This introductory text on the design and analysis of sample surveys emphasizes the practical aspects of survey problems. It begins with brief chapters on the role of sample surveys in the modern world. Thereafter, each chapter introduces a sample survey design or estimation procedure by describing the pertinent practical problem. The authors describe the methodology proposed for solving the problem and provide the details of the estimation procedure, including a compact presentation of the formulas needed to complete the analysis. Then, a practical example is worked out in complete detail. At the end of each chapter, a wealth of exercises gives students ample opportunity to practice the techniques and stretch their grasp of ideas.

Elementary Survey Sampling

Involvement of antioxidants and lipid peroxidation in the adaptation of two cool-season grasses to localized drought stress

Plants in their natural habitats adapt to drought stress in the environment through a variety of mechanisms, ranging from transient responses to low soil moisture to major survival mechanisms of escape by early flowering in absence of seasonal rainfall. However, crop plants selected by humans to yield products such as grain, vegetable, or fruit in favorable environments with high inputs of water and fertilizer are expected to yield an economic product in response to inputs. Crop plants selected for their economic yield need to survive drought stress through mechanisms that maintain crop yield. Studies on model plants for their survival under stress do not, therefore, always translate to yield of crop plants under stress, and different aspects of drought stress response need to be emphasized. The crop plant model rice ( Oryza sativa) is used here as an example to highlight mechanisms and genes for adaptation of crop plants to drought stress.

Plant adaptation to drought stress.

In recent years the importance of sustainable agriculture has risen to become one of the most important issues in agriculture. In addition, plant diseases continue to play a major limiting role in agricultural production. The control of plant diseases using classical pesticides raises serious concerns about food safety, environmental quality and pesticide resistance, which have dictated the need for alternative pest management techniques. In particular, nutrients could affect the disease tolerance or resistance of plants to pathogens. However, there are contradictory reports about the effect of nutrients on plant diseases and many factors that influence this response are not well understood. This review article summarizes the most recent information regarding the effect of nutrients, such as N, K, P, Mn, Zn, B, Cl and Si, on disease resistance and tolerance and their use in sustainable agriculture. There is a difference in the response of obligate parasites to N supply, as when there is a high N level there is an increase in severity of the infection. In contrast, in facultative parasites at high N supply there is a decrease in the severity of the infection. K decreases the susceptibility of host plants up to the optimal level for growth and beyond this point there is no further increase in resistance. In contrast to K, the role of P in resistance is variable and seemingly inconsistent. Among the micronutrients, Mn can control a number of diseases as Mn has an important role in lignin biosynthesis, phenol biosynthesis, photosynthesis and several other functions. Zn was found to have a number of different effects as in some cases it decreased, in others increased, and in others had no effect on plant susceptibility to disease. B was found to reduce the severity of many diseases because of the function that B has on cell wall structure, plant membranes and plant metabolism. Cl application can enhance host plants’ resistance to disease. Si has been shown to control a number of diseases and it is believed that Si creates a physical barrier which can restrict fungal hyphae penetration, or it may induce accumulation of antifungal compounds. Integrative plant nutrition is an essential component in sustainable agriculture, because in most cases it is more cost-effective and also environmentally friendly to control plant disease with the adequate amount of nutrients and with no pesticides. Nutrients can reduce disease to an acceptable level, or at least to a level at which further control by other cultural practices or conventional organic biocides are more successful and less expensive.

Role of nutrients in controlling plant diseases in sustainable agriculture.

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Role of Nutrients in Controlling Plant Diseases in Sustainable Agriculture: A Review

Two experiments were conducted to investigate genotypic variations in morphological, anatomical, and physiological responses of roots to drought stress in tall fescue (Festuca arundinacea Schreb.). Such information would facilitate breeding programs and management practices for improving turfgrass drought resistance. Tall fescue cultivars 'Kentucky-31' (forage-type), 'Mustang' (turf-type), and 'MIC18' (dwarf, turf-type) were examined under well-watered or drought-stress conditions in a greenhouse. Root systems of MIC18 were much shallower and smaller than those of Kentucky-31 and Mustang under well-watered conditions. After 7 d of soil drying, root dry weight was significantly lower than that of well-watered plants for both MIC18 than Kentucky-31. The reduction in root dry weight, relative to control plants, was greater for MIC18 than Kentucky-31. Root water potential and turgor pressure were reduced with soil drying, leading to cortical cell shrinkage. Kentucky-31 roots suffered less turgor loss than those of MIC18 under drying conditions. Specific root length (SRL) and root/shoot ratio increased with soil drying. Greater increases in SRL occurred for Kentucky-31 than for MIC18. More extensive root hairs developed in plants of Kentucky-31 and MIC18 stressed for 14 d than in well-watered plants. Root hairs became less extensive after 28 d of drying. After 14 and 21 d of drying, Kentucky-31 roots had significantly lower electrolyte leakage than those of MIC18. Cultivar variations in anatomical, morphological, and physiological features of roots accounted for the variability in shoot performance under drought stress noted in a previous study.

Root Anatomical, Physiological, and Morphological Responses to Drought Stress for Tall Fescue Cultivars

Water requirements for 'Meyer' zoysiagrass (Zoysia japonica Steud., hereafter re- ferred to as zoysia), 'Midlawn' bermudagrass (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy, hereafter referred to as bermuda), 'Falcon II' tall fescue (Festuca arundinacea Schreb.) and 'Brilliant' kentucky bluegrass (Poa pratensis L., hereafter referred to as bluegrass) were evaluated under a mobile rainout shelter at defi cit irrigation levels of 20% to 100% of actual evapotranspiration (ET a ), applied twice weekly, between June and September 2001 and 2002. Soil was a river-deposited silt loam (fi ne, montmorillonitic, mesic Aquic Arquidolls). Minimum annual irrigation amounts required to maintain quality ranged from 244 mm for bermuda to 552 mm for bluegrass. Turfgrass species and respective irrigation levels (% of ET a ) at which season-long acceptable turf quality was maintained in each year were bluegrass, 100% (evaluated 2001 only); tall fescue, 60% in 2001 and 80% in 2002; bermuda, 60% in both years; and zoysia, 80% in both years. A landscape manager who could tolerate one week of less- than-acceptable quality could have irrigated tall fescue at 40% ET a (224 mm) in 2001 and 60% ET a (359 mm) in 2002. Likewise, bermuda exhibited unacceptable quality on only one September rating date when irrigated at 40% ET a (163 mm) in 2001. Bermuda was able to tolerate a lower leaf relative water content (LRWC) and higher level of leaf electrolyte leakage (EL) compared to other grasses before quality declined to an unacceptable level. Turfgrass water use rates often exceed natu- ral precipitation, and during extended periods without rainfall, restrictions may be imposed limiting water that can be applied to turf areas. As such, researchers have sought to identify turf species and cultivars that have good drought resistance (Aronson et al., 1987; Carrow, 1995; Fry and Butler, 1989), and irrigation manage- ment techniques to reduce water inputs. Some grasses, such as bermuda and tall fescue, have deep root systems that help them avoid drought when precipitation is limited (Qian et al., 1996). Others, such as zoysia, have shallower root systems, but tolerate drought using osmotic adjustment and other physiological mechanisms (Qian and Fry, 1997) Over the past 20 years, several researchers have addressed the subject of defi cit irrigation, returning water in amounts less than ET a , as a water conservation technique (Feldhake et al., 1984; Fry and Butler, 1989; Qian and Engelke, 1999). Turf managers overseeing installation of new golf courses, housing developments, and other turf areas are commonly queried by government administrators as to how much ir- rigation water will be required to maintain an acceptable quality turf in the landscape. How- ever, the amount of water required to maintain LRWC and EL of zoysia, bermuda, tall fescue, and bluegrass in the transition zone.

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Minimum water requirements of four turfgrasses in the transition zone

Understanding the effects of high temperature and poor soil aeration and their interaction on growth and physiology of creeping bent-grass (Agrostis palustris Huds) will help management and breeding programs to improve summer turf quality The objective of this study was designed to examine shoot physiological responses of 'Crenshaw' and 'Penncross' to high temperature and poor soil aeration Turf was maintained in growth chambers at day/night temperatures of 22/15 degrees C (optimum) or 35/25 degrees C (high temperature, HT) Soil aeration treatments were (i) adequate aeration with oxygen diffusion rate (ODR) at 15 micrograms cm-2 min-1 by maintaining the soil medium well watered and well drained and (ii) low aeration (LA) with ODR below 02 micrograms cm-2 min-1 induced by flooding the soil medium Turf growth, quality, chlorophyll content (Chl), and net photosynthetic rate (Pn) declined with increasing temperatures or declining aeration for both Crenshaw and Penncross The HT treatment increased canopy minus air temperatures (delta T) and dark respiration rates (Rn) for both cultivars, with a greater rise in Rn for Penncross (44%) than for Crenshaw (25%) The LA treatment inhibited Rn but had no effect on delta T The combination of HT and LA had more severe adverse effects than either HT or LA alone on turf quality, leaf chlorophyll content, photosynthesis, and respiration, particularly for Penncross The results demonstrated genetic variations in shoot physiological responses to high temperature and poor soil aeration stresses in creeping bentgrass and indicated that high temperature, when combined with poor soil aeration lead to turf quality decline This was mainly due to reduced net photosynthesis and increased respiration rates

Shoot physiological responses of two bentgrass cultivars to high temperature and poor soil aeration

Turf quality declines in creeping bentgrass (Agrostis palustris Huds.) with increasing temperatures and decreasing soil aeration. This experiment examined how root activities of 'Crenshaw' and 'Penncross' were affected by high temperature and low soil aeration. Turfgrass was maintained in growth chambers at day/night temperatures of 22/15°C (optimum) or 35/25°C (high temperature, HT). Aeration treatments were: (i) adequate aeration by maintaining soil medium well-drained; (ii) low aeration (LA) induced by maintaining soil medium saturated with water. Shoot dry matter production (SDM) declined with HT + LA at 7 days of treatment (DOT) in Penncross, and at 21 and 35 DOT with HT, LA, and HT + LA for both cultivars. Reduced root dry mass was measured at 7 DOT under HT + LA, and at 21 and 35 DOT under HT, LA, or HT + LA for both cultivars. Root viability was lower after 7 DOT and 21 DOT of HT, LA, and HT + LA. Viability was reduced more in Penncross than in Crenshaw after 21 DOT with HT + LA, and 35 DOT with HT and HT + LA. Root porosity increased with LA and HT + LA, beginning 7 DOT for both cultivars, to a greater extent in Crenshaw after 21 and 35 DOT with HT + LA. The combination of HT and LA had more severe effects on viability than either HT or LA alone. Results suggest that reduction in root growth, and particularly root viability, under HT and LA could contribute to the declines and cultivar variations in bentgrass quality.

Effects of High Temperature and Poor Soil Aeration on Root Growth and Viability of Creeping Bentgrass

Understanding factors associated with drought resistance and recovery from drought stress in tall fescue (Festuca arundinaces Schreb.) is important for developing resistant cultivars and effective management strategies. Our objective was to investigate water relations, photosynthetic efficiency, and canopy characteristics of tall fescue cultivars (forage-type 'Kentucky-31', turf-type 'Mustang', and dwarf-type 'MIC18') in responses to drought stress and subsequent recovery in the field and greenhouse. During drought stress under field conditions, 'MIC18' had lower turf quality, more severe leaf wilting, and higher canopy temperature than 'Mustang' and 'Kentucky-31', indicating that 'MIC18' was more drought-sensitive. The greenhouse study comparing 'K-31' and 'MIC18' showed that leaf water status, chlorophyll fluorescence, canopy green leaf biomass, and lead area index of both cultivars declined as soil dried. Reductions in relative water content, leaf water potential, chlorophyll fluorescence, canopy green leaf biomass, and leaf area index were more severe and occurred sooner during dry down for 'MIC18' than for 'Kentucky-31'. After rewatering following 14 days of stress, leaf water deficit and turf growth recovered, to a greater degree for 'Kentucky-31' than for 'MIC18'. However, soil drying for 21 days caused long-term negative effects on leaf photosynthetic efficiency and canopy characteristics for both cultivars.

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Jack Fry

Papers

Root Anatomical, Physiological, and Morphological Responses to Drought Stress for Tall Fescue Cultivars

Minimum water requirements of four turfgrasses in the transition zone

Shoot physiological responses of two bentgrass cultivars to high temperature and poor soil aeration

Effects of High Temperature and Poor Soil Aeration on Root Growth and Viability of Creeping Bentgrass

Water Relations and Canopy Characteristics of Tall Fescue Cultivars during and after Drought Stress