Productivity Enhancement in the Salt-Affected Lands of Joint Satiana Pilot Project Area of Pakistan

SUMMARY

Salt-affected lands are common in Pakistan and cover an area of 6.8 million ha; i.e., about one-third of the total cultivated area. Reduction in yield of different crops due to salinity and waterlogging is sometimes more than 60%, and annual losses under rice-wheat rotation have been calculated at Rs. 10 billion (US$ 166 million). Other adverse effects of salinity on the community are very large and about 16 million people are affected directly by the hazards of salinity and waterlogging. Average farmers in Satiana project area (38 villages) have 4–5 ha of land, of which approximately 55% are salt-affected. This area is equipped with a modern tile drainage system but it has not shown the expected impact on the rehabilitation of salt-affected soils. Farmers of Satiana area are poor and depend on off-farm activities for their livelihood. Nevertheless, they are keen to improve their soils. A productivity enhancement program was launched in the affected area, where saline agriculture was successfully demonstrated to restore the productivity of salt-affected lands and about 405 ha were successfully rehabilitated by planting salt-tolerant trees, forage shrubs, crops and applying gypsum to improve the soil conditions. Some relevant research studies used to develop the saline agriculture strategy have also been discussed.     

Management of Soil Salinity and Alkalinity Problems in India

SUMMARY

Like the problem of salt-affected soils afflicting many other countries with arid and semi-arid climates, these lands occupy about 8.6 M ha in India out of which 3.5 M ha are in canal commands, commonly referred to as man made or wet deserts. Starting from the early systematic work of Dr. Leather about a century ago, real impetus to development and application of reclamation technologies has occurred in the post independence period, especially the seventies. Salt-affected soils are grouped into saline and alkali/sodic soils on the considerations of soil management and crop responses. Out of the 3.4 M ha of alkali lands in Indo-Gangetic Plains, about 1.0 M ha has been reclaimed by the hydro-chemical technology. Application of amendments like gypsum, equivalent to 50% gypsum requirement, to the surface 15-cm soil only was enough to start cropping with rice. Light and frequent irrigation are ideal for upland crops. Application of higher doses of nitrogen in splits to compensate for volatilization losses, organic matter additions through green manure to increase reclaiming action, skipping phosphorus application in the initial years and the application of zinc to each crop were some of the emerging recommendations. Application of low-grade pyrites also gave encouraging results in calcareous soils. Feasibility of drainage has been successfully demonstrated in 1980s for the quicker rehabilitation of saline and waterlogged soils. Provision for subsurface drains at 1.5–2.0 m depth and 50–75 m spacing in alluvial soils and 12–24 m interval in vertisol was sufficient for facilitating growing crops within 2–3 years on lands lying barren for considerable period. However, technological, economic, social, and political considerations are the major bottlenecks for large-scale amelioration of saline soils, in addition to the safer disposal of drainage waters. Strategies worked out for successful crop production on saline soils after drainage include initial leaching management (minimizing water requirement for leaching by synchronizing with monsoon rains, etc.), proper selection of crops/cultivars, irrigation (method, controlled frequency for enhancing water-table contribution, canal water use during the initial stages including presowing for conjunctive use with drainage waters) and cultural practices (furrow planting, increasing seed rate and fertility management). Some of the future issues for combating salinity and also preventing further land degradations in India are also highlighted.     

Effect of drip irrigation on soil nutrients changes of saline–sodic soils in the Songnen Plain

A field experiment was carried out to research the changes and spatial distributions of soil nutrients in saline–sodic soil for different number of cultivated years under drip irrigation. The distributions of available potassium (AK), available phosphorus (AP), nitrate nitrogen (NO₃ ^?–N), ammonium nitrogen (NH₄ ⁺–N), as well as the amount of total nitrogen (TN), total phosphorus (TP) and organic carbon (OC) in the 0–40 cm soil layers in saline–sodic soils planted with Leymus chinensis for 1, 2, and 3 years were studied. The results showed that the distance from the emitter had an obvious effect on soil nutrients. Drip irrigation had substantial effects on levels of AK, AP, and NO₃ ^?–N. The contents of AK, AP, and NO₃ ^?–N were very high in the area near the emitter in the horizontal direction. In the vertical direction, levels of all of the available and total soil nutrients decreased with increased soil depth. Levels of AK, AP, NO₃ ^?–N, NH₄ ⁺–N, TN, TP, and OC all increased with continued cultivation of crops on saline–sodic soil using drip irrigation. Compared to the nutrients found in soils from the natural L. chinensis grasslands, the contents of AK and TP were higher in the drip-irrigated soils, although the contents of AP, NO₃ ^?–N, and NH₄ ⁺–N were broadly comparable. Given the rate of improvements in nutrient levels, we forecast that the nutrients in drip-irrigated saline–sodic soils should match those of the natural L. chinensis grasslands after 3–6 years of cultivation.     

A vegetation reconstruction method to plant <Emphasis Type="Italic">Sedum spectabile</Emphasis> Boreau using drip-irrigation with saline water on a coastal saline soil in region around Bohai Gulf

Soil salinity and saline groundwater are major constraints to the cultivation of crops and landscape plants in coastal regions. With the rapid industrialization and urbanization in these areas, there is an urgent need to improve the landscape to meet the increasing demand of living environments for cities and districts. The aim of this study was to propose a method to plant Sedum spectabile Boreau, a common landscape flower plant, on a very heavy coastal saline soil using drip-irrigation with saline water in region around Bohai Gulf. The salinity levels of irrigation water were 0.8, 3.1, 4.7, 6.3a, nd 7.8 dS/m, respectively. The results showed that the revegetation method, which mainly included ‘ridge planting + saline water drip-irrigation’, was effective in planting Sedum spectabile Boreau for reclaiming coastal saline silt soil. An soil matric potential (SMP) higher above ?5 kPa after transplanted and ?10 kPa after growing season ended, and 6 mm of irrigation water can be used as indicators for Sedum spectabile Boreau drip-irrigation scheduling with 100 % survival rate when irrigated with saline water at <7.8 dS/m in initially saline soils with a gravel–sand layer after tillage. This method is combined with comprehensive utilization of the saline water, agronomic measures, collaborative repair of the soil and plants to offer new views and theoretical support for the protection and development of saline land in coastal regions.     

Field Crop Production in Areas with Saline Soils and Shallow Saline Groundwater in the San Joaquin Valley of California

SUMMARY

Salinity in soil and water is irrevocably associated with irrigated agriculture throughout the world and as a result requires that salt management becomes an integral part of the production system. With careful water management, it is possible to sustain irrigated agriculture in areas with saline soil and saline groundwater with and without subsurface drainage. The results from two field projects conducted in an area with saline soils and saline groundwater demonstrated the type of irrigation systems and management needed to sustain production of moderately salt tolerant and tolerant crops. During the first study at Murrieta farms, yields of cotton and sugar beet were maintained using both saline and non-saline water for irrigation when pre-plant irrigation and rainfall were adequate to maintain soil salinity at a tolerable level. Wheat production was reduced in areas that used saline water for irrigation. Use of saline water containing toxic elements such as boron for irrigation poses a threat to the sustainability of the system. The second study evaluated the management of furrow and subsurface drip irrigation in the presence of shallow saline groundwater. Careful management of the furrow system during pre-plant irrigation and the first irrigation of the growing season was required to prevent waterlogging. It was possible to manage the subsurface drip system to induce significant crop water use from shallow groundwater. Rainfall and pre-plant irrigation were adequate at this site to manage soil salinity.     

云南澜沧县景迈古茶园土壤养分和土壤酶活性研究

云南省分布着大量的古茶园,被认为是普洱茶的起源。澜沧县景迈古茶园是典型的栽培型古茶园,在古茶园区内大平掌处选择相邻的古茶园、台地茶园和天然林三种利用类型的土壤,进行了土壤养分和土壤酶活性的调查。结果表明:三种类型的土壤都呈明显的酸性,土壤pH在3.80~3.91,茶园土壤的酸度相对更低;三种类型的土壤主要养分含量和酶活性在表层0~20cm都比下层20~40cm高,但Mg、Al和K无明显的垂直分布;三者有机质含量都很高,有机质和氮的含量分布为台地茶园<古茶园<天然林,而磷含量为古茶园最高;土壤酶活性的差异与养分的差异不一致,不同的酶活性在三种土壤中的大小规律不一样;土壤pH与金属元素相关性显著,氮元素与其它养分相关性最强,养分与土壤酶活性有显著相关性,尤其是C、N、P和K等主要营养元素。     

Natural Biodiversity for Salinity and Alkalinity Tolerance in Scented Rice Cultivar Kalanamak

Abstract

Soil salinity and alkalinity are a widespread problem in a number of rice (Oryza sativa L.) growing countries, particularly in South Asia. Kalanamak is one of the finest quality traditional scented rices of India. Tolerance of 40 lines of Kalanamak was evaluated at pH 4.5, 7.0 and 8.9, under in vitro conditions, both in the absence and presence of 70 mM NaCl and also in Usar soil in the field at a different pH. Different lines exhibited wide variability in their sensitivity to pH and/or salt, both under in vitro and in vivo conditions. In vitro, adverse effect of salt was more pronounced at high pH (8.9). Most of the lines that showed salt tolerance relative to root and/or shoot growth at high pH under in vitro conditions, e.g., 3119, 3120, 3120-1, 3126, 3128, 3130, 3131, 3216, 3216-1, 3222, 3256, 3278 and 3319 performed well in Usar soil in the field even at pH 9-9.5. Two high quality, panicle blast-resistant and relatively salt-tolerant lines (3119 and 3131) yielded equally well or better than coarse grain cultivar Narendra Usar-2 recommended for the cultivation on Usar soil. In a multilocation field trial, Kalanamak 3119 yielded well on alkaline, coastal saline and inland saline soils. This line holds great potential for cultivation on Usar soil.     

Wild halophytic species as forage sources: Key aspects for plant breeding

The use of wild halophytic species as forage resources in saline environments has gained increasing attention. Argentina ranks third in area of saline soils in the world, with a third of its territory showing various degrees of salinity, sodicity and/or alkalinity. On this type of soils, rangelands are the main forage resource for livestock production. Many wild species have forage potential and can also be used for the rehabilitation of rangelands and for intercropping. Information about these species, as well as on the physiological and genetic bases associated with salinity tolerance, provides relevant tools for efficient selection methods. This study addresses Argentine wild halophyte species with forage potential and describes selection criteria with an emphasis on the following taxa: (a) Poaceae: subfamily Chloridoideae and tribes Paniceae and Triticeae, (b) Fabaceae and (c) Amaranthaceae (formerly known as Chenopodiaceae). The review is intended to contribute to the general discussion on strategies for the improvement of wild plant genetic resources, using forage species naturally growing in saline soils in Argentina as a case study.     

Effect of salinity on yield and 2-acetyl-1-pyrroline content in the grains of three fragrant rice cultivars (Oryza sativa L.) in Camargue (France)

Aromatic quality of rice grains is known to vary greatly with environmental factors and cultivation methods. Among the environmental factors, soil salinity is thought to have a positive impact on the content of 2-acetyl-1-pyrroline (2AP) in grains, the key volatile compound of rice aroma. This study compared 2AP content in grains of three improved fragrant rice (Oryza sativa L.) varieties grown in two fields, differing mainly in their soil salinity level. The impact of salinity on yield and main yield components was also investigated to understand the relationship between aromatic quality and yield build-up. Soil salinity was monitored by measuring the electrical conductivity (EC) of soil solution samples extracted every week. 2AP content in grains was determined by a newly developed stable isotope dilution method involving solid-phase microextraction (SPME) and GC MS/MS analysis. The results showed an increase of 2AP content in grains with salinity for the three varieties. The relationship between 2AP and mean EC of the crop fitted a single model for the three varieties (R² = 0.728). In contrast, the impact of salinity on yield and yield components differed greatly between the three varieties. One variety appeared to be very sensitive to salt stress, with significant yield loss up to 40%, while the two other varieties proved to be resistant to the salinity levels experienced by the plants, with no significant yield loss or even higher yields in saline conditions. Nevertheless, the three varieties presented a significant negative correlation between 1000 grain weight (TGW) and the mean EC of the crop, and between TGW and 2AP content. It was concluded that the increase of 2AP content with salinity resulted partially from a 2AP concentration mechanism in smaller size grains. The direct effect of salinity on 2AP synthesis through stimulation of the proline metabolism is further discussed.     

Devastation of sesame (Sesamum indicum L.) crops in different agroclimatic zones of India by genetically diverse subgroups of phytoplasma

The sesame crop is highly susceptible to infection by phytoplasmas, a class of cell wall-less plant pathogenic bacteria (Mollicutes), which is responsible for widespread loss of sesame crops in both North and South India in recent years. Therefore, characterizing the pathogen population is required before the control measures can be devised and implemented. With molecular tools based on nested polymerase chain reaction (PCR) assays, sequencing, restriction profiling, and phylogenetic analysis, phyllody-affected sesame plants collected from nine different states of India were found to be infected by phytoplasmas belonging to two 16Sr groups, namely 16SrI and II. Two subgroups of phytoplasma −16SrI-B and 16SrII-D— were prevalent in symptomatic sesame samples collected from North India, whereas phytoplasma of only the 16SrII group was found in South India. However, the latter samples were diverse, belonging to three different subgroups (16SrII-A, II-C, and II-D). In addition, yearly phyllody-affected sesame samples from Delhi for 4 consecutive years (2007–2010) showed variation in the infecting phytoplasma: the subgroup 16SrII-D was detected in samples collected in 2007, and 16SrI-B was predominantly found in the samples collected in the subsequent years. The study also provides molecular evidence for the association between 16SrI-B phytoplasma and different symptoms in sesame crops such as fasciation, little leaf, and stunting. This is the first study to report the association of the phytoplasma subgroups 16SrII-A and II-D with sesame crops in India. This study provides a baseline for designing specific detection and molecular analysis strategies for quarantine purposes. It also highlights the need for examining the dynamics of seasonal or location-specific variation in vector populations to determine the pattern of infection outbreaks.     

不同培肥方式对茶园土壤团聚体中有机碳和全氮分布的影响

通过长期定位试验,研究不施肥（CK）、100%化肥（CF）和50%化肥+50%有机肥+豆科植物（IF）等3种处理对茶园黄红壤团聚体及其有机碳（TOC）和全氮（TN）分布的影响。结果表明,各处理均以≥2βmm水稳性团聚体占优势,其质量分数高达54.95%~66.97%;同时,该级水稳性团聚体中TOC、TN储量分别是相应全土总量的33.31%~45.45%和33.76%~46.60%。其中,不同粒径水稳性团聚体TOC和TN的贡献率在IF和CF处理中的大小排序为（≥2βmm）>（<0.5~0.25βmm）>（<1~0.5βmm）>（<2~1βmm）>（<0.25~0.106βmm）,而在CK中为（≥2 mm）>（<1~0.5βmm）>（<0.5~0.25βmm）>（<2~1βmm）>（<0.25~0.106βmm）。与CK相比,IF处理可显著（P<0.05）提升≥2βmm水稳性团聚体的含量和平均重量直径,增加该粒径水稳性大团聚体中TOC和TN的含量及储量。而且,≥2βmm水稳性团聚体含量与全土TOC、TN含量均呈极显著（P<0.01）的正相关。但是,IF处理土壤不同粒径团聚体的C:N比值一般比CK低。综上表明,处理IF不仅能增加土壤及其水稳性团聚体中TOC和TN的含量及储量,而且提高水稳性团聚体的稳定性,是茶园黄红壤固碳供氮的合理培肥模式。     

盐碱地马铃薯品种适应性研究

盐碱地对马铃薯的出苗、生长以及产量均有很大的影响。该试验采用轻盐碱和重盐碱２组设计，对马铃薯品种进行适应性鉴定，试图选出适应性强，表现好的优良种质，以解决青海省西部大部分盐碱地品种缺乏的问题。试验结果表明，品种间差异极显著，抗（耐）盐碱弱的品种出苗较差，甚至出苗后又因盐碱过重而死亡，而抗（耐）盐碱较强的品种，一旦出苗即能健壮生长。轻盐碱和重盐碱２组试验间的产量差异亦极显著，轻盐碱地的产量明显高于重盐碱地。经筛选，青２９１４和固８２５无论在轻盐碱地或重盐碱地均表现高产。     

Productivity of waterlogged and salt-affected land in a Mediterranean climate using bed-furrow systems

Waterlogging and dryland salinity in Western Australia (WA) as well as in many other parts of the world have long been recognized as major constraints to productive pastures and crops. In the late 90s, bed-furrow systems were introduced to waterlogged non-saline land in high rainfall areas of Australia. That resulted in significant yield increases of broad-acre crops through a reduction of the waterlogging. It was expected that yield gains could also be realised on waterlogged and saline land, of which more than 1 million ha is present in WA. This paper examines the productivity of crops and pasture of waterlogged and salt-affected land after the implementation of bed-furrow systems. Three sites were selected in the south western Wheatbelt of WA, with different rainfall regimes and with soil salinity ranging from none to extreme. The treatments were: pasture, cropping and raised beds (RB), no-till beds (NTB) and the Control. The distribution of salinity was mapped using an electromagnetic instrument (EM38). Pasture biomass and distribution were obtained from validated multispectral images. Grain yield and distribution were obtained from calibrated yield maps. In 4 of the 12 site-years, grain yields from the bed-furrow systems were statistically significantly compared to the Control. These were mostly associated with the site in the high rainfall region. The pasture biomass declined under the impact of summer and winter grazing and salinity. Bed-furrow systems did, in general, not generate higher grain yields for a given soil salinity compared to the Control. Relative yield - salinity relationships revealed a higher salt tolerance of the various crops compared to criteria published previously. It was also found that the interaction between waterlogging and salinity was not applicable since the timing of both issues did not coincide. Despite the grain yield gains at the high rainfall site using bed-furrow systems, cropping the low-lying salt-affected and potentially waterlogged land carries high risks. Provided these are accepted, growers with access to such land may be able to extend their cropping areas considerably. It is expected that bed-furrow systems are also beneficial in the waterlogged and salt-affected regions where topographical conditions and a precipitation surplus have created such conditions, like in some of the prairie states of North America.     

Shifts in Cropping System and Its Effect on Human Nutrition: Case Study from India

SUMMARY

More than twenty cropping systems are practiced in India. Rice-wheat and rice-rice are the major cropping systems practiced in an estimated 120 districts and 50 districts of the country, respectively. The rice-wheat cropping system (RWCS) of the Indo-Gangetic Plains (IGP) region of South Asia (Bangladesh, India, Nepal, and Pakistan) is the creation of the agricultural green revolution. Higher production of rice and wheat was necessary to meet the calorie needs of an increasing population in this region; as a result, the percent of malnutrition amongst children and adults decreased during the green revolution era. However, in recent years, there has been a reduction in both the rate of malnutrition decline and of the partial and total factor productivity of the RWCS in India. One of the many reasons for the decreased rate of malnutrition decline is micronutrient deficiency. Malnutrition amongst children and adults is a silent emergency in South Asia, including India. This review compares the food consumption habits, nutritional status, and cropping system practiced for different states of India to provide reasons for shifting the rice-wheat cropping system through crop diversification. Diversification of the RWCS will increase the supply of legumes and vegetables, help to diversify the diets consumed, and increase micronutrient intake. This approach is important for a largely vegetarian population of India, and is therefore, considered to be one of several important Food Systems strategy to address the silent emergency of malnutrition in the region.     

Effects of sulfosulfuron soil residues on barley (Hordeum vulgare), sunflower (Helianthus annuus) and common vetch (vicia sativa)

The phytotoxicity and sensitivity of succeeding crops to the new sulfonylurea, sulfosulfuron, have been reported although there is insufficient data on the phytotoxic effect of field soil residues. Growth chamber bioassays were conducted to detect the presence of residues in soil samples previously treated with sulfosulfuron at the recommended rate and double rate (20 and 40 g a.i./ha) that could affect the succeeding crop. Soil samples were collected between 7 and 9 months after sulfosulfuron application in field selectivity assays at nine different locations in Northern and Central Spain. The bioassay test species were barley (Hordeum vulgare L.) ‘Graphic’, sunflower (Helianthus annuus L.) ‘Albasol’ and common vetch (Vicia sativa L.) ‘Neska’, typical crops grown in rotation with wheat (Triticum aestivum L.) in this area. Sulfosulfuron residues did not affect barley and common vetch, but inhibited shoot length, root length and root dry weight of sunflower seeded into some soils treated with the 2× rate (40 g a.i/ha) 9 months earlier.     

Long-Term Reuse of Drainage Waters of Varying Salinities for Crop Irrigation in a Cotton-Safflower Rotation System in the San Joaquin Valley of California—A Nine Year Study: II. Safflower (Carthamus tinctorius L.)

Summary

This paper reports the results on safflower crops grown in a nine-year study, conducted on a 8 ha site, to determine the feasibility of using drainage water for irrigation in a 2-year cotton/1-year safflow-er rotation system. The cotton crops were irrigated with waters of 400, 1,500, 3,000, 4,500, 6,000, and 9,000 ppm total dissolved salts, and safflower was grown only with a preplant irrigation with nonsaline water. The use of drainage water for crop irrigation may be a means of decreasing its volume. Even though safflower was never irrigated with saline drainage water directly, the residual effect of using saline water for cotton irrigation adversely impacted safflower growth and development. Safflower seed yields were reduced in plots previously irrigated with waters of 4,500 ppm or higher salinity and even more severe effects on crop growth were seen as the numbers of years of irrigation with the saline water increased. After irrigating six cotton crops, the safflower seed yield in plots irrigated with 9,000 ppm waters was reduced to only 14% of the control. The safflower oil content and quality were not affected. Impacts on plant density, shoot height, shoot biomass, and leaf ionic content also are discussed.     

Validation of a simple potato growth model in the North Central United States

A simple potato growth model was validated in 1985 and 1986 at two dryland sites, Grand Forks, ND and Rosemount, MN, and one irrigated site, Hancock, WI. At each site, Russet Burbank potatoes were grown to maximize yield. Leaf area index and leaf, stem, root, and tuber biomass data were collected from replicated experiments every two weeks. Soil matric potentials, minimum and maximum temperatures, and solar radiation also were measured. Among sites, crop development rates and solar radiation receipts were similar, but final tuber yields differed by as much as 35 Mg/ha. Model predictions of leaf, stem, and tuber dry weights were similar to observed data both in terms of maximum values attained and seasonal development except for the experiment in Grand Forks in 1986 where the model over-estimated final tuber yield by 23 Mg/ha (115%). Soil aeration or salinity, factors not currently modeled, may account for this discrepancy. Modeled yield responses to defoliation were compared with field data from one of the experimental locations. At levels of defoliation below fifty percent, proportional yield reductions were similar between observed and modeled crops.     

Identifying the spatial variability of soil constraints using multi-year remote sensing

In north-eastern Australia, soil attributes such as salinity, sodicity, acidity, and phytotoxic concentrations of chloride constrain the growth of crops. It is difficult to delineate constrained areas using conventional sampling methods. Alternatively, where crops fail, over multiple years, to pass a certain yield threshold, we might infer the presence of a soil constraint. For a wheat-growing farm over 10-year period we used remote sensing to obtain a large volume of surrogate yield data, by calibrating an archive of Normalised Difference Vegetation Index (NDVI) to an archive of (limited) ground-based observations. The model used was a generalised additive model that related wheat yield as a non-linear function of NDVI and a linear function of post-anthesis rainfall. Field locations where predicted yield consistently failed to reach the 75th percentile in a given year, over a number of years, we regarded as limited by at least one unknown soil constraint. Soil samples averaged for the constrained locations showed, compared with the unconstrained locations, relatively high concentrations of subsoil chloride, and, in the topsoil, relatively high exchangeable sodium percentage, and unused nitrate nitrogen. On-farm experiments suggested that, for constrained areas, preclusion of monoammonium phosphate (MAP) fertiliser application, coupled to gypsum amelioration, could potentially benefit the farm by A$32/ha/year (MAP) and A$207/ha/3 years (gypsum).     

Simulation for response of crop yield to soil moisture and salinity with artificial neural network

In saline fields, irrigation management often requires understanding crop responses to soil moisture and salt content. Developing models for evaluating the effects of soil moisture and salinity on crop yield is important to the application of irrigation practices in saline soil. Artificial neural network (ANN) and multi-linear regression (MLR) models respectively with 10 (ANN-10, MLR-10) and 6 (ANN-6, MLR-6) input variables, including soil moisture and salinity at crop different growth stages, were developed to simulate the response of sunflower yield to soil moisture and salinity. A connection weight method is used to understand crop sensitivity to soil moisture and salt stress of different growth stages. Compared with MLRs, both ANN models have higher precision with RMSEs of 1.1 and 1.6 t ha⁻¹, REs of 12.0% and 17.3%, and R² of 0.84 and 0.80, for ANN-10 and ANN-6, respectively. The sunflower sensitivity to soil salinity varied with the different soil salinity ranges. For low and medium saline soils, sunflower yield was more sensitive at crop squaring stage, but for high saline soil at seedling stage. High soil moisture content could compensate the yield decrease resulting from salt stress regardless of salt levels at the crop sowing stage. The response of sunflower yield to soil moisture at different stages in saline soils can be understood through the simulated results of ANN-6. Overall, the ANN models are useful for investigating and understanding the relationship between crop yield and soil moisture and salinity at different crop growth stages.     

Crop performance in permanent raised bed rice–wheat cropping system in Punjab,India

Raised beds are widely used in agriculture in developed countries and have proven to be an excellent option for wheat. Permanent raised beds may also offer benefits for rice–wheat (RW) systems in South Asia, in terms of both production and the possibility that furrow-irrigation may be more efficient than flood irrigation. The performance of a RW system on permanent raised beds (37 cm wide, 15 cm high, furrow width 30 cm) was compared with conventional cultivation on the flat on sandy loam and loam soils in replicated experiments in central Punjab, India. The experiments commenced with wheat sown in November 2002, and were continued for 8 crops.