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Precipitation is crucial for water resource renewal, but climate change alters their frequency and amounts, challenging societies for correct and effective water management. However, modifications of precipitation dynamics appear to be not uniformly distributed, both in space and time. Even in relatively small areas, precipitation shows the coexistence of positive and negative trends. Local topography seems to be a strong driver of precipitation changes. Understanding precipitation changes and their relationship with local topography is crucial for society's resilience. Taking advantage of a dense and long-lasting (1920–2019) meteorological monitoring network, we analyzed the precipitation changes over the last century in a sensitive and strategic area in the Mediterranean hotspot. The study area corresponds to northern Tuscany (Italy), where its topography comprises mountain ridges and coastal and river plains. Forty-eight rain gauges were selected with continuous annual precipitation time series. These were analyzed for trends and differences in mean annual precipitation between the stable period of 1921–1970 and the last 30-year 1990–2019. The relationship between precipitation changes and local topography was also examined. The results show the following highlights: (i) A general decrease in precipitation was found through the century, even if variability is marked. (ii) The mountain ridges show the largest decrease in mean annual precipitation. (iii) The precipitation change entity over the last century was not homogenous and was dependent on topography and geographical setting. (iv) A decrease in annual precipitation of up to 400 mm was found for the mountainous sites. [ABSTRACT FROM AUTHOR]

Sustainable agriculture has garnered increasing attention in recent times, with corn stalk retention constituting a pivotal component of sustainable agricultural practices. Presently, whole corn stalk retention (CCR), three-year rotation corn stalk retention (TYR), and standing corn stalk retention (SCR) are prevalent corn stalk management techniques in northeast China. However, the question of which corn stalk management technique is best suited to specific local climates within northeast China remained unanswered. Therefore, this manuscript investigates the impact of these corn stalk management practices on nitrogen (N), phosphorus (P), potassium (K), and soil organic amendments by analyzing long-term practical data. To gather data for analysis, three locations with varying latitudes were selected. The results indicate that local climate has a significant influence (p < 0.05) on the decomposition process and level of retained corn stalks. In locations with sufficient annual accumulated temperature and precipitation, a larger amount of corn stalk retention is acceptable. For instance, CCR is deemed suitable for Liaoning Province in China. Conversely, in locations lacking sufficient annual accumulated temperature or precipitation, an excessive amount of corn stalk retention cannot decay completely within a given period. Consequently, farmlands cannot adsorb adequate soil nutrients or organic matter derived from decomposed corn stalks. Thus, TYR or SCR is more appropriate for Heilongjiang Province in China. The findings of this research can guide farmers in optimizing corn stalk management practices according to specific local climates. [ABSTRACT FROM AUTHOR]

With the continuous increase in the amount of mulch film, "white pollution" caused by plastic fragments (PF) has seriously affected agricultural production progress and poses a great threat to the safety and health of the agricultural environment. In the present study, PFs collected from 20 mulched agricultural farmlands in Sichuan Province were investigated. The PFs were separated and screened following the density flotation method. Optical microscopy was used to assess the fragments' distribution, abundance, color, size, and morphology, and Raman spectroscopy was used to identify the types. In addition, through the analysis of a questionnaire survey, a random forest (RF) model was conducted to assess the effects of environmental factors on the amount of PF. The results showed that the abundance of PFs was the highest in Lade Town, Zigong City, reaching 1158.33 ± 52.04 particles kg−1. Meanwhile, PFs were less abundant in Foyin Town, Luzhou City, with 50.00 ± 25.00 particles kg−1; the morphology features of PF in the cultivated soil were mainly transparent (60.06%) and flaky-like (83.41%), with sizes < 5 mm (63.61%). In total, 75% of the representative PFs were PE PFs, while PVC PFs were 25%. The RF model indicated that there were significant effects due to the total mulch film amount, annual precipitation, and planting pattern on the number of derived residues (PF). This study provides data indicating the urgent need to prevent and control plastic pollution in mulch farming, specifically in the soils of Sichuan Province. [ABSTRACT FROM AUTHOR]

Hydrological variable frequency analysis is a fundamental task for water resource management and water conservancy project design. Given the deficiencies of higher distribution features for the upper tail section of hydrological variable frequency curves and the corresponding safer resulting design of water conservancy projects utilizing the empirical frequency formula and Pearson type III function-based curve fitting method, the normal cloud transform algorithm-based model for hydrological variable frequency analysis was proposed through estimation of the sample empirical frequency by the normal cloud transform algorithm, and determining the cumulative probability distribution curve by overlapping calculation of multiple conceptual cloud distribution patterns, which is also the primary innovation of the paper. Its application result in northern Anhui province, China indicated that the varying trend of the cumulative probability distribution curve of annual precipitation derived from the proposed approach was basically consistent with the result obtained through the traditional empirical frequency formula. Furthermore, the upper tail section of the annual precipitation frequency curve derived from the cloud transform algorithm varied below the calculation result utilizing the traditional empirical frequency formula, which indicated that the annual precipitation frequency calculation result utilizing the cloud transform algorithm was more optimal compared to the results obtained by the traditional empirical frequency formula. Therefore, the proposed cloud transform algorithm-based model was reliable and effective for hydrological variable frequency analysis, which can be further applied in the related research field of hydrological process analysis. [ABSTRACT FROM AUTHOR]

A constrained stochastic weather generator (CSWG) for producing daily mean air temperature and precipitation based on annual mean air temperature and precipitation from tree-ring records is developed and tested in this paper. The principle for stochastically generating daily mean air temperature assumes that temperatures in any year can be approximated by a sinusoidal wave function plus a perturbation from the baseline. The CSWG for stochastically producing daily precipitation is based on three additional assumptions: (1) In each month, the total precipitation can be estimated from annual precipitation if there exists a relationship between the annual and monthly precipitations. If that relationship exists, then (2) for each month, the number of dry days and the maximum daily precipitation can be estimated from the total precipitation in that month. Finally, (3) in each month, there exists a probability distribution of daily precipitation amount for each wet day. These assumptions allow the development of a weather generator that constrains statistically relevant daily temperature and precipitation predictions based on a specified annual value, and thus this study presents a unique method that can be used to explore historic (e.g., archeological questions) or future (e.g., climate change) daily weather conditions based upon specified annual values. [ABSTRACT FROM AUTHOR]

Annual precipitation inputs to the Lake Mweru basin, Zambia, were computed from historic data and recent gridded data sets to determine historic (1925–2013) changes in lake level and their potential impacts on the important fisheries of the lake. The results highlight a period from the early 1940s to the mid-1960s when interannual variability of inputs doubled. Existing lake level data did not capture this period but they did indicate that levels were positively correlated with precipitation one to three years previously, reflecting the hydrologic storage of the lake, the inflowing Luapula River and the upstream Bangweulu wetland complex. Lag cross-correlations of rainfall to El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole were weak and spatially and temporally discontinuous. The two drivers were generally positively correlated and induced opposing effects upon annual precipitation and lagged lake levels. This correlation became non-significant during the time of high observed interannual variability and basin inputs were prone to the vagaries of either driver independently or reinforcing drought/excess conditions. During times of high flows and persistent elevated lake levels, breeding habitat for fish increased markedly, as did nutrition supplied from the upstream wetlands. High hydrologic storage ensures that lake levels change slowly, despite contemporary precipitation totals. Therefore, good conditions for the growth of fish populations persisted for several years and populations boomed. Statistical models of biological populations indicated that such temporally autocorrelated conditions, combined with abundant habitat and nutrition can lead the "boom and bust" of fish populations witnessed historically in Lake Mweru. [ABSTRACT FROM AUTHOR]

The reported effects of nitrogen (N) fertilizer on wheat yield and nitrogen use efficiency (NUE) vary greatly, due to differences in climate, soil factors, and N management practices in different regions of China. We collected literature published during 1950–2017 that reported the yield and NUE for wheat in China, under N application and control treatments, and analyzed the data therein. A significant increase in yield was observed with N application, and varied with climate, soil factors, and N management practices in different regions. A larger increase in yield was observed under an average annual temperature of 13–15 °C, an average annual precipitation of >800 mm, respectively. Greater yield-increasing effects were observed in soil with a coarse soil texture, lower soil total N, available N, and a soil pH of ≤7 and >8, respectively. In Northwest China, the yield increase was greater under multiple coated urea applications after anthesis, while the higher NUE was observed under single coated urea application before anthesis. In North China, the yield and NUE were greater under multiple coated urea applications before anthesis. In South China, the yield and NUE were greater under multiple N applications. Consequently, to improve wheat yield and NUE, site-specific N management practices should be adopted. [ABSTRACT FROM AUTHOR]