The aim of this work is to promote the use of local organic wastes (leaves, lifs, Kornav) of date palm, as organic fertilizer, to improve the microbiological activities of sandy soil, especially the process of carbon mineralization. To do this we adopted the method of incubation under controlled parameters on representative samples of sandy soils of arid regions. It is a sandy soil taken from the southern region of Algeria, Ouargla. The analysis of overall results demonstrated a positive and significant effect of date palm residues on soil microbial activity. Thus, after 42 days of incubation, the cumulative amounts of CO2 released are 14.37 and 40.02 mg/100 g dry soil, respectively in soil enriched and unenriched (control) by the residues of date palms. Regarding the influence of these residues on microbial density, we observed a stimulatory effect of functional groups studied (cellulolytic and amylolytic germs) as well as total and fungal microflora. The overall results show the advantage of using date palm residues for improving microbiological functioning and microbial density of the sandy soil of desert areas.

The distribution and turnover of organic carbon (OC) and nitrogen (N) associated with aggregates in soils is critical for understanding the behaviour of C and N in soils. We collected soil samples from aspen (Populus simonii Carr.) woodland in the semi-arid Loess Plateau of China to investigate the distribution of aggregate-associated OC and N. The distribution of aggregates and aggregate-associated OC and N were measured, and OC and N stocks in each aggregate fraction were calculated. Across the sites and soil depths, microaggregates and the silt + clay fraction dominated the distribution of soil aggregates, which varied with site. Organic C and N accumulated mainly in the macro- and micro-aggregate fractions in loamy soils but in the silt + clay fractions in sandy soils. The OC and N stocks in the bulk soil of aspen woodland were determined by the OC and N stocks associated with silt + clay fraction. The results of this study indicate that soil texture may play an important role in assessing the distributions of soil OC and N in both bulk soils and aggregate size fractions in aspen woodland, especially in semi-arid regions. Furthermore, the establishment of aspen woodland would result in greater accumulation of OC and N in loam soils than in sandy soils.

Understanding soil evaporation in reforestation processes in an area of extreme drought is important. We examined the effects of drip-irrigated, high-salinity groundwater on the formation of soil salt crusts and subsequent soil evaporation in the Taklimakan Desert Highway Shelterbelt. Soil evaporation was measured using micro-lysimeters (MLS, 20 cm in length x 10 cm in diameter), and chemical characteristics, including SOM, total salts, ion composition and pH, were analyzed. The results showed that the inhibition efficiency of salt crusts on soil evaporation decreased from the surface to the lower soil layers. Following irrigation, the inhibition efficiency was 33.0% in the shelterbelt, which was much higher than the 13.8% observed for the bare soil. Total salt content and ion contents (Cl-, Na+, and SO42-) were much higher for the soil salt crusts than for shifting sandy soils, while the contents of other ions (Mg2+, K+, Ca2+, HCO3-, and CO32-) were very similar. The total salt content and ion composition of the salt crusts increased during the first 2 years of shelterbelt age, and decreased from 2 to 5 years. With the increasing age of the shelterbelts, the SOM of the salt crusts increased, whereas the total salts and pH decreased. We concluded that the formation of soil salt crusts results in reduced soil evaporation and the soil chemical condition functioned better for growth of the Taklimakan Desert Highway Shelterbelt.

Innovative strategies are needed to improve water and nutrient use efficiencies for sustainable production in sandy soils. Our objective was to determine the effects of applying cattle manure combined with zeolite and chemical fertilizer on (1) sunflower (Helianthus annuus L) yield and quality and (2) nutrient leaching under two irrigation regimes on a sandy soil in a semi-arid region of Iran. The experiment was carried out using a randomized complete-block design, with a split-plot arrangement of treatments and four replications. Irrigation regime (I-1: full irrigation and I-2: limited irrigation) provided the whole-plot treatments with five fertilization strategies (F1: urea, F2: urea + composted manure (CM) with 0% (w/w) zeolite, F3: urea + CM with 7% zeolite, F4: urea + CM with 14% zeolite and F5: urea + CM with 21% zeolite) providing the sub-plots. Our results showed that limited irrigation (I-2) significantly decreased dry matter yield by 10% in 2008 and 9% in 2009. Dry matter and seed yield were considerably improved by the application of manure + zeolite in both years, but the impact of their application was greater in the second year than in the first. In both years, the maximum seed protein content was achieved with the F-5 treatment, while minimum seed protein content was observed in the F-2 and F-1 treatments for 2008 and 2009, respectively. Maximum irrigation water productivity was found with the I2F5 treatment combination in 2009 (0.81 kg m(-3)), while the minimum value was found for the I1F1 combination in 2008 (0.48 kg m(-3)). The highest and lowest rates of nitrate leaching were obtained from the I1F1 (36 kg ha(-1)) and I2F5 (11 kg ha(-1)) treatment combinations, respectively. Fertilizing only with urea (F-1) resulted in the highest nitrate leaching across both irrigation regimes, while the integrated treatments (F-2, F-3, F-4 and F-5) significantly decreased nitrate leaching, compared to the F-1 treatment, particularly with full irrigation (I-1). Addition of zeolite to the CM also decreased P leaching but not as much as for nitrate leaching. We concluded that amending soil with manure and zeolite can be a beneficial approach for decreasing chemical fertilizer application rates and improving the sustainability of agricultural systems. (C) 2012 Elsevier B.V. All rights reserved.

Irrigation with treated wastewater (TWW) is commonly practiced in Israel to relieve freshwater (FW) shortages. We hypothesized that the organic matter (OM) originating from TWW irrigation alters the physico-chemical properties of the soil, induces water repellency in the soil's top layer, and consequently alters water distribution in the soil profile. In measurements taken in an avocado orchard on a clayey soil, water repellency was found in TWW-irrigated plots. In addition, smaller wetted surface areas were recorded around the drippers in comparison with FW drippers. Drier zone below soil surface was observed in TWW-emitting drippers. OM extraction from the different plots exhibited differences in quantity and quality of organic substances between TWW- and FW-irrigated soils, with a higher quantity of hydrophobic substances in the TWW-irrigated soil extract.

Considering extreme events of climate change and declining availability of appropriate quality water and/or highly productive soil resources for agriculture in dryland regions, the need to produce more food, forage and fibre will necessitate the effective utilization of marginal-quality water and soil resources. Recent research and practices have demonstrated that effective utilization of these natural resources in dry areas can improve agricultural productivity per unit area and per unit water applied. This paper focuses on the following three case studies as examples: (1) low productivity soils affected by high levels of magnesium in soil solution and on the cation exchange complex; (2) degraded sandy soils under rainfed conditions characterized by low water-holding capacity, organic matter and clay content and (3) abandoned irrigated soils with elevated levels of salts inhibiting growth of income generating crops. The results of these studies demonstrate that application of calcium-supplying phosphogypsum to high-magnesium soils, addition of clays to light textured degraded soils and phytoremediation of abandoned salt-affected soils significantly improved productivity of these soils. Furthermore, under most circumstances, these interventions were economically viable, revealing that the efficient use of marginal-quality water and soil resources has the potential to improve livelihoods amid growing populations in dry areas while reversing the natural resource degradation trend. However, considerably more investment and policy-level interventions are needed to tackle soil degradation/remediation issues across both irrigated and dryland agricultural environments if the major challenge of producing enough food, forage and fibre is to be met. Copyright (c) 2011 John Wiley & Sons, Ltd.

Cactus pear (Opuntia spp.) is an important resource in arid and semi-arid areas because of its ecological and socio-economic roles. The Moroccan newly implemented agriculture sector strategy Morocco Green Plan, Plan Maroc Vert included cactus as a major crop in many regions. In Morocco, because of a lack of research results, farming practices are very basic even if yields can significantly be improved. On the other hand research conducted in other countries (Italy, Mexico, etc.) showed that mineral nutrition is beneficial and largely soil type related. In order to improve agronomic practices INRA Agadir developed and implemented an agronomic research program on Cactus at Melk Zhar Experiment Station of INRA-Agadir. Mineral nutrition management is a key component of this project. The objective of the study was to determine the effect of nitrogen, potassium, phosphorus and magnesium amount on yield and quality of Opuntia ficus-indica. The treatments, applied on existing orchards and on newly planted ones, are: 0, 80 kg N/ha combined with 120 kg K/ha and 60 kg Mg/ha. The testing was conducted on 14 best ecotypes selected out of the national germplasm collection (with more than 200 ecotypes). The tests were conducted on a sandy soil with low organic matter content. The variables measured are: plant height, flowering, fruit yield component (weight, number/plant) and fruit sugar content. In general, the results indicate that measured variables showed differences among treatments. Nitrogen had significant impact on growth. Fertilization increased number of nopalitos three times, flowering started 5 to 15 days earlier compared to control. Regarding fruit quality, mineral nutrition improved Brix 1.5%. Finally, the different impacts induced by mineral nutrition improved general net return 15 to 25%.

本发明公开了一种干旱区重盐碱地花坛建造及花卉种植方法，涉及土壤改造方法和绿地草坪种植技术领域。一种干旱区重盐碱地花坛建造及花卉种植方法，包括18个步骤，本发明具有快速脱盐、长效持久、节约用水、节约成本、彻底清除杂草，促进园林植物生长等多种优点。

本发明涉及一种增强输电线路塔基冻土基础稳定性的措施，该措施是指首先在输电线路的塔基基础周围埋设重力式热管；然后在所述塔基基础的顶部桩端及桩体周围水平层布设保温材料；最后在地表以上围绕所述塔基基础的塔腿修筑并密实高出地表带坡降的土层即可；所述土层的内部铺设有带坡降的隔水膜。本发明将重力式热管和保温材料进行有效结合，不但可以大幅减少重力式热管的实际应用数量，在工程上可以大幅降低工程投资，减少施工难度、缩短工程措施的施工周期，而且本发明总体效能与采用热棒单一措施相比，其对输电线路冻土塔基的整体降温效能和维持塔基基础的长期稳定性均得到成倍提高和根本改变。

本发明涉及一种具有冷却效能的隔水箱阻止多年冻土上限层向基坑汇水的方法，其特征是：在设计基坑周边开挖坑槽，埋设中空隔水箱，中空隔水箱的结构是其上端开放，与外界相通，四周封闭；中空隔水箱的底部深度到达多年冻土上限以下10-50cm的位置，填土夯实，埋设平面位置距离拟开挖基坑的边缘的间距为0.5-5m。本发明通过多年冻土区冬季施工过程自然冷能的充分利用，发挥基坑四周中空隔水箱构筑的冻结壁有效作用，避免冻结层上水向基坑内大量汇集，有效保证了工程施工的顺利进行和施工工期完成的同时，降低基了坑周边冻土温度的不断，进一步保证了冻土工程的稳定性。