistance screening methods for chickpea against RLN is limited and standardization of different factors for development of a stable screening methodology distinguishing various levels of resistance is the need of the hour in RLN research.

Improvement in winter wheat productivity through regulating PSII photochemistry, photosynthesis and chlorophyll fluorescence under deficit irrigation conditions

Deficit irrigation is critical to global food production, particularly in arid and semi-arid regions with low precipitation. Given water shortage has threatened agricultural sustainability under the dry-land farming system in China, there is an urgent need to develop effective water-saving technologies. We carried out a field study under two cultivation techniques: (1) the ridge and furrow cultivation model (R); and (2) the conventional flat farming model (F), and three simulated precipitation levels (1, 275 mm; 2, 200 mm; 3, 125 mm) with two deficit irrigation levels (150 and 75 mm). We demonstrated that under the ridge furrow (R) model, rainfall harvesting planting under 150 mm deficit irrigation combined with 200 mm simulated precipitation can considerably increase net photosynthesis rate (Pn), quantum yield of PSII (ΦPSII), electron transport rate (ETR), performance index of photosynthetic PSII (Fv/Fm′), and transformation energy potential of PSII (Fv/Fo). In addition, during the jointing, anthesis and grain-filling stages, the grain and biomass yield in the R model are 18.9 and 11.1% higher than those in the flat cultivation model, respectively, primarily due to improved soil water contents. The winter wheat fluorescence parameters were significantly positively associated with the photosynthesis, biomass and wheat production. The result suggests that the R cultivation model with irrigation of 150 mm and simulated precipitation of 200 mm is an effective planting method for enhancing Pn, biomass, wheat production, and chlorophyll fluorescence parameters in dry-land farming areas.

The change of land use patterns and cover on the surface runoff in Krueng Meuraksa sub-watershed

The increasing population and the development of Lhokseumawe city from 2008-2018 resulted in changes in land use, therefore the type of land cover will be a benchmark for how much the surface run-off will occur. In this study there are six categories of land use types, thus are shrubs, plantations, settlements, open land, dryland farming and rice field. Krueng Meuraksa sub-watershed is in Lhokseumawe, North Aceh Regency, Aceh Province. The area of Krueng Meuraksa sub-watershed is 9,958.56 ha. This study aims to observe how the pattern of land use change and run-off in 2008–2018. This study uses secondary data collection methods obtained from related resources. The result shows that there is a change in land use where the area of land cover continues to increase in the residential area, on the contrary the area of land cover continues to decrease in dryland farming area. These changes lead to an increase in the coefficient of surface run-off in Krueng Meuraksa sub-watershed in 2008–2018, where in 2008 it was 0.726 and in 2018 it was 0.787. Based on the run-off coefficient, rainfall intensity and sub-watershed in Krueng Meuraksa, the amount of run-off was 333.403 m3/d in 2008 and 361.765 m3/d in 2018. The increase in the amount of run-off occurs as the run-off coefficient increases every year

Global sensitivity analysis of crop yield and transpiration from the FAO-AquaCrop model for dryland environments

• Key parameters were determined in 3 dryland areas for 84 growing seasons. • Key influential parameters are different for crop yield and transpiration. • Key influential parameters depend on the wetness condition. • Parameters’ impacts on canopy cover and biomass are stage-dependent. • Parameter sensitivities also vary with AquaCrop model version. The application of crop models towards improved local scale prediction and precision management requires the identification and description of the major factors influencing model performance. Such efforts are particularly important for dryland areas which face rapid population growth and increasing constraints on water supplies. In this study, a global sensitivity analysis on crop yield and transpiration was performed for 49 parameters in the FAO-AquaCrop model (version 6.0) across three dryland farming areas with different climatic conditions. The Morris screening method and the variance-based Extended Fourier Amplitude Sensitivity Test (EFAST) method were used to evaluate the parameter sensitivities of several staple crops (maize, soybean or winter wheat) under dry, normal and wet scenarios. Results suggest that parameter sensitivities vary with the target model output (e.g., yield, transpiration) and the wetness condition. By synthesizing parameter sensitivities under different scenarios, the key parameters affecting model performance under both high and low water stress were identified for the three crops. Overall, factors relevant to root development tended to have large impacts under high water stress, while those controlling maximum canopy cover and senescence were more influential under low water stress. Parameter sensitivities were also shown to be stage-dependent from a day-by-day analysis of canopy cover and biomass simulations. Subsequent comparison with AquaCrop version 5.0 suggests that AquaCrop version 6.0 is less sensitive to uncertainties in soil properties.

PENGARUH JARAK TANAM JAGUNG MANIS (Zea mays Saccharata STURT) DAN VARIETAS KUBIS (Brassica oleracea VAR. CAPITATA) TERHADAP HASIL JAGUNG MANIS DAN KUBIS PADA SISTEM TUMPANGSARI DI DESA CANDI KUNING, TABANAN

Diversification of plant species is needed to anticipate price fluctuation of vegetables. Intercropping system compared to monoculture can give more benefits to farmers. The arrangement of plant spacings of sweet corn and cabbage variety is expected to result in higher yields and benefits in intercropping. The field experiment, which had the objective to study the effects of plant spacing of sweet corn and cabbage variety on yields of sweet corn and cabbage in the intercropping system, had been conducted from March to July 2008. The experiment was carried out at the dryland farming area at Candikuning Village, district of Baturiti, Tabanan regency, 1.200 m asl. In the experiment, a randomized complete block design with two factors namely plant spacing of sweet corn (120 cm x40 cm, 180 cm x 40 cm and 240 cm x 40 cm) and variety of cabbage (Green Nova and Summer-Autumn) were used. Plant spacing of cabbage was 60 cm x 40 cm. All treatments were replicated four times. The results of the experiment showed that the effect of interaction between plant spacing of sweet corn and cabbage variety in intercropping was not significant on yields of sweet corn and cabbage. Individually, sweet corn plant spacing of 120 cm x40 cm gave the highest fresh weight of cob without husk (10,91 t ha"'), which was 44.50% and 80.93% respectively higher than the spacing of ! 80 cm x 40 cm and 240 cm x 40 cm. The spacing of 180 cm x 40 cm resulted in not the significantly different fresh weight of cob with husk but gave the highest fresh weight of cabbage heads (56.101 ha'1), which was 27.36% higher than that at sweet corn spacing of 120 cm x 40 cm and was not significantly different from that at 240 cm x 40 cm. Cabbage variety Green Nova gave the highest head (56.101 ha1), which was 14.48% higher than variety Summer-Autumn. Intercropping between cabbage variety Green Nova and Sweet corn at 180 cm x 40 cm spacing resulted in the highest benefit (Rp. 20,488125 t ha'1), which was Rp. 3,335500 higher than the average benefit of cabbage monoculture. The efficiency of land use in intercropping was higher (LER: 1.69) than in monoculture (LER: 1). It is suggested to use cabbage variety Green Nova intercropped with sweet corn at I 80 cm x 40 cm spacing. An experiment studying the effect of cabbage intercropped with sweet corn and other short season vegetables planted after harvesting cabbages is also suggested.

Responses of soil respiration to temperature under different mulching modes in a dryland corn field

Based on a 9-year field experiment, soil samples under straw mulching (SM), plastic film mulching (FM) and no mulching (CK) were incubated at 15, 25 and 35 ℃ for 60 d to investigate the responses of soil respiration to warming and its temperature sensitivity. The results showed that during the whole incubation period, soil respiration rate exhibited a unimodal distribution, while the cumulative soil respiration increased with an "S" curve. The cumulative soil respiration during the first 30 d accounted for about 75%-85% of total during the whole incubation period. The cumulative SM increased by 19.4% compared with CK, whereas no difference was detected between CK and FM. At 25 ℃ and 35 ℃, the mean soil respiration rate increased by 17.0% and 36.8%, and the cumulative CO2 release of soil respiration increased by 13.1% and 33.6%, respectively, compared with 15 ℃. No interaction was detected between mulching method and temperature. 97.7%-99.9% of variation in soil respiration could be explained by temperature change, with soil respiration being positively correlated with organic carbon and total nitrogen content. Compared with no mulching and plastic film mulching, straw mulching could significantly promote soil respiration by increasing the input of organic matter in the soil, but reduced the temperature sensitivity of soil respiration. Straw mulching rather than plastic film mulching would be more efficient at reducing CO2 emission in the Loess Plateau dryland farming area under the context of global warming.

Variations in soil fungal communities after continuous fertiliser treatment under the ridge and furrow rainfall harvesting system in a semiarid region of China

The ridge and furrow rainfall harvesting (RFRH) system enhances the rainfall use efficiency and crop yield in rain-fed areas of north-western China. In this study, we determined the effects of RFRH on the soil fungal community composition and diversity in a 5-year fertilisation experiment (N:P fertiliser rates of 0:0, 150:75, 300:150, and 450:225 kg ha–1 year–1) in the dryland farming area of the Loess Plateau. Excessive fertiliser application reduced the crop productivity and a moderate rate of 300:150 kg ha–1 year–1) produced the highest maize yield. The available phosphorus (AP), organic carbon, nitrate-nitrogen (NO3-N) and total nitrogen contents increased with the fertiliser rate, whereas soil water content decreased. The relative abundances of Ascomycota, Fusarium and Zygomycota increased (P < 0.05) with the fertiliser application rate, whereas those of Basidiomycota and Glomeromycota decreased (P < 0.05). The fungal diversity (Shannon–Wiener index: P = 0.016) and composition (unweighted UniFrac: P = 0.024) were significantly affected by fertilisation. The NO3-N and AP were the main factors that affected fungal composition and diversity. Thus, fertilisation changed the fungal community composition and diversity, and a higher fertiliser rate negatively affected nutrient cycling and the stability of the soil ecosystem under RFRH.

Assessment of erosion hazards due to land use change in Cianten subwatershed, Indonesia

Cianten subwatershed is a part of the Upper Cimanuk subwatershed which has high erosion values and important watersheds as it has several protection functions for the entire watershed. The research was conducted in Cianten subwatershed, Upper Cimanuk subwatershed, Garut district, West Java, Indonesia. The method used in this research was a comparative analysis survey. This method is performed by comparing the inter-time comparative effects of landuse change parameters and the prediction of erosion values with USLE formula in the period 2004-2016 in Cianten subwatershed. The results showed that there was a change of landuse type during the period 2004-2016 with the addition of land on paddy field with the width of 266,43 ha and open land with the width of 0.1 ha, while the reduction of the extent occurred in secondary dryland forest with an area of 13,75 ha, 166 ha of plantation forest, 12,9 ha of plantation, dry land farming area of 49,59 ha and shrubs of 0,98 ha. Areas that experienced the highest erosion grade class (class V) in the 2004-2016 period were in Leles District in Dano, Cangkuang, Kandangmukti and Jangkurang Villages. The highest erosion values in 2004, 2009, 2014 and 2016 were highest in open land on slope class >40%.

Influence of plastic film mulch on maize water use efficiency in the Loess Plateau of China

Water is the main limiting factor for crop growth in dryland farming areas. Plastic film mulch (PM) is widely used to improve water use efficiency (WUE) and increase crop yield over conventional methods (no mulch, NM) in China. To get a better understanding about PM influence on water use process in the field, we defined WUETWI as the ratio of yield (Y) to the total water input (TWI), and divided WUETWI into 4 steps by means of a systematic and quantitative approach. The 4 steps included ratio of available soil water (SW) to TWI (SW0+P, where SW0 is available soil water at the sowing, P is seasonal precipitation), ratio of crop evapotranspiration (ETC) to SW, ratio of crop transpiration (T) to ETC and transpiration efficiency (WUET, Y/T). Three field experiments were conducted to analyze the influence of PM on soil moisture content, water consumption, and the grain yield of dryland spring maize (Zea mays L.). Results showed that, compared with NM, spring maize yield of PM was increased by 28.6%, and the WUETWI of PM was increased by 26.4% on average in the experiment 1. Since ETc with PM was slightly higher than that with NM, the ETC/SW was increased by 3.9%. In the experiment 2, the T/ETC with PM was 77.7% on average, 30.6% higher than that with NM; the Y/T increased by 13.6% from NM to PM. Precipitation storage efficiency increased linearly with the percentage of PM. Improved crop growth under PM led to higher crop biomass and higher leaf area index, which might result in higher transpiration rate. The T/ETC under PM was also increased.

Pengaruh Populasi Tanaman terhadap Pertumbuhan dan Hasil Beberapa Varietas Jagung (Zea mays L.) Lokal di Lahan Kering

Penelitian di lahan kering bertujuan untuk mengetahui populasi tanaman yang berpengaruh meningkatkan pertumbuhan dan hasil jagung varietas lokal menggunakan rancangan acak kelompok dengan dua faktor yaitu populasi sebagai faktor pertama terdiri dari taraf perlakuan populasi 285.714 tan.ha-1, 357.143 tan.ha-1, 428.71 tan.ha-1 dan 500.000 tan.ha-1, yang diperoleh dengan menanam jagung sejumlah 4 tan.lubang-1, 5 tan.lubang-1, 6 tan.lubang-1 dan 7 tan.lubang-1 dalam jarak tanam 70 cm x 20 cm. Faktor kedua adalah varietas jagung terdiri dari taraf perlakuan Varietas Lokal Bukit, Lokal Kefa 1, Lokal Kefa 2 dan Bisi 2 sebagai kontrol. Hasil penelitian menunjukkan bahwa pada populasi 285.714 diperoleh hasil dengan berat biji kadar air 12% 7,78 g tongkol-1 dan berat biji kering oven 7,73g tongkol-1, dihasilkan oleh varietas lokal bukit. Populasi 285,714 tan.ha-1 secara tunggal memberikan hasil dengan berat biji kering oven tan-1 tertinggi (135,23g tan.-1) dan berat biji kering oven ha-1 tertinggi (7,73 t ha-1). Varietas Lokal Bukit secara tunggal memberikan hasil dengan berat biji kering oven 90,20 g tan.-1 dan berat biji kering oven 5,13 t ha-1, berpotensi dikembangkan di lahan kering khususnya di daerah Taman Mumbul, Kuta Selatan pada populasi 285.714 tan.ha-1 (4 tan.lubang-1).

Effects of conservational tillage on water characteristics in dryland farm of central Gansu, Northwest China.

Productivity is low and unstable in dryland farms of central Gansu, Northwest China. Conservational tillage is an important way for the sustainable development of agriculture. The effects of different tillage measures on soil moisture infiltration, evaporation, crop yield and water use efficiency (WUE) were investigated in this study based on a long-term experiment since 2001 in Longzhong. There were six treatments, i.e. conventional tillage with no straw (T), no-till with straw cover (NTS), no-till with no straw cover (NT), conventional tillage with straw incorporated (TS), conventional tillage with plastic mulch (TP), and no-till with plastic mulch (NTP), with annual rotation of spring wheat and pea. The results showed that compared with T, soil bulk density of NTS decreased and total porosity of soil increased significantly in wheat and pea land. Compared with conventional tillage, conservation tillage reduced soil infiltration rate in 0-5 cm in the pea field by 56.2%. Conservational tillage siginificantly increased soil saturated water conductivity in both wheat and pea lands. Compared with T, the saturated water conductivity in NTS was significantly increased by 52.8%-107.1%. Conservational tillage siginificantly reduced soil evaporation during growing season. Compared with T, the evapotranspiration of NTP, TP and NTS was significantly reduced by 14.4%-50.8%. The soil evaporation after rain was also decreased. Conservational tillage improved crop yield and water use efficiency by 9.5%-62.8% and 0.4%-50.9%, respectively. Therefore, conservational tillage could increase water use efficiency and crop yield in dryland farming area of central Gansu, Northwest China.