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1.
Yield, maturation, and forage quality of alfalfa in a black walnut alley-cropping practice 总被引：2，自引：1，他引：1
Robert L. McGraw W. Terrell Stamps James H. Houx Marc J. Linit 《Agroforestry Systems》2008,74(2):155-161
There is interest in producing alfalfa as an alley crop because alfalfa (Medicago sativa L.) is the most profitable hay crop in the USA. Field experiments were conducted near Stockton, MO in 2003 and 2004. Treatments
consisted of alfalfa grown in open plots and in plots that were alley cropped between 20-year-old black walnut trees (Juglans nigra L.) planted in rows 24.4- and 12.2-m apart. Alfalfa was sampled for three harvest cycles each year. In the alley-cropping
plots, samples were taken beneath the canopy (2.5 m from the tree row) and in the center of the alleys. Data were taken on
dry-matter yield, maturity, and forage quality. At all harvest dates over both years, yields from beneath the canopy of both
alleys and the narrow alley centers were less than yields from the wide alley centers and open plots. Yield from the wide
alley centers was similar to that in open plots in every harvest but the final harvest of 2004. Transects across the plots
indicated that yields increased linearly from the tree row to the center of both alleys. Alfalfa tended to mature faster in
the open and wide alley centers compared to beneath the canopy of both alleys and the narrow alley centers. Forage quality
differences were inconsistent across treatments. Alfalfa yield was significantly reduced and maturity was delayed by the narrow
12.2 m tree spacing, but yield was not reduced in the centers of the wider 24.4 m alleyways. 相似文献
2.
An on-farm trial was conducted to determine dry matter production of four fodder tree species and their effect on soil water
and maize production. The trees were planted in rows intercropped with maize. The four tree species selected were Acacia karroo Hayne (indigenous fodder tree), Leucaena leucocephala (Lam.) De Wit (nitrogen fixing), Morus alba L. (fodder and fruit), and Gleditsia triacanthos L. (fodder and fuel). Volumetric soil water was measured in the upper 0.3 m of soil in each row of the trial using the time
domain reflectometry technique. The neutron probe technique was used for monitoring the water content deeper in the soil.
Geostatistical methods were used to analyse treatment differences in the upper 0.3 m of soil. The soil water content did not
differ significantly between the maize and tree rows indicating that competition for water in the upper horizon was not the
reason for lower maize yields. However, at greater soil depths (75–125 cm) trees in the wide spacing used less water than
those in the narrow spacing. Light interception was an important factor in reducing maize yields in the row nearest to the
trees. High soil water values recorded during summer indicated that in the current cycle of good rainfall the plants in the
agroforestry trial were not stressed. Thus the trees do not compete with the crops for soil moisture in good rainfall seasons.
However, this study would need further evaluation for the competition for water for the low rainfall years. Since the trees
have access to water at greater depths, they are likely to be more productive into the dry season than shallow rooted crops. 相似文献
3.
以黄檗3 a生幼树为材料,对不同栽植密度的生物量进行研究,结果表明:栽植当年和翌年秋季的成活率与保存率分别为92%和91%。不同株距树高、地径生长量均达到极显著差异(P0.01),树高、地径生长量从大到小顺序依次为株距0.5 m1 m0.3 m1.5 m;而不同行距对树高、地径生长量均无影响。采用一元生物量模型计算生物量,总生物量最大的种植密度为33 300株·hm~(-2)(株行距0.3 m×1.0 m),可产生干物质3 930.06 kg·hm~(-2);最小的为3 300株·hm~(-2)(株行距1.5 m×2.0 m),干物质仅为344.08 kg·hm~(-2)。 相似文献
4.
The presence of trees in fields may help overcome the physiological stress that happens to late sown wheat (Triticum aestivum L.) in subtropical India. Wheat was planted in an agroforestry system with Eucalyptus tereticornis trees on 7 January 1998 in a fan design that provided different combinations of tree row spacing and orientations. Crop profile
microclimatic conditions and the resulting growth responses of the intercropped wheat were studied to explore the potential
of agroforestry systems to influence late sown wheat yields under different tree row spacing and orientations. Agroforestry
treatments exhibited a potential to optimize the microclimatic conditions for seedling emergence, tillering and earhead emergence
at some tree row orientations and distances from the crop. The net radiation distribution at three stages of crop growth indicated
that the radiation availability was lower in all the agroforestry treatments than for the sole crop. The tree row orientation
and distance influence the growth behavior of the crop but the effect of sun angle (which changes with season) can change
their influence over time. The deterioration or amelioration of microclimatic conditions in agroforestry with the passage
of time should be expected because of altered interaction patterns between sunrays and tree canopy resulting from changing
solar elevation and angle of sunrays. Statistically similar harvest indices in all the treatments despite lower total biological
yields in agroforestry treatments revealed that microclimatic conditions under agroforestry were more favorable for wheat
growth attributed to reduction in heat load during the post anthesis period.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
5.
为确定黑果枸杞栽植的株行距,以黑果枸杞为试验材料,采用实生苗进行田间栽植,分别设置3个不同株距1、1.2、1.5 m,以及3个栽植株行距1.5 m×2 m、1.5 m×3 m和2 m×2.5 m,通过测定株高、冠幅、分枝数、侧枝数、侧枝长、尖削度、坐果率、果实参数、产量等,比较不同株距和栽植株行距对黑果枸杞生长发育及果实表型性状的影响。结果表明,黑果枸杞人工栽培的合适株距为1.5 m,行距2~3 m,在保持单株占地面积相近的情况下,可根据需要适当地调整株行距;栽植株行距为1.5 m×3 m时,果型变异小,果实纵径、横径、果型指数等表型特征较稳定。以期为人工栽培管理提供技术参考。 相似文献
6.
Loblolly pine (Pinus taeda L.) silvopastures often are established and maintained on sites of poor soil fertility and minimal fertilizer input. Our objective was to determine whether row spacing affected yield, quality, and botanical composition of minimally managed herbage in loblolly pine early in the tree rotation. Plots were randomly located equidistant from bordering tree rows in each of eight alley width treatments that were 2.4, 3.6, 4.9, 7.3, 9.7, 12.2, 14.6 m wide, and no trees. Row spacing affected the yield, quality, and botanical composition of pasture five to six years in the rotation especially at densities exceeding 840 trees ha–1. Botanical composition shifted from predominantly cool-season to warm-season grasses between annual first- and second-harvests, respectively, which caused seasonal differences in several yield and quality traits. Tall fescue (Festuca arundinacea Schreb.) production appeared to be unsustainable under minimal management. Herbage yield generally increased, but quality and minerals (crude protein, IVDMD, Ca, and P) tended to decrease with spacing. The 4.9 m row spacing was minimally acceptable for herbage yield and quality. System design should seek to balance tree-crop yield and quality within the context of management constraints and site productivity.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
7.
8.
西南桦不同密度6a的试验结果显示:西南桦属速生树种,人工林初期生长很快,树高生长(1 5年生)达1 22 1 90m,胸径生长(3 6年生)达1 12 2 91cm。密度对树高生长有影响但不显著,而与胸径生长呈显著负相关。最大和最小密度林分间平均胸径相差2 88cm,3m×3m林分比1 5m×2m林分林木生长量高32 3%,比2m×2m林分高28 4%,比2m×3m林分高11 6%;单株材积生长与密度亦呈负相关关系,其关系式可用V=ax-b来表示。而林分蓄积则与密度呈正相关关系,即密度大林分蓄积量高,反之则小。随林龄增长,不同密度林分间蓄积差异逐渐缩小。要培育中大径材的西南桦人工林,造林密度不宜大,可考虑采用2m×3m及3m×3m的株行距。 相似文献
9.
Xiaobang Peng Yuanying Zhang Jing Cai Zaimin Jiang Shuoxin Zhang 《Agroforestry Systems》2009,76(3):569-577
Agroforestry is the most effective way to restore the disturbed lands on the Loess Plateau and to develop the poor local economy.
In order to maximize the potential benefits of tree-based intercropping systems, photosynthesis, growth and yield of soybean
and corn were studied by measuring photosynthetic active radiation (PAR), plant water deficit and soil moisture in a 4-year-old
plantation of walnut (Juglans regia L.) and plum (Prunus salicina) grown at a spacing of 5 m × 3 m on the Loess Plateau. The effects of tree competition significantly reduced PAR, net assimilation
(NA), growth and yield of individual soybean or corn plants growing nearer (1 m near tree row) to tree rows. NA was highly
correlated with growth and yield of the both crops. These correlations were higher for corn than soybeans, with corn, rather
than soybeans being more adversely impacted by tree shading. Plum, rather than walnut had the greatest competitive effect
on PAR and NA. Daily plant water deficits were non-significantly and poorly correlated with NA and growth and yield of the
both crops. However, soil moisture (20 cm depth) was significantly correlated with biomass and yield of both crops. Possible
remediation strategies are discussed to reduce tree competitive interactions on agricultural crops. 相似文献