Decomposition of Erythrina poeppigiana leaves in 3-, 9-, and 18-year-old alleycropping systems in Costa Rica

Timing the application of organic residues and therefore the release of nutrients during decomposition may be critical to the growing crop in tropical alleycropping agroforestry systems. Field experiments were carried out in Turrialba, Costa Rica, to determine differences in Erythrina poeppigiana (Walp.) O.F. Cook leaf decomposition in 3, 9 and 18-year alleycropped agroforestry systems. Treatments consisted of mulch-only, and mulch plus Arachis pintoi Krapov. and W. Gregory var. CIAT 18347 in 3 and 9-year old alleycrops under no-till cultivation. The 18-year old site consisted of treatments with mulch-only and mulch plus chicken manure under disk plow cultivation. Litterbags, filled with E. poeppigiana leaves from 3, 9 and 18-year old trees, were placed on the soil surface and collected over a period of 84 days. Results showed no significant differences in the amount of plant residues remaining after 84 days in the 3-, 9-, and 18-year-old systems, or between the manure and mulch-only treatments. Comparing mulch-only treatments, leaves in the 18-year old system decomposed most rapidly which may be due to disk-plow cultivation practices where litterbags were in direct contact with the soil as opposed to the no-till system in the younger alleycrops.     

Increasing crop yield in water scarce environments using locally available materials: An experience from semi-arid areas in Mpwapwa District, central Tanzania

This paper presents experience on working with farmers in water scarce environments in improving crop yield through the application of locally available materials in semi-arid areas of Mpwapwa District, central Tanzania. Findings are presented from the interdisciplinary study that involved documenting farmers perceptions and on-farm field experimentation. In the farmers’ perceptions study, three different traditional tillage practices applied by smallholder farmers in the area were identified. These are traditional no-till (TNT), shallow tillage (ST) and ridging tillage (RT). The impacts of various tillage practices on soil fertility improvement, reduced weed infestation, soil moisture retention and crop yield were the main factors considered by farmers when selecting a particular tillage practice to apply. In two cropping seasons (i.e. 2006/7 and 2007/8) on-farm field experimentations were carried to test the effects of the three traditional tillage practices, manure and mulching practices on soil moisture retention and crop yield. Results from this experiment showed traditional no-till fields to have the lowest soil moisture retention capacity and the lowest infiltration flow rate as well as lowest crop yield compared to other studied practices. It was observed that improving the current tillage practices by the application of manure to both ST and RT, and mulching to ST at rates affordable to smallholder farmers as identified during perception study (i.e. 5 tons/ha for manure and 3 tons/ha for mulching materials) results in increased crop yield. When the grain yield is compared between traditional no-till and shallow tillage with manure and mulching practices, the yield increase is between 50 and 100%. It was concluded that crop yield in water scarce environments such as the semi-arid areas of Mpwapwa District can be increased by applying locally available materials such as cow manure and mulching at rates affordable to smallholder farmers.     

Tree-crop interactions in hedgerow intercropping with different tree species and tea in Sri Lanka: 1. Production and resource competition

Incorporation of tree hedges along contours has been proposed as a means of reducing soil erosion and increasing soil fertility of tea (Camellia sinensis (L.) O. Kuntz) plantations on sloping terrain in high-rainfall zones of Sri Lanka. Tea yields in these hedgerow intercrops are determined by the balance between the positive (i.e., increased soil fertility) and negative (i.e., resource competition) effects of hedgerows. Therefore, the objectives of the present study were to determine: (a) the net effect of six different hedgerow species (Calliandra calothyrsus Meissner, Senna [Cassia] spectabilis (DC.) H. Irwin and Barneby, Euphatorium innulifolium (R.M. King and H. Rob.) H.B.K., Flemingia congesta Aiton F., Gliricidia sepium (Jacq.) (Kunth.) Walp. and Tithonia diversifolia (Hemsl.) A. Gray) on long-term tea yields; (b) the effect of incorporating hedgerow prunings as mulch; and (c) the relationship between hedgerow characteristics (i.e., biomass production, canopy and root growth) and tea yield variation. Tea yields, measured over one complete pruning cycle from October 1998 to September 2001, showed reductions relative to a sole tea crop under all hedgerow species except Euphatorium. The yield reductions ranged from 22 to 40%. Tea yields under Euphatorium showed increases up to 23% relative to the sole crop control. Addition of hedgerow prunings as mulch increased tea yields in all hedgerow intercrops. The yield increases ranged from 11 to 20%, with the highest being under Euphatorium. Tea yields showed a negative relationship (R²=0.38) with the pruned biomass of hedgerows. Limitation of environmental resources (e.g., water and light) and hedgerow characters which intensified resource competition (i.e., greater canopy lateral spread and height and greater root length densities, especially in the top soil layer) were responsible for observed tea yield reductions in hedgerow intercrops.     

秸杆覆盖对苹果园土壤固氮菌数量年变化的影响

在整个果树生长期内，秸杆覆盖可明显增加各土层固氮菌的数量，２０ ｃｍ土层中，年平均固氮菌数量增加１２３．８０％；２０－ ４０ ｃｍ土层中增加５１．６１％；４０－ ６０ ｃｍ土层中增加１０３．８５％。在 ０－６０ｃｍ果树的耕作层内固氮菌数量年平均增加９５．４７％，不同土层固氮菌数年变化曲线，无论覆盖与对照，均呈单峰曲线变化，高峰出现在９月。     

Interactive effects of planting time and mulching on ‘Chandler’ strawberry (Fragaria × ananassa Duch.)

Studies were conducted in ‘Chandler’ strawberry with the aim to optimize planting time and mulching material under the semi-arid region of north Indian plains. Three planting times viz., mid-September, mid-October and mid-November and three mulch materials viz., black polyethylene (50 μm), clear polyethylene (50 μm) and paddy straw (10 cm thickness) were tried with three replications in a split plot design. Mid-September planting favoured plant growth, enhanced flowering (77.3 days), which resulted in production of significantly larger fruit (13.0 g) and higher yield (174.4 g/plant) with fruit having higher TSS (9.23%), acidity (1.22%) and ascorbic acid content (44.1 mg/100 g of pulp) with lesser incidence of albinism (9.6%) and botrytis rot (8.1%) than other plantings. Plants mulched with black polyethylene have significantly better growth, and they flowered (80.2 days) and fruited early (29.2 days), and produced larger fruit (12.6 g) and higher yield (172.4 g/plant), with slightly higher incidence of albinism (20.1%), but with lower incidence of botrytis rot (7.3%) than those mulched either with clear polyethylene or paddy straw. Planting time × mulching interaction has significantly influenced plant growth; flowering and fruiting; fruit yield and quality, and albinism and botrytis rot. Plants have best growth parameters like, plant height (11.2 cm), crown spread (24.1 cm) and leaf area (87.9 cm²), they took lesser days to flowering (73.7 days) and fruiting (31.3 days), produced larger fruit (13.7 g) and higher yield (191.3 g/plant) with fruit having higher TSS (9.41%), acidity (1.17%) and higher ascorbic acid content (46.4 mg/100 g pulp) with a slightly higher incidence of albinism (10.3%), but comparatively lower incidence of botrytis rot (5.2%) when planted during mid-September and mulched with black polyethylene than other plantings and mulched either with clear polyethylene or paddy straw. These studies indicated that strawberry could be planted in mid-September with black polyethylene mulch under semi-arid regions of India for early fruiting, and higher yield of better quality fruits.     

小麦精量露播稻草覆盖高效栽培技术研究

１９９４～１９９９年,以四川稻茬麦在种植方式进行比较研究和生产示范表明,在小窝密植技术和免少耕技术基础上发展起来的小麦精量露播稻草覆盖栽培技术,具有明显的保温、调湿、改良和培肥土壤、抑制杂草和节本增产增收效应,实现了高产与简化高效、当季高产与稻田持续发展的有机结合。一般比旋耕机播栽培节约成本２１．６％,增产１０．１％,省工２３．１％,增收３５．４％;比撬窝点播栽培省工５２．７％,增产３．９％,节本     

深丘烟区烟地不同材质覆盖方式研究

研究了不同材质覆盖处理对烟田水土流失、土壤养分含量以及烤烟生长发育、产量、质量的影响。结果表明:各个覆盖处理均能减少烟田水土和养分流失,调节土壤水分含量,促进烟株生长发育,减轻病害的发生,提高烤烟的质量和产值。在5个处理中,以地膜盖垄(移栽后35 d揭膜)+稻草盖沟处理的经济效益最好,地膜盖垄处理的次之。     

贵南地区旱地马铃薯地膜覆盖栽培技术

本文介绍了贵南地区旱地马铃薯栽培的选地、整地、良种选择及处理、重施底肥、播种、地膜覆盖、田间管理、病虫草害的防治、收获与储藏、以及废旧地膜的回收与处理。     

半干旱区玉米麻地膜覆盖栽培综合效益分析

在半干旱地区玉米采用麻地膜覆盖栽培与普通地膜覆盖栽培、常规栽培进行了田间应用效果试验,研究了麻地膜覆盖栽培对土壤理化性状、土壤温度、土壤持水量、玉米生长及产量等的影响。结果表明,麻地膜覆盖栽培比常规栽培生育进程加快,株高和叶面积系数增加,根干重减少,水分利用效率增加,产量增加8.42%。麻地膜覆盖栽培经济效益低于常规栽培。     

红壤旱地不同覆盖方式对玉米产量及生态经济效益的影响

干旱严重制约了红壤旱地的开发利用。为减轻干旱对农业生产的影响,实现红壤旱地作物生产的可持续发展,作者于2004年7—10月对红壤旱地玉米进行了不同覆盖方式效益的比较试验。结果表明,覆盖种植有利于蓄水保墒,改善土壤物理性状,培肥地力,为玉米生长创造了良好的生态环境,有利于增产增收;特别是秸秆覆盖,在高温干旱季节可以降低土壤温度0.9℃,提高土壤含水量0.36%~1.96%,使土壤保持较高的含水量,其抗旱效果更佳。而地膜覆盖可提高土壤含水量0.59%~2.94%,提高0cm土壤温度2.8℃,但温度过高不利于玉米生长,再加上地膜消耗,增产增收效应不明显,因此,地膜覆盖在高温的夏季不宜采用。