Tillage systems for cotton on Mississippi river delta and loessial plains soils

Abstract

With the economic need for conservation of fuel, equipment, time, and labor, reducing inputs becomes increasingly important. A field experiment was conducted to determine the effectiveness of cultural practices such as in‐the‐row subsoiling, reduced preplant tillage, and reduced post‐plant tillage on silt loams and clay soils of the Mississippi River Delta and loessial plains. The experiment was conducted at the same sites on four soils for five growing seasons. The yield response of cotton (Gossypium hirsutum L.) to these cultural practices was determined. Minimum seedbed preparation averaged two tillage trips less than conventional seedbed preparation and post‐plant mechanical cultivations averaged 3.3 trips each year. At harvest, no significant difference due to cultural practices were found with plant population, plant heights, or percent lint at first picking. Lint yield differences as influenced by seedbed preparation were nonsignificant. Post‐plant cultivation resulted in 100 kg/ha higher lint yield on those soils that restricted root penetration. No differences due to tillage were found in the seasonal petiole nitrate concentrations indicating that mechanical tillage did not appreciably influence the ratio of nitrogen (N) to dry matter in the cotton plants. Soil water content of the conventional seedbed preparation with post‐plant cultivation was generally higher than the reduced seedbed preparation. This was attributed to an increase in infiltration and decrease in evaporation of water.     

Significance of fruit transpiration on calcium nutrition in developing apricot fruit

The first objective of this study was to search for a possible correlation between accumulation of calcium (Ca), potassium (K), and magnesium (Mg) and fruit transpiration in developing apricot (Prunus armeniaca L.) fruit. Secondly, the work aimed to determine the significance of transpirational flux on Ca nutrition. We hypothesized that if the fruit transpiration is the determining factor of Ca accumulation (phloem‐immobile element) then the import of Ca would be suppressed by restriction of fruit water loss, while the import of phloem‐mobile nutrients (i.e., K and Mg) would not be. To test this hypothesis, the seasonal changes of transpiration and of Ca, K, and Mg concentration/accumulation were assessed in fruits left to naturally transpire or under restricted transpiration (bagged fruits). Fruit transpiration was measured on detached fruits using a portable gas‐exchange equipment (ADC‐LCA4, ADC BioScientific Ltd, Hoddesdon, England). Results demonstrated that 83% of total fruit Ca content was gained within the first 4 weeks after fruit‐set, and that Ca import ceased concomitantly to a reduction of transpiration. In spite of the limitation of fruit transpiration, Ca entered the nontranspiring fruits, and its concentration was about 45% of that in control fruits suggesting that other factor(s) operated for Ca accumulation. This study provides the evidence that fruit transpiration accounted for 55% of total Ca that entered a fruit. We conclude that optimal soil Ca availability and apportioning to the fruit during the early 4 weeks of growth are essential to sustain the fruit demand of this nutrient and that some cultural practices (e.g., summer pruning, irrigation) should be tested as possible tools to improve fruit Ca nutrition via increasing fruit transpiration.     

Losses in Nitrogen Uptake by Tomato and Pepper Due to Infestation by the Weed Barnyardgrass

Abstract

Glasshouse experiments showed that the weed “barnyardgrass” (Echinochloa crus‐galli) competes for nitrogen (N) with tomato and pepper crops. Competition was more severe with pepper than with tomato, and greater in both crops the earlier the weed emerged or the longer it grew with the crops. This competition affected growth attributes, fruit yield and its components, and N uptake in both crops. Shoot N content was also affected in pepper. Significant damage to both crops occurred even when weed emergence was as late in the crop growth season as the beginning of flowering.     

Patterns of endorhizal fungal associations in fruit crops of southern India

A survey on the endorhizal status of 39 fruit crops of 25 families, indicated that 22 fruit crops had arbuscular mycorrhizal (AM)–, four had dark septate endophyte (DSE)–fungal association, and 13 had dual colonization of AM and DSE fungi. Fruit crops were capable of forming Arum‐, Paris‐, or intermediate‐types of AM morphologies of which intermediate‐type was common. To our knowledge, we report for the first time AM in 10 fruit crops and DSE‐fungal association in 17 fruit crops. The extent of AM‐ and DSE‐fungal colonization ranged from 41% to 98% and < 1% to 89.9%, respectively, in different fruit crops. Arbuscular mycorrhizal–fungal spore numbers in the rhizosphere ranged from 6 to 61 spores per 25 g of soil. Arbuscular mycorrhizal–fungal spores belonging to Acaulospora, Glomus, and Scutellospora were isolated from the rhizosphere soil.     

Seasonal patterns of nitrogen,phosphorus, potassium,calcium and magnesium in the leaves of the massachusetts cranberry

Abstract

Leaf samples from cranberry plants in Wareham, Massachusetts were collected during the 1980–82 growing seasons and analysed for N, P, K, Ca and Mg. The seasonal patterns which emerged allowed the proposal of normal ranges for the elements and optimum times for sampling. The foliar nutrient levels obtained were compared to those for cranberries grown in other areas as well as to those for crops which are grown under similar conditions.     

Chemical evaluation of vegetables grown with conventional or organic soil amendments

Abstract

Garden vegetables were grown with “organic”; or “commercial”; fertilizer amendments to the soil. Plot preparation and other general cultural practices were identical. Tomatoes, potatoes, peppers, lettuce, onions and peas were planted, and leaf tissue and edible produce were harvested. N, P, K, Ca and Mg and content of ascorbic acid were determined in some of the produce. Certain vegetables were evaluated by a trained taste panel for palata‐bility differences. Generally, the conventional plots produced more yield of vegetables, although seasonal variation was greater than variation due to soil amendments. Mineral content was essentially the same from both regimes. The taste panel preferences were not consistent. From these data, it was concluded that the two methods of vegetable production were equal for quality and nearly equal for yield over the two years.     

Sustaining Soil Quality with Legumes in No‐Tillage Systems

Abstract

Tillage, cropping system, and cover crops have seasonal and long‐term effects on the nitrogen (N) cycle and total soil organic carbon (C), which in turn affects soil quality. This study evaluated the effects of crop, cover crop, and tillage practices on inorganic N levels and total soil N, the timing of inorganic N release from hairy vetch and soybean, and the capacity for C sequestration. Cropping systems included continuous corn (Zea mays L.) and stalk residue, continuous corn and hairy vetch (Vicia villosa Roth), continuous soybeans (Glycine max L.) plus residue, and two corn/soybean rotations in corn alternate years with hairy vetch and ammonium nitrate (0, 85, and 170 kg N ha^?1). Subplot treatments were moldboard plow and no tillage. Legumes coupled with no tillage reduced the N fertilizer requirement of corn, increased plant‐available N, and augmented total soil C and N stores.     

Nutrient balance and fruit guality of marsh grapefruit growing in Southeastern Spain

Abstract

This paper describes the results of tracking the leaf levels of eight essential elements in Marsh grapefruit, growing in Southeastern Spain. The seasonal variation in leaf composition are discused from the view of the plant requirements promoted by the different physiological processes. Several fruit quality parameters were determined monthly during the ripening period.     

Nutrient status of apple orchards in Canterbury,New Zealand. 1. Levels in soil,leaves and fruit and the prevalence of storage disorders

Abstract

The nutrient status (N, P, K, Ca, Mg, K, Fe, Mn, Zn and Cu) of 26 Cox's Orange Pippin and 20 Braeburn apple orchard sites in the Canterbury region of New Zealand was evaluated by soil, leaf and fruit analysis. Concentrations of available nutrients in soils ranged widely but those in leaves and fruit were generally confined to a relatively narrow range. Concentrations of leaf N were high in the study area, as were levels of extractable soil P, and it is suggested that reductions in fertilizer additions of these nutrients would generally be appropriate.

Soil, leaf and fruit nutrient contents were generally not well correlated with one another. The only highly significant correlations (P≤0.001) were between leaf and fruit Ca for Cox's and soil and fruit Mg for Braeburn. The poor correlations were attributed to the empirical nature of soil tests, the presence of large nutrient reserves within the tree framework and the effects of cultural and environmental factors on nutrient uptake and translocation by the trees.

The storage disorders bitter pit and senescent breakdown in Cox's and lenticel blotch pit in Braeburn were observed in apples harvested from some of the study sites. Such disorders were generally associated with low concentrations of Ca (≤.2.5 mg/100 g) in samples of cortical plugs taken from fruit at harvest.     

Grewia flavescens: a potential horticultural crop?

Traditionally agricultural research has given little attention to underutilized or neglected crops. Grewia flavescens Juss., the donkey berry, is a fruit species which is found throughout semi-arid and sub-humid tropical Africa and sometimes cultivated in homegardens. The species is also known for its ornamental value and is used as a vegetable, fodder and in basketry. In Niger its fruits are mostly collected in the wild and sold at markets. The fruits are used as food and for traditional medicinal treatments. To promote this interesting neglected taxon as a horticultural crop, information on its germplasm diversity and cultivation practices is urgently needed.     

Growth and canopy structure of rice plants grown under field conditions as affected by Si application

Abstract

The ontogenetic changes of N, P, and K contents in leaves of rice, maize, soybean, adzuki bean, potato, and sugar beet were studied as the following results were obtained.

1. N content of rice and maize drastically changed at the primordia formation stage, while that of other crops did not show clear changes depending on the stage of growth.

2. P content of rice and maize was higher in upper leaves than lower leaves, but did not change appreciably in other crops.

3. K content of potato and sugar beet remained constant for a long period of time compared to other crops.

4. P-N relationship in rice and maize distinctly differed between upper and lower leaves; ratio of P content to N content of upper leaves was higher than that of lower leaves.

5. K-N relationship in potato and sugar beet was very different from that in other crops; K content remained constant regardless of the decrease in N content except for the lower leaves.

Thus, as the P-N balance of rice and maize (Gramineae crops) and K-N balance of potato and sugar beet (root crops) showed distinctive characteristics compared to other crops, the physiological significance of the mineral balance must be further investigated.     

Control of postharvest diseases of fruit by heat and fungicides: efficacy, residue levels, and residue persistence. A review

Extensive research has been done in recent years to reduce the heavy dependence on chemical fungicides to control postharvest diseases and disorders of horticultural crops. Alternative strategies were based on improved cultural practices, biological control, plant-defense promoters, and physical treatments such as UV illumination, radiofrequency treatment, heat therapy, and storage technologies. Among these, postharvest heat treatments such as hot water dips, short hot water rinsing and brushing, and hot air conditioning have reduced rot development and enhanced fruit resistance to chilling injury in sensitive cultivars while retaining fruit quality during cold storage and shelf life. Additive or synergistic increases in effectiveness were observed by integrating heat therapy with various chemical compounds, thus leading to significant reductions in the application of active ingredients to protect produce from decay. This paper highlights the knowledge on this topic with emphasis on heat therapy effects and factors affecting the uptake, persistence, and performance of fungicide residues when they are applied in combination with hot water.     

Micronutrient needs ‐ which,where, on what ‐ in the United States

Abstract

A summary of four micronutrient surveys conducted between the years 1961 and 1967 revealed that one or more of the six micronutrient elements are recommended in every state. Micronutrient recommendations may be found for all the major field, forage, vegetable, fruit and nut crops grown in the United States. Forty‐three .states recognize and make recommendations for B, 16 for Cu, 23 for Fe, 31 for Mn, 24 for Mo and 39 for Zn. Most of the recognized micronutrient deficiencies occur in specific areas and on specific crops. Cu seems to be the only micronutrient for which this is not true. The tonnage of all micronutrient fertilizers sold in 1968 represents only 0.25% of the total NPK tonnage, although its dollar value is about 2% of total dollar value of all NPK fertilizers sold.     

Nature and properties of mollisols in a semiarid region in northern Jordan

Abstract

Mollisols have developed from Quaternary deposits in northern Jordan under xeric moisture and thermic temperature regimes. The morphological features and physico‐chemical properties of three Pedons representing the major Mollisols in the arid and semiarid region in northwestern Jordan were studied. The studied soils show a wide variation in their morphological, physical, and chemical properties as a result of differences in mean annual precipitation, vegetation, and topography. Mollisols were well developed in the 450 mm precipitation zone. Also, they are confined to areas of steep slopes. These areas are either uncultivated or under tree crops They are characterized by being dry for periods in summers, but are moist in winter months. It is believed that present agricultural practices are degrading Mollisols into mollic intergrades.     

A comparison of the chemical composition of the corn leaf and the grain sorghum leaf

Abstract

Leaf samples were taken from corn and grain sorghum being grown in adjacent fields with the same soil type and with the same cultural practices insofar as possible. The samples were analyzed for N, P, K, Ca, Mg, Fe, Zn and Mn. Results show that the nutrient composition of the leaves of corn and grain sorghum were consistently different for most nutrients. The differences were sufficiently great and consistent to strongly suggest that critical nutrient levels need to be established for grain sorghum instead of using diagnostic criteria established for corn.     

Grapevine Growth and Physiological Responses to Iron Deficiency

ABSTRACT

Iron (Fe) deficiency is one of the major abiotic stresses affecting fruit tree crops growing in calcareous soils in the Mediterranean region. A better understanding of changes in the growth and physiological characteristics of grapevine plants during the development of Fe deficiency will help to improve Fe fertilizer management recommendations. An experiment was conducted in field conditions to determine the effects of Fe deficiency during vegetative growth on leaf photosynthesis, dry matter accumulation, pigments, and other physiological parameters. Iron deficiency considerably decreased leaf net photosynthetic rate, leaf area, and dry matter accumulation. Depressed photosynthesis and plant growth resulted in increased fruit abscission and changes in dry matter among plant tissues. The results help explain the effects of Fe deficiency on suppression of grapevine growth and yield and provide information for improving the diagnosis of Fe deficiency in grapevine production.     

Competition for Nitrogen Between Thorn Apple and Tomato and Pepper

The effect of emergence time of the weed Datura stramonium (thorn apple) on tomato (Lycopersicon esculentum Mill.) and pepper (Capsicum annuum L.) was evaluated in a greenhouse experiment. The closer emergence of the weed was to that of the crops, the greater was the weed's growth, seed production, and nitrogen (N) uptake. As a result, growth, fruit yield, and N uptake of the crops was reduced. Shoot N content was reduced in tomato, as was fruit N content in pepper. There was competition by the weed with the crops for N, even when weed emergence was as late as the beginning of flowering. This competition, and the damage it caused, was always more severe with respect to pepper than tomato, irrespective of weed emergence time. The earlier the emergence of Datura stramonium, the fewer were the number of fruits produced by either crop. Average fresh fruit weight in tomato was also reduced. In pepper, the average fruit weight was reduced only when the weed emerged up to the four-leaf stage of the crop. The drop in pepper fruit yield caused by weed emergence up to the four-leaf stage of the crop could be due to competition for light by the weed, in addition to competition for N. Tomato competed better against the weed than did pepper.     

雄安新区上游农业种植结构及需水时空演变

本文利用作物模型模拟小麦、玉米灌溉需水量,结合蒸发皿法估算蔬菜、果树等其他作物需水量,回溯雄安新区上游1986-2015年农业种植结构及农业需水的时空演变趋势,摸清不同作物的需水量比例及时间变化,并推算了消除降水年际波动的1970-2015年农作物灌溉需水量,探讨单纯人类活动下的农业需水量变化趋势。结果表明,1986-2015年,研究区作物播种总面积总体呈上升趋势,耕地面积多年平均84.9万hm²,有效灌溉面积平均71.3万hm²,占总耕地面积的84%。其中小麦播种面积稍有下降,玉米、蔬菜播种面积显著增加,果树种植比例在山区增加、平原区减少。研究区多年平均灌溉需水量22.52×10⁸ m³,小麦、玉米、蔬菜、果树和其他作物分别占灌溉需水总量的58.6%、12.6%、5.8%、16.3%和6.7%,受播种面积增加影响,1970-2015年,蔬菜和果树需水显著上升。从空间上来看,灌溉需水总量在上游山区上升显著,而在平原区表现为下降;排除降水的年际波动后,研究区作物需水自1970年以来一直呈上升趋势,进入20世纪80年代中期,虽然整体上升减缓,但随农业播种总面积增加和蔬菜、水果需水增加影响,需水量整体呈缓慢上升趋势。因此,控制上游农业用水,种植低耗水作物、减少耗水作物的种植面积,是恢复雄安新区清水产流的关键。     

Productivity of mung bean and sesame grown on residual fertility in multiple cropping systems

Abstract

Field experiments were conducted on an Entisol from 1984 to 1987 at Bidhan Chandra Agricultural University, West Bengal, India, to study the residual effects of N, P, and K on productivity of mung bean (Vigna radiatus Roxb.) and sesame (Sesamum indicum L.) in irrigated multiple cropping with rice‐potato‐mung bean and rice‐potato‐sesame cropping systems. The crops were grown with or without application of farmyard manure or incorporation of crop residues. Different quantities of inorganic fertilizers based on locally recommended practices for fertilization were applied to rice and potato and their residual effects on succeeding mung bean or sesame crops were assessed. Application of fertilizers at a higher rate than the recommended amounts to rice and potato in the system showed no significant residual effect on yields of succeeding mung bean or sesame compared to the yields obtained with the application of N, P, and K at 100% of the recommended rate or 75% of the recommended rate with manure or residues. Any reduction in the application of recommended amounts of fertilizers to rice or potato without compensating amounts coming from other organic sources resulted in lower productivity of succeeding mung bean and sesame.