Isotopic studies of the nitrogen balance in a cracking clay. III. Nitrogen recovery in plant and soil in relation to the depth of fertilizer addition and rainfall

Soil Research ◽  
1976 ◽  
Vol 14 (1) ◽  
pp. 75 ◽  
Author(s):  
ET Craswell ◽  
WM Strong
Keyword(s):  
Nitrogen Balance ◽  
Nitrate Nitrogen ◽  
Growing Season ◽  
Field Conditions ◽  
Fertilizer Efficiency ◽  
Soil Cores ◽  
Fertilizer Nitrogen ◽  
Plant System ◽  
Isotopic Studies ◽  
Applied Nitrogen

15N-labelled nitrate nitrogen was added at either 15 cm or 45 cm depth to 10-cm diameter undisturbed cores of black earth soil. Cores were either fallowed or planted to wheat and received either 444 mm or 255 mm of simulated and natural rain during a 17-week growing season under field conditions. Between 92 and 98 % of added 15N could be accounted for in planted or fallow cores receiving the lower rainfall, while those receiving the higher rainfall contained 75-94 %. The loss was larger where fertilizer was added at 15 cm than at 45 cm depth. Fallow cores lost more 15N than planted cores. These losses are ascribed mainly to denitrification and are discussed in relation to the results of earlier work with this particular soil-plant system. Plants yielded more, and recovered more of the fertilizer nitrogen, in those cores which received the higher rainfall. Plants recovered more applied nitrogen from 45 cm depth than from 15 cm depth. At harvest, over 40% of the applied nitrogen remained as nitrate in the planted cores which received the lower rainfall. In these cores, only 38-47 % of the fertilizer was recovered in plant tops. The significance of these results for fertilizer efficiency is discussed.

Studies on Maize (Zea mays) at Bunda, Malawi. I. Yield in Relation to Rainfall

1989 ◽  
Vol 25 (3) ◽  
pp. 357-366 ◽  
Author(s):  
D. MacColl
Keyword(s):  
Zea Mays ◽  
Growing Season ◽  
The Other ◽  
Negative Effects ◽  
Total Rainfall ◽  
Fertilizer Nitrogen ◽  
Late Planting ◽  
High Rainfall ◽  
Nitrogen Levels

SUMMARYYields of maize were determined in six years, on two soils, at up to four nitrogen levels following early and late planting. Without fertilizer nitrogen, high rainfall at the beginning of the growing season reduced yield on one soil but not on the other, while high rainfall at late silking and high total rainfall in the growing season reduced yields on both soils. As the level of fertilizer nitrogen increased, the negative effects of rainfall on yield tended to disappear. A three week delay in planting sometimes increased and sometimes decreased yield. The probable reasons for the observed effects of rainfall on yield are discussed.

Isotopic studies on the uptake of nitrogen by pasture grasses. II. Uptake of fertilizer nitrogen by Rhodes grass in posts

1964 ◽  
Vol 15 (6) ◽  
pp. 876 ◽  
Author(s):  
EF Henzell ◽  
AE Martin ◽  
PJ Ross ◽  
KP Haydock
Keyword(s):  
Linear Function ◽  
Total Nitrogen ◽  
Nitrogen Uptake ◽  
Nitrogen Fertilizer ◽  
Rhodes Grass ◽  
Fertilizer Nitrogen ◽  
Pasture Grasses ◽  
Isotopic Studies ◽  
Pretreatment Phase

Nitrogen uptake by Rhodes grass was a linear function of the quantity of 15NH4N03 applied for rates up to the equivalent of 400 lb N/ac, but the proportion of fertilizer nitrogen recovered in the plants fell significantly when the rate was increased to 800 lb N/ac. A nitrogen pretreatment equivalent to 200 lb N/ac had relatively little effect on the uptake of 15NH4N03 by the grass, despite the fact that it almost doubled the weight of roots in the pots when the 15NH4N03 was first applied. Over the range 0–400 lb N/ac, 84.1%% of added total nitrogen and 75.5% of added 15N was taken up by plants that received no nitrogen fertilizer during the pretreatment phase, and 80.3% of added total nitrogen and 71.9% of added 15N was taken up by plants that received a pretreatment of 200 lb N/ac. Fertilizer nitrogen was distributed between tops and roots in the ratio (averaged for the two pretreatments) of 5.2 : 1 for total nitrogen and 4.5 : 1 for 15N; these ratios were constant over the range 0–400 lb N/ac and were not significantly different.

Intake, digestibility in vivo and nitrogen balance in sheep of pea-wheat bi-crop silages harvested at three stages of maturity

1999 ◽  
Vol 1999 ◽  
pp. 80-80 ◽  
Author(s):  
A.T. Adesogan ◽  
M.B. Salawu ◽  
M.D. Fraser ◽  
S.T. Evans ◽  
R. Fychan ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Nitrogen Balance ◽  
Low Cost ◽  
N Balance ◽  
Animal Performance ◽  
Fertilizer Nitrogen ◽  
Three Stages ◽  
The Cost

The production and utilization of complementary cereal/legume bi-crops as ruminant feeds is beneficial for several reasons. The nitrogen fixation by the legume reduces the amount of fertilizer nitrogen required by the cereal. The cereal in turn supports the legume, thereby preventing the lodging that typifies pure stands of mature forage peas. When bi-crops are fed, the legume and cereal components respectively provide relatively low cost protein and energy, which may be synchronously supplied to the animal. In Denmark, pea-barley bi-crops are reported to reduce the cost of feeding without reducing intake and animal performance (Kristensen, 1992). However, little is known about the intake potential and level of animal performance sustainable from such bi-crops when produced and fed under UK conditions. Therefore this study determined the intake, in vivo digestibility and nitrogen (N) balance in sheep of spring sown, peawheat bi-crop silages harvested at three stages of maturity.

MORPHOLOGICAL DEVELOPMENT OF TWO ALFALFA CULTIVARS UNDER VARIOUS HARVESTING SCHEDULES

1974 ◽  
Vol 54 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Y. SINGH ◽  
J. E. WINCH
Keyword(s):  
Growth Rates ◽  
Dry Weight ◽  
Growing Season ◽  
Field Conditions ◽  
Morphological Development

Two alfalfa cultivars grown under field conditions were harvested at different stages of maturity during the growing season of 1969. The number of buds and stems that originated from various locations on the plant and the dry weight of the stems were recorded periodically. The pattern of regrowth was the same for both cultivars. During regrowth, following all stages of harvest, many buds that developed early failed to produce mature stems. Uncut alfalfa produced a second crop of regrowth stems from the bases of stems that formed the first growth. After each harvest regrowth stems originated mainly from the stubble of the most recently harvested stems. Yield reductions occurring in successive regrowths of each harvest schedule were due mainly to the production of smaller stems. Increased growth rates following more mature stages of cutting resulted mainly from faster elongation of stems developing from larger buds. The implications of these findings with respect to the breeding of alfalfa are discussed.

Effects of Time and Method of Applying Nitrogen to Dwarf Wheats

1971 ◽  
Vol 7 (1) ◽  
pp. 21-26 ◽  
Author(s):  
N. K. Jain ◽  
D. P. Maurya ◽  
H. P. Singh
Keyword(s):  
Linear Regression ◽  
Grain Yield ◽  
Foliar Application ◽  
Single Application ◽  
Straw Yield ◽  
Fertilizer Nitrogen ◽  
Heading Stage ◽  
Applied Nitrogen

SUMMARYLinear regression of grain and straw yield of dwarf wheats on level of fertilizer nitrogen was significant, but the efficiency of fertilizer nitrogen was determined by the time and method of its application. A single application as a basal dressing was the least productive for grain yield, while split fertilization at sowing and at first irrigation increased the efficiency of applied nitrogen. Further splitting in three doses did not benefit wheat. Foliar application of nitrogen to replace top dressing at the heading stage was of no advantage while replacement of a top dressing at first irrigation by urea spray at heading was definitely deleterious.

The response of perennial ryegrass to nitrogen in various periods of the growing season

1970 ◽  
Vol 75 (3) ◽  
pp. 539-546 ◽  
Author(s):  
D. W. Cowling ◽  
D. R. Lockyer
Keyword(s):  
Perennial Ryegrass ◽  
Dry Matter ◽  
Radiant Energy ◽  
Animal Husbandry ◽  
Growing Season ◽  
Experimental Results ◽  
Response Curves ◽  
Fertilizer Nitrogen ◽  
Nitrate N ◽  
Yield Responses

SUMMARYThe response of irrigated, perennial ryegrass to fertilizer nitrogen was studied in four consecutive periods of the growing season by applying 0–350 kg N/ha to a fresh sward at the start of each period, and measuring both herbage dry matter and its content of nitrogen.Responses in yield were highest in the first period, which ended at inflorescence emergence; in this period, both the percentage recovery of nitrogen and the extent of its utilization in producing dry matter were greater than in the later periods. Some damage to the sward was seen following the harvest of grass grown with the high levels of nitrogen in the first period. When the yields were 90% of the predicted maximum the nitrate-N content of the herbage ranged from 1000 to 2000 ppm, except in the first period when it was 200 ppm.The response curves were used to calculate the nitrogen requirements of the grass which would maintain given incremental yield responses. To produce near-maximum yields, irrigated grass swards may require fertilizer nitrogen equivalent to 2 kg N/ha/day prior to inflorescence emergence, and up to 5 kg N/ha/day for the remainder of the growing season.The apparent efficiency of conversion of the radiant energy, usable for photosynthesis, into plant energy averaged 3·2%; it did not vary greatly among the four periods.The experimental results indicate the seasonal requirements of grass for fertilizer nitrogen and some of the implications for animal husbandry are discussed.

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