Milton B. Jones

A rising plate meter for estimating production and utilization

The rising plate meter (RPM) ~8s used to determine fomge production 8nd livestock utilization in 8 roWion gmzing system on improved mnu8l prsture in CsUfomi8. Prior to rot8ting livestock, herb8ge weight (y) ~8s reLted to meter ruding (x) by the linnr model: J = a + bx. Fonge utilization by sheep ~8s estimrted by summing growth and dimppe8r8nce in gmzed p8stures. Fomge diuppcurnce for p8sturea WM b8sed on meter re8dinga before 8IId 8fter gmzing. Plant growth in gmzed prstures for the slime period WUI b8ued on meter readings for p8sturea not then gmzed. Use of RPM in 8 roWion gmzing system proved to be 8 quick 8nd effective wry of assedng fomge growth 8nd utilization.

Seasonal Fluctuations In Nutrient Availability In Some Northern California Annual Range Soils

We studied the effects of climate and land-use history on seasonal variations in available soil nutrients at six northern California annual range sites. Available soil N, S, P, Ca, Mg, and K were measured monthly for 2 yr. Seasonal fluctuations in inorganic N were similar for both years over all sites; levels and variations in N were highest during winter and early spring and lowest during summer. Relative levels of available S, P, and Ca were also higher early in the year and declined later in the growing season, although the patterns were much less pronounced. Exchangeable Mg and K fluctuations were generally inconsistent and relatively smaller. Sheep grazing on unimproved pasture significantly (P < 0.05) increased average levels of available soil N, S, Ca, and Mg and decreased P availability. Seeding subclover (Trifolium subterraneum) and fertilizing with P and S increased available N and S levels. Converting chaparral brush to grassland decreased the availability of Mg and K.

Nitrogen fixation by subclover associations fertilized with sulfur

SummaryThe effect of S fertilization on symbiotic N2 fixation was measured with the15N technique and the N difference method in a lysimeter study using Josephine loam (Typic Haploxurults). Nitrogen fixation by subclover (Trifolium subterraneum L.) was strongly enhanced by added S. The association of soft chess (Bromus mollis L.) or filaree (Erodium botrys (Cav.) Bertol.) with subclover increased the percentage of N in subclover that was fixed, with the results that N2 fixation was increased beyond that due to the mere increase in subclover biomass.Nitrogen fixation estimates by15N dilution and N difference methods were highly correlated (r2=0.97), and S fertilizer did not result in any significant differences in N2-fixation estimation by the two methods. Both methods were useful in distinguishing between soil N uptake and N2 fixation where S applications produced highly significant increases in both uptake and fixation.Application of sulfur fertilizers to much annual rangeland has the potential to increase pasture productivity through enhanced N2 fixation.

On the constancy of the ratio of nitrogen to sulphur in the protein of subterranean clover tops

Abstract While total N: total S ratios varied widely from 4 to 331 depending on plant part, age, N supply and S supply, there was no discernable trend in protein N: protein S ratios attributable to any of these factors. The results also show that it is difficult to extract all of the non‐protein N and non‐protein S from plant tissue. This could explain the variation in protein N: protein S ratios found by some workers.

Competition for S and N by associations of three annual range species in lysimeters

SummaryCompetition for S and N was studied on free draining lysimeters seeded to associations of three annual forages on Josephine loam (Typic Haploxerults), an important soil for revegetation to rangeland production. Forage yields increased and the botanical composition shifted toward subclover (Trifolium subterraneum L.) with added S. Sulfate uptake and plant S concentration were increased as a function of the S applied. Forage yields were related to plant S concentration and N:S ratios.Subclover and filaree (Erodium botrys (Cav.) Bertol.) obtained a larger proportion of their S from fertilizer-S than did soft chess (Bromus mollis L.). Total S uptake was largely from the applied fertilizer, 39% at the intermediate S level and 78% at high S.The replacement series design of the experiment and the use of labeled S and N permitted calculation of competition coefficients for fertilizer S, total S, soil N, and total N uptake for the species in pairwise associations. Sulfur was the factor limiting to subclover where S was not applied, and N was the limiting factor to soft chess and filaree in mixtures with subclover at high S where subclover was able to fix most of its own N. In the mixture of soft chess and filaree competition for S and N was about equally intense for both nutrients at all S levels, and filaree was dominant consistently.Comparison of two methods for estimating the fate of fertilizer S showed that differences in sulfur uptake and leachate losses over the controls provided significantly higher values for sulfur recovery than estimates based on the fate of35S.

Soil phosphorus requirements for maximum growth of northern California subclover‐annual grass pastures

Abstract Annual grassland soils of California are generally quite deficient in phosphorus (P), but the amount of fertilizer P required to obtain optimum pasture production is quite variable. This paper reports on the relationships between five soil‐P tests and the amount of applied P required to obtain near maximum growth of subclovergrass pasture on 12 sites representing four soil series in the north coastal range of California. Dry matter (DM) yield response curves resulting from application of nine levels of P were fitted to the Mitscherlich equation: y = a{l‐b([EXP(‐cx)]}, where: y = DM when x = kg/ha of P were applied, a = maximum DM when P was not limiting, and b and c are constants that were adjusted to give the best fitting curves buy an iterative algorithm. This equation was used to calculate the amount of P required to bring yields to 90% of the maximum DM represented by “a”; in the equation. Then the regression equations relating P requirements to soil‐P extracted by the Bray‐1, Olsen, and modi...

Soil characteristics related to production on subclover-grass range Trifolium subterraneum, in coastal California.

In northwestern California moisture is usually not limiting for range production during the annual winter-spring growing season. It is, therefore, important to understand how other site factors, both physical and chemical, affect range production. Ridge regression analysis and simple correlations were used to evaluate range production as related to site slope and elevation; soil depth, texture, bulk density, water holding capacity, and pH; and several chemical measures of soil fertility including available P and S, exchangeable cations, total N and S, and organic matter. Subclover (Trifolium subterraneum L.) grass production was measured at 17 typical range sites for 4 fertilizer treatments: PO&, Pa,&, PO&, P~o&~o (subscripts = kg/ha). When no fertilizer WBs applied, soil pH and available P appeared to be the 2 variables most closely related to yield. Forage production increased when P and S fertilizers were applied. When P was applied, exchangeable soil K was the most important variable releted to yield; and when S was applied, available P was the variable most closely related to production. When P and S were applied together, available P and K were most closely related to yield. While there was generally a striking response to applied S, our measures of available soil S were poorly related to production. The annual-type rangelands of California are very extensive, occupying roughly 24% of the state including both treeless and wooded areas (Love 1955). Annual plant growth commences with the first fall rain(usually in late October), continues slowly through the winter, and is very rapid for about 6 weeks beginning in early March. During the 6-month growing period soil water is not generally the limiting factor (Martin and Berry 1970). It is known that nitrogen (N), phosphorus (P), and sulfur (S) are limiting in varying degrees (Martin 1958, Jones 1974) because of the large increases in herbage production that usually occur when these elements are applied. However, various measures of soil fertility and soil-site physical characteristics and the relative importance of each to range production have not been evaluated. Northwestern California is ideal for such an evaluation due to the variability in soils, elevation, and slopes on the upland annual ranges. The purpose of this paper is to report an evaluation of chemical and physical characteristics of soils on range sites sown to subclover (Trifoliurn subterraneum L.) with and without P and S fertilization, and to determine the relative importance of these factors as they relate to annual grass-subclover yields. Materials and Methods The study was conducted in coastal California 160 km north of San Francisco, on and near the University of California Hopland Field Station. Seventeen typical annual rangeland locations The authors arc agronomist, professor (Davis), and staff research associate. Department of Agronomy and Range Science, University of California, Hopland Field station. Hopland, Calif. 95449. Authors thank K. Mayalagu for assistance with soil classification, J. Blackard for soil physical analysis, and B. San Diego for assistance in the field. Manuscript received November 23, 1981. 444 representing 3 soil series were studied: 9 Sutherlin series soils (Ultic Haploxeralfs), 5 Laughlin series soils (Ultic Haploxerolls), and 3 Josephine series soils (Typic Haploxerults). None of the sites had received any prior fertilization. Some of the chemical and physical characteristics of the soils are shown in Table 1. At each location experiments were established in September 1975 after they were mowed, raked, and disced. Inoculated subclover was seeded at 100 kg/ha. Resident annual vegetation, mainly Bromus mollis, Festuca megalura. and Erodium botrys, grew naturally. Phosphorus was applied as S-free concentrated superphosphate (22.9% P) at rates of0, 12.5, 18.8,25,37.5,50,100, 200, and 300 kg/ ha elemental P. Sulfur was applied uniformly at 90 kg/ ha as lOO-mesh elemental S to all levels of P, except that the 0 and 300 kg/ha P treatments were repeated with no S. All fertilizer treatments were replicated twice in 0.9 X 1.5-m plots in a randomized complete block design at each of the 17 sites. Yield values in this paper are reported only for the PO&, Psc&o, P&&o, and P30os90 treatments. Each treatment was sampled in late April 1976 by clipping the subclover-annual grass herbage at ground level from one 30 X 9l-cm quadrat in each replication. The whole sample was dried to a constant weight at 6oOC and weighed. The relationship of forage production to 22 soil chemical and physical properties and site characteristics were evaluated by using a simple correlation matrix and by ridge regression, a method of ameliorating problems of unstable regression coefficients resulting from highly correlated variables-multi-collinearity (Williams et al. 1979). The variables were soil organic matter (OM), total N and S, total and available S and P, exchangeable Ca, Mg, K, and Na, soil pH, water at l/3 and 15 atmospheres, bulk density, percent sand, silt, clay and gravel, depth of A and B horizons, site elevation, and % slope. Available soil water was taken as % water at I/ 2 atmosphere minus y0 water at 15 atmospheres. The ratios of the various elements were calculated and their relationships to yields evaluated. These correlation and regression analyses were run independently on each of the fertilizer treatments. A composite soil sample was taken from the surface 0 to 15 cm from each of the I7 sites before treatments were imposed. These samples were air-dried and passed through a 2-mm sieve before chemical analysis. Soil profile characteristics were determined from a pit dug beside each plot site. Soil OM was determined by a WalkIey-Black titration (Kauffman and Gardner 1976), and total soil N by a Kjeldahl procedure modified to include nitrates (Bremner 1965). Soil-extract S was analyzed by the methylene blue calorimetric procedure of Johnson and Nishita (I952), total S following a nitric-perchloric acid digestion and available S following extraction with 0.01 M Ca (H2PO& (Barrow 1967). Available P was determined by the Bray and Kurtz (1945) number I method (Bray-l P) which is more closely correlated with plant yield and P uptake than other methods on these range sites (Vaughn and Jones 1980). Exchangeable Ca, Mg, K, and Na were determined by atomic absorption spectrophotometry following extraction with neutral N ammonium acetate. Soil pH was measured in a 1:2.5 soil:water suspension. JOURNAL OF RANGE MANAGEMENT 36(4), July 1983 Results and Discussion There was a wide range in soil-site characteristics and forage production from the I7 sites (Table 1) giving rise to the possibility of sorting out the factors most closely related to yield variations with and without P and S applications. This possibility was enhanced by the fact that soil test values for P, K, and S ranged from below to above published critical levels. Gardner et al. (1979) indicated possible responses of subclover to P with Bray-l P test values up to 30 ppm, and responses to K with exchangeable K values up to 0.38 meq/ 100 g soil. Our lowest value of 3 ppm available S was considered low and 19 ppm was considered high (Reisenauer 1975). Gardner et al. ( 1979) also suggested that when exchangeable Mg was less than 0.8 meq/ 100 g soil (0.8 was our lowest value) that application of Mg should be made for increased production. They also suggested that lime beapplied when pH was less than 5.5. We only had one value less than this, at 5.3. Table 1. Mean and range of values for 17 annual rangeland locations for soil-site characteristics and forage yields.* Soil characteristic Mean Minimum Total N (%) 0.27 0.19

Soil phosphorus tests on California subclover-annual grass pastures.

We evaluated the phosphorus fertility of 19 typical, California, annual grassland, pasture soils by comparing nine soil P tests: total, Bray and Kurtz methods 1 and 2, two Olsen extractions (1:10 and 1:20 soil: extractant ratios), and the “North Carolina,” Truog, Morgan, and Bingham methods. Soil P test results were correlated with subclover-annual grass forage production and P content in the field and in the greenhouse. Correlation of soil P with actual yields and P uptake was generally better in the field than in the greenhouse. Phosphorus in the Bray and Kurtz 1 and the Olsen 1:10 and 1:20 extracts gave the best predictions of field forage production (respectively, r = 0.82, 0.73, and 0.67; P < 0.01). The relative values of the various tests in predicting field forage P content were quite similar with actual yields. The Bray and Kurtz 1 method was the most precise (r = 0.87), and the Olsen extracts were also highly correlated (P < 0.01). Bray and Kurtz 1 extractable soil P accounted for about 67 percent of the variation in subclover-annual grass forage yield and about 76 percent of the variation in forage P content. These were about 14 percent higher than with the Olsen extractants. When we consider relative precision and facility (a 60-second extraction time), the Bray and Kurtz 1 method appears to be of greater potential value for routine testing of annual pasture soils in north-coastal California.

Application of DRIS to white clover based pastures

Abstract There are basically two approaches for interpreting chemical analysis of plant tissue to assess nutrient status and fertilizer need. The oldest, called the critical value method (CVM), is based on nutrient concentrations in the sample compared with levels required for near maximum growth. The other is based on the ratios of nutrient concentrations. The Diagnosis and Recommendation Integrated System (DRIS) is a system that uses nutrient ratios, comparing these with “norms”; which are ideal ratios derived from high yielding plants. DRIS integrates the ratios to give an index for each nutrient considered and ranks them in the order of deficiencies. It is helpful in dealing with multiple deficiencies. The DRIS system has not previously been tested on white clover (Trifolium repens L.)‐based pasture in New Zealand. The purpose of this study was to develop N, S, P, K, and Ca DRIS norms for white clover; to use these norms in computing DRIS indices for clover samples from fertilizer trials; to compare t...

Mineral Concentrations of Black-Tailed Deer Diets in California Chaparral

The monthly level of phosphorus (P), sulfur (S), calcium (Ca), magnesium (Mg), and potassium (K) in the diet of black-tailed deer (Odocoileus hemionus columbianus) in mixed-age chaparral of California was determined during 1985-86. Forage samples were harvested by hand and analyzed using standard analytical methods. Annually, dietary concentrations averaged 0.16, 0.11, 0.49, 0.25, and 0.85% for P, S, Ca, Mg, and K, respectively. Levels of P and S were below the recommended minimum requirement during most months. In contrast, levels of Ca, Mg, and K were adequate during most months. To improve forage quality in mixed-age chaparral managers can implement range improvement practices, such as prescribed burning and chemical and mechanical brush control. J. WILDL. MANAGE. 52(1):37-41 Columbian black-tailed deer are an important big game animal in California. In some habitats deer densities may be low due to forage of poor quality. Most studies assessing the nutrient value of deer forage have been concentrated in the Southwest (Urness et al. 1971, Varner et al. 1977, Everitt and Gonzalez 1981) and Rocky Mountain region (Short et al. 1966, Tew 1970, Wallmo et al. 1977). In California monthly levels of forage quality of selected chaparral species have been determined (Bissell and Strong 1955, Kie 1986), but the relationship between forage quality and deer diet has usually been discussed only in terms of crude protein (Taber 1956, Taber and Dasmann 1958). We report the mineral concentrations of blacktailed deer forage in mixed-age chaparral of California. Forage components were evaluated monthly for P, S, Ca, Mg, and K to identify periods of maximum and minimum forage quality and to detect real or potential problems relating to deer management in mixed-age chaparral. 1 Present Address: EG&G Energy Measurements, % NPR-1, 35R Warehouse, P.O. Box 127, Tupman, CA 93276. This content downloaded from 157.55.39.116 on Sun, 18 Sep 2016 06:41:48 UTC All use subject to http://about.jstor.org/terms 38 BLACK-TAILED DEER DIETS * Scrivner et al. J. Wildl. Manage. 52(1):1988 Table 1. Mean percent mineral compositiona (dry-wt basis) of plant species sampled mid-monthly from June 1985 to July 1986 on the University of California Hopland Field Station.